"""The reStructuredText domain."""

from __future__ import annotations

import re
from typing import TYPE_CHECKING

from docutils.parsers.rst import directives

from sphinx import addnodes
from sphinx.directives import ObjectDescription
from sphinx.domains import Domain, ObjType
from sphinx.locale import _, __
from sphinx.roles import XRefRole
from sphinx.util import logging
from sphinx.util.nodes import make_id, make_refnode

if TYPE_CHECKING:
    from collections.abc import Iterator, Set
    from typing import Any, ClassVar

    from docutils import nodes
    from docutils.nodes import Element

    from sphinx.addnodes import desc_signature, pending_xref
    from sphinx.application import Sphinx
    from sphinx.builders import Builder
    from sphinx.environment import BuildEnvironment
    from sphinx.util.typing import ExtensionMetadata, OptionSpec

logger = logging.getLogger(__name__)

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


class ReSTMarkup(ObjectDescription[str]):
    """Description of generic reST markup."""

    option_spec: ClassVar[OptionSpec] = {
        'no-index': directives.flag,
        'no-index-entry': directives.flag,
        'no-contents-entry': directives.flag,
        'no-typesetting': directives.flag,
        '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 = self.env.domains.restructuredtext_domain
        domain.note_object(self.objtype, name, node_id, location=signode)

        if 'no-index-entry' not in self.options:
            if index_text := self.get_index_text(self.objtype, name):
                self.indexnode['entries'].append((
                    'single',
                    index_text,
                    node_id,
                    '',
                    None,
                ))

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

    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 ''

        objtype = sig_node.parent.get('objtype')
        *parents, name = sig_node['_toc_parts']
        if objtype == 'directive:option':
            return f':{name}:'
        if self.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: ClassVar[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(), maxsplit=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:
            text = f' {argument}'
            signode += addnodes.desc_annotation(text, text)
        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 = self.env.domains.restructuredtext_domain

        directive_name = self.current_directive
        if directive_name:
            prefix = f'{self.objtype}-{directive_name}'
            objname = f'{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 ''


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]]:
        # (objtype, fullname) -> (docname, node_id)
        return self.data.setdefault('objects', {})

    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: Set[str], otherdata: dict[str, Any]) -> 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,
    ) -> nodes.reference | None:
        objtypes = self.objtypes_for_role(typ)
        if not objtypes:
            return None
        for objtype in objtypes:
            result = self.objects.get((objtype, target))
            if result:
                todocname, node_id = result
                return make_refnode(
                    builder,
                    fromdocname,
                    todocname,
                    node_id,
                    contnode,
                    f'{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, nodes.reference]]:
        results: list[tuple[str, nodes.reference]] = []
        for objtype in self.object_types:
            result = self.objects.get((objtype, target))
            if result:
                todocname, node_id = result
                results.append((
                    f'rst:{self.role_for_objtype(objtype)}',
                    make_refnode(
                        builder,
                        fromdocname,
                        todocname,
                        node_id,
                        contnode,
                        f'{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) -> ExtensionMetadata:
    app.add_domain(ReSTDomain)

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