"""Utilities that are imported by multiple scripts in the tests directory."""

from __future__ import annotations

import os
import re
import subprocess
import sys
import venv
from collections.abc import Iterable, Mapping
from functools import lru_cache
from pathlib import Path
from typing import NamedTuple
from typing_extensions import Annotated

import pathspec  # type: ignore[import]
import tomli
from packaging.requirements import Requirement

try:
    from termcolor import colored as colored
except ImportError:

    def colored(text: str, color: str | None = None, on_color: str | None = None, attrs: Iterable[str] | None = None) -> str:
        return text


# A backport of functools.cache for Python <3.9
# This module is imported by mypy_test.py, which needs to run on 3.7 in CI
cache = lru_cache(None)

# Used to install system-wide packages for different OS types:
METADATA_MAPPING = {"linux": "apt_dependencies", "darwin": "brew_dependencies", "win32": "choco_dependencies"}


def strip_comments(text: str) -> str:
    return text.split("#")[0].strip()


def print_error(error: str, end: str = "\n", fix_path: tuple[str, str] = ("", "")) -> None:
    error_split = error.split("\n")
    old, new = fix_path
    for line in error_split[:-1]:
        print(colored(line.replace(old, new), "red"))
    print(colored(error_split[-1], "red"), end=end)


def print_success_msg() -> None:
    print(colored("success", "green"))


# ====================================================================
# Reading dependencies from METADATA.toml files
# ====================================================================


class PackageDependencies(NamedTuple):
    typeshed_pkgs: tuple[str, ...]
    external_pkgs: tuple[str, ...]


@cache
def get_pypi_name_to_typeshed_name_mapping() -> Mapping[str, str]:
    stub_name_map = {}
    for typeshed_name in os.listdir("stubs"):
        with Path("stubs", typeshed_name, "METADATA.toml").open("rb") as f:
            pypi_name = tomli.load(f).get("stub_distribution", f"types-{typeshed_name}")
        assert isinstance(pypi_name, str)
        stub_name_map[pypi_name] = typeshed_name
    return stub_name_map


@cache
def read_dependencies(distribution: str) -> PackageDependencies:
    """Read the dependencies listed in a METADATA.toml file for a stubs package.

    Once the dependencies have been read,
    determine which dependencies are typeshed-internal dependencies,
    and which dependencies are external (non-types) dependencies.
    For typeshed dependencies, translate the "dependency name" into the "package name";
    for external dependencies, leave them as they are in the METADATA.toml file.

    Note that this function may consider things to be typeshed stubs
    even if they haven't yet been uploaded to PyPI.
    If a typeshed stub is removed, this function will consider it to be an external dependency.
    """
    pypi_name_to_typeshed_name_mapping = get_pypi_name_to_typeshed_name_mapping()
    with Path("stubs", distribution, "METADATA.toml").open("rb") as f:
        dependencies = tomli.load(f).get("requires", [])
    assert isinstance(dependencies, list)
    typeshed, external = [], []
    for dependency in dependencies:
        assert isinstance(dependency, str)
        maybe_typeshed_dependency = Requirement(dependency).name
        if maybe_typeshed_dependency in pypi_name_to_typeshed_name_mapping:
            typeshed.append(pypi_name_to_typeshed_name_mapping[maybe_typeshed_dependency])
        else:
            # convert to Requirement and then back to str
            # to make sure that the requirements all have a normalised string representation
            # (This will also catch any malformed requirements early)
            external.append(str(Requirement(dependency)))
    return PackageDependencies(tuple(typeshed), tuple(external))


@cache
def get_recursive_requirements(package_name: str) -> PackageDependencies:
    """Recursively gather dependencies for a single stubs package.

    For example, if the stubs for `caldav`
    declare a dependency on typeshed's stubs for `requests`,
    and the stubs for requests declare a dependency on typeshed's stubs for `urllib3`,
    `get_recursive_requirements("caldav")` will determine that the stubs for `caldav`
    have both `requests` and `urllib3` as typeshed-internal dependencies.
    """
    typeshed: set[str] = set()
    external: set[str] = set()
    non_recursive_requirements = read_dependencies(package_name)
    typeshed.update(non_recursive_requirements.typeshed_pkgs)
    external.update(non_recursive_requirements.external_pkgs)
    for pkg in non_recursive_requirements.typeshed_pkgs:
        reqs = get_recursive_requirements(pkg)
        typeshed.update(reqs.typeshed_pkgs)
        external.update(reqs.external_pkgs)
    return PackageDependencies(tuple(sorted(typeshed)), tuple(sorted(external)))


# ====================================================================
# Dynamic venv creation
# ====================================================================


class VenvInfo(NamedTuple):
    pip_exe: Annotated[str, "A path to the venv's pip executable"]
    python_exe: Annotated[str, "A path to the venv's python executable"]

    @staticmethod
    def of_existing_venv(venv_dir: Path) -> VenvInfo:
        if sys.platform == "win32":
            pip = venv_dir / "Scripts" / "pip.exe"
            python = venv_dir / "Scripts" / "python.exe"
        else:
            pip = venv_dir / "bin" / "pip"
            python = venv_dir / "bin" / "python"

        return VenvInfo(str(pip), str(python))


def make_venv(venv_dir: Path) -> VenvInfo:
    try:
        venv.create(venv_dir, with_pip=True, clear=True)
    except subprocess.CalledProcessError as e:
        if "ensurepip" in e.cmd and b"KeyboardInterrupt" not in e.stdout.splitlines():
            print_error(
                "stubtest requires a Python installation with ensurepip. "
                "If on Linux, you may need to install the python3-venv package."
            )
        raise

    return VenvInfo.of_existing_venv(venv_dir)


@cache
def get_mypy_req() -> str:
    with open("requirements-tests.txt", encoding="UTF-8") as f:
        return next(line.strip() for line in f if "mypy" in line)


# ====================================================================
# Parsing the stdlib/VERSIONS file
# ====================================================================


VERSIONS_RE = re.compile(r"^([a-zA-Z_][a-zA-Z0-9_.]*): ([23]\.\d{1,2})-([23]\.\d{1,2})?$")


# ====================================================================
# Getting test-case directories from package names
# ====================================================================


class PackageInfo(NamedTuple):
    name: str
    test_case_directory: Path

    @property
    def is_stdlib(self) -> bool:
        return self.name == "stdlib"


def testcase_dir_from_package_name(package_name: str) -> Path:
    return Path("stubs", package_name, "@tests/test_cases")


def get_all_testcase_directories() -> list[PackageInfo]:
    testcase_directories = [PackageInfo("stdlib", Path("test_cases"))]
    for package_name in os.listdir("stubs"):
        potential_testcase_dir = testcase_dir_from_package_name(package_name)
        if potential_testcase_dir.is_dir():
            testcase_directories.append(PackageInfo(package_name, potential_testcase_dir))
    return sorted(testcase_directories)


# ====================================================================
# Parsing .gitignore
# ====================================================================


@cache
def get_gitignore_spec() -> pathspec.PathSpec:
    with open(".gitignore", encoding="UTF-8") as f:
        return pathspec.PathSpec.from_lines("gitwildmatch", f.readlines())


def spec_matches_path(spec: pathspec.PathSpec, path: Path) -> bool:
    normalized_path = path.as_posix()
    if path.is_dir():
        normalized_path += "/"
    return spec.match_file(normalized_path)  # type: ignore[no-any-return]