"""The reStructuredText domain."""

import re
from typing import Any, Dict, Iterator, List, Optional, Tuple, cast

from docutils.nodes import Element
from docutils.parsers.rst import directives

from sphinx import addnodes
from sphinx.addnodes import desc_signature, pending_xref
from sphinx.application import Sphinx
from sphinx.builders import Builder
from sphinx.directives import ObjectDescription
from sphinx.domains import Domain, ObjType
from sphinx.environment import BuildEnvironment
from sphinx.locale import _, __
from sphinx.roles import XRefRole
from sphinx.util import logging
from sphinx.util.nodes import make_id, make_refnode
from sphinx.util.typing import OptionSpec

logger = logging.getLogger(__name__)

dir_sig_re = re.compile(r'\.\. (.+?)::(.*)$')


class ReSTMarkup(ObjectDescription[str]):
    """
    Description of generic reST markup.
    """
    option_spec: OptionSpec = {
        'noindex': directives.flag,
        'noindexentry': directives.flag,
        'nocontentsentry': directives.flag,
    }

    def add_target_and_index(self, name: str, sig: str, signode: desc_signature) -> None:
        node_id = make_id(self.env, self.state.document, self.objtype, name)
        signode['ids'].append(node_id)
        self.state.document.note_explicit_target(signode)

        domain = cast(ReSTDomain, self.env.get_domain('rst'))
        domain.note_object(self.objtype, name, node_id, location=signode)

        if 'noindexentry' not in self.options:
            indextext = self.get_index_text(self.objtype, name)
            if indextext:
                self.indexnode['entries'].append(('single', indextext, node_id, '', None))

    def get_index_text(self, objectname: str, name: str) -> str:
        return ''

    def make_old_id(self, name: str) -> str:
        """Generate old styled node_id for reST markups.

        .. note:: Old Styled node_id was used until Sphinx-3.0.
                  This will be removed in Sphinx-5.0.
        """
        return self.objtype + '-' + name

    def _object_hierarchy_parts(self, sig_node: desc_signature) -> Tuple[str, ...]:
        if 'fullname' not in sig_node:
            return ()
        directive_names = []
        for parent in self.env.ref_context.get('rst:directives', ()):
            directive_names += parent.split(':')
        name = sig_node['fullname']
        return tuple(directive_names + name.split(':'))

    def _toc_entry_name(self, sig_node: desc_signature) -> str:
        if not sig_node.get('_toc_parts'):
            return ''

        config = self.env.app.config
        objtype = sig_node.parent.get('objtype')
        *parents, name = sig_node['_toc_parts']
        if objtype == 'directive:option':
            return f':{name}:'
        if config.toc_object_entries_show_parents in {'domain', 'all'}:
            name = ':'.join(sig_node['_toc_parts'])
        if objtype == 'role':
            return f':{name}:'
        if objtype == 'directive':
            return f'.. {name}::'
        return ''


def parse_directive(d: str) -> Tuple[str, str]:
    """Parse a directive signature.

    Returns (directive, arguments) string tuple.  If no arguments are given,
    returns (directive, '').
    """
    dir = d.strip()
    if not dir.startswith('.'):
        # Assume it is a directive without syntax
        return (dir, '')
    m = dir_sig_re.match(dir)
    if not m:
        return (dir, '')
    parsed_dir, parsed_args = m.groups()
    if parsed_args.strip():
        return (parsed_dir.strip(), ' ' + parsed_args.strip())
    else:
        return (parsed_dir.strip(), '')


class ReSTDirective(ReSTMarkup):
    """
    Description of a reST directive.
    """
    def handle_signature(self, sig: str, signode: desc_signature) -> str:
        name, args = parse_directive(sig)
        desc_name = f'.. {name}::'
        signode['fullname'] = name.strip()
        signode += addnodes.desc_name(desc_name, desc_name)
        if len(args) > 0:
            signode += addnodes.desc_addname(args, args)
        return name

    def get_index_text(self, objectname: str, name: str) -> str:
        return _('%s (directive)') % name

    def before_content(self) -> None:
        if self.names:
            directives = self.env.ref_context.setdefault('rst:directives', [])
            directives.append(self.names[0])

    def after_content(self) -> None:
        directives = self.env.ref_context.setdefault('rst:directives', [])
        if directives:
            directives.pop()


class ReSTDirectiveOption(ReSTMarkup):
    """
    Description of an option for reST directive.
    """
    option_spec: OptionSpec = ReSTMarkup.option_spec.copy()
    option_spec.update({
        'type': directives.unchanged,
    })

    def handle_signature(self, sig: str, signode: desc_signature) -> str:
        try:
            name, argument = re.split(r'\s*:\s+', sig.strip(), 1)
        except ValueError:
            name, argument = sig, None

        desc_name = f':{name}:'
        signode['fullname'] = name.strip()
        signode += addnodes.desc_name(desc_name, desc_name)
        if argument:
            signode += addnodes.desc_annotation(' ' + argument, ' ' + argument)
        if self.options.get('type'):
            text = ' (%s)' % self.options['type']
            signode += addnodes.desc_annotation(text, text)
        return name

    def add_target_and_index(self, name: str, sig: str, signode: desc_signature) -> None:
        domain = cast(ReSTDomain, self.env.get_domain('rst'))

        directive_name = self.current_directive
        if directive_name:
            prefix = '-'.join([self.objtype, directive_name])
            objname = ':'.join([directive_name, name])
        else:
            prefix = self.objtype
            objname = name

        node_id = make_id(self.env, self.state.document, prefix, name)
        signode['ids'].append(node_id)
        self.state.document.note_explicit_target(signode)
        domain.note_object(self.objtype, objname, node_id, location=signode)

        if directive_name:
            key = name[0].upper()
            pair = [_('%s (directive)') % directive_name,
                    _(':%s: (directive option)') % name]
            self.indexnode['entries'].append(('pair', '; '.join(pair), node_id, '', key))
        else:
            key = name[0].upper()
            text = _(':%s: (directive option)') % name
            self.indexnode['entries'].append(('single', text, node_id, '', key))

    @property
    def current_directive(self) -> str:
        directives = self.env.ref_context.get('rst:directives')
        if directives:
            return directives[-1]
        else:
            return ''

    def make_old_id(self, name: str) -> str:
        """Generate old styled node_id for directive options.

        .. note:: Old Styled node_id was used until Sphinx-3.0.
                  This will be removed in Sphinx-5.0.
        """
        return '-'.join([self.objtype, self.current_directive, name])


class ReSTRole(ReSTMarkup):
    """
    Description of a reST role.
    """
    def handle_signature(self, sig: str, signode: desc_signature) -> str:
        desc_name = f':{sig}:'
        signode['fullname'] = sig.strip()
        signode += addnodes.desc_name(desc_name, desc_name)
        return sig

    def get_index_text(self, objectname: str, name: str) -> str:
        return _('%s (role)') % name


class ReSTDomain(Domain):
    """ReStructuredText domain."""
    name = 'rst'
    label = 'reStructuredText'

    object_types = {
        'directive':        ObjType(_('directive'), 'dir'),
        'directive:option': ObjType(_('directive-option'), 'dir'),
        'role':             ObjType(_('role'),      'role'),
    }
    directives = {
        'directive': ReSTDirective,
        'directive:option': ReSTDirectiveOption,
        'role':      ReSTRole,
    }
    roles = {
        'dir':  XRefRole(),
        'role': XRefRole(),
    }
    initial_data: Dict[str, Dict[Tuple[str, str], str]] = {
        'objects': {},  # fullname -> docname, objtype
    }

    @property
    def objects(self) -> Dict[Tuple[str, str], Tuple[str, str]]:
        return self.data.setdefault('objects', {})  # (objtype, fullname) -> (docname, node_id)

    def note_object(self, objtype: str, name: str, node_id: str, location: Any = None) -> None:
        if (objtype, name) in self.objects:
            docname, node_id = self.objects[objtype, name]
            logger.warning(__('duplicate description of %s %s, other instance in %s') %
                           (objtype, name, docname), location=location)

        self.objects[objtype, name] = (self.env.docname, node_id)

    def clear_doc(self, docname: str) -> None:
        for (typ, name), (doc, _node_id) in list(self.objects.items()):
            if doc == docname:
                del self.objects[typ, name]

    def merge_domaindata(self, docnames: List[str], otherdata: Dict) -> None:
        # XXX check duplicates
        for (typ, name), (doc, node_id) in otherdata['objects'].items():
            if doc in docnames:
                self.objects[typ, name] = (doc, node_id)

    def resolve_xref(self, env: BuildEnvironment, fromdocname: str, builder: Builder,
                     typ: str, target: str, node: pending_xref, contnode: Element
                     ) -> Optional[Element]:
        objtypes = self.objtypes_for_role(typ)
        for objtype in objtypes:
            todocname, node_id = self.objects.get((objtype, target), (None, None))
            if todocname:
                return make_refnode(builder, fromdocname, todocname, node_id,
                                    contnode, target + ' ' + objtype)
        return None

    def resolve_any_xref(self, env: BuildEnvironment, fromdocname: str, builder: Builder,
                         target: str, node: pending_xref, contnode: Element
                         ) -> List[Tuple[str, Element]]:
        results: List[Tuple[str, Element]] = []
        for objtype in self.object_types:
            todocname, node_id = self.objects.get((objtype, target), (None, None))
            if todocname:
                results.append(('rst:' + self.role_for_objtype(objtype),
                                make_refnode(builder, fromdocname, todocname, node_id,
                                             contnode, target + ' ' + objtype)))
        return results

    def get_objects(self) -> Iterator[Tuple[str, str, str, str, str, int]]:
        for (typ, name), (docname, node_id) in self.data['objects'].items():
            yield name, name, typ, docname, node_id, 1


def setup(app: Sphinx) -> Dict[str, Any]:
    app.add_domain(ReSTDomain)

    return {
        'version': 'builtin',
        'env_version': 2,
        'parallel_read_safe': True,
        'parallel_write_safe': True,
    }
