"""Transforms for LaTeX builder."""

from __future__ import annotations

from typing import TYPE_CHECKING, cast

from docutils import nodes
from docutils.transforms.references import Substitutions

from sphinx import addnodes
from sphinx.builders.latex.nodes import (
    captioned_literal_block,
    footnotemark,
    footnotetext,
    math_reference,
    thebibliography,
)
from sphinx.locale import __
from sphinx.transforms import SphinxTransform
from sphinx.transforms.post_transforms import SphinxPostTransform
from sphinx.util.nodes import NodeMatcher

if TYPE_CHECKING:
    from typing import Any

    from docutils.nodes import Element, Node

    from sphinx.application import Sphinx
    from sphinx.util.typing import ExtensionMetadata

URI_SCHEMES = ('mailto:', 'http:', 'https:', 'ftp:')


class FootnoteDocnameUpdater(SphinxTransform):
    """Add docname to footnote and footnote_reference nodes."""

    default_priority = 700
    TARGET_NODES = (nodes.footnote, nodes.footnote_reference)

    def apply(self, **kwargs: Any) -> None:
        matcher = NodeMatcher(*self.TARGET_NODES)
        for node in matcher.findall(self.document):
            node['docname'] = self.env.current_document.docname


class SubstitutionDefinitionsRemover(SphinxPostTransform):
    """Remove ``substitution_definition`` nodes from doctrees."""

    # should be invoked after Substitutions process
    default_priority = Substitutions.default_priority + 1
    formats = ('latex',)

    def run(self, **kwargs: Any) -> None:
        for node in list(self.document.findall(nodes.substitution_definition)):
            node.parent.remove(node)


class ShowUrlsTransform(SphinxPostTransform):
    """Expand references to inline text or footnotes.

    For more information, see :confval:`latex_show_urls`.

    .. note:: This transform is used for integrated doctree
    """

    default_priority = 400
    formats = ('latex',)

    # references are expanded to footnotes (or not)
    expanded = False

    def run(self, **kwargs: Any) -> None:
        try:
            # replace id_prefix temporarily
            settings: Any = self.document.settings
            id_prefix = settings.id_prefix
            settings.id_prefix = 'show_urls'

            self.expand_show_urls()
            if self.expanded:
                self.renumber_footnotes()
        finally:
            # restore id_prefix
            settings.id_prefix = id_prefix

    def expand_show_urls(self) -> None:
        show_urls = self.config.latex_show_urls
        if show_urls is False or show_urls == 'no':
            return

        for node in list(self.document.findall(nodes.reference)):
            uri = node.get('refuri', '')
            if uri.startswith(URI_SCHEMES):
                uri = uri.removeprefix('mailto:')
                if node.astext() != uri:
                    index = node.parent.index(node)
                    docname = self.get_docname_for_node(node)
                    if show_urls == 'footnote':
                        fn, fnref = self.create_footnote(uri, docname)
                        node.parent.insert(index + 1, fn)
                        node.parent.insert(index + 2, fnref)

                        self.expanded = True
                    else:  # all other true values (b/w compat)
                        textnode = nodes.Text(' (%s)' % uri)
                        node.parent.insert(index + 1, textnode)

    def get_docname_for_node(self, node: Node) -> str:
        while node:
            if isinstance(node, nodes.document):
                return self.env.path2doc(node['source']) or ''
            elif isinstance(node, addnodes.start_of_file):
                return node['docname']
            else:
                node = node.parent

        try:
            source = node['source']
        except TypeError:
            raise ValueError(__('Failed to get a docname!')) from None
        msg = __('Failed to get a docname for source %r!') % source
        raise ValueError(msg)

    def create_footnote(
        self, uri: str, docname: str
    ) -> tuple[nodes.footnote, nodes.footnote_reference]:
        reference = nodes.reference('', nodes.Text(uri), refuri=uri, nolinkurl=True)
        footnote = nodes.footnote(uri, auto=1, docname=docname)
        footnote['names'].append('#')
        footnote += nodes.label('', '#')
        footnote += nodes.paragraph('', '', reference)
        self.document.note_autofootnote(footnote)

        footnote_ref = nodes.footnote_reference(
            '[#]_', auto=1, refid=footnote['ids'][0], docname=docname
        )
        footnote_ref += nodes.Text('#')
        self.document.note_autofootnote_ref(footnote_ref)
        footnote.add_backref(footnote_ref['ids'][0])

        return footnote, footnote_ref

    def renumber_footnotes(self) -> None:
        collector = FootnoteCollector(self.document)
        self.document.walkabout(collector)

        num = 0
        for footnote in collector.auto_footnotes:
            # search unused footnote number
            while True:
                num += 1
                if str(num) not in collector.used_footnote_numbers:
                    break

            # assign new footnote number
            old_label = cast('nodes.label', footnote[0])
            old_label.replace_self(nodes.label('', str(num)))
            if old_label in footnote['names']:
                footnote['names'].remove(old_label.astext())
            footnote['names'].append(str(num))

            # update footnote_references by new footnote number
            docname = footnote['docname']
            for ref in collector.footnote_refs:
                if docname == ref['docname'] and footnote['ids'][0] == ref['refid']:
                    ref.remove(ref[0])
                    ref += nodes.Text(str(num))


class FootnoteCollector(nodes.NodeVisitor):
    """Collect footnotes and footnote references on the document"""

    def __init__(self, document: nodes.document) -> None:
        self.auto_footnotes: list[nodes.footnote] = []
        self.used_footnote_numbers: set[str] = set()
        self.footnote_refs: list[nodes.footnote_reference] = []
        super().__init__(document)

    def unknown_visit(self, node: Node) -> None:
        pass

    def unknown_departure(self, node: Node) -> None:
        pass

    def visit_footnote(self, node: nodes.footnote) -> None:
        if node.get('auto'):
            self.auto_footnotes.append(node)
        else:
            for name in node['names']:
                self.used_footnote_numbers.add(name)

    def visit_footnote_reference(self, node: nodes.footnote_reference) -> None:
        self.footnote_refs.append(node)


class LaTeXFootnoteTransform(SphinxPostTransform):
    """Convert footnote definitions and references to appropriate form to LaTeX.

    * Replace footnotes on restricted zone (e.g. headings) by footnotemark node.
      In addition, append a footnotetext node after the zone.

      Before::