from __future__ import annotations

import os
import pkgutil
import sys
from functools import lru_cache

long_versions = [
    "2.6.9",
    "2.7.9",
    "3.2.6",
    "3.3.6",
    "3.4.3",
    "3.5",
    "3.6",
    "3.7",
    "3.8",
    "3.9",
    "3.10",
    "3.11",
    "3.12",
    "3.13",
    "3.14",
]

short_versions = [".".join(x.split(".")[:2]) for x in long_versions]


def get_canonical_version(version: str) -> str:
    if version in long_versions:
        version = ".".join(version.split(".")[:2])
    elif version not in short_versions:
        raise ValueError(f"No such version: {version}")

    return version


def stdlib_list(version: str | None = None) -> list[str]:
    """
    Given a ``version``, return a ``list`` of names of the Python Standard
    Libraries for that version.

    :param str|None version: The version (as a string) whose list of libraries you want
        (formatted as ``X.Y``, e.g. ``"2.7"`` or ``"3.10"``).

        If not specified, the current version of Python will be used.

    :return: A list of standard libraries from the specified version of Python
    :rtype: list
    """

    version = (
        get_canonical_version(version)
        if version is not None
        else ".".join(str(x) for x in sys.version_info[:2])
    )

    module_list_file = os.path.join("lists", f"{version}.txt")

    data = pkgutil.get_data("stdlib_list", module_list_file).decode()  # type: ignore[union-attr]

    result = [y for x in data.splitlines() if (y := x.strip())]

    return result


@lru_cache(maxsize=16)
def _stdlib_list_with_cache(version: str | None = None) -> frozenset[str]:
    """Internal cached version of `stdlib_list`"""
    return frozenset(stdlib_list(version=version))


def in_stdlib(module_name: str, version: str | None = None) -> bool:
    """
    Return a ``bool`` indicating if module ``module_name`` is in the list of stdlib
    symbols for python version ``version``. If ``version`` is ``None`` (default), the
    version of current python interpreter is used.

    Note that ``True`` will be returned for built-in modules too, since this project
    considers they are part of stdlib. See :issue:21.

    It relies on ``@lru_cache`` to cache the stdlib list and query results for similar
    calls. Therefore it is much more efficient than ``module_name in stdlib_list()``
    especially if you wish to perform multiple checks.

    :param str|None module_name: The module name (as a string) to query for.
    :param str|None version: The version (as a string) whose list of libraries you want
        (formatted as ``X.Y``, e.g. ``"2.7"`` or ``"3.10"``).

        If not specified, the current version of Python will be used.

    :return: A bool indicating if the given module name is part of standard libraries
        for the specified version of Python.
    :rtype: list
    """
    ref_list = _stdlib_list_with_cache(version=version)
    return module_name in ref_list
