"""Utilities used in generating docs."""

import ast
import importlib.util
import inspect
import os
import subprocess
import typing
from pathlib import Path

import docutils.nodes
import docutils.parsers.rst.states
import git
import releases
import sphinx.util.logging

logger = sphinx.util.logging.getLogger(__name__)


def get_build_root() -> Path:
    """Get the project root folder for the current build."""
    root = Path.cwd()
    if root.name == "docs":
        root = root.parent
    return root


def linkcode_resolve(repo_link: str, domain: str, info: dict[str, str]) -> typing.Optional[str]:
    """
    Function called by linkcode to get the URL for a given resource.

    See for more details:
    https://www.sphinx-doc.org/en/master/usage/extensions/linkcode.html#confval-linkcode_resolve
    """
    if domain != "py":
        raise Exception("Unknown domain passed to linkcode function.")

    symbol_name = info["fullname"]

    build_root = get_build_root()

    # Import the package to find files
    origin = build_root / info["module"].replace(".", "/")
    search_locations = []

    if origin.is_dir():
        search_locations.append(origin.absolute().as_posix())
        origin = origin / "__init__.py"
    else:
        origin = Path(origin.absolute().as_posix() + ".py")
        if not origin.exists():
            raise Exception(f"Could not find `{info['module']}` as a package or file.")

    # We can't use a normal import (importlib.import_module), because the module can conflict with another copy
    # in multiversion builds. We load the module from the file location instead
    spec = importlib.util.spec_from_file_location(info["module"], origin, submodule_search_locations=search_locations)
    module = importlib.util.module_from_spec(spec)
    spec.loader.exec_module(module)

    symbol = [module]
    for name in symbol_name.split("."):
        symbol.append(getattr(symbol[-1], name))
        symbol_name = name

    try:
        lines, start = inspect.getsourcelines(symbol[-1])
        end = start + len(lines)
    except TypeError:
        # Find variables by parsing the ast
        source = ast.parse(inspect.getsource(symbol[-2]))
        while isinstance(source.body[0], ast.ClassDef):
            source = source.body[0]

        pos = _global_assign_pos(source, symbol_name)
        if pos is None:
            raise Exception(f"Could not find symbol `{symbol_name}` in {module.__name__}.")
        else:
            start, end = pos
        _, offset = inspect.getsourcelines(symbol[-2])
        if offset != 0:
            offset -= 1
        start += offset
        end += offset

    file = Path(inspect.getfile(module)).relative_to(build_root).as_posix()

    try:
        sha = git.Repo(build_root).commit().hexsha
    except git.InvalidGitRepositoryError:
        # We are building a historical version, no git data available
        sha = build_root.name

    url = f"{repo_link}/blob/{sha}/{file}#L{start}"
    if end != start:
        url += f"-L{end}"

    return url


class NodeWithBody(typing.Protocol):
    """An AST node with the body attribute."""

    body: list[ast.AST]


def _global_assign_pos(ast_: NodeWithBody, name: str) -> typing.Union[tuple[int, int], None]:
    """
    Find the first instance where the `name` global is defined in `ast_`.

    Check top-level assignments and assignments nested in top-level if blocks.
    """
    for ast_obj in ast_.body:
        if isinstance(ast_obj, ast.Assign):
            names = []
            for target in ast_obj.targets:
                if isinstance(target, ast.Tuple):
                    names.extend([name.id for name in target.elts if isinstance(name, ast.Name)])
                else:
                    if isinstance(target, ast.Name):
                        names.append(target.id)

            if name in names:
                return ast_obj.lineno, ast_obj.end_lineno

        elif isinstance(ast_obj, ast.If):
            pos_in_if = _global_assign_pos(ast_obj, name)
            if pos_in_if is not None:
                return pos_in_if


def cleanup() -> None:
    """Remove unneeded autogenerated doc files, and clean up others."""
    included = __get_included()

    for file in (get_build_root() / "docs" / "output").iterdir():
        if file.name in ("botcore.rst", "botcore.exts.rst", "botcore.utils.rst") and file.name in included:
            content = file.read_text(encoding="utf-8").splitlines(keepends=True)

            # Rename the extension to be less wordy
            # Example: botcore.exts -> Botcore Exts
            title = content[0].split()[0].strip().replace("botcore.", "").replace(".", " ").title()
            title = f"{title}\n{'=' * len(title)}\n\n"
            content = title, *content[3:]

            file.write_text("".join(content), encoding="utf-8")

        elif file.name in included:
            # Clean up the submodule name so it's just the name without the top level module name
            # example: `botcore.regex module` -> `regex`
            lines = file.read_text(encoding="utf-8").splitlines(keepends=True)
            lines[0] = lines[0].replace("module", "").strip().split(".")[-1] + "\n"
            file.write_text("".join(lines))

        else:
            # These are files that have not been explicitly included in the docs via __all__
            file.unlink()
            continue

        # Take the opportunity to configure autodoc
        content = file.read_text(encoding="utf-8").replace("undoc-members", "special-members")
        file.write_text(content, encoding="utf-8")


def build_api_doc() -> None:
    """Generate auto-module directives using apidoc."""
    cmd = os.getenv("APIDOC_COMMAND") or "sphinx-apidoc -o docs/output botcore -feM"
    cmd = cmd.split()

    build_root = get_build_root()
    output_folder = build_root / cmd[cmd.index("-o") + 1]

    if output_folder.exists():
        logger.info(f"Skipping api-doc for {output_folder.as_posix()} as it already exists.")
        return

    result = subprocess.run(cmd, cwd=build_root, stdout=subprocess.PIPE, check=True, env=os.environ)
    logger.debug("api-doc Output:\n" + result.stdout.decode(encoding="utf-8") + "\n")

    cleanup()


def __get_included() -> set[str]:
    """Get a list of files that should be included in the final build."""

    def get_all_from_module(module_name: str) -> set[str]:
        try:
            module = importlib.import_module(module_name)
        except ModuleNotFoundError:
            return set()
        _modules = {module.__name__ + ".rst"}

        if hasattr(module, "__all__"):
            for sub_module in module.__all__:
                _modules.update(get_all_from_module(sub_module))

        return _modules

    return get_all_from_module("botcore")


def reorder_release_entries(release_list: list[releases.Release]) -> None:
    """
    Sort `releases` based on `release.type`.

    This is meant to be used as an override for `releases.reorder_release_entries` to support
    custom types.
    """
    order = {"breaking": 0, "feature": 1, "bug": 2, "support": 3}
    for release in release_list:
        release["entries"].sort(key=lambda entry: order[entry.type])


def emphasized_url(
    name: str, rawtext: str, text: str, lineno: int, inliner: docutils.parsers.rst.states.Inliner, *__
) -> tuple[list, list]:
    """
    Sphinx role to add hyperlinked literals.

    ReST: :literal-url:`Google <https://google.com>`
    Markdown equivalent: [`Google`](https://google.com)

    Refer to https://docutils.sourceforge.io/docs/howto/rst-roles.html for details on the input and output.
    """
    arguments = text.rsplit(maxsplit=1)
    if len(arguments) != 2:
        message = inliner.reporter.error(
            f"`{name}` expects a message and a URL, formatted as: :{name}:`message <url>`",
            line=lineno
        )
        problem = inliner.problematic(text, rawtext, message)
        return [problem], [message]

    message, url = arguments
    url: str = url[1:-1]  # Remove the angled brackets off the start and end

    literal = docutils.nodes.literal(rawtext, message)
    return [docutils.nodes.reference(rawtext, "", literal, refuri=url)], []


def get_recursive_file_uris(folder: Path, match_pattern: str) -> list[str]:
    """Get the URI of any file relative to folder which matches the `match_pattern` regex."""
    return [file.relative_to(folder).as_posix() for file in folder.rglob(match_pattern)]