from __future__ import unicode_literals

import re

from .common import InfoExtractor
from ..compat import (
    compat_HTTPError,
    compat_kwargs,
    compat_str,
    compat_urllib_request,
    compat_urlparse,
)
from ..utils import (
    determine_ext,
    extract_attributes,
    ExtractorError,
    float_or_none,
    int_or_none,
    js_to_json,
    sanitized_Request,
    try_get,
    unescapeHTML,
    url_or_none,
    urlencode_postdata,
)


class UdemyIE(InfoExtractor):
    IE_NAME = "udemy"
    _VALID_URL = r"""(?x)
                    https?://
                        (?:[^/]+\.)?udemy\.com/
                        (?:
                            [^#]+\#/lecture/|
                            lecture/view/?\?lectureId=|
                            [^/]+/learn/v4/t/lecture/
                        )
                        (?P<id>\d+)
                    """
    _LOGIN_URL = (
        "https://www.udemy.com/join/login-popup/?displayType=ajax&showSkipButton=1"
    )
    _ORIGIN_URL = "https://www.udemy.com"
    _NETRC_MACHINE = "udemy"

    _TESTS = [
        {
            "url": "https://www.udemy.com/java-tutorial/#/lecture/172757",
            "md5": "98eda5b657e752cf945d8445e261b5c5",
            "info_dict": {
                "id": "160614",
                "ext": "mp4",
                "title": "Introduction and Installation",
                "description": "md5:c0d51f6f21ef4ec65f091055a5eef876",
                "duration": 579.29,
            },
            "skip": "Requires udemy account credentials",
        },
        {
            # new URL schema
            "url": "https://www.udemy.com/electric-bass-right-from-the-start/learn/v4/t/lecture/4580906",
            "only_matching": True,
        },
        {
            # no url in outputs format entry
            "url": "https://www.udemy.com/learn-web-development-complete-step-by-step-guide-to-success/learn/v4/t/lecture/4125812",
            "only_matching": True,
        },
        {
            # only outputs rendition
            "url": "https://www.udemy.com/how-you-can-help-your-local-community-5-amazing-examples/learn/v4/t/lecture/3225750?start=0",
            "only_matching": True,
        },
        {
            "url": "https://wipro.udemy.com/java-tutorial/#/lecture/172757",
            "only_matching": True,
        },
    ]

    def _extract_course_info(self, webpage, video_id):
        course = (
            self._parse_json(
                unescapeHTML(
                    self._search_regex(
                        r'ng-init=["\'].*\bcourse=({.+?})[;"\']',
                        webpage,
                        "course",
                        default="{}",
                    )
                ),
                video_id,
                fatal=False,
            )
            or {}
        )
        course_id = course.get("id") or self._search_regex(
            [r'data-course-id=["\'](\d+)', r"&quot;courseId&quot;\s*:\s*(\d+)"],
            webpage,
            "course id",
        )
        return course_id, course.get("title")

    def _enroll_course(self, base_url, webpage, course_id):
        def combine_url(base_url, url):
            return (
                compat_urlparse.urljoin(base_url, url)
                if not url.startswith("http")
                else url
            )

        checkout_url = unescapeHTML(
            self._search_regex(
                r'href=(["\'])(?P<url>(?:https?://(?:www\.)?udemy\.com)?/(?:payment|cart)/checkout/.+?)\1',
                webpage,
                "checkout url",
                group="url",
                default=None,
            )
        )
        if checkout_url:
            raise ExtractorError(
                "Course %s is not free. You have to pay for it before you can download. "
                "Use this URL to confirm purchase: %s"
                % (course_id, combine_url(base_url, checkout_url)),
                expected=True,
            )

        enroll_url = unescapeHTML(
            self._search_regex(
                r'href=(["\'])(?P<url>(?:https?://(?:www\.)?udemy\.com)?/course/subscribe/.+?)\1',
                webpage,
                "enroll url",
                group="url",
                default=None,
            )
        )
        if enroll_url:
            webpage = self._download_webpage(
                combine_url(base_url, enroll_url),
                course_id,
                "Enrolling in the course",
                headers={"Referer": base_url},
            )
            if ">You have enrolled in" in webpage:
                self.to_screen("%s: Successfully enrolled in the course" % course_id)

    def _download_lecture(self, course_id, lecture_id):
        return self._download_json(
            "https://www.udemy.com/api-2.0/users/me/subscribed-courses/%s/lectures/%s?"
            % (course_id, lecture_id),
            lecture_id,
            "Downloading lecture JSON",
            query={
                "fields[lecture]": "title,description,view_html,asset",
                "fields[asset]": "asset_type,stream_url,thumbnail_url,download_urls,stream_urls,captions,data",
            },
        )

    def _handle_error(self, response):
        if not isinstance(response, dict):
            return
        error = response.get("error")
        if error:
            error_str = "Udemy returned error #%s: %s" % (
                error.get("code"),
                error.get("message"),
            )
            error_data = error.get("data")
            if error_data:
                error_str += " - %s" % error_data.get("formErrors")
            raise ExtractorError(error_str, expected=True)

    def _download_webpage_handle(self, *args, **kwargs):
        headers = kwargs.get("headers", {}).copy()
        headers[
            "User-Agent"
        ] = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/72.0.3626.109 Safari/537.36"
        kwargs["headers"] = headers
        ret = super(UdemyIE, self)._download_webpage_handle(
            *args, **compat_kwargs(kwargs)
        )
        if not ret:
            return ret
        webpage, _ = ret
        if any(
            p in webpage
            for p in (
                ">Please verify you are a human",
                "Access to this page has been denied because we believe you are using automation tools to browse the website",
                '"_pxCaptcha"',
            )
        ):
            raise ExtractorError(
                "Udemy asks you to solve a CAPTCHA. Login with browser, "
                "solve CAPTCHA, then export cookies and pass cookie file to "
                "youtube-dl with --cookies.",
                expected=True,
            )
        return ret

    def _download_json(self, url_or_request, *args, **kwargs):
        headers = {
            "X-Udemy-Snail-Case": "true",
            "X-Requested-With": "XMLHttpRequest",
        }
        for cookie in self._downloader.cookiejar:
            if cookie.name == "client_id":
                headers["X-Udemy-Client-Id"] = cookie.value
            elif cookie.name == "access_token":
                headers["X-Udemy-Bearer-Token"] = cookie.value
                headers["X-Udemy-Authorization"] = "Bearer %s" % cookie.value

        if isinstance(url_or_request, compat_urllib_request.Request):
            for header, value in headers.items():
                url_or_request.add_header(header, value)
        else:
            url_or_request = sanitized_Request(url_or_request, headers=headers)

        response = super(UdemyIE, self)._download_json(url_or_request, *args, **kwargs)
        self._handle_error(response)
        return response

    def _real_initialize(self):
        self._login()

    def _login(self):
        username, password = self._get_login_info()
        if username is None:
            return

        login_popup = self._download_webpage(
            self._LOGIN_URL, None, "Downloading login popup"
        )

        def is_logged(webpage):
            return any(
                re.search(p, webpage)
                for p in (
                    r'href=["\'](?:https://www\.udemy\.com)?/user/logout/',
                    r">Logout<",
                )
            )

        # already logged in
        if is_logged(login_popup):
            return

        login_form = self._form_hidden_inputs("login-form", login_popup)

        login_form.update(
            {
                "email": username,
                "password": password,
            }
        )

        response = self._download_webpage(
            self._LOGIN_URL,
            None,
            "Logging in",
            data=urlencode_postdata(login_form),
            headers={
                "Referer": self._ORIGIN_URL,
                "Origin": self._ORIGIN_URL,
            },
        )

        if not is_logged(response):
            error = self._html_search_regex(
                r'(?s)<div[^>]+class="form-errors[^"]*">(.+?)</div>',
                response,
                "error message",
                default=None,
            )
            if error:
                raise ExtractorError("Unable to login: %s" % error, expected=True)
            raise ExtractorError("Unable to log in")

    def _real_extract(self, url):
        lecture_id = self._match_id(url)

        webpage = self._download_webpage(url, lecture_id)

        course_id, _ = self._extract_course_info(webpage, lecture_id)

        try:
            lecture = self._download_lecture(course_id, lecture_id)
        except ExtractorError as e:
            # Error could possibly mean we are not enrolled in the course
            if isinstance(e.cause, compat_HTTPError) and e.cause.code == 403:
                self._enroll_course(url, webpage, course_id)
                lecture = self._download_lecture(course_id, lecture_id)
            else:
                raise

        title = lecture["title"]
        description = lecture.get("description")

        asset = lecture["asset"]

        asset_type = asset.get("asset_type") or asset.get("assetType")
        if asset_type != "Video":
            raise ExtractorError(
                "Lecture %s is not a video" % lecture_id, expected=True
            )

        stream_url = asset.get("stream_url") or asset.get("streamUrl")
        if stream_url:
            youtube_url = self._search_regex(
                r"(https?://www\.youtube\.com/watch\?v=.*)",
                stream_url,
                "youtube URL",
                default=None,
            )
            if youtube_url:
                return self.url_result(youtube_url, "Youtube")

        video_id = compat_str(asset["id"])
        thumbnail = asset.get("thumbnail_url") or asset.get("thumbnailUrl")
        duration = float_or_none(asset.get("data", {}).get("duration"))

        subtitles = {}
        automatic_captions = {}

        formats = []

        def extract_output_format(src, f_id):
            return {
                "url": src.get("url"),
                "format_id": "%sp" % (src.get("height") or f_id),
                "width": int_or_none(src.get("width")),
                "height": int_or_none(src.get("height")),
                "vbr": int_or_none(src.get("video_bitrate_in_kbps")),
                "vcodec": src.get("video_codec"),
                "fps": int_or_none(src.get("frame_rate")),
                "abr": int_or_none(src.get("audio_bitrate_in_kbps")),
                "acodec": src.get("audio_codec"),
                "asr": int_or_none(src.get("audio_sample_rate")),
                "tbr": int_or_none(src.get("total_bitrate_in_kbps")),
                "filesize": int_or_none(src.get("file_size_in_bytes")),
            }

        outputs = asset.get("data", {}).get("outputs")
        if not isinstance(outputs, dict):
            outputs = {}

        def add_output_format_meta(f, key):
            output = outputs.get(key)
            if isinstance(output, dict):
                output_format = extract_output_format(output, key)
                output_format.update(f)
                return output_format
            return f

        def extract_formats(source_list):
            if not isinstance(source_list, list):
                return
            for source in source_list:
                video_url = url_or_none(source.get("file") or source.get("src"))
                if not video_url:
                    continue
                if (
                    source.get("type") == "application/x-mpegURL"
                    or determine_ext(video_url) == "m3u8"
                ):
                    formats.extend(
                        self._extract_m3u8_formats(
                            video_url,
                            video_id,
                            "mp4",
                            entry_protocol="m3u8_native",
                            m3u8_id="hls",
                            fatal=False,
                        )
                    )
                    continue
                format_id = source.get("label")
                f = {
                    "url": video_url,
                    "format_id": "%sp" % format_id,
                    "height": int_or_none(format_id),
                }
                if format_id:
                    # Some videos contain additional metadata (e.g.
                    # https://www.udemy.com/ios9-swift/learn/#/lecture/3383208)
                    f = add_output_format_meta(f, format_id)
                formats.append(f)

        def extract_subtitles(track_list):
            if not isinstance(track_list, list):
                return
            for track in track_list:
                if not isinstance(track, dict):
                    continue
                if track.get("kind") != "captions":
                    continue
                src = url_or_none(track.get("src"))
                if not src:
                    continue
                lang = (
                    track.get("language") or track.get("srclang") or track.get("label")
                )
                sub_dict = (
                    automatic_captions
                    if track.get("autogenerated") is True
                    else subtitles
                )
                sub_dict.setdefault(lang, []).append(
                    {
                        "url": src,
                    }
                )

        for url_kind in ("download", "stream"):
            urls = asset.get("%s_urls" % url_kind)
            if isinstance(urls, dict):
                extract_formats(urls.get("Video"))

        captions = asset.get("captions")
        if isinstance(captions, list):
            for cc in captions:
                if not isinstance(cc, dict):
                    continue
                cc_url = url_or_none(cc.get("url"))
                if not cc_url:
                    continue
                lang = try_get(cc, lambda x: x["locale"]["locale"], compat_str)
                sub_dict = (
                    automatic_captions if cc.get("source") == "auto" else subtitles
                )
                sub_dict.setdefault(lang or "en", []).append(
                    {
                        "url": cc_url,
                    }
                )

        view_html = lecture.get("view_html")
        if view_html:
            view_html_urls = set()
            for source in re.findall(r"<source[^>]+>", view_html):
                attributes = extract_attributes(source)
                src = attributes.get("src")
                if not src:
                    continue
                res = attributes.get("data-res")
                height = int_or_none(res)
                if src in view_html_urls:
                    continue
                view_html_urls.add(src)
                if (
                    attributes.get("type") == "application/x-mpegURL"
                    or determine_ext(src) == "m3u8"
                ):
                    m3u8_formats = self._extract_m3u8_formats(
                        src,
                        video_id,
                        "mp4",
                        entry_protocol="m3u8_native",
                        m3u8_id="hls",
                        fatal=False,
                    )
                    for f in m3u8_formats:
                        m = re.search(
                            r"/hls_(?P<height>\d{3,4})_(?P<tbr>\d{2,})/", f["url"]
                        )
                        if m:
                            if not f.get("height"):
                                f["height"] = int(m.group("height"))
                            if not f.get("tbr"):
                                f["tbr"] = int(m.group("tbr"))
                    formats.extend(m3u8_formats)
                else:
                    formats.append(
                        add_output_format_meta(
                            {
                                "url": src,
                                "format_id": "%dp" % height if height else None,
                                "height": height,
                            },
                            res,
                        )
                    )

            # react rendition since 2017.04.15 (see
            # https://github.com/ytdl-org/youtube-dl/issues/12744)
            data = self._parse_json(
                self._search_regex(
                    r'videojs-setup-data=(["\'])(?P<data>{.+?})\1',
                    view_html,
                    "setup data",
                    default="{}",
                    group="data",
                ),
                video_id,
                transform_source=unescapeHTML,
                fatal=False,
            )
            if data and isinstance(data, dict):
                extract_formats(data.get("sources"))
                if not duration:
                    duration = int_or_none(data.get("duration"))
                extract_subtitles(data.get("tracks"))

            if not subtitles and not automatic_captions:
                text_tracks = self._parse_json(
                    self._search_regex(
                        r'text-tracks=(["\'])(?P<data>\[.+?\])\1',
                        view_html,
                        "text tracks",
                        default="{}",
                        group="data",
                    ),
                    video_id,
                    transform_source=lambda s: js_to_json(unescapeHTML(s)),
                    fatal=False,
                )
                extract_subtitles(text_tracks)

        if not formats and outputs:
            for format_id, output in outputs.items():
                f = extract_output_format(output, format_id)
                if f.get("url"):
                    formats.append(f)

        self._sort_formats(
            formats, field_preference=("height", "width", "tbr", "format_id")
        )

        return {
            "id": video_id,
            "title": title,
            "description": description,
            "thumbnail": thumbnail,
            "duration": duration,
            "formats": formats,
            "subtitles": subtitles,
            "automatic_captions": automatic_captions,
        }


class UdemyCourseIE(UdemyIE):
    IE_NAME = "udemy:course"
    _VALID_URL = r"https?://(?:[^/]+\.)?udemy\.com/(?P<id>[^/?#&]+)"
    _TESTS = [
        {
            "url": "https://www.udemy.com/java-tutorial/",
            "only_matching": True,
        },
        {
            "url": "https://wipro.udemy.com/java-tutorial/",
            "only_matching": True,
        },
    ]

    @classmethod
    def suitable(cls, url):
        return (
            False if UdemyIE.suitable(url) else super(UdemyCourseIE, cls).suitable(url)
        )

    def _real_extract(self, url):
        course_path = self._match_id(url)

        webpage = self._download_webpage(url, course_path)

        course_id, title = self._extract_course_info(webpage, course_path)

        self._enroll_course(url, webpage, course_id)

        response = self._download_json(
            "https://www.udemy.com/api-2.0/courses/%s/cached-subscriber-curriculum-items"
            % course_id,
            course_id,
            "Downloading course curriculum",
            query={
                "fields[chapter]": "title,object_index",
                "fields[lecture]": "title,asset",
                "page_size": "1000",
            },
        )

        entries = []
        chapter, chapter_number = [None] * 2
        for entry in response["results"]:
            clazz = entry.get("_class")
            if clazz == "lecture":
                asset = entry.get("asset")
                if isinstance(asset, dict):
                    asset_type = asset.get("asset_type") or asset.get("assetType")
                    if asset_type != "Video":
                        continue
                lecture_id = entry.get("id")
                if lecture_id:
                    entry = {
                        "_type": "url_transparent",
                        "url": "https://www.udemy.com/%s/learn/v4/t/lecture/%s"
                        % (course_path, entry["id"]),
                        "title": entry.get("title"),
                        "ie_key": UdemyIE.ie_key(),
                    }
                    if chapter_number:
                        entry["chapter_number"] = chapter_number
                    if chapter:
                        entry["chapter"] = chapter
                    entries.append(entry)
            elif clazz == "chapter":
                chapter_number = entry.get("object_index")
                chapter = entry.get("title")

        return self.playlist_result(entries, course_id, title)
