#! /usr/bin/python3
# Copyright © 2013 Piotr Ożarowski <piotr@debian.org>
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.

import logging
from configparser import ConfigParser
from os import environ
from os.path import exists
from subprocess import Popen, PIPE
from typing import NamedTuple


SUPPORTED: dict[str, tuple[tuple[int, int], ...]] = {
    "cpython3": ((3, 8),),
}
DEFAULT: dict[str, tuple[int, int]] = {
    "cpython3": (3, 8),
}

log = logging.getLogger("dhpython")


class CPythonVersions(NamedTuple):
    default: tuple[int, int] | None
    supported: tuple[tuple[int, int], ...]


def _parse_version(version: str) -> tuple[int, int]:
    parts = version.split(".")
    assert len(parts) == 2
    return (int(parts[0]), int(parts[1]))


def cpython_versions(major: int) -> CPythonVersions:
    assert major > 2
    default_ver: tuple[int, int] | None = None
    supported_vers: tuple[tuple[int, int], ...] = ()
    ver = str(major)
    supported = environ.get(f"DEBPYTHON{ver}_SUPPORTED")
    default = environ.get(f"DEBPYTHON{ver}_DEFAULT")
    if not supported or not default:
        config = ConfigParser()
        config.read(f"/usr/share/python{ver}/debian_defaults")
        if not default:
            default = config.get("DEFAULT", "default-version", fallback="")[6:]
        if not supported:
            supported = config.get(
                "DEFAULT", "supported-versions", fallback=""
            ).replace("python", "")
    if default:
        try:
            default_ver = _parse_version(default)
        except Exception as err:
            log.warning("invalid debian_defaults file: %s", err)
    if supported:
        try:
            supported_vers = tuple(_parse_version(i) for i in supported.split(","))
        except Exception as err:
            log.warning("invalid debian_defaults file: %s", err)
    return CPythonVersions(
        default=default_ver,
        supported=supported_vers,
    )


def from_file(fpath: str) -> None:
    if not exists(fpath):
        raise ValueError("missing interpreter: %s" % fpath)
    command = f"{fpath} --version"
    with Popen(command, shell=True, stdout=PIPE, encoding="utf-8") as process:
        stdout, _ = process.communicate()

    print(stdout)


cpython3 = cpython_versions(3)
if cpython3.default:
    DEFAULT["cpython3"] = cpython3.default
if cpython3.supported:
    SUPPORTED["cpython3"] = cpython3.supported


if __name__ == "__main__":
    import sys

    if len(sys.argv) != 3:
        print("invalid number of arguments", file=sys.stderr)
        sys.exit(1)
    if sys.argv[1] == "default":
        print(".".join(str(i) for i in DEFAULT[sys.argv[2]]))
    elif sys.argv[1] == "supported":
        print(",".join(".".join(str(i) for i in v) for v in SUPPORTED[sys.argv[2]]))