import os

from fontbakery.profiles.universal import UNIVERSAL_PROFILE_CHECKS
from fontbakery.status import INFO, WARN, ERROR, SKIP, PASS, FAIL
from fontbakery.section import Section
from fontbakery.callable import check, disable
from fontbakery.utils import (add_check_overrides,
                              bullet_list,
                              filesize_formatting,
                              markdown_table)
from fontbakery.message import Message, KEEP_ORIGINAL_MESSAGE
from fontbakery.fonts_profile import profile_factory
from fontbakery.constants import (NameID,
                                  PlatformID,
                                  WindowsEncodingID,
                                  WindowsLanguageID,
                                  MacintoshEncodingID,
                                  MacintoshLanguageID,
                                  LATEST_TTFAUTOHINT_VERSION)
from .googlefonts_conditions import * # pylint: disable=wildcard-import,unused-wildcard-import
from glyphsets import codepoints
ENCODINGS_DIR = codepoints.nam_dir


profile_imports = ('fontbakery.profiles.universal',)
profile = profile_factory(default_section=Section("Google Fonts"))

profile.configuration_defaults = {
    "com.google.fonts/check/file_size": {
        "WARN_SIZE": 1 * 1024 * 1024,
        "FAIL_SIZE": 9 * 1024 * 1024
    }
}

OVERRIDDEN_CHECKS = [
    "com.adobe.fonts/check/freetype_rasterizer",
]

METADATA_CHECKS = [
    'com.google.fonts/check/metadata/parses',
    'com.google.fonts/check/metadata/unknown_designer',
    'com.google.fonts/check/metadata/multiple_designers',
    'com.google.fonts/check/metadata/designer_values',
    'com.google.fonts/check/metadata/listed_on_gfonts',
    'com.google.fonts/check/metadata/unique_full_name_values',
    'com.google.fonts/check/metadata/unique_weight_style_pairs',
    'com.google.fonts/check/metadata/license',
    'com.google.fonts/check/metadata/menu_and_latin',
    'com.google.fonts/check/metadata/subsets_order',
    'com.google.fonts/check/metadata/includes_production_subsets',
    'com.google.fonts/check/metadata/copyright',
    'com.google.fonts/check/metadata/familyname',
    'com.google.fonts/check/metadata/has_regular',
    'com.google.fonts/check/metadata/regular_is_400',
    'com.google.fonts/check/metadata/nameid/family_name',
    'com.google.fonts/check/metadata/nameid/post_script_name',
    'com.google.fonts/check/metadata/nameid/full_name',
    'com.google.fonts/check/metadata/nameid/family_and_full_names', # FIXME! This seems redundant!
    'com.google.fonts/check/metadata/nameid/copyright',
    'com.google.fonts/check/metadata/nameid/font_name', # FIXME! This looks suspiciously similar to com.google.fonts/check/metadata/nameid/family_name
    'com.google.fonts/check/metadata/match_fullname_postscript',
    'com.google.fonts/check/metadata/match_filename_postscript',
    'com.google.fonts/check/metadata/match_weight_postscript',
    'com.google.fonts/check/metadata/valid_name_values',
    'com.google.fonts/check/metadata/valid_full_name_values',
    'com.google.fonts/check/metadata/valid_filename_values',
    'com.google.fonts/check/metadata/valid_post_script_name_values',
    'com.google.fonts/check/metadata/valid_copyright',
    'com.google.fonts/check/metadata/reserved_font_name',
    'com.google.fonts/check/metadata/copyright_max_length',
    'com.google.fonts/check/metadata/filenames',
    'com.google.fonts/check/metadata/italic_style',
    'com.google.fonts/check/metadata/normal_style',
    'com.google.fonts/check/metadata/fontname_not_camel_cased',
    'com.google.fonts/check/metadata/match_name_familyname',
    'com.google.fonts/check/metadata/canonical_weight_value',
    'com.google.fonts/check/metadata/os2_weightclass',
    'com.google.fonts/check/metadata/canonical_style_names',
    'com.google.fonts/check/metadata/broken_links',
    'com.google.fonts/check/metadata/undeclared_fonts',
    'com.google.fonts/check/metadata/category',
    'com.google.fonts/check/metadata/gf_axisregistry_valid_tags',
    'com.google.fonts/check/metadata/gf_axisregistry_bounds',
    'com.google.fonts/check/metadata/consistent_axis_enumeration',
    'com.google.fonts/check/metadata/escaped_strings',
    'com.google.fonts/check/metadata/designer_profiles',
    'com.google.fonts/check/metadata/family_directory_name',
    'com.google.fonts/check/metadata/can_render_samples',
    'com.google.fonts/check/metadata/unsupported_subsets',
    'com.google.fonts/check/metadata/category_hints'
]

DESCRIPTION_CHECKS = [
    'com.google.fonts/check/description/broken_links',
    'com.google.fonts/check/description/valid_html',
    'com.google.fonts/check/description/min_length',
    'com.google.fonts/check/description/git_url',
    'com.google.fonts/check/description/eof_linebreak',
    'com.google.fonts/check/description/family_update',
    'com.google.fonts/check/description/urls',
    'com.google.fonts/check/description/noto_has_article'
]

FAMILY_CHECKS = [
#   'com.google.fonts/check/family/equal_numbers_of_glyphs',
#   'com.google.fonts/check/family/equal_glyph_names',
    'com.google.fonts/check/family/has_license',
    'com.google.fonts/check/family/control_chars',
    'com.google.fonts/check/family/tnum_horizontal_metrics',
    'com.google.fonts/check/family/italics_have_roman_counterparts'
]

NAME_TABLE_CHECKS = [
    'com.google.fonts/check/name/unwanted_chars',
    'com.google.fonts/check/name/license',
    'com.google.fonts/check/name/license_url',
    'com.google.fonts/check/name/family_and_style_max_length',
    'com.google.fonts/check/name/line_breaks',
    'com.google.fonts/check/name/rfn'
]


# The glyphs checks will be enabled once
#  we implement check polymorphism
# https://github.com/googlefonts/fontbakery/issues/3436
GLYPHSAPP_CHECKS = [
#DISABLED:    'com.google.fonts/check/glyphs_file/name/family_and_style_max_length',
#DISABLED:    'com.google.fonts/check/glyphs_file/font_copyright'
]

REPO_CHECKS = [
    'com.google.fonts/check/repo/dirname_matches_nameid_1',
    'com.google.fonts/check/repo/vf_has_static_fonts',
    'com.google.fonts/check/repo/upstream_yaml_has_required_fields',
    'com.google.fonts/check/repo/fb_report',
    'com.google.fonts/check/repo/zip_files',
    'com.google.fonts/check/repo/sample_image',
    'com.google.fonts/check/license/OFL_copyright',
    'com.google.fonts/check/license/OFL_body_text'
]

FONT_FILE_CHECKS = [
    'com.google.fonts/check/glyph_coverage',
    'com.google.fonts/check/canonical_filename',
    'com.google.fonts/check/usweightclass',
    'com.google.fonts/check/fstype',
    'com.google.fonts/check/vendor_id',
    'com.google.fonts/check/ligature_carets',
    'com.google.fonts/check/production_glyphs_similarity',
    'com.google.fonts/check/fontv',
#DISABLED:     'com.google.fonts/check/production_encoded_glyphs',
    'com.google.fonts/check/glyf_nested_components',
    'com.google.fonts/check/varfont/generate_static',
    'com.google.fonts/check/kerning_for_non_ligated_sequences',
    'com.google.fonts/check/name/description_max_length',
    'com.google.fonts/check/fvar_name_entries',
    'com.google.fonts/check/version_bump',
    'com.google.fonts/check/epar',
    'com.google.fonts/check/font_copyright',
    'com.google.fonts/check/italic_angle',
    'com.google.fonts/check/has_ttfautohint_params',
    'com.google.fonts/check/name/version_format',
    'com.google.fonts/check/name/familyname_first_char',
    'com.google.fonts/check/hinting_impact',
    'com.google.fonts/check/file_size',
    'com.google.fonts/check/varfont/has_HVAR',
    'com.google.fonts/check/font_names',
    'com.google.fonts/check/gasp',
    'com.google.fonts/check/name/mandatory_entries',
    'com.google.fonts/check/name/copyright_length',
    'com.google.fonts/check/fontdata_namecheck',
    'com.google.fonts/check/name/ascii_only_entries',
    'com.google.fonts/check/fvar_instances',
    'com.google.fonts/check/old_ttfautohint',
    'com.google.fonts/check/vttclean',
    'com.google.fonts/check/aat',
    'com.google.fonts/check/mac_style',
    'com.google.fonts/check/fsselection',
    'com.google.fonts/check/smart_dropout',
    'com.google.fonts/check/integer_ppem_if_hinted',
    'com.google.fonts/check/unitsperem_strict',
    'com.google.fonts/check/vertical_metrics',
    'com.google.fonts/check/vertical_metrics_regressions',
    'com.google.fonts/check/cjk_vertical_metrics',
    'com.google.fonts/check/cjk_vertical_metrics_regressions',
    'com.google.fonts/check/cjk_not_enough_glyphs',
    'com.google.fonts/check/varfont_duplicate_instance_names',
    'com.google.fonts/check/varfont/consistent_axes',
    'com.google.fonts/check/varfont/unsupported_axes',
    'com.google.fonts/check/varfont/grade_reflow',
    'com.google.fonts/check/gf_axisregistry/fvar_axis_defaults',
    'com.google.fonts/check/STAT/gf_axisregistry',
    'com.google.fonts/check/STAT/axis_order',
    'com.google.fonts/check/mandatory_avar_table',
    'com.google.fonts/check/missing_small_caps_glyphs',
    'com.google.fonts/check/stylisticset_description',
    'com.google.fonts/check/os2/use_typo_metrics',
    'com.google.fonts/check/meta/script_lang_tags',
    'com.google.fonts/check/no_debugging_tables',
    'com.google.fonts/check/render_own_name',
    'com.google.fonts/check/STAT',
    'com.google.fonts/check/colorfont_tables',
]

GOOGLEFONTS_PROFILE_CHECKS = \
    UNIVERSAL_PROFILE_CHECKS + \
    METADATA_CHECKS + \
    DESCRIPTION_CHECKS + \
    FAMILY_CHECKS + \
    NAME_TABLE_CHECKS + \
    REPO_CHECKS + \
    FONT_FILE_CHECKS + \
    GLYPHSAPP_CHECKS


@check(
    id = 'com.google.fonts/check/canonical_filename',
    rationale = """
        A font's filename must be composed as "<familyname>-<stylename>.ttf":

        - Nunito-Regular.ttf
        
        - Oswald-BoldItalic.ttf


        Variable fonts must list the axis tags in alphabetical order in
        square brackets and separated by commas:

        - Roboto[wdth,wght].ttf
        
        - Familyname-Italic[wght].ttf
    """,
    proposal = 'legacy:check/001'
)
def com_google_fonts_check_canonical_filename(ttFont):
    """Checking file is named canonically."""
    from axisregistry import build_filename
    current_filename = os.path.basename(ttFont.reader.file.name)
    expected_filename = build_filename(ttFont)
    if current_filename != expected_filename:
        yield FAIL, Message('bad-filename',
                            f'Expected "{expected_filename}. Got {current_filename}.')
    else:
        yield PASS, f'Font filename is correct, "{current_filename}".'


@check(
    id = 'com.google.fonts/check/description/broken_links',
    conditions = ['description_html'],
    rationale = """
        The snippet of HTML in the DESCRIPTION.en_us.html file is added to the font
        family webpage on the Google Fonts website. For that reason, all hyperlinks
        in it must be properly working.
    """,
    proposal = 'legacy:check/003'
)
def com_google_fonts_check_description_broken_links(description_html):
    """Does DESCRIPTION file contain broken links?"""
    import requests
    from lxml import etree
    doc = description_html
    broken_links = []
    unique_links = []
    for a_href in doc.iterfind('.//a[@href]'):
        link = a_href.get("href")

        # avoid requesting the same URL more then once
        if link in unique_links:
            continue

        if link.startswith("mailto:") and \
           "@" in link and \
           "." in link.split("@")[1]:
            yield INFO,\
                  Message("email",
                          f"Found an email address: {link}")
            continue

        unique_links.append(link)
        try:
            response = requests.head(link, allow_redirects=True, timeout=10)
            code = response.status_code
            # Status 429: "Too Many Requests" is acceptable
            # because it means the website is probably ok and
            # we're just perhaps being too agressive in probing the server!
            if code not in [requests.codes.ok,
                            requests.codes.too_many_requests]:
                broken_links.append(f"{link} (status code: {code})")
        except requests.exceptions.Timeout:
            yield WARN,\
                  Message("timeout",
                          f"Timedout while attempting to access: '{link}'."
                          f" Please verify if that's a broken link.")
        except requests.exceptions.RequestException:
            broken_links.append(link)

    if len(broken_links) > 0:
        broken_links_list = '\n\t'.join(broken_links)
        yield FAIL,\
              Message("broken-links",
                      f"The following links are broken"
                      f" in the DESCRIPTION file:\n\t"
                      f"{broken_links_list}")
    else:
        yield PASS, "All links in the DESCRIPTION file look good!"


@check(
    id = 'com.google.fonts/check/description/urls',
    conditions = ['description_html'],
    rationale = """
        The snippet of HTML in the DESCRIPTION.en_us.html file is added to the font
        family webpage on the Google Fonts website.

        Google Fonts has a content formatting policy for that snippet that expects the
        text content of links not to include the http:// or https:// prefixes.
    """,
    proposal = 'https://github.com/googlefonts/fontbakery/issues/3497'
)
def com_google_fonts_check_description_urls(description_html):
    """URLs on DESCRIPTION file must not display http(s) prefix."""
    from lxml import etree
    passed = True
    for a_href in description_html.iterfind('.//a[@href]'):
        link_text = a_href.text
        if link_text.startswith("http://") or \
            link_text.startswith("https://"):
            passed = False
            yield WARN,\
                  Message("prefix-found",
                          f'Please remove the "http(s)://"'
                          f' prefix from the link text "{link_text}"')
            continue

    if passed:
        yield PASS, "All good!"


@condition
def description_html(description):
    if not description:
        return

    from lxml import etree
    html = "<html>" + description + "</html>"
    try:
        return etree.fromstring(html)
    except etree.XMLSyntaxError:
        return None


@check(
    id = 'com.google.fonts/check/description/git_url',
    conditions = ['description_html',
                  'not is_noto'],
    rationale = """
        The contents of the DESCRIPTION.en-us.html file are displayed on the
        Google Fonts website in the about section of each font family specimen page.

        Since all of the Google Fonts collection is composed of libre-licensed fonts,
        this check enforces a policy that there must be a hypertext link in that page
        directing users to the repository where the font project files are
        made available.

        Such hosting is typically done on sites like Github, Gitlab, GNU Savannah or
        any other git-based version control service.
    """,
    proposal = 'https://github.com/googlefonts/fontbakery/issues/2523'
)
def com_google_fonts_check_description_git_url(description_html):
    """Does DESCRIPTION file contain a upstream Git repo URL?"""
    git_urls = []
    for a_href in description_html.iterfind('.//a[@href]'):
        link = a_href.get("href")
        if "://git" in link:
            git_urls.append(link)
            yield INFO,\
                  Message("url-found",
                          f"Found a git repo URL: {link}")

    if len(git_urls) > 0:
        yield PASS, "Looks great!"
    else:
        yield FAIL,\
              Message("lacks-git-url",
                      "Please host your font project on a public Git repo"
                      " (such as GitHub or GitLab) and place a link"
                      " in the DESCRIPTION.en_us.html file.")


@check(
    id = 'com.google.fonts/check/description/valid_html',
    conditions = ['description'],
    rationale = """
        Sometimes people write malformed HTML markup. This check should ensure the
        file is good.

        Additionally, when packaging families for being pushed to the `google/fonts`
        git repo, if there is no DESCRIPTION.en_us.html file, some older versions of
        the `add_font.py` tool insert a placeholder description file which contains
        invalid html. This file needs to either be replaced with an existing
        description file or edited by hand.
    """,
    proposal = ['legacy:check/004',
                'https://github.com/googlefonts/fontbakery/issues/2664']
)
def com_google_fonts_check_description_valid_html(descfile, description):
    """Is this a proper HTML snippet?"""
    passed = True

    if "<html>" in description or "</html>" in description:
        yield FAIL,\
              Message("html-tag",
                      f"{descfile} should not have an <html> tag,"
                      f" since it should only be a snippet that will"
                      f" later be included in the Google Fonts"
                      f" font family specimen webpage.")

    from lxml import html
    try:
        html.fromstring("<html>" + description + "</html>")
    except Exception as e:
        passed = False
        yield FAIL,\
              Message("malformed-snippet",
                      f"{descfile} does not look like a propper HTML snippet."
                      f" Please look for syntax errors."
                      f" Maybe the following parser error message can help"
                      f" you find what's wrong:\n"
                      f"----------------\n"
                      f"{e}\n"
                      f"----------------\n")

    if "<p>" not in description or "</p>" not in description:
        passed = False
        yield FAIL,\
              Message("lacks-paragraph",
                      f"{descfile} does not include an HTML <p> tag.")

    if passed:
        yield PASS, f"{descfile} is a propper HTML file."


@check(
    id = 'com.google.fonts/check/description/min_length',
    conditions = ['description'],
    proposal = 'legacy:check/005'
)
def com_google_fonts_check_description_min_length(description):
    """DESCRIPTION.en_us.html must have more than 200 bytes."""
    if len(description) <= 200:
        yield FAIL,\
              Message("too-short",
                      "DESCRIPTION.en_us.html must"
                      " have size larger than 200 bytes.")
    else:
        yield PASS, "DESCRIPTION.en_us.html is larger than 200 bytes."


@check(
    id = 'com.google.fonts/check/description/eof_linebreak',
    conditions = ['description'],
    rationale = """
        Some older text-handling tools sometimes misbehave if the last line of data
        in a text file is not terminated with a newline character (also known as '\\n').

        We know that this is a very small detail, but for the sake of keeping all
        DESCRIPTION.en_us.html files uniformly formatted throughout the GFonts
        collection, we chose to adopt the practice of placing this final linebreak
        character on them.
    """,
    proposal = 'https://github.com/googlefonts/fontbakery/issues/2879'
)
def com_google_fonts_check_description_eof_linebreak(description):
    """DESCRIPTION.en_us.html should end in a linebreak."""
    if description[-1] != '\n':
        yield WARN,\
              Message("missing-eof-linebreak",
                      "The last characther on DESCRIPTION.en_us.html"
                      " is not a line-break. Please add it.")
    else:
        yield PASS, ":-)"


@check(
    id = 'com.google.fonts/check/metadata/parses',
    conditions = ['family_directory'],
    rationale = """
        The purpose of this check is to ensure that the METADATA.pb file is not malformed.
    """,
    proposal = 'https://github.com/googlefonts/fontbakery/issues/2248'
)
def com_google_fonts_check_metadata_parses(family_directory):
    """Check METADATA.pb parse correctly."""
    from google.protobuf import text_format
    from fontbakery.utils import get_FamilyProto_Message
    try:
        pb_file = os.path.join(family_directory, "METADATA.pb")
        get_FamilyProto_Message(pb_file)
        yield PASS, "METADATA.pb parsed successfuly."
    except text_format.ParseError as e:
        yield FAIL,\
              Message("parsing-error",
                      f"Family metadata at {family_directory} failed to parse.\n"
                      f"TRACEBACK:\n{e}")
    except FileNotFoundError:
        yield SKIP,\
              Message("file-not-found",
                      f"Font family at '{family_directory}' lacks a METADATA.pb file.")


@check(
    id = 'com.google.fonts/check/metadata/unknown_designer',
    conditions = ['family_metadata'],
    proposal = ['legacy:check/007',
                'https://github.com/googlefonts/fontbakery/issues/800']
)
def com_google_fonts_check_metadata_unknown_designer(family_metadata):
    """Font designer field in METADATA.pb must not be 'unknown'."""
    if family_metadata.designer.lower() == 'unknown':
        yield FAIL,\
              Message("unknown-designer",
                      f"Font designer field is '{family_metadata.designer}'.")
    else:
        yield PASS, "Font designer field is not 'unknown'."


@check(
    id = 'com.google.fonts/check/metadata/multiple_designers',
    conditions = ['family_metadata'],
    rationale = """
        For a while the string "Multiple designers" was used as a placeholder on
        METADATA.pb files. We should replace all those instances with actual designer
        names so that proper credits are displayed on the Google Fonts family
        specimen pages.

        If there's more than a single designer, the designer names must be
        separated by commas.
    """,
    proposal = 'https://github.com/googlefonts/fontbakery/issues/2766'
)
def com_google_fonts_check_metadata_multiple_designers(family_metadata):
    """Font designer field in METADATA.pb must not contain 'Multiple designers'."""
    if 'multiple designer' in family_metadata.designer.lower():
        yield FAIL,\
              Message("multiple-designers",
                      f"Font designer field is '{family_metadata.designer}'."
                      f" Please add an explicit comma-separated list of designer names.")
    else:
        yield PASS, "Looks good."


@check(
    id = 'com.google.fonts/check/metadata/designer_values',
    conditions = ['family_metadata'],
    rationale = """
        We must use commas instead of forward slashes because the server-side code
        at the fonts.google.com directory will segment the string on the commas into
        a list of names and display the first item in the list as the
        "principal designer" while the remaining names are identified as "contributors".

        See eg https://fonts.google.com/specimen/Rubik
    """,
    proposal = 'https://github.com/googlefonts/fontbakery/issues/2479'
)
def com_google_fonts_check_metadata_designer_values(family_metadata):
    """Multiple values in font designer field in
       METADATA.pb must be separated by commas."""

    if '/' in family_metadata.designer:
        yield FAIL,\
              Message("slash",
                      f"Font designer field contains a forward slash"
                      f" '{family_metadata.designer}'."
                      f" Please use commas to separate multiple names instead.")
    else:
        yield PASS, "Looks good."


@check(
    id = 'com.google.fonts/check/metadata/broken_links',
    conditions = ['family_metadata']
)
def com_google_fonts_check_metadata_broken_links(family_metadata):
    """Does METADATA.pb copyright field contain broken links?"""
    import requests
    broken_links = []
    unique_links = []
    for font_metadata in family_metadata.fonts:
        copyright = font_metadata.copyright
        if "mailto:" in copyright:
            # avoid reporting more then once
            if copyright in unique_links:
                continue

            unique_links.append(copyright)
            yield INFO,\
                  Message("email",
                          f"Found an email address: {copyright}")
            continue

        if "http" in copyright:
            link = "http" + copyright.split("http")[1]

            for endchar in [' ', ')']:
                if endchar in link:
                    link = link.split(endchar)[0]

            # avoid requesting the same URL more then once
            if link in unique_links:
                continue

            unique_links.append(link)
            try:
                response = requests.head(link, allow_redirects=True, timeout=10)
                code = response.status_code
                # Status 429: "Too Many Requests" is acceptable
                # because it means the website is probably ok and
                # we're just perhaps being too agressive in probing the server!
                if code not in [requests.codes.ok,
                                requests.codes.too_many_requests]:
                    broken_links.append(("{} (status code: {})").format(link, code))
            except requests.exceptions.Timeout:
                yield WARN,\
                      Message("timeout",
                              f"Timed out while attempting to access: '{link}'."
                              f" Please verify if that's a broken link.")
            except requests.exceptions.RequestException:
                broken_links.append(link)

    if len(broken_links) > 0:
        broken_links_list = '\n\t'.join(broken_links)
        yield FAIL,\
              Message("broken-links",
                      f"The following links are broken"
                      f" in the METADATA.pb file:\n\t"
                      f"{broken_links_list}")
    else:
        yield PASS, "All links in the METADATA.pb file look good!"


@check(
    id = 'com.google.fonts/check/metadata/undeclared_fonts',
    conditions = ['family_metadata'],
    rationale = """
        The set of font binaries available, except the ones on a "static" subdir,
        must match exactly those declared on the METADATA.pb file.

        Also, to avoid confusion, we expect that font files (other than statics)
        are not placed on subdirectories.
    """,
    proposal = 'https://github.com/googlefonts/fontbakery/issues/2575'
)
def com_google_fonts_check_metadata_undeclared_fonts(family_metadata, family_directory):
    """Ensure METADATA.pb lists all font binaries."""

    pb_binaries = []
    for font_metadata in family_metadata.fonts:
        pb_binaries.append(font_metadata.filename)

    passed = True
    binaries = []
    for entry in os.listdir(family_directory):
        if entry != "static" and os.path.isdir(os.path.join(family_directory, entry)):
            for filename in os.listdir(os.path.join(family_directory, entry)):
                if filename[-4:] in [".ttf", ".otf"]:
                    path = os.path.join(family_directory, entry, filename)
                    passed = False
                    yield WARN,\
                          Message("font-on-subdir",
                                  f'The file "{path}" is a font binary'
                                  f' in a subdirectory.\n'
                                  f'Please keep all font files (except VF statics)'
                                  f' directly on the root directory side-by-side'
                                  f' with its corresponding METADATA.pb file.')
        else:
            # Note: This does not include any font binaries placed in a "static" subdir!
            if entry[-4:] in [".ttf", ".otf"]:
                binaries.append(entry)


    for filename in sorted(set(pb_binaries) - set(binaries)):
        passed = False
        yield FAIL,\
              Message("file-missing",
                      f'The file "{filename}" declared on METADATA.pb'
                      f' is not available in this directory.')


    for filename in sorted(set(binaries) - set(pb_binaries)):
        passed = False
        yield FAIL,\
              Message("file-not-declared",
                      f'The file "{filename}" is not declared on METADATA.pb')

    if passed:
        yield PASS, "OK"


@check(
    id = 'com.google.fonts/check/metadata/category',
    conditions = ['family_metadata'],
    rationale = """
        There are only five acceptable values for the category field in a METADATA.pb file:

        - MONOSPACE

        - SANS_SERIF

        - SERIF

        - DISPLAY

        - HANDWRITING

        This check is meant to avoid typos in this field.
    """,
    proposal = 'https://github.com/googlefonts/fontbakery/issues/2972'
)
def com_google_fonts_check_metadata_category(family_metadata):
    """Ensure METADATA.pb category field is valid."""
    ok = True
    for category in family_metadata.category:
        if category not in ["MONOSPACE",
                            "SANS_SERIF",
                            "SERIF",
                            "DISPLAY",
                            "HANDWRITING"]:
            ok = False
            yield FAIL,\
                  Message('bad-value',
                          f'The field category has "{category}"'
                          f' which is not valid.')
    if ok:
        yield PASS, "OK!"


@disable # TODO: re-enable after addressing issue #1998
@check(
    id = 'com.google.fonts/check/family/equal_numbers_of_glyphs',
    conditions = ['are_ttf',
                  'stylenames_are_canonical'],
    proposal = 'legacy:check/011'
)
def com_google_fonts_check_family_equal_numbers_of_glyphs(ttFonts):
    """Fonts have equal numbers of glyphs?"""
    from .googlefonts_conditions import canonical_stylename

    # ttFonts is an iterator, so here we make a list from it
    # because we'll have to iterate twice in this check implementation:
    the_ttFonts = list(ttFonts)

    failed = False
    max_stylename = None
    max_count = 0
    max_glyphs = None
    for ttFont in the_ttFonts:
        fontname = ttFont.reader.file.name
        stylename = canonical_stylename(fontname)
        this_count = len(ttFont['glyf'].glyphs)
        if this_count > max_count:
            max_count = this_count
            max_stylename = stylename
            max_glyphs = set(ttFont['glyf'].glyphs)

    for ttFont in the_ttFonts:
        fontname = ttFont.reader.file.name
        stylename = canonical_stylename(fontname)
        these_glyphs = set(ttFont['glyf'].glyphs)
        this_count = len(these_glyphs)
        if this_count != max_count:
            failed = True
            all_glyphs = max_glyphs.union(these_glyphs)
            common_glyphs = max_glyphs.intersection(these_glyphs)
            diff = all_glyphs - common_glyphs
            diff_count = len(diff)
            if diff_count < 10:
                diff = ", ".join(diff)
            else:
                diff = ", ".join(list(diff)[:10]) + " (and more)"

            yield FAIL,\
                  Message("glyph-count-diverges",
                          f"{stylename} has {this_count} glyphs while"
                          f" {max_stylename} has {max_count} glyphs."
                          f" There are {diff_count} different glyphs"
                          f" among them: {sorted(diff)}")
    if not failed:
        yield PASS, ("All font files in this family have"
                     " an equal total ammount of glyphs.")


@disable # TODO: re-enable after addressing issue #1998
@check(
    id = 'com.google.fonts/check/family/equal_glyph_names',
    conditions = ['are_ttf'],
    proposal = 'legacy:check/012'
)
def com_google_fonts_check_family_equal_glyph_names(ttFonts):
    """Fonts have equal glyph names?"""
    from .googlefonts_conditions import style

    fonts = list(ttFonts)

    all_glyphnames = set()
    for ttFont in fonts:
        all_glyphnames |= set(ttFont["glyf"].glyphs.keys())

    missing = {}
    available = {}
    for glyphname in all_glyphnames:
        missing[glyphname] = []
        available[glyphname] = []

    failed = False
    for ttFont in fonts:
        fontname = ttFont.reader.file.name
        these_ones = set(ttFont["glyf"].glyphs.keys())
        for glyphname in all_glyphnames:
            if glyphname not in these_ones:
                failed = True
                missing[glyphname].append(fontname)
            else:
                available[glyphname].append(fontname)

    for gn in sorted(missing.keys()):
        if missing[gn]:
            available_styles = [style(k) for k in available[gn]]
            missing_styles = [style(k) for k in missing[gn]]
            if None not in available_styles + missing_styles:
                # if possible, use stylenames in the log messages.
                avail = ', '.join(sorted(vailable_styles))
                miss = ', '.join(sorted(missing_styles))
            else:
                # otherwise, print filenames:
                avail = ', '.join(sorted(available[gn]))
                miss = ', '.join(sorted(missing[gn]))

            yield FAIL,\
                  Message("missing-glyph",
                          f"Glyphname '{gn}' is defined on {avail}"
                          f" but is missing on {miss}.")

    if not failed:
        yield PASS, "All font files have identical glyph names."


@check(
    id = 'com.google.fonts/check/fstype',
    rationale = """
        The fsType in the OS/2 table is a legacy DRM-related field. Fonts in the
        Google Fonts collection must have it set to zero (also known as
        "Installable Embedding"). This setting indicates that the fonts can be
        embedded in documents and permanently installed by applications on
        remote systems.

        More detailed info is available at:
        https://docs.microsoft.com/en-us/typography/opentype/spec/os2#fstype
    """,
    proposal = 'legacy:check/016'
)
def com_google_fonts_check_fstype(ttFont):
    """Checking OS/2 fsType does not impose restrictions."""
    value = ttFont['OS/2'].fsType
    if value != 0:
        FSTYPE_RESTRICTIONS = {
            0x0002: ("* The font must not be modified, embedded or exchanged in"
                     " any manner without first obtaining permission of"
                     " the legal owner."),
            0x0004: ("The font may be embedded, and temporarily loaded on the"
                     " remote system, but documents that use it must"
                     " not be editable."),
            0x0008: ("The font may be embedded but must only be installed"
                     " temporarily on other systems."),
            0x0100: ("The font may not be subsetted prior to embedding."),
            0x0200: ("Only bitmaps contained in the font may be embedded."
                     " No outline data may be embedded.")
        }
        restrictions = ""
        for bit_mask in FSTYPE_RESTRICTIONS.keys():
            if value & bit_mask:
                restrictions += FSTYPE_RESTRICTIONS[bit_mask]

        if value & 0b1111110011110001:
            restrictions += ("* There are reserved bits set,"
                             " which indicates an invalid setting.")

        yield FAIL,\
              Message("drm",
                      f"In this font fsType is set to {value} meaning that:\n"
                      f"{restrictions}\n"
                      f"\n"
                      f"No such DRM restrictions can be enabled on the"
                      f" Google Fonts collection, so the fsType field"
                      f" must be set to zero (Installable Embedding) instead.")
    else:
        yield PASS, "OS/2 fsType is properly set to zero."


@check(
    id = 'com.google.fonts/check/vendor_id',
    conditions = ['registered_vendor_ids'],
    rationale = """
        Microsoft keeps a list of font vendors and their respective contact info. This
        list is updated regularly and is indexed by a 4-char "Vendor ID" which is
        stored in the achVendID field of the OS/2 table.

        Registering your ID is not mandatory, but it is a good practice since some
        applications may display the type designer / type foundry contact info on some
        dialog and also because that info will be visible on Microsoft's website:

        https://docs.microsoft.com/en-us/typography/vendors/

        This check verifies whether or not a given font's vendor ID is registered in
        that list or if it has some of the default values used by the most common
        font editors.

        Each new FontBakery release includes a cached copy of that list of vendor IDs.
        If you registered recently, you're safe to ignore warnings emitted by this
        check, since your ID will soon be included in one of our upcoming releases.
    """,
    proposal = 'legacy:check/018'
)
def com_google_fonts_check_vendor_id(ttFont, registered_vendor_ids):
    """Checking OS/2 achVendID."""

    SUGGEST_MICROSOFT_VENDORLIST_WEBSITE = (
        "If you registered it recently, then it's safe to ignore this warning message."
        " Otherwise, you should set it to your own unique 4 character code,"
        " and register it with Microsoft at"
        " https://www.microsoft.com/typography/links/vendorlist.aspx\n")

    vid = ttFont['OS/2'].achVendID
    bad_vids = ['UKWN', 'ukwn', 'PfEd']
    if vid is None:
        yield WARN,\
              Message("not-set",
                      f"OS/2 VendorID is not set."
                      f" {SUGGEST_MICROSOFT_VENDORLIST_WEBSITE}")
    elif vid in bad_vids:
        yield WARN,\
              Message("bad",
                      f"OS/2 VendorID is '{vid}', a font editor default."
                      f" {SUGGEST_MICROSOFT_VENDORLIST_WEBSITE}")
    elif vid not in registered_vendor_ids.keys():
        yield WARN,\
              Message("unknown",
                      f"OS/2 VendorID value '{vid}' is not yet recognized."
                      f" {SUGGEST_MICROSOFT_VENDORLIST_WEBSITE}")
    else:
        yield PASS, f"OS/2 VendorID '{vid}' looks good!"


@condition
def font_codepoints(ttFont):
    codepoints = set()
    for table in ttFont['cmap'].tables:
        if (table.platformID == PlatformID.WINDOWS and
            table.platEncID == WindowsEncodingID.UNICODE_BMP):
            codepoints.update(table.cmap.keys())
    return codepoints


@check(
    id = 'com.google.fonts/check/glyph_coverage',
    rationale = """
        Google Fonts expects that fonts in its collection support at least the minimal
        set of characters defined in the `GF-latin-core` glyph-set.
    """,
    conditions = ["font_codepoints"],
    proposal = 'https://github.com/googlefonts/fontbakery/pull/2488'
)
def com_google_fonts_check_glyph_coverage(ttFont, font_codepoints, config):
    """Check Google Fonts glyph coverage."""
    from glyphsets import GFGlyphData as glyph_data
    import unicodedata2

    def missing_encoded_glyphs(glyphs):
        encoded_glyphs = [g["unicode"] for g in glyphs if g["unicode"]]
        return ['0x%04X (%s)\n' % (c, unicodedata2.name(chr(c))) for c in encoded_glyphs]

    missing_mandatory_glyphs = glyph_data.missing_glyphsets_in_font(ttFont, threshold=0.0)
    missing_optional_glyphs = glyph_data.missing_glyphsets_in_font(ttFont, threshold=0.8)
    passed = True
    if "GF_Latin_Core" in missing_mandatory_glyphs:
        missing = missing_encoded_glyphs(missing_mandatory_glyphs["GF_Latin_Core"])
        if missing:
            passed = False
            yield FAIL,\
                Message("missing-codepoints",
                        f"Missing required codepoints:\n\n"
                        f"{bullet_list(config, missing)}")
    elif len(missing_optional_glyphs) > 0 and "GF_Latin_Core" not in missing_optional_glyphs:
        for glyphset_name, glyphs in missing_optional_glyphs.items():
            if glyphset_name == "GF_Latin_Core":
                continue
            missing = missing_encoded_glyphs(glyphs)
            if missing:
                passed = False
                yield WARN,\
                    Message("missing-codepoints",
                            f"{glyphset_name} is almost fulfilled. Missing codepoints:\n\n"
                            f"{bullet_list(config, missing)}")
    if passed:
        yield PASS, "OK"


@check(
    id = 'com.google.fonts/check/metadata/unsupported_subsets',
    rationale = """
        This check ensures that the subsets specified on a METADATA.pb file are
        actually supported (even if only partially) by the font files.

        Subsets for which none of the codepoints are supported will cause the
        check to FAIL.
    """,
    conditions = ["family_metadata"],
    proposal = 'https://github.com/googlefonts/fontbakery/issues/3533',
    severity = 10, # max severity because this blocks font pushes to production.
)
def com_google_fonts_check_metadata_unsupported_subsets(family_metadata, ttFont, font_codepoints):
    """Check for METADATA subsets with zero support."""
    from glyphsets.subsets import SUBSETS
    codepoints.set_encoding_path(ENCODINGS_DIR)

    passed = True
    for subset in family_metadata.subsets:
        if subset == "menu":
            continue

        if subset not in SUBSETS:
            yield FAIL,\
                  Message("unknown-subset",
                          f"Please remove the unrecognized subset '{subset}'"
                          f" from the METADATA.pb file.")
            continue

        subset_codepoints = codepoints.CodepointsInSubset(subset, unique_glyphs=True)
        if len(subset_codepoints.intersection(font_codepoints)) == 0:
            passed = False
            yield FAIL,\
                  Message("unsupported-subset",
                          f"Please remove '{subset}' from METADATA.pb since none"
                          f" of its glyphs are supported by this font file.")
    if passed:
        yield PASS, "OK"


@check(
    id = 'com.google.fonts/check/name/unwanted_chars',
    proposal = 'legacy:check/019'
)
def com_google_fonts_check_name_unwanted_chars(ttFont):
    """Substitute copyright, registered and trademark
       symbols in name table entries."""
    failed = False
    replacement_map = [("\u00a9", '(c)'),
                       ("\u00ae", '(r)'),
                       ("\u2122", '(tm)')]
    for name in ttFont['name'].names:
        string = str(name.string, encoding=name.getEncoding())
        for mark, ascii_repl in replacement_map:
            new_string = string.replace(mark, ascii_repl)
            if string != new_string:
                yield FAIL,\
                      Message("unwanted-chars",
                              f"NAMEID #{name.nameID} contains symbols that"
                              f" should be replaced by '{ascii_repl}'.")
                failed = True
    if not failed:
        yield PASS, ("No need to substitute copyright, registered and"
                     " trademark symbols in name table entries of this font.")


@check(
    id = 'com.google.fonts/check/usweightclass',
    conditions = ['expected_style'],
    rationale = """
        Google Fonts expects variable fonts, static ttfs and static otfs to have
        differing OS/2 usWeightClass values.

        - For Variable Fonts, Thin-Black must be 100-900
        
        - For static ttfs, Thin-Black can be 100-900 or 250-900
        
        - For static otfs, Thin-Black must be 250-900

        If static otfs are set lower than 250, text may appear blurry in
        legacy Windows applications.

        Glyphsapp users can change the usWeightClass value of an instance by adding
        a 'weightClass' customParameter.
    """,
    proposal = 'legacy:check/020'
)
def com_google_fonts_check_usweightclass(ttFont, expected_style):
    """Checking OS/2 usWeightClass."""
    from fontbakery.profiles.shared_conditions import (
        is_ttf,
        is_cff,
        is_variable_font
    )

    failed = False
    expected_value = expected_style.usWeightClass
    weight_name = expected_style.name
    value = ttFont['OS/2'].usWeightClass
    has_expected_value = value == expected_value
    fail_message = \
        "OS/2 usWeightClass is '{}' when it should be '{}'."

    if is_variable_font(ttFont):
        if not has_expected_value:
            failed = True
            yield FAIL,\
                  Message("bad-value",
                          fail_message.format(value, expected_value))
    # overrides for static Thin and ExtaLight fonts
    # for static ttfs, we don't mind if Thin is 250 and ExtraLight is 275.
    # However, if the values are incorrect we will recommend they set Thin
    # to 100 and ExtraLight to 250.
    # for static otfs, Thin must be 250 and ExtraLight must be 275
    elif "Thin" in weight_name:
        if is_ttf(ttFont) and value not in [100, 250]:
            failed = True
            yield FAIL,\
                  Message("bad-value",
                          fail_message.format(value, expected_value))
        if is_cff(ttFont) and value != 250:
            failed = True
            yield FAIL,\
                  Message("bad-value",
                          fail_message.format(value, 250))

    elif "ExtraLight" in weight_name:
        if is_ttf(ttFont) and value not in [200, 275]:
            failed = True
            yield FAIL,\
                  Message("bad-value",
                          fail_message.format(value, expected_value))
        if is_cff(ttFont) and value != 275:
            failed = True
            yield FAIL,\
                  Message("bad-value",
                          fail_message.format(value, 275))

    elif not has_expected_value:
        failed = True
        yield FAIL,\
              Message("bad-value",
                      fail_message.format(value, expected_value))

    if not failed:
        yield PASS, "OS/2 usWeightClass is good"


@check(
    id = 'com.google.fonts/check/family/has_license',
    conditions = ['gfonts_repo_structure'],
    proposal = 'legacy:check/028'
)
def com_google_fonts_check_family_has_license(licenses, config):
    """Check font has a license."""
    from fontbakery.utils import pretty_print_list

    if len(licenses) > 1:
        filenames = [os.path.basename(f) for f in licenses]
        yield FAIL,\
              Message("multiple",
                      f"More than a single license file found:"
                      f" {pretty_print_list(config, filenames)}")
    elif not licenses:
        yield FAIL,\
              Message("no-license",
                      "No license file was found."
                      " Please add an OFL.txt or a LICENSE.txt file."
                      " If you are running fontbakery on a Google Fonts"
                      " upstream repo, which is fine, just make sure"
                      " there is a temporary license file in the same folder.")
    else:
        yield PASS, f"Found license at '{licenses[0]}'"


@check(
    id = 'com.google.fonts/check/license/OFL_copyright',
    conditions = ['license_contents'],
    rationale = """
        An OFL.txt file's first line should be the font copyright e.g:
        "Copyright 2019 The Montserrat Project Authors
        (https://github.com/julietaula/montserrat)"
    """,
    severity = 10, # max severity because licensing mistakes can cause legal problems.
    proposal = 'https://github.com/googlefonts/fontbakery/issues/2764'
)
def com_google_fonts_check_license_OFL_copyright(license_contents):
    """Check license file has good copyright string."""
    import re
    string = license_contents.strip().split('\n')[0].lower()
    does_match = re.search(EXPECTED_COPYRIGHT_PATTERN, string)
    if does_match:
        yield PASS, "looks good"
    else:
        yield FAIL,\
              Message('bad-format',
                      f'First line in license file is:\n\n'
                      f'"{string}"\n\n'
                      f'which does not match the expected format, similar to:\n\n'
                      f'"Copyright 2022 The Familyname Project Authors (git url)"')


@check(
    id = 'com.google.fonts/check/license/OFL_body_text',
    conditions = ['is_ofl',
                  'license_contents'],
    rationale = """
        Check OFL body text is correct.
        Often users will accidently delete parts of the body text.
    """,
    severity = 10, # max severity because licensing mistakes can cause legal problems.
    proposal = 'https://github.com/googlefonts/fontbakery/issues/3352'
)
def com_google_fonts_check_license_OFL_body_text(license_contents):
    """Check OFL body text is correct.""" 
    from fontbakery.constants import OFL_BODY_TEXT

    if not OFL_BODY_TEXT in license_contents.replace("http://", "https://"):
        yield FAIL,\
              Message("incorrect-ofl-body-text",
                      "The OFL.txt body text is incorrect. Please use"
                      " https://github.com/googlefonts/Unified-Font-Repository"
                      "/blob/main/OFL.txt as a template."
                      " You should only modify the first line.")
    else:
        yield PASS, "OFL license body text is correct"


@check(
    id = 'com.google.fonts/check/name/license',
    conditions = ['license'],
    rationale = """
        A known licensing description must be provided in the NameID 14
        (LICENSE DESCRIPTION) entries of the name table.

        The source of truth for this check (to determine which license is in use)
        is a file placed side-by-side to your font project including the licensing terms.

        Depending on the chosen license, one of the following string snippets is
        expected to be found on the NameID 13 (LICENSE DESCRIPTION) entries of the
        name table:
        
        - "This Font Software is licensed under the SIL Open Font License, Version 1.1.
          This license is available with a FAQ at: https://scripts.sil.org/OFL"
  
        - "Licensed under the Apache License, Version 2.0"
  
        - "Licensed under the Ubuntu Font Licence 1.0."


        Currently accepted licenses are Apache or Open Font License. For a small set
        of legacy families the Ubuntu Font License may be acceptable as well.

        When in doubt, please choose OFL for new font projects.
    """,
    proposal = 'legacy:check/029'
)
def com_google_fonts_check_name_license(ttFont, license):
    """Check copyright namerecords match license file."""
    from fontbakery.constants import PLACEHOLDER_LICENSING_TEXT
    failed = False
    http_warn = False
    placeholder = PLACEHOLDER_LICENSING_TEXT[license]
    entry_found = False
    for i, nameRecord in enumerate(ttFont["name"].names):
        if nameRecord.nameID == NameID.LICENSE_DESCRIPTION:
            entry_found = True
            value = nameRecord.toUnicode()
            if "http://" in value:
                yield WARN,\
                      Message("http-in-description",
                              f'Please consider using HTTPS URLs at'
                              f' name table entry [plat={nameRecord.platformID},'
                              f' enc={nameRecord.platEncID},'
                              f' name={nameRecord.nameID}]')
                value = "https://".join(value.split("http://"))
                http_warn = True

            if value != placeholder:
                failed = True
                yield FAIL,\
                      Message("wrong",
                              f'License file {license} exists but'
                              f' NameID {NameID.LICENSE_DESCRIPTION}'
                              f' (LICENSE DESCRIPTION) value on platform'
                              f' {nameRecord.platformID}'
                              f' ({PlatformID(nameRecord.platformID).name})'
                              f' is not specified for that.'
                              f' Value was: "{value}"'
                              f' Must be changed to "{placeholder}"')
    if http_warn:
        yield WARN,\
              Message("http",
                      "For now we're still accepting http URLs,"
                      " but you should consider using https instead.\n")

    if not entry_found:
        yield FAIL,\
              Message("missing",
                      f"Font lacks NameID {NameID.LICENSE_DESCRIPTION}"
                      f" (LICENSE DESCRIPTION). A proper licensing"
                      f" entry must be set.")
    elif not failed:
        yield PASS, "Licensing entry on name table is correctly set."


@check(
    id = 'com.google.fonts/check/name/license_url',
    rationale = """
        A known license URL must be provided in the NameID 14 (LICENSE INFO URL)
        entry of the name table.

        The source of truth for this check is the licensing text found on the NameID 13
        entry (LICENSE DESCRIPTION).

        The string snippets used for detecting licensing terms are:

        - "This Font Software is licensed under the SIL Open Font License, Version 1.1.
          This license is available with a FAQ at: https://scripts.sil.org/OFL"

        - "Licensed under the Apache License, Version 2.0"

        - "Licensed under the Ubuntu Font Licence 1.0."


        Currently accepted licenses are Apache or Open Font License.
        For a small set of legacy families the Ubuntu Font License may be acceptable as well.

        When in doubt, please choose OFL for new font projects.
    """,
    conditions = ['familyname'],
    proposal = 'legacy:check/030'
)
def com_google_fonts_check_name_license_url(ttFont, familyname):
    """License URL matches License text on name table?"""
    from fontbakery.constants import PLACEHOLDER_LICENSING_TEXT
    LEGACY_UFL_FAMILIES = ["Ubuntu", "UbuntuCondensed", "UbuntuMono"]
    LICENSE_URL = {
        'OFL.txt': 'https://scripts.sil.org/OFL',
        'LICENSE.txt': 'https://www.apache.org/licenses/LICENSE-2.0',
        'UFL.txt': 'https://www.ubuntu.com/legal/terms-and-policies/font-licence'
    }
    LICENSE_NAME = {
        'OFL.txt': 'Open Font',
        'LICENSE.txt': 'Apache',
        'UFL.txt': 'Ubuntu Font License'
    }
    detected_license = False
    http_warn = False
    for license in ['OFL.txt', 'LICENSE.txt', 'UFL.txt']:
        placeholder = PLACEHOLDER_LICENSING_TEXT[license]
        for nameRecord in ttFont['name'].names:
            string = nameRecord.string.decode(nameRecord.getEncoding())
            if nameRecord.nameID == NameID.LICENSE_DESCRIPTION:
                if "http://" in string:
                    yield WARN,\
                          Message("http-in-description",
                                  f'Please consider using HTTPS URLs at'
                                  f' name table entry [plat={nameRecord.platformID},'
                                  f' enc={nameRecord.platEncID},'
                                  f' name={nameRecord.nameID}]')
                    string = "https://".join(string.split("http://"))
                    http_warn = True

                if string == placeholder:
                    detected_license = license
                    break

    if detected_license == "UFL.txt" and familyname not in LEGACY_UFL_FAMILIES:
        yield FAIL,\
              Message("ufl",
                      "The Ubuntu Font License is only acceptable on"
                      " the Google Fonts collection for legacy font"
                      " families that already adopted such license."
                      " New Families should use eigther Apache or"
                      " Open Font License.")
    else:
        found_good_entry = False
        if not detected_license:
            yield SKIP, ("Could not infer the font license."
                         " Please ensure NameID 13 (LICENSE DESCRIPTION) is properly set.")
            return
        else:
            failed = False
            expected = LICENSE_URL[detected_license]
            for nameRecord in ttFont['name'].names:
                if nameRecord.nameID == NameID.LICENSE_INFO_URL:
                    string = nameRecord.string.decode(nameRecord.getEncoding())
                    if "http://" in string:
                        yield WARN,\
                              Message("http-in-license-info",
                                      f'Please consider using HTTPS URLs at'
                                      f' name table entry [plat={nameRecord.platformID},'
                                      f' enc={nameRecord.platEncID},'
                                      f' name={nameRecord.nameID}]')
                        string = "https://".join(string.split("http://"))
                    if string == expected:
                        found_good_entry = True
                    else:
                        failed = True
                        yield FAIL,\
                              Message("licensing-inconsistency",
                                      f"Licensing inconsistency in name table entries!"
                                      f" NameID={NameID.LICENSE_DESCRIPTION}"
                                      f" (LICENSE DESCRIPTION) indicates"
                                      f" {LICENSE_NAME[detected_license]} licensing,"
                                      f" but NameID={NameID.LICENSE_INFO_URL}"
                                      f" (LICENSE URL) has '{string}'."
                                      f" Expected: '{expected}'")
        if http_warn:
            yield WARN,\
                  Message("http",
                          "For now we're still accepting http URLs,"
                          " but you should consider using https instead.\n")

        if not found_good_entry:
            yield FAIL,\
                  Message("no-license-found",
                          f"A known license URL must be provided in"
                          f" the NameID {NameID.LICENSE_INFO_URL}"
                          f" (LICENSE INFO URL) entry."
                          f" Currently accepted licenses are"
                          f" Apache: '{LICENSE_URL['LICENSE.txt']}'"
                          f" or Open Font License: '{LICENSE_URL['OFL.txt']}'"
                          f"\n"
                          f"For a small set of legacy families the Ubuntu"
                          f" Font License '{LICENSE_URL['UFL.txt']}' may be"
                          f" acceptable as well."
                          f"\n"
                          f"When in doubt, please choose OFL for"
                          f" new font projects.")
        else:
            if failed:
                yield FAIL,\
                      Message("bad-entries",
                              f"Even though a valid license URL was seen in the"
                              f" name table, there were also bad entries."
                              f" Please review NameIDs {NameID.LICENSE_DESCRIPTION}"
                              f" (LICENSE DESCRIPTION) and {NameID.LICENSE_INFO_URL}"
                              f" (LICENSE INFO URL).")
            else:
                yield PASS, "Font has a valid license URL in NAME table."


@check(
    id = 'com.google.fonts/check/name/description_max_length',
    rationale = """
        An old FontLab version had a bug which caused it to store copyright notices
        in nameID 10 entries.

        In order to detect those and distinguish them from actual legitimate usage of
        this name table entry, we expect that such strings do not exceed a reasonable
        length of 200 chars.

        Longer strings are likely instances of the FontLab bug.
    """,
    proposal = 'legacy:check/032'
)
def com_google_fonts_check_name_description_max_length(ttFont):
    """Description strings in the name table must not exceed 200 characters."""
    failed = False
    for name in ttFont['name'].names:
        if (name.nameID == NameID.DESCRIPTION and
            len(name.string.decode(name.getEncoding())) > 200):
            failed = True
            break

    if failed:
        yield WARN,\
              Message("too-long",
                      f"A few name table entries with ID={NameID.DESCRIPTION}"
                      f" (NameID.DESCRIPTION) are longer than 200 characters."
                      f" Please check whether those entries are copyright"
                      f" notices mistakenly stored in the description"
                      f" string entries by a bug in an old FontLab version."
                      f" If that's the case, then such copyright notices"
                      f" must be removed from these entries.")
    else:
        yield PASS, "All description name records have reasonably small lengths."


@check(
    id = 'com.google.fonts/check/hinting_impact',
    conditions = ['hinting_stats'],
    rationale = """
        This check is merely informative, displaying and useful comparison of filesizes
        of hinted versus unhinted font files.
    """,
    proposal = 'legacy:check/054'
)
def com_google_fonts_check_hinting_impact(font, hinting_stats):
    """Show hinting filesize impact."""
    hinted = hinting_stats["hinted_size"]
    dehinted = hinting_stats["dehinted_size"]
    increase = hinted - dehinted
    change = (float(hinted)/dehinted - 1) * 100

    hinted_size = filesize_formatting(hinted)
    dehinted_size = filesize_formatting(dehinted)
    increase = filesize_formatting(increase)

    yield INFO,\
          Message("size-impact",
                  f"Hinting filesize impact:\n"
                  f"\n"
                  f" |               | {font}          |\n"
                  f" |:------------- | ---------------:|\n"
                  f" | Dehinted Size | {dehinted_size} |\n"
                  f" | Hinted Size   | {hinted_size}   |\n"
                  f" | Increase      | {increase}      |\n"
                  f" | Change        | {change:.1f} %  |\n")


@check(
    id = 'com.google.fonts/check/file_size',
    rationale = """
        Serving extremely large font files on Google Fonts causes usability issues.
        This check ensures that file sizes are reasonable.
    """,
    severity = 10,
    proposal = 'https://github.com/googlefonts/fontbakery/issues/3320',
    configs = ["WARN_SIZE",
               "FAIL_SIZE"]
)
def com_google_fonts_check_file_size(font):
    """Ensure files are not too large."""
    size = os.stat(font).st_size
    if size > FAIL_SIZE:
        yield FAIL,\
              Message("massive-font",
                      f"Font file is {filesize_formatting(size)}, "
                      f"larger than limit {filesize_formatting(FAIL_SIZE)}")
    elif size > WARN_SIZE:
        yield WARN,\
              Message("large-font",
                      f"Font file is {filesize_formatting(size)}; "
                      f"ideally it should be less than {filesize_formatting(WARN_SIZE)}")
    else:
        yield PASS, "Font had a reasonable file size"


@check(
    id = 'com.google.fonts/check/name/version_format',
    proposal = 'legacy:check/055'
)
def com_google_fonts_check_name_version_format(ttFont):
    """Version format is correct in 'name' table?"""
    from fontbakery.utils import get_name_entry_strings
    import re
    def is_valid_version_format(value):
        return re.match(r'Version\s0*[1-9][0-9]*\.\d+', value)

    failed = False
    version_entries = get_name_entry_strings(ttFont, NameID.VERSION_STRING)
    if len(version_entries) == 0:
        failed = True
        yield FAIL,\
              Message("no-version-string",
                      f"Font lacks a NameID.VERSION_STRING"
                      f" (nameID={NameID.VERSION_STRING}) entry")
    for ventry in version_entries:
        if not is_valid_version_format(ventry):
            failed = True
            yield FAIL,\
                  Message("bad-version-strings",
                          f'The NameID.VERSION_STRING'
                          f' (nameID={NameID.VERSION_STRING}) value must'
                          f' follow the pattern "Version X.Y" with X.Y'
                          f' greater than or equal to 1.000.'
                          f' Current version string is: "{ventry}"')
    if not failed:
        yield PASS, "Version format in NAME table entries is correct."


@check(
    id = 'com.google.fonts/check/has_ttfautohint_params',
    proposal = 'https://github.com/googlefonts/fontbakery/issues/1773'
)
def com_google_fonts_check_has_ttfautohint_params(ttFont):
    """Font has ttfautohint params?"""
    from fontbakery.utils import get_name_entry_strings

    def ttfautohint_version(value):
        # example string:
        #'Version 1.000; ttfautohint (v0.93) -l 8 -r 50 -G 200 -x 14 -w "G"
        import re
        results = re.search(r'ttfautohint \(v(.*)\) ([^;]*)', value)
        if results:
            return results.group(1), results.group(2)

    version_strings = get_name_entry_strings(ttFont, NameID.VERSION_STRING)
    failed = True
    for vstring in version_strings:
        values = ttfautohint_version(vstring)
        if values:
            ttfa_version, params = values
            if params:
                yield PASS,\
                      Message("ok",
                              f"Font has ttfautohint params ({params})")
                failed = False
        else:
            yield SKIP,\
                  Message("not-hinted",
                          "Font appears to our heuristic as"
                          " not hinted using ttfautohint.")
            failed = False

    if failed:
        yield FAIL,\
              Message("lacks-ttfa-params",
                      "Font is lacking ttfautohint params on its"
                      " version strings on the name table.")


@check(
    id = 'com.google.fonts/check/old_ttfautohint',
    conditions = ['is_ttf'],
    rationale = """
        Check if font has been hinted with an outdated version of ttfautohint.
    """,
    proposal = 'legacy:check/056'
)
def com_google_fonts_check_old_ttfautohint(ttFont):
    """Font has old ttfautohint applied?"""
    from fontbakery.utils import get_name_entry_strings

    def ttfautohint_version(values):
        import re
        for value in values:
            results = re.search(r'ttfautohint \(v(.*)\)', value)
            if results:
                return results.group(1)

    version_strings = get_name_entry_strings(ttFont, NameID.VERSION_STRING)
    ttfa_version = ttfautohint_version(version_strings)
    if len(version_strings) == 0:
        yield FAIL,\
              Message("lacks-version-strings",
                      "This font file lacks mandatory "
                      "version strings in its name table.")
    elif ttfa_version is None:
        yield INFO,\
              Message("version-not-detected",
                      f"Could not detect which version of"
                      f" ttfautohint was used in this font."
                      f" It is typically specified as a comment"
                      f" in the font version entries of the 'name' table."
                      f" Such font version strings are currently:"
                      f" {version_strings}")
    else:
        try:
            if LATEST_TTFAUTOHINT_VERSION > ttfa_version:
                yield WARN,\
                      Message("old-ttfa",
                              f"ttfautohint used in font = {ttfa_version};"
                              f" latest = {LATEST_TTFAUTOHINT_VERSION};"
                              f" Need to re-run with the newer version!")
            else:
                yield PASS, (f"Font has been hinted with ttfautohint {ttfa_version}"
                             f" which is greater than or equal to the latest"
                             f" known version {LATEST_TTFAUTOHINT_VERSION}")
        except ValueError:
            yield FAIL,\
                  Message("parse-error",
                          f"Failed to parse ttfautohint version values:"
                          f" latest = '{LATEST_TTFAUTOHINT_VERSION}';"
                          f" used_in_font = '{ttfa_version}'")


@check(
    id = 'com.google.fonts/check/epar',
    rationale = """
        The EPAR table is/was a way of expressing common licensing permissions and
        restrictions in metadata; while almost nothing supported it, Dave Crossland
        wonders that adding it to everything in Google Fonts could help make it
        more popular.

        More info is available at:
        https://davelab6.github.io/epar/
    """,
    severity = 1,
    proposal = 'https://github.com/googlefonts/fontbakery/issues/226'
)
def com_google_fonts_check_epar(ttFont):
    """EPAR table present in font?"""

    if "EPAR" not in ttFont:
        yield INFO,\
              Message("lacks-EPAR",
                      "EPAR table not present in font. To learn more see"
                      " https://github.com/googlefonts/fontbakery/issues/818")
    else:
        yield PASS, "EPAR table present in font."


@check(
    id = 'com.google.fonts/check/gasp',
    conditions = ['is_ttf'],
    rationale = """
        Traditionally version 0 'gasp' tables were set so that font sizes below 8 ppem
        had no grid fitting but did have antialiasing. From 9-16 ppem, just grid fitting.
        And fonts above 17ppem had both antialiasing and grid fitting toggled on.
        The use of accelerated graphics cards and higher resolution screens make this
        approach obsolete. Microsoft's DirectWrite pushed this even further with much
        improved rendering built into the OS and apps.

        In this scenario it makes sense to simply toggle all 4 flags ON for all font sizes.
    """,
    proposal = 'legacy:check/062'
)
def com_google_fonts_check_gasp(ttFont):
    """Is the Grid-fitting and Scan-conversion Procedure ('gasp') table
       set to optimize rendering?"""

    NON_HINTING_MESSAGE = ("If you are dealing with an unhinted font,"
                           " it can be fixed by running the fonts through"
                           " the command 'gftools fix-nonhinting'\n"
                           "GFTools is available at"
                           " https://pypi.org/project/gftools/")

    if "gasp" not in ttFont.keys():
        yield FAIL,\
              Message("lacks-gasp",
                      "Font is missing the 'gasp' table."
                      " Try exporting the font with autohinting enabled.\n" + \
                      NON_HINTING_MESSAGE)
    else:
        if not isinstance(ttFont["gasp"].gaspRange, dict):
            yield FAIL,\
                  Message("empty",
                          "The 'gasp' table has no values.\n" + \
                          NON_HINTING_MESSAGE)
        else:
            failed = False
            if 0xFFFF not in ttFont["gasp"].gaspRange:
                yield WARN,\
                      Message("lacks-ffff-range",
                              "The 'gasp' table does not have an entry"
                              " that applies for all font sizes."
                              " The gaspRange value for such entry should"
                              " be set to 0xFFFF.")
            else:
                gasp_meaning = {
                    0x01: "- Use grid-fitting",
                    0x02: "- Use grayscale rendering",
                    0x04: "- Use gridfitting with ClearType symmetric smoothing",
                    0x08: "- Use smoothing along multiple axes with ClearType®"
                }
                table = []
                for key in ttFont["gasp"].gaspRange.keys():
                    value = ttFont["gasp"].gaspRange[key]
                    meaning = []
                    for flag, info in gasp_meaning.items():
                        if value & flag:
                            meaning.append(info)

                    meaning = "\n\t".join(meaning)
                    table.append(f"PPM <= {key}:\n\tflag = 0x{value:02X}\n\t{meaning}")

                table = "\n".join(table)
                yield INFO,\
                      Message("ranges",
                              f"These are the ppm ranges declared on"
                              f" the gasp table:\n\n{table}\n")

                for key in ttFont["gasp"].gaspRange.keys():
                    if key != 0xFFFF:
                        yield WARN,\
                              Message("non-ffff-range",
                                      f"The gasp table has a range of {key}"
                                      f" that may be unneccessary.")
                        failed = True
                    else:
                        value = ttFont["gasp"].gaspRange[0xFFFF]
                        if value != 0x0F:
                            failed = True
                            yield WARN,\
                                  Message("unset-flags",
                                          f"The gasp range 0xFFFF value 0x{value:02X}"
                                          f" should be set to 0x0F.")
                if not failed:
                    yield PASS, ("The 'gasp' table is correctly set, with one "
                                 "gaspRange:value of 0xFFFF:0x0F.")


@check(
    id = 'com.google.fonts/check/name/familyname_first_char',
    rationale = """
        Font family names which start with a numeral are often not discoverable
        in Windows applications.
    """,
    proposal = 'legacy:check/067'
)
def com_google_fonts_check_name_familyname_first_char(ttFont):
    """Make sure family name does not begin with a digit."""
    from fontbakery.utils import get_name_entry_strings
    failed = False
    for familyname in get_name_entry_strings(ttFont, NameID.FONT_FAMILY_NAME):
        digits = map(str, range(0, 10))
        if familyname[0] in digits:
            yield FAIL,\
                  Message("begins-with-digit",
                          f"Font family name '{familyname}' begins with a digit!")
            failed = True
    if failed is False:
        yield PASS, "Font family name first character is not a digit."


@check(
    id = 'com.google.fonts/check/name/ascii_only_entries',
    rationale = """
        The OpenType spec requires ASCII for the POSTSCRIPT_NAME (nameID 6).

        For COPYRIGHT_NOTICE (nameID 0) ASCII is required because that string should be
        the same in CFF fonts which also have this requirement in the OpenType spec.

        Note:
        A common place where we find non-ASCII strings is on name table entries
        with NameID > 18, which are expressly for localising the ASCII-only IDs
        into Hindi / Arabic / etc.
    """,
    proposal = ['legacy:check/074',
                'https://github.com/googlefonts/fontbakery/issues/1663']
)
def com_google_fonts_check_name_ascii_only_entries(ttFont):
    """Are there non-ASCII characters in ASCII-only NAME table entries?"""
    bad_entries = []
    for name in ttFont["name"].names:
        if name.nameID == NameID.COPYRIGHT_NOTICE or \
           name.nameID == NameID.POSTSCRIPT_NAME:
            string = name.string.decode(name.getEncoding())
            try:
                string.encode('ascii')
            except:
                bad_entries.append(name)
                badstring = string.encode("ascii",
                                          errors='xmlcharrefreplace')
                yield FAIL,\
                      Message("bad-string",
                              (f"Bad string at"
                               f" [nameID {name.nameID}, '{name.getEncoding()}']:"
                               f" '{badstring}'"))
    if len(bad_entries) > 0:
        yield FAIL,\
              Message("non-ascii-strings",
                      (f"There are {len(bad_entries)} strings containing"
                        " non-ASCII characters in the ASCII-only"
                        " NAME table entries."))
    else:
        yield PASS, ("None of the ASCII-only NAME table entries"
                     " contain non-ASCII characteres.")


@check(
    id = 'com.google.fonts/check/metadata/listed_on_gfonts',
    conditions = ['family_metadata'],
    proposal = 'legacy:check/082'
)
def com_google_fonts_check_metadata_listed_on_gfonts(font, listed_on_gfonts_api):
    """METADATA.pb: Fontfamily is listed on Google Fonts API?"""
    if not listed_on_gfonts_api:
        yield WARN,\
              Message("not-found",
                      "Family not found via Google Fonts API.")
    else:
        yield PASS, "Font is properly listed via Google Fonts API."


@check(
    id = 'com.google.fonts/check/metadata/unique_full_name_values',
    conditions = ['family_metadata'],
    proposal = 'legacy:check/083'
)
def com_google_fonts_check_metadata_unique_full_name_values(family_metadata):
    """METADATA.pb: check if fonts field only has
       unique "full_name" values.
    """
    fonts = {}
    for f in family_metadata.fonts:
        fonts[f.full_name] = f

    if len(set(fonts.keys())) != len(family_metadata.fonts):
        yield FAIL,\
              Message("duplicated",
                      'Found duplicated "full_name" values'
                      ' in METADATA.pb fonts field.')
    else:
        yield PASS, ('METADATA.pb "fonts" field only has'
                     ' unique "full_name" values.')


@check(
    id = 'com.google.fonts/check/metadata/unique_weight_style_pairs',
    conditions = ['family_metadata'],
    proposal = 'legacy:check/084'
)
def com_google_fonts_check_metadata_unique_weight_style_pairs(family_metadata):
    """METADATA.pb: check if fonts field
       only contains unique style:weight pairs.
    """
    pairs = {}
    for f in family_metadata.fonts:
        styleweight = f"{f.style}:{f.weight}"
        pairs[styleweight] = 1
    if len(set(pairs.keys())) != len(family_metadata.fonts):
        yield FAIL,\
              Message("duplicated",
                      "Found duplicated style:weight pair"
                      " in METADATA.pb fonts field.")
    else:
        yield PASS, ("METADATA.pb \"fonts\" field only has"
                     " unique style:weight pairs.")


@check(
    id = 'com.google.fonts/check/metadata/license',
    conditions = ['family_metadata'],
    proposal = 'legacy:check/085'
)
def com_google_fonts_check_metadata_license(family_metadata):
    """METADATA.pb license is "APACHE2", "UFL" or "OFL"?"""
    expected_licenses = ["APACHE2", "OFL", "UFL"]
    if family_metadata.license in expected_licenses:
        yield PASS, (f'Font license is declared in METADATA.pb'
                     f' as "{family_metadata.license}"')
    else:
        yield FAIL,\
              Message("bad-license",
                      f'METADATA.pb license field ("{family_metadata.license}")'
                      f' must be one of the following: {expected_licenses}')


@check(
    id = 'com.google.fonts/check/metadata/menu_and_latin',
    conditions = ['family_metadata'],
    proposal = ['legacy:check/086',
                'https://github.com/googlefonts/fontbakery/issues/912#issuecomment-237935444']
)
def com_google_fonts_check_metadata_menu_and_latin(family_metadata):
    """METADATA.pb should contain at least "menu" and "latin" subsets."""
    missing = []
    for s in ["menu", "latin"]:
        if s not in list(family_metadata.subsets):
            missing.append(s)

    if missing != []:
        if len(missing) == 2:
            missing = "both"
        else:
            missing = f'"{missing[0]}"'

        yield FAIL,\
              Message("missing",
                      f'Subsets "menu" and "latin" are mandatory,'
                      f' but METADATA.pb is missing {missing}.')
    else:
        yield PASS, 'METADATA.pb contains "menu" and "latin" subsets.'


@check(
    id = 'com.google.fonts/check/metadata/subsets_order',
    conditions = ['family_metadata'],
    proposal = 'legacy:check/087'
)
def com_google_fonts_check_metadata_subsets_order(family_metadata):
    """METADATA.pb subsets should be alphabetically ordered."""
    expected = list(sorted(family_metadata.subsets))

    if list(family_metadata.subsets) != expected:
        yield FAIL,\
              Message("not-sorted",
                      ("METADATA.pb subsets are not sorted "
                       "in alphabetical order: Got ['{}']"
                       " and expected ['{}']"
                       "").format("', '".join(family_metadata.subsets),
                                  "', '".join(expected)))
    else:
        yield PASS, "METADATA.pb subsets are sorted in alphabetical order."


@check(
    id = 'com.google.fonts/check/metadata/includes_production_subsets',
    conditions = ['family_metadata',
                  'production_metadata',
                  'listed_on_gfonts_api'],
    rationale = """
        Check METADATA.pb file includes the same subsets as the family in production.
    """,
    proposal = 'https://github.com/googlefonts/fontbakery/issues/2989'
)
def com_google_fonts_check_metadata_includes_production_subsets(family_metadata,
                                                                production_metadata):
    """Check METADATA.pb includes production subsets."""
    prod_families_metadata = {i['family']: i for i in production_metadata["familyMetadataList"]}
    prod_family_metadata = prod_families_metadata[family_metadata.name]

    prod_subsets = set(prod_family_metadata["subsets"])
    local_subsets = set(family_metadata.subsets)
    missing_subsets = prod_subsets - local_subsets
    if len(missing_subsets) > 0:
        yield FAIL,\
              Message("missing-subsets",
                      f"The following subsets are missing [{', '.join(sorted(missing_subsets))}]")
    else:
        yield PASS, "No missing subsets"


@check(
    id = 'com.google.fonts/check/metadata/copyright',
    conditions = ['family_metadata'],
    proposal = 'legacy:check/088'
)
def com_google_fonts_check_metadata_copyright(family_metadata):
    """METADATA.pb: Copyright notice is the same in all fonts?"""
    copyright = None
    fail = False
    for f in family_metadata.fonts:
        if copyright and f.copyright != copyright:
            fail = True
        copyright = f.copyright
    if fail:
        yield FAIL,\
              Message("inconsistency",
                      "METADATA.pb: Copyright field value"
                      " is inconsistent across family")
    else:
        yield PASS, "Copyright is consistent across family"


@check(
    id = 'com.google.fonts/check/metadata/familyname',
    conditions = ['family_metadata'],
    proposal = 'legacy:check/089'
)
def com_google_fonts_check_metadata_familyname(family_metadata):
    """Check that METADATA.pb family values are all the same."""
    name = ""
    fail = False
    for f in family_metadata.fonts:
        if name and f.name != name:
            fail = True
        name = f.name
    if fail:
        yield FAIL,\
              Message("inconsistency",
                      'METADATA.pb: Family name is not the same'
                      ' in all metadata "fonts" items.')
    else:
        yield PASS, ('METADATA.pb: Family name is the same'
                     ' in all metadata "fonts" items.')


@check(
    id = 'com.google.fonts/check/metadata/has_regular',
    conditions = ['family_metadata'],
    proposal = 'legacy:check/090'
)
def com_google_fonts_check_metadata_has_regular(family_metadata):
    """METADATA.pb: According to Google Fonts standards,
       families should have a Regular style.
    """
    from .googlefonts_conditions import has_regular_style

    if has_regular_style(family_metadata):
        yield PASS, "Family has a Regular style."
    else:
        yield FAIL,\
              Message("lacks-regular",
                      "This family lacks a Regular"
                      " (style: normal and weight: 400)"
                      " as required by Google Fonts standards."
                      " If family consists of a single-weight non-Regular style only,"
                      " consider the Google Fonts specs for this case:"
                      " https://github.com/googlefonts/gf-docs/tree/main/Spec#single-weight-families")


@check(
    id = 'com.google.fonts/check/metadata/regular_is_400',
    conditions = ['family_metadata',
                  'has_regular_style'],
    proposal = 'legacy:check/091'
)
def com_google_fonts_check_metadata_regular_is_400(family_metadata):
    """METADATA.pb: Regular should be 400."""
    badfonts = []
    for f in family_metadata.fonts:
        if f.full_name.endswith("Regular") and f.weight != 400:
            badfonts.append(f"{f.filename} (weight: {f.weight})")
    if len(badfonts) > 0:
        yield FAIL,\
              Message("not-400",
                      f'METADATA.pb: Regular font weight must be 400.'
                      f' Please fix these: {", ".join(badfonts)}')
    else:
        yield PASS, "Regular has weight = 400."


@check(
    id = 'com.google.fonts/check/metadata/nameid/family_name',
    conditions = ['font_metadata'],
    proposal = 'legacy:check/092'
)
def com_google_fonts_check_metadata_nameid_family_name(ttFont, font_metadata):
    """Checks METADATA.pb font.name field matches
       family name declared on the name table.
    """
    from fontbakery.utils import get_name_entry_strings

    familynames = get_name_entry_strings(ttFont, NameID.TYPOGRAPHIC_FAMILY_NAME)
    if not familynames:
        familynames = get_name_entry_strings(ttFont, NameID.FONT_FAMILY_NAME)
    if len(familynames) == 0:
        yield FAIL,\
              Message("missing",
                      (f"This font lacks a FONT_FAMILY_NAME entry"
                       f" (nameID = {NameID.FONT_FAMILY_NAME})"
                       f" in the name table."))
    else:
        if font_metadata.name not in familynames:
            yield FAIL,\
                  Message("mismatch",
                          (f'Unmatched family name in font:'
                           f' TTF has "{familynames[0]}" while METADATA.pb'
                           f' has "{font_metadata.name}"'))
        else:
            yield PASS, (f'Family name "{font_metadata.name}" is identical'
                         f' in METADATA.pb and on the TTF file.')

@check(
    id = 'com.google.fonts/check/metadata/nameid/post_script_name',
    conditions = ['font_metadata'],
    proposal = 'legacy:093'
)
def com_google_fonts_check_metadata_nameid_post_script_name(ttFont, font_metadata):
    """Checks METADATA.pb font.post_script_name matches
       postscript name declared on the name table.
    """
    failed = False
    from fontbakery.utils import get_name_entry_strings

    postscript_names = get_name_entry_strings(ttFont, NameID.POSTSCRIPT_NAME)
    if len(postscript_names) == 0:
        failed = True
        yield FAIL,\
              Message("missing",
                      (f"This font lacks a POSTSCRIPT_NAME entry"
                       f" (nameID = {NameID.POSTSCRIPT_NAME})"
                       f" in the name table."))
    else:
        for psname in postscript_names:
            if psname != font_metadata.post_script_name:
                failed = True
                yield FAIL,\
                      Message("mismatch",
                              (f'Unmatched postscript name in font:'
                               f' TTF has "{psname}" while METADATA.pb has'
                               f' "{font_metadata.post_script_name}".'))
    if not failed:
        yield PASS, (f'Postscript name "{font_metadata.post_script_name}"'
                     f' is identical in METADATA.pb and on the TTF file.')


@check(
    id = 'com.google.fonts/check/metadata/nameid/full_name',
    conditions = ['font_metadata'],
    proposal = 'legacy:check/094'
)
def com_google_fonts_check_metadata_nameid_full_name(ttFont, font_metadata):
    """METADATA.pb font.full_name value matches
       fullname declared on the name table?
    """
    from fontbakery.utils import get_name_entry_strings

    full_fontnames = get_name_entry_strings(ttFont, NameID.FULL_FONT_NAME)
    if len(full_fontnames) == 0:
        yield FAIL,\
              Message("lacks-entry",
                      (f"This font lacks a FULL_FONT_NAME entry"
                       f" (nameID = {NameID.FULL_FONT_NAME})"
                       f" in the name table."))
    else:
        for full_fontname in full_fontnames:
            if full_fontname != font_metadata.full_name:
                yield FAIL,\
                      Message("mismatch",
                              (f'Unmatched fullname in font:'
                               f' TTF has "{full_fontname}" while METADATA.pb'
                               f' has "{font_metadata.full_name}".'))
            else:
                yield PASS, (f'Font fullname "{full_fontname}" is identical'
                             f' in METADATA.pb and on the TTF file.')


@check(
    id = 'com.google.fonts/check/metadata/nameid/font_name',
    conditions = ['font_metadata',
                  'style'],
    proposal = 'legacy:check/095'
)
def com_google_fonts_check_metadata_nameid_font_name(ttFont, style, font_metadata):
    """METADATA.pb font.name value should be same as
       the family name declared on the name table.
    """
    from fontbakery.utils import get_name_entry_strings
    from fontbakery.constants import RIBBI_STYLE_NAMES

    if style in RIBBI_STYLE_NAMES:
        font_familynames = get_name_entry_strings(ttFont, NameID.FONT_FAMILY_NAME)
        nameid = NameID.FONT_FAMILY_NAME
    else:
        font_familynames = get_name_entry_strings(ttFont, NameID.TYPOGRAPHIC_FAMILY_NAME)
        nameid = NameID.TYPOGRAPHIC_FAMILY_NAME

    if len(font_familynames) == 0:
        yield FAIL,\
              Message("lacks-entry",
                      f"This font lacks a {NameID(nameid).name} entry"
                      f" (nameID = {nameid}) in the name table.")
    else:
        for font_familyname in font_familynames:
            if font_familyname != font_metadata.name:
                yield FAIL,\
                      Message("mismatch",
                              f'Unmatched familyname in font:'
                              f' TTF has familyname = "{font_familyname}" while'
                              f' METADATA.pb has font.name = "{font_metadata.name}".')
            else:
                yield PASS, (f'OK: Family name "{font_metadata.name}" is identical'
                             f' in METADATA.pb and on the TTF file.')


@check(
    id = 'com.google.fonts/check/metadata/match_fullname_postscript',
    conditions = ['font_metadata'],
    proposal = 'legacy:check/096'
)
def com_google_fonts_check_metadata_match_fullname_postscript(font_metadata):
    """METADATA.pb font.full_name and font.post_script_name
       fields have equivalent values ?
    """
    import re
    regex = re.compile(r"\W")
    post_script_name = regex.sub("", font_metadata.post_script_name)
    fullname = regex.sub("", font_metadata.full_name)
    if fullname != post_script_name:
        yield FAIL,\
              Message("mismatch",
                      f'METADATA.pb font full_name = "{font_metadata.full_name}"'
                      f' does not match'
                      f' post_script_name = "{font_metadata.post_script_name}"')
    else:
        yield PASS, ('METADATA.pb font fields "full_name" and'
                     ' "post_script_name" have equivalent values.')


@check(
    id = 'com.google.fonts/check/metadata/match_filename_postscript',
    conditions = ['font_metadata',
                  'not is_variable_font'],
    # FIXME: We'll want to review this once
    #        naming rules for varfonts are settled.
    proposal = 'legacy:check/097'
)
def com_google_fonts_check_metadata_match_filename_postscript(font_metadata):
    """METADATA.pb font.filename and font.post_script_name
       fields have equivalent values?
    """
    post_script_name = font_metadata.post_script_name
    filename = os.path.splitext(font_metadata.filename)[0]

    if filename != post_script_name:
        yield FAIL,\
              Message("mismatch",
                      f'METADATA.pb font filename = "{font_metadata.filename}"'
                      f' does not match'
                      f' post_script_name="{font_metadata.post_script_name}".')
    else:
        yield PASS, ('METADATA.pb font fields "filename" and'
                     ' "post_script_name" have equivalent values.')


@check(
    id = 'com.google.fonts/check/metadata/valid_name_values',
    conditions = ['style',
                  'font_metadata'],
    proposal = 'legacy:check/098'
)
def com_google_fonts_check_metadata_valid_name_values(style,
                                                      font_metadata,
                                                      font_familynames,
                                                      typographic_familynames):
    """METADATA.pb font.name field contains font name in right format?"""
    from fontbakery.constants import RIBBI_STYLE_NAMES
    if style in RIBBI_STYLE_NAMES:
        familynames = font_familynames
    else:
        familynames = typographic_familynames

    failed = False
    for font_familyname in familynames:
        if font_familyname not in font_metadata.name:
            failed = True
            yield FAIL,\
                  Message("mismatch",
                          f'METADATA.pb font.name field ("{font_metadata.name}")'
                          f' does not match'
                          f' correct font name format ("{font_familyname}").')
    if not failed:
        yield PASS, ("METADATA.pb font.name field contains"
                     " font name in right format.")


@check(
    id = 'com.google.fonts/check/metadata/valid_full_name_values',
    conditions = ['style',
                  'font_metadata'],
    proposal = 'legacy:check/099'
)
def com_google_fonts_check_metadata_valid_full_name_values(style,
                                                           font_metadata,
                                                           font_familynames,
                                                           typographic_familynames):
    """METADATA.pb font.full_name field contains font name in right format?"""
    from fontbakery.constants import RIBBI_STYLE_NAMES
    if style in RIBBI_STYLE_NAMES:
        familynames = font_familynames
        if familynames == []:
            yield SKIP, "No FONT_FAMILYNAME"
    else:
        familynames = typographic_familynames
        if familynames == []:
            yield SKIP, "No TYPOGRAPHIC_FAMILYNAME"

    for font_familyname in familynames:
        if font_familyname in font_metadata.full_name:
            yield PASS, (f'METADATA.pb font.full_name field contains'
                         f' font name in right format.'
                         f' ("{font_familyname}" in "{font_metadata.full_name}")')
        else:
            yield FAIL,\
                  Message("mismatch",
                          f'METADATA.pb font.full_name field'
                          f' ("{font_metadata.full_name}")'
                          f' does not match correct font name format'
                          f' ("{font_familyname}").')


@check(
    id = 'com.google.fonts/check/metadata/valid_filename_values',
    conditions = ['style', # This means the font filename
                           # (source of truth here) is good
                  'family_metadata'],
    proposal = 'legacy:check/100'
)
def com_google_fonts_check_metadata_valid_filename_values(font,
                                                          family_metadata):
    """METADATA.pb font.filename field contains font name in right format?"""
    expected = os.path.basename(font)
    failed = True
    for font_metadata in family_metadata.fonts:
        if font_metadata.filename == expected:
            failed = False
            yield PASS, ("METADATA.pb filename field contains"
                         " font name in right format.")
            break
    if failed:
        yield FAIL,\
              Message("bad-field",
                      f'None of the METADATA.pb filename fields match'
                      f' correct font name format ("{expected}").')


@check(
    id = 'com.google.fonts/check/metadata/valid_post_script_name_values',
    conditions = ['font_metadata',
                  'font_familynames'],
    proposal = 'legacy:check/101'
)
def com_google_fonts_check_metadata_valid_post_script_name_values(font_metadata,
                                                                  font_familynames):
    """METADATA.pb font.post_script_name field
       contains font name in right format?
    """
    for font_familyname in font_familynames:
        psname = "".join(str(font_familyname).split())
        if psname in "".join(font_metadata.post_script_name.split("-")):
            yield PASS, ("METADATA.pb postScriptName field"
                         " contains font name in right format.")
        else:
            yield FAIL,\
                  Message("mismatch",
                          f'METADATA.pb'
                          f' postScriptName ("{font_metadata.post_script_name}")'
                          f' does not match'
                          f' correct font name format ("{font_familyname}").')


EXPECTED_COPYRIGHT_PATTERN = \
r'copyright [0-9]{4}(\-[0-9]{4})? (the .* project authors \([^\@]*\)|google llc. all rights reserved)'

@check(
    id = 'com.google.fonts/check/metadata/valid_copyright',
    conditions = ['font_metadata'],
    rationale = """
        The expected pattern for the copyright string adheres to the following rules:
        
        * It must say "Copyright" followed by a 4 digit year (optionally followed by
          a hyphen and another 4 digit year)

        * Then it must say "The <familyname> Project Authors"

        * And within parentheses, a URL for a git repository must be provided

        * The check is case insensitive and does not validate whether the familyname
          is correct, even though we'd expect it is (and we may soon update the check
          to validate that aspect as well!)


        Here is an example of a valid copyright string:

        "Copyright 2017 The Archivo Black Project Authors
         (https://github.com/Omnibus-Type/ArchivoBlack)"
    """,
    proposal = 'legacy:check/102'
)
def com_google_fonts_check_metadata_valid_copyright(font_metadata):
    """Copyright notices match canonical pattern in METADATA.pb"""
    import re

    string = font_metadata.copyright.lower()
    if re.search(EXPECTED_COPYRIGHT_PATTERN, string):
        yield PASS, "METADATA.pb copyright string is good"
    else:
        yield FAIL,\
              Message("bad-notice-format",
                      f'METADATA.pb: Copyright notices should match'
                      f' a pattern similar to:\n'
                      f' "Copyright 2020 The Familyname Project Authors (git url)"'
                      f'\n'
                      f'But instead we have got:\n"{string}"')


@check(
    id = 'com.google.fonts/check/font_copyright',
    proposal = 'https://github.com/googlefonts/fontbakery/pull/2383'
)
def com_google_fonts_check_font_copyright(ttFont):
    """Copyright notices match canonical pattern in fonts"""
    import re
    from fontbakery.utils import get_name_entry_strings

    failed = False
    for string in get_name_entry_strings(ttFont, NameID.COPYRIGHT_NOTICE):
        if re.search(EXPECTED_COPYRIGHT_PATTERN, string.lower()):
            yield PASS, (f"Name Table entry: Copyright field '{string}'"
                         f" matches canonical pattern.")
        else:
            failed = True
            yield FAIL,\
                  Message("bad-notice-format",
                          f'Name Table entry: Copyright notices should match'
                          f' a pattern similar to: "Copyright 2019'
                          f' The Familyname Project Authors (git url)"\n'
                          f'But instead we have got:\n"{string}"')
    if not failed:
        yield PASS, "Name table copyright entries are good"


@disable
@check(
    id = 'com.google.fonts/check/glyphs_file/font_copyright'
)
def com_google_fonts_check_glyphs_file_font_copyright(glyphsFile):
    """Copyright notices match canonical pattern in fonts"""
    import re

    string = glyphsFile.copyright.lower()
    if re.search(EXPECTED_COPYRIGHT_PATTERN, string):
        yield PASS, (f"Name Table entry: Copyright field '{string}'"
                     f" matches canonical pattern.")
    else:
        yield FAIL,\
              Message("bad-notice-format",
                      f'Copyright notices should match'
                      f' a pattern similar to: "Copyright 2019'
                      f' The Familyname Project Authors (git url)"\n'
                      f'But instead we have got:\n"{string}"')


@check(
    id = 'com.google.fonts/check/metadata/reserved_font_name',
    conditions = ['font_metadata',
                  'not rfn_exception'],
    proposal = 'legacy:check/103'
)
def com_google_fonts_check_metadata_reserved_font_name(font_metadata):
    """Copyright notice on METADATA.pb should not contain 'Reserved Font Name'."""
    if "Reserved Font Name" in font_metadata.copyright:
        yield WARN,\
              Message("rfn",
                      f'METADATA.pb:'
                      f' copyright field ("{font_metadata.copyright}")'
                      f' contains "Reserved Font Name".'
                      f' This is an error except in a few specific rare cases.')
    else:
        yield PASS, ('METADATA.pb copyright field'
                     ' does not contain "Reserved Font Name".')


@check(
    id = 'com.google.fonts/check/metadata/copyright_max_length',
    conditions = ['font_metadata'],
    proposal = 'legacy:check/104'
)
def com_google_fonts_check_metadata_copyright_max_length(font_metadata):
    """METADATA.pb: Copyright notice shouldn't exceed 500 chars."""
    if len(font_metadata.copyright) > 500:
        yield FAIL,\
              Message("max-length",
                      "METADATA.pb: Copyright notice exceeds"
                      " maximum allowed lengh of 500 characteres.")
    else:
        yield PASS, "Copyright notice string is shorter than 500 chars."


@check(
    id = 'com.google.fonts/check/metadata/filenames',
    rationale = """
        Note:
        This check only looks for files in the current directory.

        Font files in subdirectories are checked by these other two checks:
         - com.google.fonts/check/metadata/undeclared_fonts
         - com.google.fonts/check/repo/vf_has_static_fonts

        We may want to merge them all into a single check.
    """,
    conditions = ['family_metadata'],
    proposal = 'https://github.com/googlefonts/fontbakery/issues/2597'
)
def com_google_fonts_check_metadata_filenames(fonts, family_directory, family_metadata):
    """METADATA.pb: Font filenames match font.filename entries?"""

    passed = True
    metadata_filenames = []
    font_filenames = [f for f in os.listdir(family_directory) if f[-4:] in [".ttf", ".otf"]]
    for font_metadata in family_metadata.fonts:
        if font_metadata.filename not in font_filenames:
            passed = False
            yield FAIL,\
                  Message("file-not-found",
                          f'Filename "{font_metadata.filename}" is listed on'
                          f' METADATA.pb but an actual font file'
                          f' with that name was not found.')
        metadata_filenames.append(font_metadata.filename)

    for font in font_filenames:
        if font not in metadata_filenames:
            passed = False
            yield FAIL,\
                  Message("file-not-declared",
                          f'Filename "{font}" is not declared'
                          f' on METADATA.pb as a font.filename entry.')
    if passed:
        yield PASS, "Filenames in METADATA.pb look good."


@check(
    id = 'com.google.fonts/check/metadata/italic_style',
    conditions = ['font_metadata'],
    proposal = 'legacy:check/106'
)
def com_google_fonts_check_metadata_italic_style(ttFont, font_metadata):
    """METADATA.pb font.style "italic" matches font internals?"""
    from fontbakery.utils import get_name_entry_strings
    from fontbakery.constants import MacStyle

    if font_metadata.style != "italic":
        yield SKIP, "This check only applies to italic fonts."
    else:
        font_fullname = get_name_entry_strings(ttFont, NameID.FULL_FONT_NAME)
        if len(font_fullname) == 0:
            yield SKIP, "Font lacks fullname entries in name table."
            # this fail scenario was already checked above
            # (passing those previous checks is a prerequisite for this one)
            # FIXME: Could we pack this into a condition ?
        else:
            # FIXME: here we only check the first name entry.
            #        Should we iterate over them all ? Or should we check
            #        if they're all the same?
            font_fullname = font_fullname[0]

            if not bool(ttFont["head"].macStyle & MacStyle.ITALIC):
                yield FAIL,\
                      Message("bad-macstyle",
                              ("METADATA.pb style has been set to italic"
                               " but font macStyle is improperly set."))
            elif not font_fullname.split("-")[-1].endswith("Italic"):
                yield FAIL,\
                      Message("bad-fullfont-name",
                              (f'Font macStyle Italic bit is set'
                               f' but nameID {NameID.FULL_FONT_NAME}'
                               f' ("{font_fullname}") is not'
                               f' ended with "Italic".'))
            else:
                yield PASS, ('OK: METADATA.pb font.style "italic"'
                             ' matches font internals.')


@check(
    id = 'com.google.fonts/check/metadata/normal_style',
    conditions = ['font_metadata'],
    proposal = 'legacy:check/107'
)
def com_google_fonts_check_metadata_normal_style(ttFont, font_metadata):
    """METADATA.pb font.style "normal" matches font internals?"""
    from fontbakery.utils import get_name_entry_strings
    from fontbakery.constants import MacStyle

    if font_metadata.style != "normal":
        yield SKIP, "This check only applies to normal fonts."
        # FIXME: declare a common condition called "normal_style"
    else:
        font_familyname = get_name_entry_strings(ttFont, NameID.FONT_FAMILY_NAME)
        font_fullname = get_name_entry_strings(ttFont, NameID.FULL_FONT_NAME)
        if len(font_familyname) == 0 or len(font_fullname) == 0:
            yield SKIP, ("Font lacks familyname and/or"
                         " fullname entries in name table.")
            # FIXME: This is the same SKIP condition as in check/metadata/italic_style
            #        so we definitely need to address them with a common condition!
        else:
            font_familyname = font_familyname[0]
            font_fullname = font_fullname[0]

            if bool(ttFont["head"].macStyle & MacStyle.ITALIC):
                yield FAIL,\
                      Message("bad-macstyle",
                              ("METADATA.pb style has been set to normal"
                               " but font macStyle is improperly set."))
            elif font_familyname.split("-")[-1].endswith('Italic'):
                yield FAIL,\
                      Message("familyname-italic",
                              (f'Font macStyle indicates a non-Italic font,'
                               f' but nameID {NameID.FONT_FAMILY_NAME}'
                               f' (FONT_FAMILY_NAME: "{font_familyname}")'
                               f' ends with "Italic".'))
            elif font_fullname.split("-")[-1].endswith("Italic"):
                yield FAIL,\
                      Message("fullfont-italic",
                              (f'Font macStyle indicates a non-Italic font,'
                               f' but nameID {NameID.FULL_FONT_NAME}'
                               f' (FULL_FONT_NAME: "{font_fullname}")'
                               f' ends with "Italic".'))
            else:
                yield PASS, ('METADATA.pb font.style "normal"'
                             ' matches font internals.')


@check(
    id = 'com.google.fonts/check/metadata/nameid/family_and_full_names',
    conditions = ['font_metadata'],
    proposal = 'legacy:check/108'
)
def com_google_fonts_check_metadata_nameid_family_and_full_names(ttFont, font_metadata):
    """METADATA.pb font.name and font.full_name fields match
       the values declared on the name table?
    """
    from fontbakery.utils import get_name_entry_strings

    font_familynames = get_name_entry_strings(ttFont, NameID.TYPOGRAPHIC_FAMILY_NAME)
    if font_familynames:
        font_familyname = font_familynames[0]
    else:
        font_familyname = get_name_entry_strings(ttFont, NameID.FONT_FAMILY_NAME)[0]
    font_fullname = get_name_entry_strings(ttFont, NameID.FULL_FONT_NAME)[0]
    # FIXME: common condition/name-id check as in the two previous checks.

    if font_fullname != font_metadata.full_name:
        yield FAIL,\
              Message("fullname-mismatch",
                      (f'METADATA.pb: Fullname "{font_metadata.full_name}"'
                       f' does not match name table entry "{font_fullname}"!'))

    elif font_familyname != font_metadata.name:
        yield FAIL,\
              Message("familyname-mismatch",
                      (f'METADATA.pb Family name "{font_metadata.name}"'
                       f' does not match name table entry "{font_familyname}"!'))
    else:
        yield PASS, ("METADATA.pb familyname and fullName fields"
                     " match corresponding name table entries.")


@check(
    id = 'com.google.fonts/check/metadata/fontname_not_camel_cased',
    rationale = """
        We currently have a policy of avoiding camel-cased font family names other
        than in a very small set of exceptions.
        
        If you want to have your family name added to the exceptions list, please read
        the instructions at https://github.com/googlefonts/fontbakery/issues/3270
    """,
    conditions = ['font_metadata',
                  'not camelcased_familyname_exception'],
    proposal = 'legacy:check/109'
)
def com_google_fonts_check_metadata_fontname_not_camel_cased(font_metadata):
    """METADATA.pb: Check if fontname is not camel cased."""
    import re
    if bool(re.match(r'([A-Z][a-z]+){2,}', font_metadata.name)):
        yield FAIL,\
              Message("camelcase",
                      f'METADATA.pb: "{font_metadata.name}" is a CamelCased name.'
                      f' To solve this, simply use spaces'
                      f' instead in the font name.')
    else:
        yield PASS, "Font name is not camel-cased."


@check(
    id = 'com.google.fonts/check/metadata/match_name_familyname',
    conditions = ['family_metadata', # that's the family-wide metadata!
                  'font_metadata'],  # and this one's specific to a single file
    proposal = 'legacy:check/110'
)
def com_google_fonts_check_metadata_match_name_familyname(family_metadata, font_metadata):
    """METADATA.pb: Check font name is the same as family name."""
    if font_metadata.name != family_metadata.name:
        yield FAIL,\
              Message("mismatch",
                      f'METADATA.pb: {font_metadata.filename}:\n'
                      f' Family name "{family_metadata.name}"'
                      f' does not match'
                      f' font name: "{font_metadata.name}"')
    else:
        yield PASS, "Font name is the same as family name."


@check(
    id = 'com.google.fonts/check/metadata/canonical_weight_value',
    conditions = ['font_metadata'],
    proposal = 'legacy:check/111'
)
def com_google_fonts_check_metadata_canonical_weight_value(font_metadata):
    """METADATA.pb: Check that font weight has a canonical value."""
    first_digit = font_metadata.weight / 100
    if (font_metadata.weight % 100) != 0 or \
       (first_digit < 1 or first_digit > 9):
        yield FAIL,\
              Message("bad-weight",
                      f"METADATA.pb: The weight is declared"
                      f" as {font_metadata.weight} which is not a"
                      f" multiple of 100 between 100 and 900.")
    else:
        yield PASS, "Font weight has a canonical value."


@check(
    id = 'com.google.fonts/check/metadata/os2_weightclass',
    rationale =  """
        Check METADATA.pb font weights are correct.

        For static fonts, the metadata weight should be the same as the static font's
        OS/2 usWeightClass.

        For variable fonts, the weight value should be 400 if the font's wght axis range
        includes 400, otherwise it should be the value closest to 400.
    """,
    conditions = ['font_metadata'],
    proposal = ['legacy:check/112',
                'https://github.com/googlefonts/fontbakery/issues/2683']
)
def com_google_fonts_check_metadata_os2_weightclass(ttFont,
                                                    font_metadata):
    """Check METADATA.pb font weights are correct."""
    from .shared_conditions import is_variable_font
    # Weight name to value mapping:
    GF_API_WEIGHT_NAMES = {100: "Thin",
                           200: "ExtraLight",
                           250: "Thin", # Legacy. Pre-vf epoch
                           275: "ExtraLight", # Legacy. Pre-vf epoch
                           300: "Light",
                           400: "Regular",
                           500: "Medium",
                           600: "SemiBold",
                           700: "Bold",
                           800: "ExtraBold",
                           900: "Black"}
    CSS_WEIGHT_NAMES = {
        100: "Thin",
        200: "ExtraLight",
        300: "Light",
        400: "Regular",
        500: "Medium",
        600: "SemiBold",
        700: "Bold",
        800: "ExtraBold",
        900: "Black"
    }
    if is_variable_font(ttFont):
        axes = {f.axisTag: f for f in ttFont["fvar"].axes}
        if 'wght' not in axes:
            # if there isn't a wght axis, use the OS/2.usWeightClass
            font_weight = ttFont['OS/2'].usWeightClass
            should_be = "the same"
        else:
            # if the wght range includes 400, use 400
            wght_includes_400 = axes['wght'].minValue <= 400 and axes['wght'].maxValue >= 400
            if wght_includes_400:
                font_weight = 400
                should_be = ("400 because it is a varfont which includes"
                             " this coordinate in its 'wght' axis")
            else:
                # if 400 isn't in the wght axis range, use the value closest to 400
                if abs(axes['wght'].minValue - 400) < abs(axes['wght'].maxValue - 400):
                    font_weight = axes['wght'].minValue
                else:
                    font_weight = axes['wght'].maxValue
                should_be = (f"{font_weight} because it is the closest value to 400"
                             f" on the 'wght' axis of this variable font")
    else:
        font_weight = ttFont["OS/2"].usWeightClass
        if font_weight not in [250, 275]:
            should_be = "the same"
        else:
            if font_weight == 250: expected_value = 100 # "Thin"
            if font_weight == 275: expected_value = 200 # "ExtraLight"
            should_be = (f'{expected_value}, corresponding to'
                         f' CSS weight name "{CSS_WEIGHT_NAMES[expected_value]}"')

    gf_weight_name = GF_API_WEIGHT_NAMES.get(font_weight, "bad value")
    css_weight_name = CSS_WEIGHT_NAMES.get(font_metadata.weight)

    if gf_weight_name != css_weight_name:
        yield FAIL,\
              Message("mismatch",
                      f'OS/2 table has usWeightClass={ttFont["OS/2"].usWeightClass},'
                      f' meaning "{gf_weight_name}" on the Google Fonts API.\n\n'
                      f'On METADATA.pb it should be {should_be},'
                      f' but instead got {font_metadata.weight}.\n')
    else:
        yield PASS, ("OS/2 usWeightClass or wght axis value matches"
                     " weight specified at METADATA.pb")


@check(
    id = 'com.google.fonts/check/metadata/match_weight_postscript',
    conditions = ['font_metadata',
                  'not is_variable_font'],
    proposal = 'legacy:check/113'
)
def com_google_fonts_check_metadata_match_weight_postscript(font_metadata):
    """METADATA.pb weight matches postScriptName for static fonts."""
    WEIGHTS = {
        "Thin": 100,
        "ThinItalic": 100,
        "ExtraLight": 200,
        "ExtraLightItalic": 200,
        "Light": 300,
        "LightItalic": 300,
        "Regular": 400,
        "Italic": 400,
        "Medium": 500,
        "MediumItalic": 500,
        "SemiBold": 600,
        "SemiBoldItalic": 600,
        "Bold": 700,
        "BoldItalic": 700,
        "ExtraBold": 800,
        "ExtraBoldItalic": 800,
        "Black": 900,
        "BlackItalic": 900
    }
    pair = []
    for k, weight in WEIGHTS.items():
        if weight == font_metadata.weight:
            pair.append((k, weight))

    if not pair:
        yield FAIL, ("METADATA.pb: Font weight value ({})"
                     " is invalid.").format(font_metadata.weight)
    elif not (font_metadata.post_script_name.endswith('-' + pair[0][0]) or
              font_metadata.post_script_name.endswith('-' + pair[1][0])):
        yield FAIL, ("METADATA.pb: Mismatch between postScriptName (\"{}\")"
                     " and weight value ({}). The name must be"
                     " ended with \"{}\" or \"{}\"."
                     "").format(font_metadata.post_script_name,
                                pair[0][1],
                                pair[0][0],
                                pair[1][0])
    else:
        yield PASS, "Weight value matches postScriptName."


@check(
    id = 'com.google.fonts/check/metadata/canonical_style_names',
    conditions = ['font_metadata'],
    proposal = 'legacy:check/115'
)
def com_google_fonts_check_metadata_canonical_style_names(ttFont, font_metadata):
    """METADATA.pb: Font styles are named canonically?"""
    from .shared_conditions import is_italic

    if font_metadata.style not in ["italic", "normal"]:
        yield SKIP, ('This check only applies to font styles declared'
                     ' as "italic" or "normal" on METADATA.pb.')
    else:
        if is_italic(ttFont) and font_metadata.style != "italic":
            yield FAIL,\
                  Message("italic",
                          f'The font style is "{font_metadata.style}"'
                          f' but it should be "italic".')
        elif not is_italic(ttFont) and font_metadata.style != "normal":
            yield FAIL,\
                  Message("normal",
                          f'The font style is "{font_metadata.style}"'
                          f' but it should be "normal".')
        else:
            yield PASS, "Font styles are named canonically."


@check(
    id = 'com.google.fonts/check/unitsperem_strict',
    rationale = """
        Even though the OpenType spec allows unitsPerEm to be any value between 16
        and 16384, the Google Fonts project aims at a narrower set of reasonable values.

        The spec suggests usage of powers of two in order to get some performance
        improvements on legacy renderers, so those values are acceptable.

        But values of 500 or 1000 are also acceptable, with the added benefit that it
        makes upm math easier for designers, while the performance hit of not using a
        power of two is most likely negligible nowadays.

        Additionally, values above 2048 would likely result in unreasonable
        filesize increases.
    """,
    proposal = 'legacy:check/116'
)
def com_google_fonts_check_unitsperem_strict(ttFont):
    """ Stricter unitsPerEm criteria for Google Fonts. """
    upm_height = ttFont["head"].unitsPerEm
    ACCEPTABLE = [16, 32, 64, 128, 256, 500,
                  512, 1000, 1024, 2000, 2048]
    if upm_height > 2048 and upm_height <= 4096:
        yield WARN,\
              Message("large-value",
                      f"Font em size (unitsPerEm) is {upm_height}"
                      f" which may be too large (causing filesize bloat),"
                      f" unless you are sure that the detail level"
                      f" in this font requires that much precision.")
    elif upm_height not in ACCEPTABLE:
        yield FAIL,\
              Message("bad-value",
                      f"Font em size (unitsPerEm) is {upm_height}."
                      f" If possible, please consider using 1000."
                      f" Good values for unitsPerEm,"
                      f" though, are typically these: {ACCEPTABLE}.")
    else:
        yield PASS, f"Font em size is good (unitsPerEm = {upm_height})."


@check(
    id = 'com.google.fonts/check/version_bump',
    conditions = ['api_gfonts_ttFont',
                  'github_gfonts_ttFont'],
    proposal = 'legacy:check/117'
)
def com_google_fonts_check_version_bump(ttFont,
                                        api_gfonts_ttFont,
                                        github_gfonts_ttFont):
    """Version number has increased since previous release on Google Fonts?"""
    v_number = ttFont["head"].fontRevision
    api_gfonts_v_number = api_gfonts_ttFont["head"].fontRevision
    github_gfonts_v_number = github_gfonts_ttFont["head"].fontRevision
    failed = False

    if v_number == api_gfonts_v_number:
        failed = True
        yield FAIL, (f"Version number {v_number} is equal to"
                     f" version on Google Fonts.")

    if v_number < api_gfonts_v_number:
        failed = True
        yield FAIL, (f"Version number {v_number} is less than"
                     f" version on Google Fonts ({api_gfonts_v_number}).")

    if v_number == github_gfonts_v_number:
        failed = True
        yield FAIL, (f"Version number {v_number} is equal to"
                     f" version on Google Fonts GitHub repo.")

    if v_number < github_gfonts_v_number:
        failed = True
        yield FAIL, (f"Version number {v_number} is less than"
                     f" version on Google Fonts GitHub repo ({github_gfonts_v_number}).")

    if not failed:
        yield PASS, (f"Version number {v_number} is greater than"
                     f" version on Google Fonts GitHub ({github_gfonts_v_number})"
                     f" and production servers ({api_gfonts_v_number}).")


@check(
    id = 'com.google.fonts/check/production_glyphs_similarity',
    conditions = ['api_gfonts_ttFont'],
    proposal = 'legacy:check/118'
)
def com_google_fonts_check_production_glyphs_similarity(ttFont, api_gfonts_ttFont, config):
    """Glyphs are similiar to Google Fonts version?"""
    from fontbakery.utils import pretty_print_list

    def glyphs_surface_area(ttFont):
        """Calculate the surface area of a glyph's ink"""
        from fontTools.pens.areaPen import AreaPen
        glyphs = {}
        glyph_set = ttFont.getGlyphSet()
        area_pen = AreaPen(glyph_set)

        for glyph in glyph_set.keys():
            glyph_set[glyph].draw(area_pen)

            area = area_pen.value
            area_pen.value = 0
            glyphs[glyph] = area
        return glyphs

    bad_glyphs = []
    these_glyphs = glyphs_surface_area(ttFont)
    gfonts_glyphs = glyphs_surface_area(api_gfonts_ttFont)

    shared_glyphs = set(these_glyphs) & set(gfonts_glyphs)

    this_upm = ttFont['head'].unitsPerEm
    gfonts_upm = api_gfonts_ttFont['head'].unitsPerEm

    for glyph in shared_glyphs:
        # Normalize area difference against comparison's upm
        this_glyph_area = (these_glyphs[glyph] / this_upm) * gfonts_upm
        gfont_glyph_area = (gfonts_glyphs[glyph] / gfonts_upm) * this_upm

        if abs(this_glyph_area - gfont_glyph_area) > 7000:
            bad_glyphs.append(glyph)

    if bad_glyphs:
        formatted_list = "\t* " + pretty_print_list(config,
                                                    sorted(bad_glyphs),
                                                    sep="\n\t* ")

        yield WARN, ("Following glyphs differ greatly from"
                     f" Google Fonts version:\n{formatted_list}")
    else:
        yield PASS, ("Glyphs are similar in"
                     " comparison to the Google Fonts version.")


@check(
    id = 'com.google.fonts/check/fsselection',
    conditions = ['style'],
    proposal = 'legacy:check/129'
)
def com_google_fonts_check_fsselection(ttFont, style):
    """Checking OS/2 fsSelection value."""
    from fontbakery.utils import check_bit_entry
    from fontbakery.constants import (STATIC_STYLE_NAMES,
                                      RIBBI_STYLE_NAMES,
                                      FsSelection)

    # Checking fsSelection REGULAR bit:
    expected = "Regular" in style or \
               (style in STATIC_STYLE_NAMES and
                style not in RIBBI_STYLE_NAMES and
                "Italic" not in style)
    yield check_bit_entry(ttFont, "OS/2", "fsSelection",
                          expected,
                          bitmask=FsSelection.REGULAR,
                          bitname="REGULAR")

    # Checking fsSelection ITALIC bit:
    expected = "Italic" in style
    yield check_bit_entry(ttFont, "OS/2", "fsSelection",
                          expected,
                          bitmask=FsSelection.ITALIC,
                          bitname="ITALIC")

    # Checking fsSelection BOLD bit:
    expected = style in ["Bold", "BoldItalic"]
    yield check_bit_entry(ttFont, "OS/2", "fsSelection",
                          expected,
                          bitmask=FsSelection.BOLD,
                          bitname="BOLD")


@check(
    id = 'com.google.fonts/check/italic_angle',
    conditions = ['style'],
    rationale = """
        The 'post' table italicAngle property should be a reasonable amount, likely
        not more than -20°, never more than -30°, and never greater than 0°. Note that
        in the OpenType specification, the value is negative for a lean rightwards.

        https://docs.microsoft.com/en-us/typography/opentype/spec/post
    """,
    proposal = 'legacy:check/130'
)
def com_google_fonts_check_italic_angle(ttFont, style):
    """Checking post.italicAngle value."""
    failed = False
    value = ttFont["post"].italicAngle

    # Checking that italicAngle <= 0
    if value > 0:
        failed = True
        yield FAIL,\
              Message("positive",
                      (f"The value of post.italicAngle is positive, which"
                       f" is likely a mistake and should become negative,"
                       f" from {value} to {-value}."))

    # Checking that italicAngle is less than 20° (not good) or 30° (bad)
    # Also note we invert the value to check it in a clear way
    if abs(value) > 30:
        failed = True
        yield FAIL,\
              Message("over-minus30-degrees",
                      (f"The value of post.italicAngle ({value}) is very high"
                       f" (over -30°!) and should be confirmed."))
    elif abs(value) > 20:
        failed = True
        yield WARN,\
              Message("over-minus20-degrees",
                      (f"The value of post.italicAngle ({value}) seems very high"
                       f" (over -20°!) and should be confirmed."))


    # Checking if italicAngle matches font style:
    if "Italic" in style:
        if ttFont['post'].italicAngle == 0:
            failed = True
            yield FAIL,\
                  Message("zero-italic",
                          ("Font is italic, so post.italicAngle"
                           " should be non-zero."))
    else:
        if ttFont["post"].italicAngle != 0:
            failed = True
            yield FAIL,\
                  Message("non-zero-normal",
                          ("Font is not italic, so post.italicAngle"
                           " should be equal to zero."))

    if not failed:
        yield PASS, (f'Value of post.italicAngle is {value}'
                     f' with style="{style}".')


@check(
    id = 'com.google.fonts/check/mac_style',
    conditions = ['style'],
    rationale = """
        The values of the flags on the macStyle entry on the 'head' OpenType table
        that describe whether a font is bold and/or italic must be coherent with the
        actual style of the font as inferred by its filename.
    """,
    proposal = 'legacy:check/131'
)
def com_google_fonts_check_mac_style(ttFont, style):
    """Checking head.macStyle value."""
    from fontbakery.utils import check_bit_entry
    from fontbakery.constants import MacStyle

    # Checking macStyle ITALIC bit:
    expected = "Italic" in style
    yield check_bit_entry(ttFont, "head", "macStyle",
                          expected,
                          bitmask=MacStyle.ITALIC,
                          bitname="ITALIC")

    # Checking macStyle BOLD bit:
    expected = style in ["Bold", "BoldItalic"]
    yield check_bit_entry(ttFont, "head", "macStyle",
                          expected,
                          bitmask=MacStyle.BOLD,
                          bitname="BOLD")


@check(
    id = 'com.google.fonts/check/font_names',
    conditions = ['expected_font_names'],
    rationale = """
        Google Fonts has several rules which need to be adhered to when
        setting a font's name table. Please read:
        https://googlefonts.github.io/gf-guide/statics.html#supported-styles
        https://googlefonts.github.io/gf-guide/statics.html#style-linking
        https://googlefonts.github.io/gf-guide/statics.html#unsupported-styles
        https://googlefonts.github.io/gf-guide/statics.html#single-weight-families
    """,
    proposal = 'https://github.com/googlefonts/fontbakery/pull/3800'
)
def com_google_fonts_check_font_names(ttFont, expected_font_names):
    """Check font names are correct"""
    def style_names(nametable):
        res = {}
        for nameID in (
            NameID.FONT_FAMILY_NAME,
            NameID.FONT_SUBFAMILY_NAME,
            NameID.FULL_FONT_NAME,
            NameID.POSTSCRIPT_NAME,
            NameID.TYPOGRAPHIC_FAMILY_NAME,
            NameID.TYPOGRAPHIC_SUBFAMILY_NAME
        ):
            rec = nametable.getName(nameID, 3, 1, 0x409)
            if rec:
                res[nameID] = rec.toUnicode()
        return res

    font_names = style_names(ttFont['name'])
    expected_names = style_names(expected_font_names['name'])

    name_ids = {
        NameID.FONT_FAMILY_NAME: "Family Name",
        NameID.FONT_SUBFAMILY_NAME: "Subfamily Name",
        NameID.FULL_FONT_NAME: "Full Name",
        NameID.POSTSCRIPT_NAME: "Poscript Name",
        NameID.TYPOGRAPHIC_FAMILY_NAME: "Typographic Family Name",
        NameID.TYPOGRAPHIC_SUBFAMILY_NAME: "Typographic Subfamily Name",
    }
    table = []
    for nameID in set(font_names.keys()) | set(expected_names.keys()):
        id_name = name_ids[nameID]
        row = {"nameID": id_name}
        if nameID in font_names:
            row["current"] = font_names[nameID]
        else:
            row["current"] = "N/A"
        if nameID in expected_names:
            row["expected"] = expected_names[nameID]
        else:
            row["expected"] = "N/A"
        table.append(row)

    new_names = set(font_names) - set(expected_names)
    missing_names = set(expected_names) - set(font_names)
    same_names = set(font_names) & set(expected_names)

    md_table = markdown_table(table)

    passed = True
    if new_names or missing_names:
        passed = False

    for nameID in same_names:
        if nameID == NameID.FULL_FONT_NAME and \
            all([
                " Regular" in expected_names[nameID],
                font_names[nameID] == expected_names[nameID].replace(" Regular", "")
            ]):
                yield WARN, Message('lacks-regular', "Regular missing from full name")
        elif font_names[nameID] != expected_names[nameID]:
            passed = False

    if not passed:
        yield FAIL, Message('bad-names',
                            f'Font names are incorrect:\n\n{md_table}')
    else:
        yield PASS, f"Font names are good:\n\n{md_table}"


# FIXME!
# Temporarily disabled since GFonts hosted Cabin files seem to have changed in ways
# that break some of the assumptions in the check implementation below.
# More info at https://github.com/googlefonts/fontbakery/issues/2581
@disable
@check(
    id = 'com.google.fonts/check/production_encoded_glyphs',
    conditions = ['api_gfonts_ttFont'],
    proposal = 'legacy:check/154'
)
def com_google_fonts_check_production_encoded_glyphs(ttFont, api_gfonts_ttFont):
    """Check font has same encoded glyphs as version hosted on
    fonts.google.com"""
    cmap = ttFont['cmap'].getcmap(3, 1).cmap
    gf_cmap = api_gfonts_ttFont['cmap'].getcmap(3, 1).cmap
    missing_codepoints = set(gf_cmap.keys()) - set(cmap.keys())

    if missing_codepoints:
        hex_codepoints = ['0x' + hex(c).upper()[2:].zfill(4) for c
                          in sorted(missing_codepoints)]
        yield FAIL,\
              Message("lost-glyphs",
                      f"Font is missing the following glyphs"
                      f" from the previous release"
                      f" [{', '.join(hex_codepoints)}]")
    else:
        yield PASS, ('Font has all the glyphs from the previous release')


@check(
    id = 'com.google.fonts/check/metadata/nameid/copyright',
    conditions = ['font_metadata'],
    proposal = 'legacy:check/155'
)
def com_google_fonts_check_metadata_nameid_copyright(ttFont, font_metadata):
    """Copyright field for this font on METADATA.pb matches
       all copyright notice entries on the name table ?"""
    failed = False
    for nameRecord in ttFont['name'].names:
        string = nameRecord.string.decode(nameRecord.getEncoding())
        if nameRecord.nameID == NameID.COPYRIGHT_NOTICE and\
           string != font_metadata.copyright:
            failed = True
            yield FAIL,\
                  Message("mismatch",
                          f'Copyright field for this font on METADATA.pb'
                          f' ("{font_metadata.copyright}") differs from'
                          f' a copyright notice entry on the name table:'
                          f' "{string}"')
    if not failed:
        yield PASS, ("Copyright field for this font on METADATA.pb matches"
                     " copyright notice entries on the name table.")


@check(
    id = 'com.google.fonts/check/name/mandatory_entries',
    conditions = ['style'],
    proposal = 'legacy:check/156'
)
def com_google_fonts_check_name_mandatory_entries(ttFont, style):
    """Font has all mandatory 'name' table entries?"""
    from fontbakery.utils import get_name_entry_strings
    from fontbakery.constants import RIBBI_STYLE_NAMES

    required_nameIDs = [NameID.FONT_FAMILY_NAME,
                        NameID.FONT_SUBFAMILY_NAME,
                        NameID.FULL_FONT_NAME,
                        NameID.POSTSCRIPT_NAME]
    if style not in RIBBI_STYLE_NAMES:
        required_nameIDs += [NameID.TYPOGRAPHIC_FAMILY_NAME,
                             NameID.TYPOGRAPHIC_SUBFAMILY_NAME]
    passed = True
    # The font must have at least these name IDs:
    for nameId in required_nameIDs:
        if len(get_name_entry_strings(ttFont, nameId)) == 0:
            passed = False
            yield FAIL,\
                  Message("missing-entry",
                          f"Font lacks entry with nameId={nameId}"
                          f" ({NameID(nameId).name})")
    if passed:
        yield PASS, "Font contains values for all mandatory name table entries."


@check(
    id = 'com.google.fonts/check/name/copyright_length',
    rationale = """
        This is an arbitrary max length for the copyright notice field of the name
        table. We simply don't want such notices to be too long. Typically such notices
        are actually much shorter than this with a length of roughly 70 or 80 characters.
    """,
    proposal = 'https://github.com/googlefonts/fontbakery/issues/1603'
)
def com_google_fonts_check_name_copyright_length(ttFont):
    """Length of copyright notice must not exceed 500 characters."""
    from fontbakery.utils import get_name_entries

    failed = False
    for notice in get_name_entries(ttFont, NameID.COPYRIGHT_NOTICE):
        notice_str = notice.string.decode(notice.getEncoding())
        if len(notice_str) > 500:
            failed = True
            yield FAIL,\
                  Message("too-long",
                          f'The length of the following copyright notice'
                          f' ({len(notice_str)}) exceeds 500 chars:'
                          f' "{notice_str}"')
    if not failed:
        yield PASS, ("All copyright notice name entries on the"
                     " 'name' table are shorter than 500 characters.")


@check(
    id = 'com.google.fonts/check/fontdata_namecheck',
    rationale = """
        We need to check names are not already used, and today the best place to check
        that is http://namecheck.fontdata.com
    """,
    conditions = ["familyname"],
    proposal = 'https://github.com/googlefonts/fontbakery/issues/494'
)
def com_google_fonts_check_fontdata_namecheck(ttFont, familyname):
    """Familyname must be unique according to namecheck.fontdata.com"""
    import requests
    FB_ISSUE_TRACKER = "https://github.com/googlefonts/fontbakery/issues"
    NAMECHECK_URL = "http://namecheck.fontdata.com"
    try:
        # Since October 2019, it seems that we need to fake our user-agent
        # in order to get correct query results
        FAKE = 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_10_1)'
        response = requests.post(NAMECHECK_URL,
                                 params={'q': familyname},
                                 headers={'User-Agent': FAKE},
                                 timeout=10)
        data = response.content.decode("utf-8")
        if "fonts by that exact name" in data:
            yield INFO,\
                  Message("name-collision",
                          f'The family name "{familyname}" seems'
                          f' to be already in use.\n'
                          f'Please visit {NAMECHECK_URL} for more info.')
        else:
            yield PASS, "Font familyname seems to be unique."
    except:
        import sys
        yield ERROR,\
              Message("namecheck-service",
                      f"Failed to access: {NAMECHECK_URL}.\n"
                      f"\t\tThis check relies on the external service"
                      f" http://namecheck.fontdata.com via the internet."
                      f" While the service cannot be reached or does not"
                      f" respond this check is broken.\n"
                      f"\n"
                      f"\t\tYou can exclude this check with the command line"
                      f" option:\n"
                      f"\t\t-x com.google.fonts/check/fontdata_namecheck\n"
                      f"\n"
                      f"\t\tOr you can wait until the service is available again.\n"
                      f"\t\tIf the problem persists please report this issue"
                      f" at: {FB_ISSUE_TRACKER}\n"
                      f"\n"
                      f"\t\tOriginal error message:\n"
                      f"\t\t{sys.exc_info()[0]}")


@check(
    id = 'com.google.fonts/check/fontv',
    rationale = """
        The git sha1 tagging and dev/release features of Source Foundry `font-v` tool
        are awesome and we would love to consider upstreaming the approach into
        fontmake someday. For now we only emit a WARN if a given font does not yet
        follow the experimental versioning style, but at some point we may start
        enforcing it.
    """,
    proposal = 'https://github.com/googlefonts/fontbakery/issues/1563'
)
def com_google_fonts_check_fontv(ttFont):
    """Check for font-v versioning."""
    from fontv.libfv import FontVersion

    fv = FontVersion(ttFont)
    if fv.version and (fv.is_development or fv.is_release):
        yield PASS, "Font version string looks GREAT!"
    else:
        yield INFO,\
              Message("bad-format",
                      f'Version string is: "{fv.get_name_id5_version_string()}"\n'
                      f'The version string must ideally include a git commit hash'
                      f' and either a "dev" or a "release" suffix such as in the'
                      f' example below:\n'
                      f'"Version 1.3; git-0d08353-release"')


# Disabling this check since the previous implementation was
# bogus due to the way fonttools encodes the data into the TTF
# files and the new attempt at targetting the real problem is
# still not quite right.
# FIXME: reimplement this addressing the actual root cause of the issue.
# See also ongoing discussion at:
# https://github.com/googlefonts/fontbakery/issues/1727
@disable
@check(
    id = 'com.google.fonts/check/negative_advance_width',
    rationale = """
        Advance width values in the Horizontal Metrics (htmx) table cannot be negative
        since they are encoded as unsigned 16-bit values. But some programs may infer
        and report a negative advance by looking up the x-coordinates of the glyphs
        directly on the glyf table.

        There are reports of broken versions of Glyphs.app causing this kind of problem
        as reported at [1] and [2].
        
        This check detects and reports such malformed glyf table entries.
        
        
        [1] https://github.com/googlefonts/fontbakery/issues/1720
        
        [2] https://github.com/fonttools/fonttools/pull/1198
    """,
    conditions = ['is_ttf'],
    proposal = 'https://github.com/googlefonts/fontbakery/issues/1720'
)
def com_google_fonts_check_negative_advance_width(ttFont):
    """Check that advance widths cannot be inferred as negative."""
    failed = False
    for glyphName in ttFont["glyf"].glyphs:
        coords = ttFont["glyf"][glyphName].coordinates
        rightX = coords[-3][0]
        leftX = coords[-4][0]
        advwidth = rightX - leftX
        if advwidth < 0:
            failed = True
            yield FAIL,\
                  Message("bad-coordinates",
                          f'Glyph "{glyphName}" has bad coordinates on the glyf'
                          f' table, which may lead to the advance width to be'
                          f' interpreted as a negative value ({advwidth}).')
    if not failed:
        yield PASS, "The x-coordinates of all glyphs look good."


@check(
    id = 'com.google.fonts/check/glyf_nested_components',
    rationale = """
        There have been bugs rendering variable fonts with nested components.
        Additionally, some static fonts with nested components have been reported
        to have rendering and printing issues.

        For more info, see:
        * https://github.com/googlefonts/fontbakery/issues/2961
        * https://github.com/arrowtype/recursive/issues/412
    """,
    conditions = ['is_ttf'],
    proposal = 'https://github.com/googlefonts/fontbakery/issues/2961'
)
def com_google_fonts_check_glyf_nested_components(ttFont, config):
    """Check glyphs do not have components which are themselves components."""
    from fontbakery.utils import pretty_print_list
    failed = []
    for glyph_name in ttFont['glyf'].keys():
        glyph = ttFont['glyf'][glyph_name]
        if not glyph.isComposite():
            continue
        for comp in glyph.components:
            if ttFont['glyf'][comp.glyphName].isComposite():
                failed.append(glyph_name)
    if failed:
        formatted_list = "\t* " + pretty_print_list(config,
                                                    failed,
                                                    sep="\n\t* ")
        yield FAIL,\
              Message('found-nested-components',
                      f"The following glyphs have components which"
                      f" themselves are component glyphs:\n"
                      f"{formatted_list}")
    else:
        yield PASS, ("Glyphs do not contain nested components.")


@check(
    id = 'com.google.fonts/check/varfont/consistent_axes',
    rationale = """
        In order to facilitate the construction of intuitive and friendly user
        interfaces, all variable font files in a given family should have the same set
        of variation axes. Also, each axis must have a consistent setting of min/max
        value ranges accross all the files.
    """,
    conditions = ['VFs'],
    proposal = 'https://github.com/googlefonts/fontbakery/issues/2810'
)
def com_google_fonts_check_varfont_consistent_axes(VFs):
    """Ensure that all variable font files have the same set of axes and axis ranges."""
    ref_ranges = {}
    for vf in VFs:
        ref_ranges.update({k.axisTag: (k.minValue, k.maxValue)
                           for k in vf['fvar'].axes})

    passed = True
    for vf in VFs:
        for axis in ref_ranges:
            if axis not in map(lambda x: x.axisTag, vf['fvar'].axes):
                passed = False
                yield FAIL,\
                      Message("missing-axis",
                              f"{os.path.basename(vf.reader.file.name)}:"
                              f" lacks a '{axis}' variation axis.")

    expected_ranges = {axis: {(vf['fvar'].axes[vf['fvar'].axes.index(axis)].minValue,
                               vf['fvar'].axes[vf['fvar'].axes.index(axis)].maxValue) for vf in VFs}
                       for axis in ref_ranges
                       if axis in vf['fvar'].axes}

    for axis, ranges in expected_ranges:
        if len(ranges) > 1:
            passed = False
            yield FAIL,\
                  Message("inconsistent-axis-range",
                          "Axis 'axis' has diverging ranges accross the family: {ranges}.")

    if passed:
        yield PASS, "All looks good!"


@check(
    id = 'com.google.fonts/check/varfont/generate_static',
    rationale = """
        Google Fonts may serve static fonts which have been generated from variable
        fonts. This test will attempt to generate a static ttf using fontTool's
        varLib mutator.

        The target font will be the mean of each axis e.g:

        ## VF font axes

        - min weight, max weight = 400, 800
        
        - min width, max width = 50, 100

        ## Target Instance

        - weight = 600
        
        - width = 75
    """,
    conditions = ['is_variable_font'],
    proposal = 'https://github.com/googlefonts/fontbakery/issues/1727'
)
def com_google_fonts_check_varfont_generate_static(ttFont):
    """Check a static ttf can be generated from a variable font."""
    import tempfile
    from fontTools.varLib import mutator

    try:
        loc = {k.axisTag: float((k.maxValue + k.minValue) / 2)
               for k in ttFont['fvar'].axes}
        with tempfile.TemporaryFile() as instance:
            font = mutator.instantiateVariableFont(ttFont, loc)
            font.save(instance)
            yield PASS, ("fontTools.varLib.mutator"
                         " generated a static font instance")
    except Exception as e:
        yield FAIL,\
              Message("varlib-mutator",
                      f"fontTools.varLib.mutator failed"
                      f" to generated a static font instance\n"
                      f"{repr(e)}")


@check(
    id = 'com.google.fonts/check/varfont/has_HVAR',
    rationale = """
        Not having a HVAR table can lead to costly text-layout operations on some
        platforms, which we want to avoid.

        So, all variable fonts on the Google Fonts collection should have an HVAR
        with valid values.

        More info on the HVAR table can be found at:
        https://docs.microsoft.com/en-us/typography/opentype/spec/otvaroverview#variation-data-tables-and-miscellaneous-requirements
    """, # FIX-ME: We should clarify which are these
         #         platforms in which there can be issues
         #         with costly text-layout operations
         #         when an HVAR table is missing!
    conditions = ['is_variable_font'],
    proposal = 'https://github.com/googlefonts/fontbakery/issues/2119'
)
def com_google_fonts_check_varfont_has_HVAR(ttFont):
    """Check that variable fonts have an HVAR table."""
    if "HVAR" in ttFont.keys():
        yield PASS, ("This variable font contains an HVAR table.")
    else:
        yield FAIL,\
              Message("lacks-HVAR",
                      "All variable fonts on the Google Fonts collection"
                      " must have a properly set HVAR table in order"
                      " to avoid costly text-layout operations on"
                      " certain platforms.")


@check(
    id = 'com.google.fonts/check/smart_dropout',
    conditions = ['is_ttf',
                  'not VTT_hinted'],
    rationale = """
        This setup is meant to ensure consistent rendering quality for fonts across
        all devices (with different rendering/hinting capabilities).

        Below is the snippet of instructions we expect to see in the fonts:
        B8 01 FF    PUSHW 0x01FF
        85          SCANCTRL (unconditinally turn on
                              dropout control mode)
        B0 04       PUSHB 0x04
        8D          SCANTYPE (enable smart dropout control)

        "Smart dropout control" means activating rules 1, 2 and 5:
        Rule 1: If a pixel's center falls within the glyph outline,
                that pixel is turned on.
        Rule 2: If a contour falls exactly on a pixel's center,
                that pixel is turned on.
        Rule 5: If a scan line between two adjacent pixel centers
                (either vertical or horizontal) is intersected
                by both an on-Transition contour and an off-Transition
                contour and neither of the pixels was already turned on
                by rules 1 and 2, turn on the pixel which is closer to
                the midpoint between the on-Transition contour and
                off-Transition contour. This is "Smart" dropout control.

        For more detailed info (such as other rules not enabled in this snippet),
        please refer to the TrueType Instruction Set documentation.
    """,
    proposal = 'legacy:check/072'
)
def com_google_fonts_check_smart_dropout(ttFont):
    """Font enables smart dropout control in "prep" table instructions?"""
    INSTRUCTIONS = b"\xb8\x01\xff\x85\xb0\x04\x8d"

    if ("prep" in ttFont and
        INSTRUCTIONS in ttFont["prep"].program.getBytecode()):
        yield PASS, ("'prep' table contains instructions"
                      " enabling smart dropout control.")
    else:
        yield FAIL,\
              Message("lacks-smart-dropout",
                      "The 'prep' table does not contain TrueType"
                      " instructions enabling smart dropout control."
                      " To fix, export the font with autohinting enabled,"
                      " or run ttfautohint on the font, or run the"
                      " `gftools fix-nonhinting` script.")


@check(
    id = 'com.google.fonts/check/vttclean',
    rationale = """
        The goal here is to reduce filesizes and improve pageloading when dealing
        with webfonts.

        The VTT Talk sources are not necessary at runtime and endup being just dead
        weight when left embedded in the font binaries. The sources should be kept on
        the project files but stripped out when building release binaries.
    """,
    proposal = 'https://github.com/googlefonts/fontbakery/issues/2059'
)
def com_google_fonts_check_vtt_clean(ttFont, vtt_talk_sources):
    """There must not be VTT Talk sources in the font."""

    if vtt_talk_sources:
        yield FAIL,\
              Message("has-vtt-sources",
                      f"Some tables containing VTT Talk (hinting) sources"
                      f" were found in the font and should be removed in order"
                      f" to reduce total filesize:"
                      f" {', '.join(vtt_talk_sources)}")
    else:
        yield PASS, "There are no tables with VTT Talk sources embedded in the font."


@check(
    id = 'com.google.fonts/check/aat',
    rationale = """
        Apple's TrueType reference manual [1] describes SFNT tables not in the
        Microsoft OpenType specification [2] and these can sometimes sneak into final
        release files, but Google Fonts should only have OpenType tables.

        [1] https://developer.apple.com/fonts/TrueType-Reference-Manual/RM06/Chap6.html
        [2] https://docs.microsoft.com/en-us/typography/opentype/spec/
    """,
    proposal = 'https://github.com/googlefonts/fontbakery/pull/2190'
)
def com_google_fonts_check_aat(ttFont):
    """Are there unwanted Apple tables?"""
    UNWANTED_TABLES = {
        'EBSC', 'Zaph', 'acnt', 'ankr', 'bdat', 'bhed', 'bloc',
        'bmap', 'bsln', 'fdsc', 'feat', 'fond', 'gcid', 'just',
        'kerx', 'lcar', 'ltag', 'mort', 'morx', 'opbd', 'prop',
        'trak', 'xref'
    }
    unwanted_tables_found = []
    for table in ttFont.keys():
        if table in UNWANTED_TABLES:
            unwanted_tables_found.append(table)

    if len(unwanted_tables_found) > 0:
        unwanted_list = ''.join(f"* {tag}\n" for tag in unwanted_tables_found)
        yield FAIL,\
              Message("has-unwanted-tables",
                      f"Unwanted AAT tables were found"
                      f" in the font and should be removed, either by"
                      f" fonttools/ttx or by editing them using the tool"
                      f" they built with:\n\n"
                      f" {unwanted_list}")
    else:
        yield PASS, "There are no unwanted AAT tables."


@check(
    id = 'com.google.fonts/check/STAT',
    conditions = ['is_variable_font',
                  'expected_font_names'],
    rationale = """
        Check a font's STAT table contains compulsory Axis Values which exist
        in the Google Fonts Axis Registry.

        We cannot determine what Axis Values the user will set for axes such as
        opsz, GRAD since these axes are unique for each font so we'll skip them.
    """,
    proposal = 'https://github.com/googlefonts/fontbakery/pull/3800'
)
def com_google_fonts_check_stat(ttFont, expected_font_names):
    """Check a font's STAT table contains compulsory Axis Values."""
    if "STAT" not in ttFont:
        yield FAIL, "Font is missing STAT table"
        return

    axes_to_check = {
        "CASL", "CRSV", "FILL", "FLAR", "MONO",
        "SOFT", "VOLM", "wdth", "wght", "WONK"
    }

    def stat_axis_values(ttFont, include_axes=axes_to_check):
        name = ttFont["name"]
        stat = ttFont["STAT"].table
        axes = [a.AxisTag for a in stat.DesignAxisRecord.Axis]
        res = {}
        if ttFont["STAT"].table.AxisValueCount == 0:
            return res
        axis_values = stat.AxisValueArray.AxisValue
        for ax in axis_values:
            # Google Fonts axis registry cannot check format 4 Axis Values
            if ax.Format == 4:
                continue
            axis_tag = axes[ax.AxisIndex]
            if axis_tag not in include_axes:
                continue
            ax_name = name.getName(ax.ValueNameID, 3, 1, 0x409).toUnicode()
            if ax.Format == 2:
                value = ax.NominalValue
            else:
                value = ax.Value
            res[(axis_tag, ax_name)] = {
                "Axis": axis_tag,
                "Name": ax_name,
                "Flags": ax.Flags,
                "Value": value,
                "LinkedValue": None if not hasattr(ax, "LinkedValue") else ax.LinkedValue
            }
        return res

    font_axis_values = stat_axis_values(ttFont)
    expected_axis_values = stat_axis_values(expected_font_names)

    table = []
    for axis, name in set(font_axis_values.keys()) | set(expected_axis_values.keys()):
        row = {}
        key = (axis, name)
        if key in font_axis_values:
            row["Name"] = name
            row["Axis"] = axis
            row["Current Value"] = font_axis_values[key]["Value"]
            row["Current Flags"] = font_axis_values[key]["Flags"]
            row["Current LinkedValue"] = font_axis_values[key]["LinkedValue"]
        else:
            row["Name"] = name
            row["Axis"] = axis
            row["Current Value"] = "N/A"
            row["Current Flags"] = "N/A"
            row["Current LinkedValue"] = "N/A"
        if key in expected_axis_values:
            row["Name"] = name
            row["Axis"] = axis
            row["Expected Value"] = expected_axis_values[key]["Value"]
            row["Expected Flags"] = expected_axis_values[key]["Flags"]
            row["Expected LinkedValue"] = expected_axis_values[key]["LinkedValue"]
        else:
            row["Name"] = name
            row["Axis"] = axis
            row["Expected Value"] = "N/A"
            row["Expected Flags"] = "N/A"
            row["Expected LinkedValue"] = "N/A"
        table.append(row)
    table.sort(key=lambda k: (k["Axis"], str(k["Expected Value"])))
    md_table = markdown_table(table)

    passed = True
    is_italic = any(a.axisTag in ["ital", "slnt"] for a in ttFont["fvar"].axes)
    missing_ital_av = any("Italic" in r["Name"] for r in table)
    if is_italic and missing_ital_av:
        passed = False
        yield FAIL, Message("missing-ital-axis-values",
            "Italic Axis Value missing.")

    if font_axis_values != expected_axis_values:
        passed = False
        yield FAIL, Message('bad-axis-values',
            f"Compulsory STAT Axis Values are incorrect:\n\n {md_table}\n")
    if passed:
        yield PASS, "Compulsory STAT Axis Values are correct."


@check(
    id = 'com.google.fonts/check/fvar_instances',
    conditions = ['is_variable_font',
                  'expected_font_names'],
    rationale = """
        Check a font's fvar instance coordinates comply with our guidelines:
        https://googlefonts.github.io/gf-guide/variable.html#fvar-instances
    """,
    proposal = 'https://github.com/googlefonts/fontbakery/pull/3800'
)
def com_google_fonts_check_fvar_instances(ttFont, expected_font_names):
    """Check variable font instances"""
    def get_instances(ttFont):
        name = ttFont['name']
        fvar = ttFont['fvar']
        res = {}
        for inst in fvar.instances:
            inst_name = name.getName(inst.subfamilyNameID, 3, 1, 0x409)
            if not inst_name:
                continue
            res[inst_name.toUnicode()] = inst.coordinates
        return res
    font_instances = get_instances(ttFont)
    expected_instances = get_instances(expected_font_names)
    table = []
    for name in set(font_instances.keys()) | set(expected_instances.keys()):
        row = {"Name": name}
        if name in font_instances:
            row["current"] = ", ".join([f"{k}={v}" for k,v in font_instances[name].items()])
        else:
            row["current"] = "N/A"
        if name in expected_instances:
            row["expected"] = ", ".join([f"{k}={v}" for k,v in expected_instances[name].items()])
        else:
            row["expected"] = "N/A"
        table.append(row)
    table = sorted(table, key=lambda k: str(k["expected"]))

    missing = set(expected_instances.keys()) - set(font_instances.keys())
    new = set(font_instances.keys()) - set(expected_instances.keys())
    same = set(font_instances.keys()) & set(expected_instances.keys())
    # check if instances have correct weight.
    if all("wght" in expected_instances[i] for i in expected_instances):
        wght_wrong = any(font_instances[i]["wght"] != expected_instances[i]["wght"] for i in same)
    else:
        wght_wrong = False

    md_table = markdown_table(table)
    if any([wght_wrong, missing, new]):
        hints = ""
        if missing:
            hints += "- Add missing instances\n"
        if new:
            hints += "- Delete additional instances\n"
        if wght_wrong:
            hints += "- wght coordinates are wrong for some instances"
        yield FAIL, Message('bad-fvar-instances',
                            f"fvar instances are incorrect:\n{hints}\n{md_table}")
    elif any(font_instances[i] != expected_instances[i] for i in same):
        yield WARN, Message("suspicious-fvar-coords",
            (f"fvar instance coordinates for non-wght axes are not the same as the fvar defaults. "
             f"This may be intentional so please check with the font author:\n\n{md_table}"))
    else:
        yield PASS, f"fvar instances are good:\n\n{md_table}"


@check(
    id = 'com.google.fonts/check/fvar_name_entries',
    conditions = ['is_variable_font'],
    rationale = """
        The purpose of this check is to make sure that all name entries referenced
        by variable font instances do exist in the name table.
    """,
    proposal = 'https://github.com/googlefonts/fontbakery/issues/2069'
)
def com_google_fonts_check_fvar_name_entries(ttFont):
    """All name entries referenced by fvar instances exist on the name table?"""

    failed = False
    for instance in ttFont["fvar"].instances:

        entries = [entry for entry in ttFont["name"].names
                   if entry.nameID == instance.subfamilyNameID]
        if len(entries) == 0:
            failed = True
            yield FAIL,\
                  Message("missing-name",
                          f"Named instance with coordinates {instance.coordinates}"
                          f" lacks an entry on the name table"
                          f" (nameID={instance.subfamilyNameID}).")

    if not failed:
        yield PASS, "OK"


@check(
    id = 'com.google.fonts/check/family/tnum_horizontal_metrics',
    conditions = ['RIBBI_ttFonts'],
    rationale = """
        Tabular figures need to have the same metrics in all styles in order to allow
        tables to be set with proper typographic control, but to maintain the placement
        of decimals and numeric columns between rows.

        Here's a good explanation of this:
        https://www.typography.com/techniques/fonts-for-financials/#tabular-figs
    """,
    proposal = 'https://github.com/googlefonts/fontbakery/issues/2278'
)
def com_google_fonts_check_family_tnum_horizontal_metrics(RIBBI_ttFonts):
    """All tabular figures must have the same width across the RIBBI-family."""
    tnum_widths = {}
    for ttFont in RIBBI_ttFonts:
        glyphs = ttFont.getGlyphSet()
        tnum_glyphs = [(glyph_id, glyphs[glyph_id])
                       for glyph_id in glyphs.keys()
                       if glyph_id.endswith(".tnum")]
        for glyph_id, glyph in tnum_glyphs:
            if glyph.width not in tnum_widths:
                tnum_widths[glyph.width] = [glyph_id]
            else:
                tnum_widths[glyph.width].append(glyph_id)

    if len(tnum_widths.keys()) > 1:
        max_num = 0
        most_common_width = None
        for width, glyphs in tnum_widths.items():
            if len(glyphs) > max_num:
                max_num = len(glyphs)
                most_common_width = width

        del tnum_widths[most_common_width]
        yield FAIL,\
              Message("inconsistent-widths",
                      f"The most common tabular glyph width is"
                      f" {most_common_width}. But there are other"
                      f" tabular glyphs with different widths"
                      f" such as the following ones:\n\t{tnum_widths}.")
    else:
        yield PASS, "OK"


@check(
    id = 'com.google.fonts/check/integer_ppem_if_hinted',
    conditions = ['is_hinted'],
    rationale = """
        Hinted fonts must have head table flag bit 3 set.

        Per https://docs.microsoft.com/en-us/typography/opentype/spec/head,
        bit 3 of Head::flags decides whether PPEM should be rounded. This bit should
        always be set for hinted fonts.

        Note:
        Bit 3 = Force ppem to integer values for all internal scaler math;
                May use fractional ppem sizes if this bit is clear;
    """,
    proposal = 'https://github.com/googlefonts/fontbakery/issues/2338'
)
def com_google_fonts_check_integer_ppem_if_hinted(ttFont):
    """PPEM must be an integer on hinted fonts."""

    if ttFont["head"].flags & (1 << 3):
        yield PASS, "OK"
    else:
        yield FAIL,\
              Message("bad-flags",
                      ("This is a hinted font, so it must have bit 3 set"
                       " on the flags of the head table, so that"
                       " PPEM values will be rounded into an integer"
                       " value.\n"
                       "\n"
                       "This can be accomplished by using the"
                       " 'gftools fix-hinting' command.\n"
                       "\n"
                       "# create virtualenv\n"
                       "python3 -m venv venv"
                       "\n"
                       "# activate virtualenv\n"
                       "source venv/bin/activate"
                       "\n"
                       "# install gftools\n"
                       "pip install git+https://www.github.com"
                       "/googlefonts/tools"))


@check(
    id = 'com.google.fonts/check/ligature_carets',
    conditions = ['ligature_glyphs'],
    rationale = """
        All ligatures in a font must have corresponding caret (text cursor) positions
        defined in the GDEF table, otherwhise, users may experience issues with
        caret rendering.

        If using GlyphsApp or UFOs, ligature carets can be defined as anchors with
        names starting with 'caret_'. These can be compiled with fontmake as of
        version v2.4.0.
    """,
    proposal = 'https://github.com/googlefonts/fontbakery/issues/1225'
)
def com_google_fonts_check_ligature_carets(ttFont, ligature_glyphs):
    """Are there caret positions declared for every ligature?"""
    if ligature_glyphs == -1:
        yield FAIL,\
              Message("malformed",
                      ("Failed to lookup ligatures."
                       " This font file seems to be malformed."
                       " For more info, read:"
                       " https://github.com/googlefonts/fontbakery/issues/1596"))
    elif "GDEF" not in ttFont:
        yield WARN,\
              Message("GDEF-missing",
                      ("GDEF table is missing, but it is mandatory"
                       " to declare it on fonts that provide ligature"
                       " glyphs because the caret (text cursor)"
                       " positioning for each ligature must be"
                       " provided in this table."))
    else:
        lig_caret_list = ttFont["GDEF"].table.LigCaretList
        if lig_caret_list is None:
            missing = set(ligature_glyphs)
        else:
            missing = set(ligature_glyphs) - set(lig_caret_list.Coverage.glyphs)

        if lig_caret_list is None or lig_caret_list.LigGlyphCount == 0:
            yield WARN,\
                  Message("lacks-caret-pos",
                          "This font lacks caret position values"
                          " for ligature glyphs on its GDEF table.")
        elif missing:
            missing = "\n\t- ".join(sorted(missing))
            yield WARN,\
                  Message("incomplete-caret-pos-data",
                          f"This font lacks caret positioning"
                          f" values for these ligature glyphs:"
                          f"\n\t- {missing}\n\n  ")
        else:
            yield PASS, "Looks good!"


@check(
    id = 'com.google.fonts/check/kerning_for_non_ligated_sequences',
    conditions = ['ligatures',
                  'has_kerning_info'],
    rationale = """
        Fonts with ligatures should have kerning on the corresponding non-ligated
        sequences for text where ligatures aren't used
        (eg https://github.com/impallari/Raleway/issues/14).
    """,
    proposal = 'https://github.com/googlefonts/fontbakery/issues/1145'
)
def com_google_fonts_check_kerning_for_non_ligated_sequences(ttFont, config, ligatures, has_kerning_info):
    """Is there kerning info for non-ligated sequences?"""
    def look_for_nonligated_kern_info(table):
        for pairpos in table.SubTable:
            for i, glyph in enumerate(pairpos.Coverage.glyphs):
                if not hasattr(pairpos, 'PairSet'):
                    continue
                for pairvalue in pairpos.PairSet[i].PairValueRecord:
                    kern_pair = (glyph, pairvalue.SecondGlyph)
                    if kern_pair in ligature_pairs:
                        ligature_pairs.remove(kern_pair)

    def ligatures_sequences(pairs):
        return [f"{first} + {second}" for first, second in pairs]

    if ligatures == -1:
        yield FAIL,\
              Message("malformed",
                      "Failed to lookup ligatures."
                      " This font file seems to be malformed."
                      " For more info, read:"
                      " https://github.com/googlefonts/fontbakery/issues/1596")
    else:
        ligature_pairs = []
        for first, comp in ligatures.items():
            for components in comp:
                while components:
                    pair = (first, components[0])
                    if pair not in ligature_pairs:
                        ligature_pairs.append(pair)
                    first = components[0]
                    components.pop(0)

        for record in ttFont["GSUB"].table.FeatureList.FeatureRecord:
            if record.FeatureTag == 'kern':
                for index in record.Feature.LookupListIndex:
                    lookup = ttFont["GSUB"].table.LookupList.Lookup[index]
                    look_for_nonligated_kern_info(lookup)

        if ligature_pairs:
            yield WARN,\
                  Message("lacks-kern-info",
                          f"GPOS table lacks kerning info for the following"
                          f" non-ligated sequences:\n\n"
                          f"{bullet_list(config, ligatures_sequences(ligature_pairs))}")
        else:
            yield PASS, ("GPOS table provides kerning info for "
                         "all non-ligated sequences.")


@check(
    id = 'com.google.fonts/check/name/family_and_style_max_length',
    rationale = """
        According to a GlyphsApp tutorial [1], in order to make sure all versions of
        Windows recognize it as a valid font file, we must make sure that the
        concatenated length of the familyname (NameID.FONT_FAMILY_NAME) and
        style (NameID.FONT_SUBFAMILY_NAME) strings in the name table do not
        exceed 20 characters.

        After discussing the problem in more detail at FontBakery issue #2179 [2] we
        decided that allowing up to 27 chars would still be on the safe side, though.

        [1] https://glyphsapp.com/tutorials/multiple-masters-part-3-setting-up-instances
        [2] https://github.com/googlefonts/fontbakery/issues/2179
    """,
    proposal = 'https://github.com/googlefonts/fontbakery/issues/1488',
    misc_metadata = {
        # Somebody with access to Windows should make some experiments
        # and confirm that this is really the case.
        'affects': [('Windows', 'unspecified')],
    }
)
def com_google_fonts_check_name_family_and_style_max_length(ttFont):
    """Combined length of family and style must not exceed 27 characters."""
    from fontbakery.utils import (get_name_entries,
                                  get_name_entry_strings)
    failed = False
    for familyname in get_name_entries(ttFont,
                                       NameID.FONT_FAMILY_NAME):
        # we'll only match family/style name entries with the same platform ID:
        plat = familyname.platformID
        familyname_str = familyname.string.decode(familyname.getEncoding())
        for stylename_str in get_name_entry_strings(ttFont,
                                                    NameID.FONT_SUBFAMILY_NAME,
                                                    platformID=plat):
            if len(familyname_str + stylename_str) > 27:
                failed = True
                yield WARN,\
                      Message("too-long",
                              f"The combined length of family and style"
                              f" exceeds 27 chars in the following"
                              f" '{PlatformID(plat).name}' entries:\n"
                              f" FONT_FAMILY_NAME = '{familyname_str}' /"
                              f" SUBFAMILY_NAME = '{stylename_str}'\n"
                              f"\n"
                              f"Please take a look at the conversation at"
                              f" https://github.com/googlefonts/fontbakery/issues/2179"
                              f" in order to understand the reasoning behind these"
                              f" name table records max-length criteria.")
    if not failed:
        yield PASS, "All name entries are good."


@disable
@check(
    id = 'com.google.fonts/check/glyphs_file/name/family_and_style_max_length',
)
def com_google_fonts_check_glyphs_file_name_family_and_style_max_length(glyphsFile):
    """Combined length of family and style must not exceed 27 characters."""

    too_long = []
    for instance in glyphsFile.instances:
        if len(instance.fullName) > 27:
            too_long.append(instance.fullName)

    if too_long:
        too_long_list = "\n  - " + "\n  - ".join(too_long)
        yield WARN,\
              Message("too-long",
                      f"The fullName length exceeds 27 chars in the"
                      f" following entries:\n"
                      f"{too_long_list}\n"
                      f"\n"
                      f"Please take a look at the conversation at"
                      f" https://github.com/googlefonts/fontbakery/issues/2179"
                      f" in order to understand the reasoning behind these"
                      f" name table records max-length criteria.")
    else:
        yield PASS, "ok"


@check(
    id = 'com.google.fonts/check/name/line_breaks',
    rationale = """
        There are some entries on the name table that may include more than one line
        of text. The Google Fonts team, though, prefers to keep the name table entries
        short and simple without line breaks.

        For instance, some designers like to include the full text of a font license in
        the "copyright notice" entry, but for the GFonts collection this entry should
        only mention year, author and other basic info in a manner enforced by
        com.google.fonts/check/font_copyright
    """,
    proposal = 'legacy:check/057'
)
def com_google_fonts_check_name_line_breaks(ttFont):
    """Name table entries should not contain line-breaks."""
    failed = False
    for name in ttFont["name"].names:
        string = name.string.decode(name.getEncoding())
        if "\n" in string:
            failed = True
            yield FAIL,\
                  Message("line-break",
                          f"Name entry {NameID(name.nameID).name}"
                          f" on platform {PlatformID(name.platformID).name}"
                          f" contains a line-break.")
    if not failed:
        yield PASS, ("Name table entries are all single-line"
                     " (no line-breaks found).")


@check(
    id = 'com.google.fonts/check/name/rfn',
    rationale = """
        Some designers adopt the "Reserved Font Name" clause of the OFL license. This
        means that the original author reserves the rights to the family name and other
        people can only distribute modified versions using a different family name.

        Google Fonts published updates to the fonts in the collection in order to fix
        issues and/or implement further improvements to the fonts. It is important to
        keep the family name so that users of the webfonts can benefit from the updates.
        Since it would forbid such usage scenario, all families in the GFonts collection
        are required to not adopt the RFN clause.

        This check ensures "Reserved Font Name" is not mentioned in the name table.
    """,
    conditions = ['not rfn_exception'],
    proposal = 'https://github.com/googlefonts/fontbakery/issues/1380'
)
def com_google_fonts_check_name_rfn(ttFont, familyname):
    """Name table strings must not contain the string 'Reserved Font Name'."""
    ok = True
    for entry in ttFont["name"].names:
        string = entry.toUnicode()
        if "This license is copied below, and is also available with a FAQ" in string:
            # This is the OFL text in a name table entry.
            # It contains the term 'Reserved Font Name' in one of its clauses,
            # so we will ignore this here.
            continue

        import re
        matches = re.search(r'with [Rr]eserved [Ff]ont [Nn]ame (.*)\.', string)

        if matches:
            reserved_font_name = matches.group(1)
            if reserved_font_name in familyname:
                yield FAIL,\
                      Message("rfn",
                              f'Name table entry contains "Reserved Font Name":\n'
                              f'\t"{string}"\n'
                              f'\n'
                              f'This is an error except in a few specific rare cases.')
            else:
                yield WARN,\
                      Message("legacy-familyname",
                              f'Name table entry contains "Reserved Font Name" for a'
                              f' family name ({reserved_font_name}) that differs'
                              f' from the currently used family name ({familyname}),'
                              f' which is fine.')
            ok = False

    if ok:
        yield PASS, 'None of the name table strings contain "Reserved Font Name".'


@check(
    id = 'com.google.fonts/check/family/control_chars',
    conditions = ['are_ttf'],
    rationale = """
        Use of some unacceptable control characters in the U+0000 - U+001F range can
        lead to rendering issues on some platforms.

        Acceptable control characters are defined as .null (U+0000) and
        CR (U+000D) for this test.
    """,
    proposal = 'https://github.com/googlefonts/fontbakery/pull/2430'
)
def com_google_fonts_check_family_control_chars(ttFonts):
    """Does font file include unacceptable control character glyphs?"""
    # list of unacceptable control character glyph names
    # definition includes the entire control character Unicode block except:
    #    - .null (U+0000)
    #    - CR (U+000D)
    unacceptable_cc_list = [
        "uni0001",
        "uni0002",
        "uni0003",
        "uni0004",
        "uni0005",
        "uni0006",
        "uni0007",
        "uni0008",
        "uni0009",
        "uni000A",
        "uni000B",
        "uni000C",
        "uni000E",
        "uni000F",
        "uni0010",
        "uni0011",
        "uni0012",
        "uni0013",
        "uni0014",
        "uni0015",
        "uni0016",
        "uni0017",
        "uni0018",
        "uni0019",
        "uni001A",
        "uni001B",
        "uni001C",
        "uni001D",
        "uni001E",
        "uni001F"
    ]

    # a dict with key:value of font path that failed check : list of unacceptable glyph names
    failed_font_dict = {}

    for ttFont in ttFonts:
        font_failed = False
        unacceptable_glyphs_in_set = []  # a list of unacceptable glyph names identified
        glyph_name_set = set(ttFont["glyf"].glyphs.keys())
        fontname = ttFont.reader.file.name

        for unacceptable_glyph_name in unacceptable_cc_list:
            if unacceptable_glyph_name in glyph_name_set:
                font_failed = True
                unacceptable_glyphs_in_set.append(unacceptable_glyph_name)

        if font_failed:
            failed_font_dict[fontname] = unacceptable_glyphs_in_set

    if len(failed_font_dict) > 0:
        msg_unacceptable = "The following unacceptable control characters were identified:\n"
        for fnt in failed_font_dict.keys():
            msg_unacceptable += f" {fnt}: {', '.join(failed_font_dict[fnt])}\n"
        yield FAIL,\
              Message("unacceptable",
                      f"{msg_unacceptable}")
    else:
        yield PASS, ("Unacceptable control characters were not identified.")


@check(
    id = 'com.google.fonts/check/family/italics_have_roman_counterparts',
    rationale = """
        For each font family on Google Fonts, every Italic style must have
        a Roman sibling.

        This kind of problem was first observed at [1] where the Bold style was
        missing but BoldItalic was included.

        [1] https://github.com/google/fonts/pull/1482
    """,
    proposal = 'https://github.com/googlefonts/fontbakery/issues/1733'
)
def com_google_fonts_check_family_italics_have_roman_counterparts(fonts, config):
    """Ensure Italic styles have Roman counterparts."""

    italics = [f for f in fonts if 'Italic' in f]
    missing_roman = []
    for italic in italics:
        if '-' not in os.path.basename(italic) \
            or len(os.path.basename(italic).split('-')[-1].split('.')) != 2:
            yield WARN,\
                  Message('bad-filename',
                          f"Filename seems to be incorrect: '{italic}'")

        style = os.path.basename(italic).split('-')[-1].split('.')[0]
        is_varfont = '[' in style

        # to remove the axes syntax used on variable-font filenames:
        if is_varfont:
            style = style.split('[')[0]

        if style == 'Italic':
            if is_varfont:
                # "Familyname-Italic[wght,wdth].ttf" => "Familyname[wght,wdth].ttf"
                roman_counterpart = italic.replace('-Italic', '')
            else:
                # "Familyname-Italic.ttf" => "Familyname-Regular.ttf"
                roman_counterpart = italic.replace('Italic', 'Regular')
        else:
            # "Familyname-BoldItalic[wght,wdth].ttf" => "Familyname-Bold[wght,wdth].ttf"
            roman_counterpart = italic.replace('Italic', '')

        if roman_counterpart not in fonts:
            missing_roman.append(italic)

    if missing_roman:
        from fontbakery.utils import pretty_print_list
        missing_roman = pretty_print_list(config,
                                          missing_roman)
        yield FAIL,\
              Message('missing-roman',
                      f"Italics missing a Roman counterpart: {missing_roman}")
    else:
        yield PASS, "OK"


@check(
    id = 'com.google.fonts/check/repo/dirname_matches_nameid_1',
    conditions = ['gfonts_repo_structure',
                  'not is_variable_font'],
    proposal = 'https://github.com/googlefonts/fontbakery/issues/2302'
)
def com_google_fonts_check_repo_dirname_match_nameid_1(fonts,
                                                       gfonts_repo_structure):
    """Directory name in GFonts repo structure must
       match NameID 1 of the regular."""
    from fontTools.ttLib import TTFont
    from fontbakery.utils import (get_name_entry_strings,
                                  get_absolute_path,
                                  get_regular)
    regular = get_regular(fonts)
    if not regular:
        yield FAIL,\
              Message("lacks-regular",
                      "The font seems to lack a regular."
                      " If family consists of a single-weight non-Regular style only,"
                      " consider the Google Fonts specs for this case:"
                      " https://github.com/googlefonts/gf-docs/tree/main/Spec#single-weight-families")
        return

    entry = get_name_entry_strings(TTFont(regular), NameID.FONT_FAMILY_NAME)[0]
    expected = entry.lower()
    expected = "".join(expected.split(' '))
    expected = "".join(expected.split('-'))

    license, familypath, filename = get_absolute_path(regular).split(os.path.sep)[-3:]
    if familypath == expected:
        yield PASS, "OK"
    else:
        yield FAIL,\
              Message("mismatch",
                      f"Family name on the name table ('{entry}') does not match"
                      f" directory name in the repo structure ('{familypath}')."
                      f" Expected '{expected}'.")


@check(
    id = 'com.google.fonts/check/repo/vf_has_static_fonts',
    conditions = ['family_directory',
                  'gfonts_repo_structure'],
    rationale = """
        Variable font family directories kept in the google/fonts git repo may include
        a static/ subdir containing static fonts.
        
        These files are meant to be served for users that still lack support for
        variable fonts in their web browsers.
    """,
    proposal = 'https://github.com/googlefonts/fontbakery/issues/2654'
)
def com_google_fonts_check_repo_vf_has_static_fonts(family_directory):
    """A static fonts directory with at least two fonts must accompany variable fonts"""
    static_dir = os.path.join(family_directory, 'static')
    if os.path.exists(static_dir):
        has_static_fonts = any([f for f in os.listdir(static_dir)
                                if f.endswith('.ttf')])
        if has_static_fonts:
            yield PASS, 'OK'
        else:
            yield FAIL,\
                  Message("empty",
                          'There is a "static" dir but it is empty.'
                          ' Either add static fonts or delete the directory.')
    else:
        yield WARN,\
              Message("missing",
                      'Please consider adding a subdirectory called "static/"'
                      ' and including in it static font files.')


@check(
    id = 'com.google.fonts/check/repo/fb_report',
    conditions = ['family_directory'],
    rationale = """
        A FontBakery report is ephemeral and so should be used for posting issues on a
        bug-tracker instead of being hosted in the font project repository.
    """,
    proposal = 'https://github.com/googlefonts/fontbakery/issues/2888'
)
def com_google_fonts_check_repo_fb_report(family_directory):
    """A font repository should not include fontbakery report files"""
    from fontbakery.utils import filenames_ending_in

    has_report_files = any([f for f in filenames_ending_in(".json", family_directory)
                            if '"result"' in open(f).read()])
    if not has_report_files:
        yield PASS, 'OK'
    else:
        yield WARN,\
              Message("fb-report",
                      "There's no need to keep a copy of Font Bakery reports in the"
                      " repository, since they are ephemeral; Font Bakery has"
                      " a 'github markdown' output mode to make it easy to file"
                      " reports as issues.")


@check(
    id = "com.google.fonts/check/repo/upstream_yaml_has_required_fields",
    rationale = """
        If a family has been pushed using the gftools packager, we must check that all
        the required fields in the upstream.yaml file have been populated.
    """,
    conditions = ["upstream_yaml"],
    severity = 10,
    proposal = 'https://github.com/googlefonts/fontbakery/issues/3338'
)
def com_google_fonts_check_repo_upstream_yaml_has_required_fields(upstream_yaml):
    """Check upstream.yaml file contains all required fields"""
    required_fields = set(["branch", "files"])
    upstream_fields = set(upstream_yaml.keys())

    missing_fields = required_fields - upstream_fields
    if missing_fields:
        yield FAIL,\
              Message('missing-fields',
                      f"The upstream.yaml file is missing the following fields:"
                      f" {list(missing_fields)}")
    else:
        yield PASS, "The upstream.yaml file contains all necessary fields"


@check(
    id = 'com.google.fonts/check/repo/zip_files',
    conditions = ['family_directory'],
    rationale = """
        Sometimes people check in ZIPs into their font project repositories. While we
        accept the practice of checking in binaries, we believe that a ZIP is a step
        too far ;)

        Note: a source purist position is that only source files and build scripts
        should be checked in.
    """,
    proposal = 'https://github.com/googlefonts/fontbakery/issues/2903'
)
def com_google_fonts_check_repo_zip_files(family_directory, config):
    """A font repository should not include ZIP files"""
    from fontbakery.utils import (filenames_ending_in,
                                  pretty_print_list)

    COMMON_ZIP_EXTENSIONS = [".zip", ".7z", ".rar"]
    zip_files = []
    for ext in COMMON_ZIP_EXTENSIONS:
        zip_files.extend(filenames_ending_in(ext, family_directory))

    if not zip_files:
        yield PASS, 'OK'
    else:
        files_list = pretty_print_list(config,
                                       zip_files,
                                       sep='\n\t* ')
        yield FAIL,\
              Message("zip-files",
                      f"Please do not host ZIP files on the project repository."
                      f" These files were detected:\n"
                      f"\t* {files_list}")


@check(
    id = 'com.google.fonts/check/vertical_metrics',
    conditions = ['not remote_styles',
                  'not is_cjk_font'],
    rationale = """
        This check generally enforces Google Fonts’ vertical metrics specifications.
        In particular:
        * lineGap must be 0
        * Sum of hhea ascender+abs(descender)+linegap must be
          between 120% and 200% of UPM
        * Warning if sum is over 150% of UPM

        The threshold levels 150% (WARN) and 200% (FAIL) are somewhat arbitrarily chosen
        and may hint at a glaring mistake in the metrics calculations or UPM settings.

        Our documentation includes further information:
        https://github.com/googlefonts/gf-docs/tree/main/VerticalMetrics
    """,
    proposal = 'https://github.com/googlefonts/fontbakery/pull/3762'
)
def com_google_fonts_check_vertical_metrics(ttFont):
    """Check font follows the Google Fonts vertical metric schema"""
    from .shared_conditions import typo_metrics_enabled
    filename = os.path.basename(ttFont.reader.file.name)

    # Check necessary tables are present.
    missing_tables = False
    required = ["OS/2", "hhea", "head"]
    for key in required:
        if key not in ttFont:
            missing_tables = True
            yield FAIL,\
                  Message(f'lacks-{key}',
                          f"{filename} lacks a '{key}' table.")

    if missing_tables:
        return

    font_upm = ttFont['head'].unitsPerEm
    font_metrics = {
        'OS/2.sTypoAscender': ttFont['OS/2'].sTypoAscender,
        'OS/2.sTypoDescender': ttFont['OS/2'].sTypoDescender,
        'OS/2.sTypoLineGap': ttFont['OS/2'].sTypoLineGap,
        'hhea.ascent': ttFont['hhea'].ascent,
        'hhea.descent': ttFont['hhea'].descent,
        'hhea.lineGap': ttFont['hhea'].lineGap,
        'OS/2.usWinAscent': ttFont['OS/2'].usWinAscent,
        'OS/2.usWinDescent': ttFont['OS/2'].usWinDescent
    }
    expected_metrics = {
        'OS/2.sTypoLineGap': 0,
        'hhea.lineGap': 0,
    }

    failed = False
    warn = False

    # Check typo metrics and hhea lineGap match our expected values
    for k in expected_metrics:
        if font_metrics[k] != expected_metrics[k]:
            failed = True
            yield FAIL,\
                  Message(f'bad-{k}',
                          f'{k} is "{font_metrics[k]}" it should be {expected_metrics[k]}')

    hhea_sum = (font_metrics['hhea.ascent'] +
                abs(font_metrics['hhea.descent']) +
                font_metrics['hhea.lineGap']) / font_upm

    # Check the sum of the hhea metrics is not below 1.2
    # (120% of upm or 1200 units for 1000 upm font)
    if hhea_sum < 1.2:
        failed = True
        yield FAIL,\
            Message('bad-hhea-range',
                'The sum of hhea.ascender+abs(hhea.descender)+hhea.lineGap '
                f'is {int(hhea_sum*font_upm)} when it should be at least {int(font_upm*1.2)}')

    # Check the sum of the hhea metrics is below 2.0
    elif hhea_sum > 2.0:
        failed = True
        yield FAIL,\
            Message('bad-hhea-range',
                'The sum of hhea.ascender+abs(hhea.descender)+hhea.lineGap '
                f'is {int(hhea_sum*font_upm)} when it should be at most {int(font_upm*2.0)}')

    # Check the sum of the hhea metrics is between 1.1-1.5x of the font's upm
    elif hhea_sum > 1.5:
        warn = True
        yield WARN,\
            Message('bad-hhea-range',
                "We recommend the absolute sum of the hhea metrics should be"
                f" between 1.2-1.5x of the font's upm. This font has {hhea_sum}x ({int(hhea_sum*font_upm)})")

    if not failed and not warn:
        yield PASS, 'Vertical metrics are good'


@check(
    id = 'com.google.fonts/check/vertical_metrics_regressions',
    conditions = ['regular_remote_style',
                  'not is_cjk_font'],
    rationale = """
        If the family already exists on Google Fonts, we need to ensure that the
        checked family's vertical metrics are similar. This check will test the
        following schema which was outlined in Fontbakery issue #1162 [1]:

        - The family should visually have the same vertical metrics as the Regular
          style hosted on Google Fonts.
        
        - If the family on Google Fonts has differing hhea and typo metrics, the family
          being checked should use the typo metrics for both the hhea and typo entries.
        
        - If the family on Google Fonts has use typo metrics not enabled and the family
          being checked has it enabled, the hhea and typo metrics should use the family
          on Google Fonts winAscent and winDescent values.
        
        - If the upms differ, the values must be scaled so the visual appearance is
          the same.

        [1] https://github.com/googlefonts/fontbakery/issues/1162
    """,
    proposal = 'https://github.com/googlefonts/fontbakery/issues/1162'
)
def com_google_fonts_check_vertical_metrics_regressions(regular_ttFont, regular_remote_style):
    """Check if the vertical metrics of a family are similar to the same
    family hosted on Google Fonts."""
    import math
    from .shared_conditions import (is_variable_font,
                                    get_instance_axis_value,
                                    typo_metrics_enabled)

    gf_ttFont = regular_remote_style
    ttFont = regular_ttFont

    upm_scale = ttFont['head'].unitsPerEm / gf_ttFont['head'].unitsPerEm

    gf_has_typo_metrics = typo_metrics_enabled(gf_ttFont)
    ttFont_has_typo_metrics = typo_metrics_enabled(ttFont)

    failed = False
    if gf_has_typo_metrics:
        if not ttFont_has_typo_metrics:
            failed = True
            yield FAIL, Message("bad-fsselection-bit7",
                                "fsSelection bit 7 needs to be enabled because "
                                "the family on Google Fonts has it enabled.")
            # faux enable it so we can see which metrics also need changing
            ttFont_has_typo_metrics = True
        expected_ascender = math.ceil(gf_ttFont['OS/2'].sTypoAscender * upm_scale)
        expected_descender = math.ceil(gf_ttFont['OS/2'].sTypoDescender * upm_scale)
    else:
        # if the win metrics have changed, the updated fonts must have bit 7
        # enabled
        if (math.ceil(gf_ttFont['OS/2'].usWinAscent * upm_scale),
            math.ceil(gf_ttFont['OS/2'].usWinDescent * upm_scale)) != \
           (math.ceil(ttFont['OS/2'].usWinAscent),
            math.ceil(ttFont['OS/2'].usWinDescent)):
               if not ttFont_has_typo_metrics:
                   failed = True
                   yield FAIL, Message("bad-fsselection-bit7",
                                       "fsSelection bit 7 needs to be enabled "
                                       "because the win metrics differ from "
                                       "the family on Google Fonts.")
                   ttFont_has_typo_metrics = True
        expected_ascender = math.ceil(gf_ttFont["OS/2"].usWinAscent * upm_scale)
        expected_descender = -math.ceil(gf_ttFont["OS/2"].usWinDescent * upm_scale)

    full_font_name = ttFont['name'].getName(
        NameID.FULL_FONT_NAME,
        PlatformID.WINDOWS,
        UnicodeEncodingID.UNICODE_1_1,
        WindowsLanguageID.ENGLISH_USA
    ).toUnicode()
    typo_ascender = ttFont['OS/2'].sTypoAscender
    typo_descender = ttFont['OS/2'].sTypoDescender
    hhea_ascender = ttFont['hhea'].ascent
    hhea_descender = ttFont['hhea'].descent

    if typo_ascender != expected_ascender:
        failed = True
        yield FAIL,\
              Message("bad-typo-ascender",
                      f"{full_font_name}:"
                      f" OS/2 sTypoAscender is {typo_ascender}"
                      f" when it should be {expected_ascender}")

    if typo_descender != expected_descender:
        failed = True
        yield FAIL,\
              Message("bad-typo-descender",
                      f"{full_font_name}:"
                      f" OS/2 sTypoDescender is {typo_descender}"
                      f" when it should be {expected_descender}")

    if hhea_ascender != expected_ascender:
        failed = True
        yield FAIL,\
              Message("bad-hhea-ascender",
                      f"{full_font_name}:"
                      f" hhea Ascender is {hhea_ascender}"
                      f" when it should be {expected_ascender}")

    if hhea_descender != expected_descender:
        failed = True
        yield FAIL,\
              Message("bad-hhea-descender",
                      f"{full_font_name}:"
                      f" hhea Descender is {hhea_descender}"
                      f" when it should be {expected_descender}")
    if not failed:
        yield PASS, "Vertical metrics have not regressed."


@check(
    id = 'com.google.fonts/check/cjk_vertical_metrics',
    conditions = ['is_cjk_font',
                  'not remote_styles'],
    rationale = """
        CJK fonts have different vertical metrics when compared to Latin fonts.
        We follow the schema developed by dr Ken Lunde for Source Han Sans and
        the Noto CJK fonts.

        Our documentation includes further information:
        https://github.com/googlefonts/gf-docs/tree/main/Spec#cjk-vertical-metrics
    """,
    proposal = 'https://github.com/googlefonts/fontbakery/pull/2797'
)
def com_google_fonts_check_cjk_vertical_metrics(ttFont):
    """Check font follows the Google Fonts CJK vertical metric schema"""
    from .shared_conditions import is_cjk_font, typo_metrics_enabled
    filename = os.path.basename(ttFont.reader.file.name)

    # Check necessary tables are present.
    missing_tables = False
    required = ["OS/2", "hhea", "head"]
    for key in required:
        if key not in ttFont:
            missing_tables = True
            yield FAIL,\
                  Message(f'lacks-{key}',
                          f"{filename} lacks a '{key}' table.")

    if missing_tables:
        return

    font_upm = ttFont['head'].unitsPerEm
    font_metrics = {
        'OS/2.sTypoAscender': ttFont['OS/2'].sTypoAscender,
        'OS/2.sTypoDescender': ttFont['OS/2'].sTypoDescender,
        'OS/2.sTypoLineGap': ttFont['OS/2'].sTypoLineGap,
        'hhea.ascent': ttFont['hhea'].ascent,
        'hhea.descent': ttFont['hhea'].descent,
        'hhea.lineGap': ttFont['hhea'].lineGap,
        'OS/2.usWinAscent': ttFont['OS/2'].usWinAscent,
        'OS/2.usWinDescent': ttFont['OS/2'].usWinDescent
    }
    expected_metrics = {
        'OS/2.sTypoAscender': round(font_upm * 0.88),
        'OS/2.sTypoDescender': round(font_upm * -0.12),
        'OS/2.sTypoLineGap': 0,
        'hhea.lineGap': 0,
    }

    failed = False
    warn = False

    # Check fsSelection bit 7 is not enabled
    if typo_metrics_enabled(ttFont):
        failed = True
        yield FAIL,\
              Message('bad-fselection-bit7',
                      'OS/2 fsSelection bit 7 must be disabled')

    # Check typo metrics and hhea lineGap match our expected values
    for k in expected_metrics:
        if font_metrics[k] != expected_metrics[k]:
            failed = True
            yield FAIL,\
                  Message(f'bad-{k}',
                          f'{k} is "{font_metrics[k]}" it should be {expected_metrics[k]}')

    # Check hhea and win values match
    if font_metrics['hhea.ascent'] != font_metrics['OS/2.usWinAscent']:
        failed = True
        yield FAIL,\
              Message('ascent-mismatch',
                      'hhea.ascent must match OS/2.usWinAscent')

    if abs(font_metrics['hhea.descent']) != font_metrics['OS/2.usWinDescent']:
        failed = True
        yield FAIL,\
              Message('descent-mismatch',
                      'hhea.descent must match absolute value of OS/2.usWinDescent')

    # Check the sum of the hhea metrics is between 1.1-1.5x of the font's upm
    hhea_sum = (font_metrics['hhea.ascent'] +
                abs(font_metrics['hhea.descent']) +
                font_metrics['hhea.lineGap']) / font_upm
    if not 1.1 < hhea_sum <= 1.5:
        warn = True
        yield WARN,\
              Message('bad-hhea-range',
                      f"We recommend the absolute sum of the hhea metrics should be"
                      f" between 1.1-1.4x of the font's upm. This font has {hhea_sum}x")

    if not failed and not warn:
        yield PASS, 'Vertical metrics are good'


@check(
    id = 'com.google.fonts/check/cjk_vertical_metrics_regressions',
    conditions = ['is_cjk_font',
                  'regular_remote_style'],
    rationale = """
        Check CJK family has the same vertical metrics as the same family
        hosted on Google Fonts.
    """,
    proposal = 'https://github.com/googlefonts/fontbakery/pull/3244'
)
def com_google_fonts_check_cjk_vertical_metrics_regressions(regular_ttFont, regular_remote_style):
    """Check if the vertical metrics of a CJK family are similar to the same
    family hosted on Google Fonts."""
    import math
    gf_ttFont = regular_remote_style
    ttFont = regular_ttFont

    upm_scale = ttFont['head'].unitsPerEm / gf_ttFont['head'].unitsPerEm

    failed = False
    for tbl, attrib in [
        ("OS/2", "sTypoAscender"),
        ("OS/2", "sTypoDescender"),
        ("OS/2", "sTypoLineGap"),
        ("OS/2", "usWinAscent"),
        ("OS/2", "usWinDescent"),
        ("hhea", "ascent"),
        ("hhea", "descent"),
        ("hhea", "lineGap"),
        ]:
        gf_val = math.ceil(getattr(gf_ttFont[tbl], attrib) * upm_scale)
        f_val = math.ceil(getattr(ttFont[tbl], attrib))
        if gf_val != f_val:
            failed = True
            yield FAIL,\
                  Message("cjk-metric-regression",
                          f" {tbl} {attrib} is {f_val}"
                          f" when it should be {gf_val}")
    if not failed:
        yield PASS, "CJK vertical metrics are good"


@check(
    id = 'com.google.fonts/check/cjk_not_enough_glyphs',
    conditions = ['is_cjk_font'],
    rationale = """
        Hangul has 40 characters and it's the smallest CJK writing system.

        If a font contains less CJK glyphs than this writing system, we inform the
        user that some glyphs may be encoded incorrectly.
    """,
    proposal = 'https://github.com/googlefonts/fontbakery/pull/3214'
)
def com_google_fonts_check_cjk_not_enough_glyphs(ttFont):
    """Does the font contain less than 40 CJK characters?"""
    from .shared_conditions import get_cjk_glyphs
    cjk_glyphs = get_cjk_glyphs(ttFont)
    cjk_glyph_count = len(cjk_glyphs)
    if cjk_glyph_count > 0 and cjk_glyph_count < 40:
        if cjk_glyph_count == 1:
            N_CJK_glyphs = "There is only one CJK glyph"
        else:
            N_CJK_glyphs = f"There are only {cjk_glyph_count} CJK glyphs"

        yield WARN,\
              Message('cjk-not-enough-glyphs',
                      f"{N_CJK_glyphs} when there needs to be at least 40"
                      f" in order to support the smallest CJK writing system, Hangul.\n"
                      f"The following CJK glyphs were found:\n"
                      f"{cjk_glyphs}\n"
                      f"Please check that these glyphs have the correct unicodes.")
    else:
        yield PASS, "Font has the correct quantity of CJK glyphs"


@check(
    id = 'com.google.fonts/check/varfont_duplicate_instance_names',
    rationale = """
        This check's purpose is to detect duplicate named instances names in a
        given variable font.
        Repeating instance names may be the result of instances for several VF axes
        defined in `fvar`, but since currently only weight+italic tokens are allowed
        in instance names as per GF specs, they ended up repeating.
        Instead, only a base set of fonts for the most default representation of the
        family can be defined through instances in the `fvar` table, all other
        instances will have to be left to access through the `STAT` table.
    """,
    conditions = ['is_variable_font'],
    proposal = 'https://github.com/googlefonts/fontbakery/issues/2986'
)
def com_google_fonts_check_varfont_duplicate_instance_names(ttFont):
    """Check variable font instances don't have duplicate names"""
    seen = set()
    duplicate = set()
    found_all_eng_name_recs = True
    PLAT_ID = PlatformID.WINDOWS
    ENC_ID = WindowsEncodingID.UNICODE_BMP
    LANG_ID = WindowsLanguageID.ENGLISH_USA

    for instance in ttFont['fvar'].instances:
        name_id = instance.subfamilyNameID
        name = ttFont['name'].getName(name_id, PLAT_ID, ENC_ID, LANG_ID)

        if name:
            name = name.toUnicode()

            if name in seen:
                duplicate.add(name)
            else:
                seen.add(name)
        else:
            found_all_eng_name_recs = False
            yield FAIL, Message(
                'name-record-not-found',
                f"A 'name' table record for platformID {PLAT_ID},"
                f" encodingID {ENC_ID}, languageID {LANG_ID}({LANG_ID:04X}),"
                f" and nameID {name_id} was not found.")

    if duplicate:
        duplicate_instances = ''.join(f'* {inst}\n' for inst in sorted(duplicate))
        yield FAIL,\
              Message('duplicate-instance-names',
                      'Following instances names are duplicate:\n\n'
                      f'{duplicate_instances}')

    elif found_all_eng_name_recs:
        yield PASS, "Instance names are unique"


@check(
    id = 'com.google.fonts/check/varfont/unsupported_axes',
    rationale = """
        The 'ital' axis is not supported yet in Google Chrome.

        For the time being, we need to ensure that VFs do not contain this axis.
        Once browser support is better, we can deprecate this check.

        For more info regarding browser support, see:
        https://arrowtype.github.io/vf-slnt-test/
    """,
    conditions = ['is_variable_font'],
    proposal = 'https://github.com/googlefonts/fontbakery/issues/2866'
)
def com_google_fonts_check_varfont_unsupported_axes(ttFont):
    """ Ensure VFs do not contain the ital axis. """
    from fontbakery.profiles.shared_conditions import ital_axis
    if ital_axis(ttFont):
        yield FAIL,\
              Message("unsupported-ital",
                      'The "ital" axis is not yet well supported on Google Chrome.')
    else:
        yield PASS, "Looks good!"


@check(
    id = 'com.google.fonts/check/varfont/grade_reflow',
    rationale = """
        The grade (GRAD) axis should not change any advanceWidth or kerning data
        across its design space. This is because altering the advance width of glyphs
        can cause text reflow.
    """,
    conditions = ['is_variable_font'],
    proposal = 'https://github.com/googlefonts/fontbakery/issues/3187'
)
def com_google_fonts_check_varfont_grade_reflow(ttFont, config):
    """ Ensure VFs with the GRAD axis do not vary horizontal advance. """
    from fontbakery.profiles.shared_conditions import grad_axis
    from fontbakery.utils import (all_kerning,
                                  pretty_print_list)
    if not grad_axis(ttFont):
        yield SKIP,\
              Message("no-grad",
                      "This font has no GRAD axis")
        return

    gvar = ttFont["gvar"]
    bad_glyphs = set()
    for glyph, deltas in gvar.variations.items():
        for delta in deltas:
            if "GRAD" not in delta.axes:
                continue
            if any(c is not None and c != (0, 0)
                   for c in delta.coordinates[-4:]):
                bad_glyphs.add(glyph)

    if bad_glyphs:
        bad_glyphs_list = pretty_print_list(config,
                                            list(bad_glyphs))
        yield FAIL,\
              Message("grad-causes-reflow",
                      f"The following glyphs have variation in horizontal"
                      f" advance due to the GRAD axis: {bad_glyphs_list}")

    # Determine if any kerning rules vary the horizontal advance.
    # This is going to get grubby.
    bad_kerning = False

    if "GDEF" in ttFont and hasattr(ttFont["GDEF"].table, "VarStore"):
        effective_regions = []
        varstore = ttFont["GDEF"].table.VarStore
        regions = varstore.VarRegionList.Region
        grad_index = [x.axisTag == "GRAD"
                      for x in ttFont["fvar"].axes].index(True)
        for ix, region in enumerate(regions):
            axis_tent = region.VarRegionAxis[grad_index]
            effective = (axis_tent.StartCoord != axis_tent.PeakCoord
                         or axis_tent.PeakCoord != axis_tent.EndCoord)
            if effective:
              effective_regions.append(ix)

        # Some regions vary *something* along the GRAD axis. But what?
        if effective_regions:
            kerning = all_kerning(ttFont)
            for left, right, v1, v2 in kerning:
                if v1 and hasattr(v1, "XAdvDevice") and v1.XAdvDevice:
                    variation = [v1.XAdvDevice.StartSize, v1.XAdvDevice.EndSize]
                    regions = varstore.VarData[variation[0]].VarRegionIndex
                    if any(region in effective_regions for region in regions):
                        deltas = varstore.VarData[variation[0]].Item[variation[1]]
                        effective_deltas = [deltas[ix]
                                            for ix, region in enumerate(regions)
                                            if region in effective_regions]
                        if any(x for x in effective_deltas):
                            yield FAIL,\
                                  Message("grad-kern-causes-reflow",
                                          f"Kerning rules cause variation in"
                                          f" horizontal advance on the GRAD axis"
                                          f" (e.g. {left}/{right})")
                            bad_kerning = True
                            break

    # Check kerning here
    if not bad_glyphs and not bad_kerning:
        yield PASS, ("No variations or kern rules vary "
                     "horizontal advance along the GRAD axis")


@check(
    id = 'com.google.fonts/check/metadata/gf_axisregistry_bounds',
    rationale = """
        Each axis range in a METADATA.pb file must be registered, and within the bounds
        of the axis definition in the Google Fonts Axis Registry, available at
        https://github.com/google/fonts/tree/main/axisregistry
    """,
    conditions = ['is_variable_font',
                  'family_metadata',
                  'GFAxisRegistry'],
    proposal = 'https://github.com/googlefonts/fontbakery/issues/3010'
)
def com_google_fonts_check_gf_axisregistry_bounds(family_metadata, GFAxisRegistry):
    """ Validate METADATA.pb axes values are within gf_axisregistry bounds. """
    passed = True
    for axis in family_metadata.axes:
        if axis.tag in GFAxisRegistry.keys():
            expected = GFAxisRegistry[axis.tag]
            if axis.min_value < expected.min_value or axis.max_value > expected.max_value:
                passed = False
                yield FAIL,\
                      Message('bad-axis-range',
                              f"The range in the font variation axis"
                              f" '{axis.tag}' ({expected.display_name}"
                              f" min:{axis.min_value} max:{axis.max_value})"
                              f" does not comply with the expected maximum range,"
                              f" as defined on Google Fonts Axis Registry"
                              f" (min:{expected.min_value} max:{expected.max_value}).")
    if passed:
        yield PASS, "OK"


@check(
    id = 'com.google.fonts/check/metadata/gf_axisregistry_valid_tags',
    rationale = """
        Ensure all axes in a METADATA.pb file are registered in the
        Google Fonts Axis Registry, available at
        https://github.com/google/fonts/tree/main/axisregistry

        Why does Google Fonts have its own Axis Registry?

        We support a superset of the OpenType axis registry axis set, and use
        additional metadata for each axis. Axes present in a font file but not in this
        registry will not function via our API. No variable font is expected to
        support all of the axes here.

        Any font foundry or distributor library that offers variable fonts has a
        implicit, latent, de-facto axis registry, which can be extracted by scanning
        the library for axes' tags, labels, and min/def/max values. While in 2016
        Microsoft originally offered to include more axes in the OpenType 1.8
        specification (github.com/microsoft/OpenTypeDesignVariationAxisTags), as of
        August 2020, this effort has stalled. We hope more foundries and distributors
        will publish documents like this that make their axes explicit, to encourage
        of adoption of variable fonts throughout the industry, and provide source
        material for a future update to the OpenType specification's axis registry.
    """,
    conditions = ['is_variable_font',
                  'family_metadata',
                  'GFAxisRegistry'],
    proposal = 'https://github.com/googlefonts/fontbakery/issues/3022'
)
def com_google_fonts_check_gf_axisregistry_valid_tags(family_metadata, GFAxisRegistry):
    """ Validate METADATA.pb axes tags are defined in gf_axisregistry. """
    passed = True
    for axis in family_metadata.axes:
        if axis.tag not in GFAxisRegistry.keys():
            passed = False
            yield FAIL,\
                  Message('bad-axis-tag',
                          f"The font variation axis '{axis.tag}'"
                          f" is not yet registered on Google Fonts Axis Registry.")

    if passed:
        yield PASS, "OK"


@check(
    id = 'com.google.fonts/check/gf_axisregistry/fvar_axis_defaults',
    rationale = """
        Check that axis defaults have a corresponding fallback name registered at the
        Google Fonts Axis Registry, available at
        https://github.com/google/fonts/tree/main/axisregistry

        This is necessary for the following reasons:

        To get ZIP files downloads on Google Fonts to be accurate — otherwise the
        chosen default font is not generated. The Newsreader family, for instance, has
        a default value on the 'opsz' axis of 16pt. If 16pt was not a registered
        fallback position, then the ZIP file would instead include another position
        as default (such as 14pt).

        For the Variable fonts to display the correct location on the specimen page.

        For VF with no weight axis to be displayed at all. For instance, Ballet, which
        has no weight axis, was not appearing in sandbox because default position on
        'opsz' axis was 16pt, and it was not yet a registered fallback positon.
    """,
    conditions = ['is_variable_font',
                  'GFAxisRegistry'],
    proposal = 'https://github.com/googlefonts/fontbakery/issues/3141'
)
def com_google_fonts_check_gf_axisregistry_fvar_axis_defaults(ttFont, GFAxisRegistry):
    """ Validate defaults on fvar table match registered fallback names in GFAxisRegistry. """

    passed = True
    for axis in ttFont['fvar'].axes:
        if axis.axisTag not in GFAxisRegistry:
            continue
        fallbacks = GFAxisRegistry[axis.axisTag].fallback
        if axis.defaultValue not in [f.value for f in fallbacks]:
            passed = False
            yield FAIL,\
                  Message('not-registered',
                          f"The defaul value {axis.axisTag}:{axis.defaultValue} is not"
                          f" registered as an axis fallback name on the Google Axis Registry.\n"
                          f"\tYou should consider suggesting the addition of this value to the registry"
                          f" or adopted one of the existing fallback names for this axis:\n"
                          f"\t{fallbacks}")
    if passed:
        yield PASS, "OK"


@check(
    id = 'com.google.fonts/check/STAT/gf_axisregistry',
    rationale = """
        Check that particle names and values on STAT table match the fallback names
        in each axis entry at the Google Fonts Axis Registry, available at
        https://github.com/google/fonts/tree/main/axisregistry
    """,
    conditions = ['is_variable_font',
                  'GFAxisRegistry'],
    proposal = 'https://github.com/googlefonts/fontbakery/issues/3022'
)
def com_google_fonts_check_STAT_gf_axisregistry_names(ttFont, GFAxisRegistry):
    """ Validate STAT particle names and values match the fallback names in GFAxisRegistry. """

    def normalize_name(name):
        return ''.join(name.split(' '))

    passed = True
    format4_entries = False
    if "STAT" not in ttFont:
        yield FAIL, "Font is missing STAT table."
        return
    axis_value_array = ttFont['STAT'].table.AxisValueArray
    if not axis_value_array:
        yield FAIL, Message("missing-axis-values",
                            "STAT table is missing Axis Value Records")
        return

    for axis_value in axis_value_array.AxisValue:
        if axis_value.Format == 4:
            coords = []
            for record in axis_value.AxisValueRecord:
                axis = ttFont['STAT'].table.DesignAxisRecord.Axis[record.AxisIndex]
                coords.append(f"{axis.AxisTag}:{record.Value}")
            coords = ", ".join(coords)

            name_entry = ttFont['name'].getName(axis_value.ValueNameID,
                                                PlatformID.WINDOWS,
                                                WindowsEncodingID.UNICODE_BMP,
                                                WindowsLanguageID.ENGLISH_USA)
            format4_entries = True
            yield INFO,\
                  Message("format-4",
                          f"'{name_entry.toUnicode()}' at ({coords})")
            continue

        axis = ttFont['STAT'].table.DesignAxisRecord.Axis[axis_value.AxisIndex]
        if axis.AxisTag in GFAxisRegistry.keys():
            fallbacks = GFAxisRegistry[axis.AxisTag].fallback
            fallbacks = {f.name: f.value for f in fallbacks}

            # Here we assume that it is enough to check for only the Windows,
            # English USA entry corresponding to a given nameID. It is up to other
            # checks to ensure all different platform/encoding entries
            # with a given nameID are consistent in the name table.
            name_entry = ttFont['name'].getName(axis_value.ValueNameID,
                                                PlatformID.WINDOWS,
                                                WindowsEncodingID.UNICODE_BMP,
                                                WindowsLanguageID.ENGLISH_USA)

            # Here "name_entry" has the user-friendly name of the current AxisValue
            # We want to ensure that this string shows up as a "fallback" name
            # on the GF Axis Registry for this specific variation axis tag.
            name = normalize_name(name_entry.toUnicode())
            expected_names = [normalize_name(n) for n in fallbacks.keys()]
            if hasattr(axis_value, 'Value'): # Format 1 & 3
                is_value = axis_value.Value
            elif hasattr(axis_value, 'NominalValue'): # Format 2
                is_value = axis_value.NominalValue
            if name not in expected_names:
                expected_names = ", ".join(expected_names)
                passed = False
                yield FAIL,\
                      Message('invalid-name',
                              f"On the font variation axis '{axis.AxisTag}', the name '{name_entry.toUnicode()}'"
                              f" is not among the expected ones ({expected_names}) according"
                              f" to the Google Fonts Axis Registry.")
            elif is_value != fallbacks[name_entry.toUnicode()]:
                passed = False
                yield FAIL,\
                      Message("bad-coordinate",
                              (f"Axis Value for '{axis.AxisTag}':'{name_entry.toUnicode()}' is"
                               f" expected to be '{fallbacks[name_entry.toUnicode()]}'"
                               f" but this font has '{name_entry.toUnicode()}'='{axis_value.Value}'."))

    if format4_entries:
        yield INFO,\
              Message("format-4",
                      "The GF Axis Registry does not currently contain fallback names"
                      " for the combination of values for more than a single axis,"
                      " which is what these 'format 4' entries are designed to describe,"
                      " so this check will ignore them for now.")

    if passed:
        yield PASS, "OK"


@check(
    id = 'com.google.fonts/check/metadata/consistent_axis_enumeration',
    rationale = """
        All font variation axes present in the font files must be properly declared
        on METADATA.pb so that they can be served by the GFonts API.
    """,
    conditions = ['is_variable_font',
                  'family_metadata'],
    proposal = 'https://github.com/googlefonts/fontbakery/issues/3051'
)
def com_google_fonts_check_metadata_consistent_axis_enumeration(family_metadata, ttFont, config):
    """ Validate VF axes match the ones declared on METADATA.pb. """
    from fontbakery.utils import pretty_print_list

    passed = True
    md_axes = set(axis.tag for axis in family_metadata.axes)
    fvar_axes = set(axis.axisTag for axis in ttFont['fvar'].axes)
    missing = sorted(fvar_axes - md_axes)
    extra = sorted(md_axes - fvar_axes)

    if missing:
        passed = False
        yield FAIL,\
              Message('missing-axes',
                      f"The font variation axes {pretty_print_list(config, missing)}"
                      f" are present in the font's fvar table but are not"
                      f" declared on the METADATA.pb file.")
    if extra:
        passed = False
        yield FAIL,\
              Message('extra-axes',
                      f"The METADATA.pb file lists font variation axes that"
                      f" are not supported but this family: {pretty_print_list(config, extra)}")
    if passed:
        yield PASS, "OK"


@check(
    id = 'com.google.fonts/check/STAT/axis_order',
    rationale = """
        This is (for now) a merely informative check to detect what's the axis ordering
        declared on the STAT table of fonts in the Google Fonts collection.

        We may later update this to enforce some unified axis ordering scheme,
        yet to be determined.
    """,
    proposal = 'https://github.com/googlefonts/fontbakery/issues/3049'
)
def com_google_fonts_check_STAT_axis_order(fonts):
    """ Check axis ordering on the STAT table. """
    from collections import Counter
    from fontTools.ttLib import TTFont

    no_stat = 0
    summary = []
    for font in fonts:
        try:
            ttFont = TTFont(font)
            if 'STAT' in ttFont:
                order = {}
                for axis in ttFont['STAT'].table.DesignAxisRecord.Axis:
                    order[axis.AxisTag] = axis.AxisOrdering

                summary.append('-'.join(sorted(order.keys(), key=order.get)))
            else:
                no_stat += 1
                yield SKIP,\
                      Message('missing-STAT',
                              f"This font does not have a STAT table: {font}")
        except:
            yield INFO,\
                  Message('bad-font',
                          f"Something wrong with {font}")

    report = "\n\t".join(map(str, Counter(summary).most_common()))
    yield INFO,\
          Message('summary',
                  f"From a total of {len(fonts)} font files,"
                  f" {no_stat} of them ({100.0*no_stat/len(fonts):.2f}%)"
                  f" lack a STAT table.\n"
                  f"\n"
                  f"\tAnd these are the most common STAT axis orderings:\n"
                  f"\t{report}")


@check(
    id = 'com.google.fonts/check/metadata/escaped_strings',
    rationale = """
        In some cases we've seen designer names and other fields with escaped strings
        in METADATA files. Nowadays the strings can be full unicode strings and
        do not need escaping.
    """,
    conditions = ["metadata_file"],
    proposal = 'https://github.com/googlefonts/fontbakery/issues/2932'
)
def com_google_fonts_check_metadata_escaped_strings(metadata_file):
    """Ensure METADATA.pb does not use escaped strings."""
    passed = True
    for line in open(metadata_file, "r").readlines():
        for quote_char in ["'", "\""]:
            segments = line.split(quote_char)
            if len(segments) >= 3:
                a_string = segments[1]
                if "\\" in a_string:
                    passed = False
                    yield FAIL,\
                          Message('escaped-strings',
                                  f"Found escaped chars at '{a_string}'."
                                  f" Please use an unicode string instead.")
    if passed:
        yield PASS, "OK"


@check(
    id = 'com.google.fonts/check/metadata/designer_profiles',
    rationale = """
        Google Fonts has a catalog of designers.

        This check ensures that the online entries of the catalog can be found based
        on the designer names listed on the METADATA.pb file.

        It also validates the URLs and file formats are all correctly set.
    """,
    conditions = ['family_metadata'],
    proposal = 'https://github.com/googlefonts/fontbakery/issues/3083'
)
def com_google_fonts_check_metadata_designer_profiles(family_metadata):
    """METADATA.pb: Designers are listed correctly on the Google Fonts catalog?"""
    DESIGNER_INFO_RAW_URL = ("https://raw.githubusercontent.com/google/"
                             "fonts/master/catalog/designers/{}/")
    from fontbakery.utils import get_DesignerInfoProto_Message
    import requests

    # NOTE: See issue #3316
    TRANSLATE = {
        'á': 'a',
        'é': 'e',
        'í': 'i',
        'ó': 'o',
        'ú': 'u',
        'à': 'a',
        'è': 'e',
        'ì': 'i',
        'ò': 'o',
        'ù': 'u',
        'ń': 'n',
        'ø': 'o',
        'ř': 'r',
        'ś': 's',
        'ß': 'ss',
        'ł': 'l',
        'ã': 'a',
        'ı': 'i',
        'ü': 'ue'
    }
    def normalize(name):
        """ Restrict the designer name to lowercase a-z and numbers"""
        import string
        normalized_name = ""
        for c in name.lower():
            if c in string.ascii_letters or c in "0123456789":
                normalized_name += c
            elif c in TRANSLATE.keys():
                normalized_name += TRANSLATE[c]
        return normalized_name

    passed = True
    for designer in family_metadata.designer.split(','):
        designer = designer.strip()
        normalized_name = normalize(designer)
        if normalized_name == "multipledesigners":
            yield FAIL,\
                  Message("multiple-designers",
                          f"Font family {family_metadata.name} does not explicitely"
                          f" mention the names of its designers on its METADATA.pb file.")
            continue

        url = DESIGNER_INFO_RAW_URL.format(normalized_name) + "info.pb"
        response = requests.get(url)
        if response.status_code != requests.codes.OK:
            passed = False
            yield WARN,\
                  Message("profile-not-found",
                          f"It seems that {designer} is still not listed on"
                          f" the designers catalog. Please submit a photo and"
                          f" a link to a webpage where people can learn more"
                          f" about the work of this designer/typefoundry.")
            continue

        info = get_DesignerInfoProto_Message(response.content)
        if info.designer != designer.strip():
            passed = False
            yield FAIL,\
                  Message("mismatch",
                          f"Designer name at METADATA.pb ({designer})"
                          f" is not the same as listed on the designers"
                          f" catalog ({info.designer}) available at {url}")

        if info.link != "":
            passed = False
            yield FAIL,\
                  Message("link-field",
                          "Currently the link field is not used by the GFonts API."
                          " Designer webpage links should, for now, be placed"
                          " directly on the bio.html file.")

        if not info.avatar.file_name and designer != "Google":
            passed = False
            yield FAIL,\
                  Message("missing-avatar",
                          f"Designer {designer} still does not have an avatar image. "
                          f"Please provide one.")
        else:
            avatar_url = DESIGNER_INFO_RAW_URL.format(normalized_name) + info.avatar.file_name
            response = requests.get(avatar_url)
            if response.status_code != requests.codes.OK:
                passed = False
                yield FAIL,\
                      Message("bad-avatar-filename",
                              f"The avatar filename provided seems to be incorrect: ({avatar_url})")

    if passed:
        yield PASS, "OK"


@check(
    id = 'com.google.fonts/check/mandatory_avar_table',
    rationale = """
        Most variable fonts should include an avar table to correctly define
        axes progression rates.

        For example, a weight axis from 0% to 100% doesn't map directly to 100 to 1000,
        because a 10% progression from 0% may be too much to define the 200,
        while 90% may be too little to define the 900.

        If the progression rates of axes is linear, this check can be ignored.
        Fontmake will also skip adding an avar table if the progression rates
        are linear. However, we still recommend designers visually proof each
        instance is at the expected weight, width etc.
    """,
    conditions = ["is_variable_font"],
    proposal = 'https://github.com/googlefonts/fontbakery/issues/3100'
    # NOTE: This is a high-priority WARN.
)
def com_google_fonts_check_mandatory_avar_table(ttFont):
    """Ensure variable fonts include an avar table."""
    if "avar" not in ttFont:
        yield WARN,\
              Message('missing-avar',
                      "This variable font does not have an avar table.")
    else:
        yield PASS, "OK"


@check(
    id = 'com.google.fonts/check/description/family_update',
    rationale = """
        We want to ensure that any significant changes to the font family are
        properly mentioned in the DESCRIPTION file.

        In general, it means that the contents of the DESCRIPTION.en_us.html file
        will typically change if when font files are updated. Please treat this check
        as a reminder to do so whenever appropriate!
    """,
    conditions = ["description",
                  "github_gfonts_description"],
    proposal = 'https://github.com/googlefonts/fontbakery/issues/3182'
)
def com_google_fonts_check_description_family_update(description, github_gfonts_description):
    """On a family update, the DESCRIPTION.en_us.html file should ideally also be updated."""
    if github_gfonts_description == description:
        yield WARN,\
              Message('description-not-updated',
                      "The DESCRIPTION.en_us.html file in this family has not changed"
                      " in comparison to the latest font release on the"
                      " google/fonts github repo.\n"
                      "Please consider mentioning note-worthy improvements made"
                      " to the family recently.")
    else:
        yield PASS, "OK"


@check(
    id = 'com.google.fonts/check/missing_small_caps_glyphs',
    rationale = """
        Ensure small caps glyphs are available if
        a font declares smcp or c2sc OT features.
    """,
    proposal = 'https://github.com/googlefonts/fontbakery/issues/3154'
)
def com_google_fonts_check_missing_small_caps_glyphs(ttFont):
    """Check small caps glyphs are available."""

    passed = True
    if 'GSUB' in ttFont and ttFont['GSUB'].table.FeatureList is not None:
        llist = ttFont['GSUB'].table.LookupList
        for record in range(ttFont['GSUB'].table.FeatureList.FeatureCount):
            feature = ttFont['GSUB'].table.FeatureList.FeatureRecord[record]
            tag = feature.FeatureTag
            if tag in ['smcp', 'c2sc']:
                for index in feature.Feature.LookupListIndex:
                    subtable = llist.Lookup[index].SubTable[0]
                    if subtable.LookupType == 7:
                        # This is an Extension lookup
                        # used for reaching 32-bit offsets
                        # within the GSUB table.
                        subtable = subtable.ExtSubTable
                    smcp_glyphs = set(subtable.mapping.values())
                    missing = smcp_glyphs - set(ttFont.getGlyphNames())
                    if missing:
                        passed = False
                        missing = "\n\t - " + "\n\t - ".join(missing)
                        yield FAIL,\
                              Message('missing-glyphs',
                                      f"These '{tag}' glyphs are missing:\n"
                                      f"{missing}")
                break

    if passed:
        yield PASS, "OK"


@check(
    id = 'com.google.fonts/check/stylisticset_description',
    rationale = """
        Stylistic sets should provide description text. Programs such as InDesign,
        TextEdit and Inkscape use that info to display to the users so that they know
        what a given stylistic set offers.
    """,
    proposal = 'https://github.com/googlefonts/fontbakery/issues/3155'
)
def com_google_fonts_check_stylisticset_description(ttFont):
    """Ensure Stylistic Sets have description."""

    passed = True
    if 'GSUB' in ttFont and ttFont['GSUB'].table.FeatureList is not None:
        for record in range(ttFont['GSUB'].table.FeatureList.FeatureCount):
            feature = ttFont['GSUB'].table.FeatureList.FeatureRecord[record]
            tag = feature.FeatureTag
            SSETS = [f'ss{n+1:02d}' for n in range(20)]
            assert 'ss00' not in SSETS
            assert 'ss01' in SSETS
            assert 'ss20' in SSETS
            assert 'ss21' not in SSETS
            if tag in SSETS:
                if feature.Feature.FeatureParams == None:
                    passed = False
                    yield WARN,\
                          Message('missing-description',
                                  f"The stylistic set {tag} lacks"
                                  f" a description string on the 'name' table.")
                else:
                    pass # TODO: Maybe here we can add code to make sure
                         #       that the referenced nameid does exist
                         #       in the name table.
    if passed:
        yield PASS, "OK"


@check(
    id = "com.google.fonts/check/os2/use_typo_metrics",
    rationale = """
        All fonts on the Google Fonts collection should have OS/2.fsSelection bit 7
        (USE_TYPO_METRICS) set. This requirement is part of the vertical metrics scheme
        established as a Google Fonts policy aiming at a common ground supported by
        all major font rendering environments.

        For more details, read:
        https://github.com/googlefonts/gf-docs/blob/main/VerticalMetrics/README.md

        Below is the portion of that document that is most relevant to this check:

        Use_Typo_Metrics must be enabled. This will force MS Applications to use the
        OS/2 Typo values instead of the Win values. By doing this, we can freely set
        the Win values to avoid clipping and control the line height with the typo
        values. It has the added benefit of future line height compatibility. When
        a new script is added, we simply change the Win values to the new yMin
        and yMax, without needing to worry if the line height have changed.
    """,
    conditions = ['not is_cjk_font'],
    severity = 10,
    proposal = 'https://github.com/googlefonts/fontbakery/issues/3241'
)
def com_google_fonts_check_os2_fsselectionbit7(ttFonts):
    """OS/2.fsSelection bit 7 (USE_TYPO_METRICS) is set in all fonts."""

    bad_fonts = []
    for ttFont in ttFonts:
        if not ttFont["OS/2"].fsSelection & (1 << 7):
            bad_fonts.append(ttFont.reader.file.name)

    if bad_fonts:
        yield FAIL,\
              Message('missing-os2-fsselection-bit7',
                      f"OS/2.fsSelection bit 7 (USE_TYPO_METRICS) was"
                      f"NOT set in the following fonts: {bad_fonts}.")
    else:
        yield PASS, "OK"


@check(
    id = "com.google.fonts/check/meta/script_lang_tags",
    rationale = """
        The OpenType 'meta' table originated at Apple. Microsoft added it to OT with
        just two DataMap records:

        - dlng: comma-separated ScriptLangTags that indicate which scripts,
          or languages and scripts, with possible variants, the font is designed for.

        - slng: comma-separated ScriptLangTags that indicate which scripts,
          or languages and scripts, with possible variants, the font supports.


        The slng structure is intended to describe which languages and scripts the
        font overall supports. For example, a Traditional Chinese font that also
        contains Latin characters, can indicate Hant,Latn, showing that it supports
        Hant, the Traditional Chinese variant of the Hani script, and it also
        supports the Latn script.

        The dlng structure is far more interesting. A font may contain various glyphs,
        but only a particular subset of the glyphs may be truly "leading" in the design,
        while other glyphs may have been included for technical reasons. Such a
        Traditional Chinese font could only list Hant there, showing that it’s designed
        for Traditional Chinese, but the font would omit Latn, because the developers
        don’t think the font is really recommended for purely Latin-script use.

        The tags used in the structures can comprise just script, or also language
        and script. For example, if a font has Bulgarian Cyrillic alternates in the
        locl feature for the cyrl BGR OT languagesystem, it could also indicate in
        dlng explicitly that it supports bul-Cyrl. (Note that the scripts and languages
        in meta use the ISO language and script codes, not the OpenType ones).

        This check ensures that the font has the meta table containing the
        slng and dlng structures.

        All families in the Google Fonts collection should contain the 'meta' table.
        Windows 10 already uses it when deciding on which fonts to fall back to.
        The Google Fonts API and also other environments could use the data for
        smarter filtering. Most importantly, those entries should be added
        to the Noto fonts.

        In the font making process, some environments store this data in external
        files already. But the meta table provides a convenient way to store this
        inside the font file, so some tools may add the data, and unrelated tools
        may read this data. This makes the solution much more portable and universal.
    """,
    severity = 3,
    proposal = 'https://github.com/googlefonts/fontbakery/issues/3349'
)
def com_google_fonts_check_meta_script_lang_tags(ttFont):
    """Ensure fonts have ScriptLangTags declared on the 'meta' table."""

    if "meta" not in ttFont:
        yield WARN,\
              Message('lacks-meta-table',
                      "This font file does not have a 'meta' table.")

    else:
        if 'dlng' not in ttFont['meta'].data:
            yield FAIL,\
                  Message('missing-dlng-tag',
                          "Please specify which languages and scripts"
                          " this font is designed for.")
        else:
            yield INFO,\
                  Message('dlng-tag',
                          f"{ttFont['meta'].data['dlng']}")

        if 'slng' not in ttFont['meta'].data:
            yield FAIL,\
                  Message('missing-slng-tag',
                          "Please specify which languages and scripts"
                          " this font supports.")
        else:
            yield INFO,\
                  Message('slng-tag',
                          f"{ttFont['meta'].data['slng']}")


@check(
    id = "com.google.fonts/check/no_debugging_tables",
    rationale = """
        Tables such as `Debg` are useful in the pre-production stages of font
        development, but add unnecessary bloat to a production font and should
        be removed before release.
    """,
    severity = 6,
    proposal = 'https://github.com/googlefonts/fontbakery/issues/3357',
)
def com_google_fonts_check_no_debugging_tables(ttFont):
    """Ensure fonts do not contain any pre-production tables."""

    DEBUGGING_TABLES = ["Debg", "FFTM"]
    found = [t for t in DEBUGGING_TABLES if t in ttFont]
    if found:
        tables_list = ", ".join(found)
        yield WARN,\
              Message("has-debugging-tables",
                      f"This font file contains the following"
                      f" pre-production tables: {tables_list}")
    else:
        yield PASS, "OK"


@check(
    id = "com.google.fonts/check/metadata/family_directory_name",
    rationale = """
        We want the directory name of a font family to be predictable and directly
        derived from the family name, all lowercased and removing spaces.
    """,
    conditions = ['family_metadata',
                  'family_directory'],
    proposal = 'https://github.com/googlefonts/fontbakery/issues/3421',
)
def com_google_fonts_check_metadata_family_directory_name(family_metadata, family_directory):
    """Check font family directory name."""

    dir_name = os.path.basename(family_directory)
    expected = family_metadata.name.replace(" ", "").lower()
    if expected != dir_name:
        yield FAIL,\
              Message("bad-directory-name",
                      f'Family name on METADATA.pb is "{family_metadata.name}"\n'
                      f'Directory name is "{dir_name}"\n'
                      f'Expected "{expected}"')
    else:
        yield PASS, f'Directory name is "{dir_name}", as expected.'


@check(
    id = "com.google.fonts/check/render_own_name",
    rationale = """
        A base expectation is that a font family's regular/default (400 roman) style
        can render its 'menu name' (nameID 1) in itself.
    """,
    proposal = 'https://github.com/googlefonts/fontbakery/issues/3159',
)
def com_google_fonts_check_render_own_name(ttFont):
    """Check font can render its own name."""
    from fontbakery.utils import can_shape

    menu_name = ttFont["name"].getName(
        NameID.FONT_FAMILY_NAME,
        PlatformID.WINDOWS,
        WindowsEncodingID.UNICODE_BMP,
        WindowsLanguageID.ENGLISH_USA
    ).toUnicode()
    if can_shape(ttFont, menu_name):
        yield PASS, f'Font can successfully render its own name ({menu_name})'
    else:
        yield FAIL,\
              Message("render-own-name",
                      f'.notdef glyphs were found when attempting to render {menu_name}')

@check(
    id = "com.google.fonts/check/repo/sample_image",
    rationale = """
        In order to showcase what a font family looks like, the project's README.md
        file should ideally include a sample image and highlight it in the upper
        portion of the document, no more than 10 lines away from the top of the file.
    """,
    conditions = ["readme_contents",
                  "readme_directory"],
    proposal = 'https://github.com/googlefonts/fontbakery/issues/2898',
)
def com_google_fonts_check_repo_sample_image(readme_contents, readme_directory, config):
    """Check README.md has a sample image."""
    import re
    image_path = False
    line_number = 0
    for line in readme_contents.split('\n'):
        if line.strip() == "":
            continue

        line_number += 1
        # We're looking for something like this:
        # ![Raleway font sample](documents/raleway-promo.jpg)
        # And we accept both png and jpg files
        result = re.match(r'\!\[.*\]\((.*\.(png|jpg))\)', line)
        if result:
            image_path = result[1]
            break

    local_image_files = []
    for (dirpath, dirnames, filenames) in os.walk(readme_directory):
        local_image_files.extend([os.path.join(dirpath[len(readme_directory)+1:], filename)
                                  for filename in filenames
                                  if filename.endswith('.jpg') or
                                     filename.endswith('.png')])

    if local_image_files:
        sample_tip = local_image_files[0]
    else:
        sample_tip = 'samples/some-sample-image.jpg'
    MARKDOWN_IMAGE_SYNTAX_TIP = (f'You can use something like this:\n\n'
                                 f'\t![font sample]({sample_tip})')

    if image_path:
        if image_path not in local_image_files:
            yield FAIL,\
                  Message("image-missing",
                          f'The referenced sample image could not be found:'
                          f' {os.path.join(readme_directory, image_path)}\n')
        else:
            if line_number < 10:
                yield PASS, "Looks good!"
            else:
                yield WARN,\
                      Message("not-ideal-placement",
                              'Please consider placing the sample image closer'
                              ' to the top of the README document so that it is'
                              ' more immediately viewed by readers.\n')
    else: # if no image reference was found on README.md:
        if local_image_files:
            yield WARN,\
                  Message("image-not-displayed",
                          f'Even though the README.md file does not display'
                          f' a font sample image, a few image files were found:\n\n'
                          f'{bullet_list(config, local_image_files)}\n'
                          f'\n'
                          f'Please consider including one of those images on the README.\n'
                          f'{MARKDOWN_IMAGE_SYNTAX_TIP}\n')
        else:
            yield WARN,\
                  Message("no-sample",
                          f'Please add a font sample image to the README.md file.\n'
                          f'{MARKDOWN_IMAGE_SYNTAX_TIP}\n')


@check(
    id = "com.google.fonts/check/metadata/can_render_samples",
    rationale = """
        In order to prevent tofu from being seen on fonts.google.com, this check
        verifies that all samples provided on METADATA.pb can be properly
        rendered by the font.
    """,
    conditions = ["family_metadata"],
    proposal = ['https://github.com/googlefonts/fontbakery/issues/3419',
                'https://github.com/googlefonts/fontbakery/issues/3605']
)
def com_google_fonts_check_metadata_can_render_samples(ttFont, family_metadata):
    """Check samples can be rendered."""
    from fontbakery.utils import can_shape
    from gflanguages import LoadLanguages

    passed = True
    if not family_metadata.sample_glyphs:
       passed = False
       yield INFO,\
             Message('no-samples',
                     'No sample_glyphs on METADATA.pb')
    else:
        for item in family_metadata.sample_glyphs:
            if not can_shape(ttFont, item.glyphs):
                passed = False
                yield FAIL,\
                      Message('sample-glyphs',
                              f"Font can't render the following sample glyphs:\n"
                              f"'{item.name}': '{item.glyphs}'")

    languages = LoadLanguages()
    for lang in family_metadata.languages:
        # Note: checking agains all samples often results in
        #       a way too verbose output. That's why I only left
        #       the "tester" string for now.
        SAMPLES = {
            #'styles': languages[lang].sample_text.styles,
            'tester': languages[lang].sample_text.tester,
            #'specimen_16': languages[lang].sample_text.specimen_16,
            #'specimen_21': languages[lang].sample_text.specimen_21,
            #'specimen_32': languages[lang].sample_text.specimen_32,
            #'specimen_36': languages[lang].sample_text.specimen_36,
            #'specimen_48': languages[lang].sample_text.specimen_48
        }
        for sample_type, sample_text in SAMPLES.items():
            if not can_shape(ttFont, sample_text):
                passed = False
                yield FAIL,\
                      Message('sample-text',
                              f'Font can\'t render "{lang}" sample text:\n'
                              f'"{sample_text}"\n')

    if passed:
       yield PASS, "OK."


@check(
    id = "com.google.fonts/check/metadata/category_hints",
    rationale = """
        Sometimes the font familyname contains words that hint at which is the most
        likely correct category to be declared on METADATA.pb
    """,
    conditions = ["family_metadata"],
    proposal = 'https://github.com/googlefonts/fontbakery/issues/3624'
)
def com_google_fonts_check_metadata_category_hint(family_metadata):
    """Check if category on METADATA.pb matches what can be inferred from the family name."""

    HINTS = {
        "SANS_SERIF": ["Sans",
                       "Grotesk",
                       "Grotesque"],
        "SERIF": ["Old Style",
                  "Transitional",
                  "Garamond",
                  "Serif",
                  "Slab"],
        "DISPLAY": ["Display"],
        "HANDWRITING": ["Hand",
                        "Script"]
    }

    inferred_category = None
    for category, hints in HINTS.items():
        for hint in hints:
            if hint in family_metadata.name:
                inferred_category = category
                break

    if (inferred_category is not None and
        not inferred_category in family_metadata.category):
       yield WARN,\
             Message('inferred-category',
                     f'Familyname seems to hint at "{inferred_category}" but'
                     f' METADATA.pb declares it as "{family_metadata.category}".')
    else:
       yield PASS, "OK."


@check(
    id = "com.google.fonts/check/colorfont_tables",
    rationale = """
        No one color font format supports all major user agents, but the combination
        of COLR & SVG tables is pretty good.

        A smart server could prune away one or the other based on user agent,
        and a dumb server will at least have something that works.

        Fonts that do not pass this check can be fixed with the maximum_color tool
        available at https://github.com/googlefonts/nanoemoji
    """,
    proposal = 'https://github.com/googlefonts/fontbakery/issues/3886'
)
def com_google_fonts_check_colorfont_tables(ttFont):
    """Fonts must have neither or both the tables 'COLR' and 'SVG'."""
    SUGGESTED_FIX = ("To fix this, please run the font through the maximum_color tool"
                     " that installs as part of the nanoemoji package"
                     " (https://github.com/googlefonts/nanoemoji)")
    if 'COLR' in ttFont.keys() and 'SVG' not in ttFont.keys():
        yield FAIL,\
              Message('missing-table',
                      "This is a color font (it has a 'COLR' table)"
                      " but it lacks an 'SVG' table. " + SUGGESTED_FIX)
    elif 'COLR' not in ttFont.keys() and 'SVG' in ttFont.keys():
        yield FAIL,\
              Message('missing-table',
                      "This is a color font (it has a 'SVG' table)"
                      " but it lacks an 'COLR' table. " + SUGGESTED_FIX)
    else:
        yield PASS, "Looks good!"

@check(
    id = 'com.google.fonts/check/description/noto_has_article',
    conditions = ['is_noto'],
    rationale = """
        Noto fonts are displayed in a different way on the fonts.google.com
         web site, and so must also contain an article about them.
    """,
    proposal = 'https://github.com/googlefonts/fontbakery/issues/3841'
)
def com_google_fonts_check_description_noto_has_article(font):
    """Noto fonts must have an ARTICLE.en_us.html file"""
    directory = os.path.dirname(font)
    descfilepath = os.path.join(directory, "article", "ARTICLE.en_us.html")
    if os.path.exists(descfilepath):
        yield PASS, "ARTICLE.en_us.html exists"
    else:
        yield FAIL,\
              Message('missing-article',
                      "This is a Noto font but it lacks an ARTICLE.en_us.html file")


###############################################################################

def is_librebarcode(font):
    font_filenames = [
        "LibreBarcode39-Regular.ttf",
        "LibreBarcode39Text-Regular.ttf",
        "LibreBarcode128-Regular.ttf",
        "LibreBarcode128Text-Regular.ttf",
        "LibreBarcode39Extended-Regular.ttf",
        "LibreBarcode39ExtendedText-Regular.ttf"
    ]
    for font_filename in font_filenames:
        if font_filename in font:
            return True


def check_skip_filter(checkid, font=None, **iterargs):
    if font and is_librebarcode(font) and\
       checkid in (
        # See: https://github.com/graphicore/librebarcode/issues/3
        'com.google.fonts/check/monospace',
        'com.google.fonts/check/gpos_kerning_info',
        'com.google.fonts/check/currency_chars',
        'com.google.fonts/check/whitespace_ink'):
        return False, ('LibreBarcode is blacklisted for this check, see '
                       'https://github.com/graphicore/librebarcode/issues/3')

    if checkid == 'com.google.fonts/check/unitsperem':
        # This is the one inherited from the OpenType profile, but:
        return False, ('Google Fonts has a stricter policy which is enforced by'
                       ' com.google.fonts/check/unitsperem_strict')

    return True, None


profile.check_skip_filter = check_skip_filter
profile.auto_register(globals())

profile.check_log_override(
    # From universal.py
    "com.adobe.fonts/check/freetype_rasterizer",
    overrides=(("freetype-not-installed", FAIL, KEEP_ORIGINAL_MESSAGE),),
    reason="For Google Fonts, this check is very important and should never be skipped.",
)

GOOGLEFONTS_PROFILE_CHECKS = add_check_overrides(
    GOOGLEFONTS_PROFILE_CHECKS, profile.profile_tag, OVERRIDDEN_CHECKS
)

profile.test_expected_checks(GOOGLEFONTS_PROFILE_CHECKS, exclusive=True)
