from functools import lru_cache
from pathlib import Path
from typing import Any, Union

import material
from mkdocs.config.defaults import MkDocsConfig
from mkdocs.structure.files import File, Files
from mkdocs.structure.nav import Link, Navigation, Section
from mkdocs.structure.pages import Page

non_translated_sections = [
    "reference/",
    "release-notes.md",
    "fastapi-people.md",
    "external-links.md",
    "newsletter.md",
    "management-tasks.md",
    "management.md",
]


@lru_cache
def get_missing_translation_content(docs_dir: str) -> str:
    docs_dir_path = Path(docs_dir)
    missing_translation_path = docs_dir_path.parent.parent / "missing-translation.md"
    return missing_translation_path.read_text(encoding="utf-8")


@lru_cache
def get_mkdocs_material_langs() -> list[str]:
    material_path = Path(material.__file__).parent
    material_langs_path = material_path / "templates" / "partials" / "languages"
    langs = [file.stem for file in material_langs_path.glob("*.html")]
    return langs


class EnFile(File):
    pass


def on_config(config: MkDocsConfig, **kwargs: Any) -> MkDocsConfig:
    available_langs = get_mkdocs_material_langs()
    dir_path = Path(config.docs_dir)
    lang = dir_path.parent.name
    if lang in available_langs:
        config.theme["language"] = lang
    if not (config.site_url or "").endswith(f"{lang}/") and lang != "en":
        config.site_url = f"{config.site_url}{lang}/"
    return config


def resolve_file(*, item: str, files: Files, config: MkDocsConfig) -> None:
    item_path = Path(config.docs_dir) / item
    if not item_path.is_file():
        en_src_dir = (Path(config.docs_dir) / "../../en/docs").resolve()
        potential_path = en_src_dir / item
        if potential_path.is_file():
            files.append(
                EnFile(
                    path=item,
                    src_dir=str(en_src_dir),
                    dest_dir=config.site_dir,
                    use_directory_urls=config.use_directory_urls,
                )
            )


def resolve_files(*, items: list[Any], files: Files, config: MkDocsConfig) -> None:
    for item in items:
        if isinstance(item, str):
            resolve_file(item=item, files=files, config=config)
        elif isinstance(item, dict):
            assert len(item) == 1
            values = list(item.values())
            if not values:
                continue
            if isinstance(values[0], str):
                resolve_file(item=values[0], files=files, config=config)
            elif isinstance(values[0], list):
                resolve_files(items=values[0], files=files, config=config)
            else:
                raise ValueError(f"Unexpected value: {values}")


def on_files(files: Files, *, config: MkDocsConfig) -> Files:
    resolve_files(items=config.nav or [], files=files, config=config)
    if "logo" in config.theme:
        resolve_file(item=config.theme["logo"], files=files, config=config)
    if "favicon" in config.theme:
        resolve_file(item=config.theme["favicon"], files=files, config=config)
    resolve_files(items=config.extra_css, files=files, config=config)
    resolve_files(items=config.extra_javascript, files=files, config=config)
    return files


def generate_renamed_section_items(
    items: list[Union[Page, Section, Link]], *, config: MkDocsConfig
) -> list[Union[Page, Section, Link]]:
    new_items: list[Union[Page, Section, Link]] = []
    for item in items:
        if isinstance(item, Section):
            new_title = item.title
            new_children = generate_renamed_section_items(item.children, config=config)
            first_child = new_children[0]
            if isinstance(first_child, Page):
                if first_child.file.src_path.endswith("index.md"):
                    # Read the source so that the title is parsed and available
                    first_child.read_source(config=config)
                    new_title = first_child.title or new_title
            # Creating a new section makes it render it collapsed by default
            # no idea why, so, let's just modify the existing one
            # new_section = Section(title=new_title, children=new_children)
            item.title = new_title.split("{ #")[0]
            item.children = new_children
            new_items.append(item)
        else:
            new_items.append(item)
    return new_items


def on_nav(
    nav: Navigation, *, config: MkDocsConfig, files: Files, **kwargs: Any
) -> Navigation:
    new_items = generate_renamed_section_items(nav.items, config=config)
    return Navigation(items=new_items, pages=nav.pages)


def on_pre_page(page: Page, *, config: MkDocsConfig, files: Files) -> Page:
    return page


def on_page_markdown(
    markdown: str, *, page: Page, config: MkDocsConfig, files: Files
) -> str:
    # Set metadata["social"]["cards_layout_options"]["title"] to clean title (without
    # permalink)
    title = page.title
    clean_title = title.split("{ #")[0]
    if clean_title:
        page.meta.setdefault("social", {})
        page.meta["social"].setdefault("cards_layout_options", {})
        page.meta["social"]["cards_layout_options"]["title"] = clean_title

    if isinstance(page.file, EnFile):
        for excluded_section in non_translated_sections:
            if page.file.src_path.startswith(excluded_section):
                return markdown
        missing_translation_content = get_missing_translation_content(config.docs_dir)
        header = ""
        body = markdown
        if markdown.startswith("#"):
            header, _, body = markdown.partition("\n\n")
        return f"{header}\n\n{missing_translation_content}\n\n{body}"
    return markdown
