# Copyright 2023 Oliver Smith
# SPDX-License-Identifier: GPL-3.0-or-later
"""Functions that work with pmaports.

See also:
- pmb/helpers/repo.py (work with binary package repos)
- pmb/helpers/package.py (work with both)
"""
import glob
from pmb.core import get_context
from pmb.helpers import logging
from pathlib import Path
from typing import Optional, Sequence, Dict

from pmb.types import PmbArgs
import pmb.parse

def _find_apkbuilds() -> Dict[str, Path]:
    # Try to get a cached result first (we assume that the aports don't change
    # in one pmbootstrap call)
    apkbuilds = pmb.helpers.other.cache.get("pmb.helpers.pmaports.apkbuilds")
    if apkbuilds is not None:
        return apkbuilds

    apkbuilds = {}
    for apkbuild in glob.iglob(f"{get_context().config.aports}/**/*/APKBUILD", recursive=True):
        package = Path(apkbuild).parent.name
        if package in apkbuilds:
            raise RuntimeError(f"Package {package} found in multiple aports "
                               "subfolders. Please put it only in one folder.")
        apkbuilds[package] = Path(apkbuild)

    # Sort dictionary so we don't need to do it over and over again in
    # get_list()
    apkbuilds = dict(sorted(apkbuilds.items()))

    # Save result in cache
    pmb.helpers.other.cache["pmb.helpers.pmaports.apkbuilds"] = apkbuilds
    return apkbuilds


def get_list() -> Sequence[str]:
    """ :returns: list of all pmaport pkgnames (["hello-world", ...]) """
    return list(_find_apkbuilds().keys())


def guess_main_dev(subpkgname) -> Optional[Path]:
    """Check if a package without "-dev" at the end exists in pmaports or not, and log the appropriate message.

    Don't call this function directly, use guess_main() instead.

    :param subpkgname: subpackage name, must end in "-dev"
    :returns: full path to the pmaport or None
    """
    pkgname = subpkgname[:-4]
    path = _find_apkbuilds().get(pkgname)
    if path:
        logging.verbose(subpkgname + ": guessed to be a subpackage of " +
                        pkgname + " (just removed '-dev')")
        return path.parent

    logging.verbose(subpkgname + ": guessed to be a subpackage of " + pkgname +
                    ", which we can't find in pmaports, so it's probably in"
                    " Alpine")
    return None


def guess_main(subpkgname) -> Optional[Path]:
    """Find the main package by assuming it is a prefix of the subpkgname.

    We do that, because in some APKBUILDs the subpkgname="" variable gets
    filled with a shell loop and the APKBUILD parser in pmbootstrap can't
    parse this right. (Intentionally, we don't want to implement a full shell
    parser.)

    :param subpkgname: subpackage name (e.g. "u-boot-some-device")
    :returns: * full path to the aport, e.g.:
                "/home/user/code/pmbootstrap/aports/main/u-boot"
              * None when we couldn't find a main package
    """
    # Packages ending in -dev: just assume that the originating aport has the
    # same pkgname, except for the -dev at the end. If we use the other method
    # below on subpackages, we may end up with the wrong package. For example,
    # if something depends on plasma-framework-dev, and plasma-framework is in
    # Alpine, but plasma is in pmaports, then the cutting algorithm below would
    # pick plasma instead of plasma-framework.
    if subpkgname.endswith("-dev"):
        return guess_main_dev(subpkgname)

    # Iterate until the cut up subpkgname is gone
    words = subpkgname.split("-")
    while len(words) > 1:
        # Remove one dash-separated word at a time ("a-b-c" -> "a-b")
        words.pop()
        pkgname = "-".join(words)

        # Look in pmaports
        path = _find_apkbuilds().get(pkgname)
        if path:
            logging.verbose(subpkgname + ": guessed to be a subpackage of " +
                            pkgname)
            return path.parent

    return None

def _find_package_in_apkbuild(package: str, path: Path) -> bool:
    """Look through subpackages and all provides to see if the APKBUILD at the specified path
    contains (or provides) the specified package.

    :param package: The package to search for
    :param path: The path to the apkbuild
    :return: True if the APKBUILD contains or provides the package
    """
    apkbuild = pmb.parse.apkbuild(path)

    # Subpackages
    if package in apkbuild["subpackages"]:
        return True

    # Search for provides in both package and subpackages
    apkbuild_pkgs = [apkbuild, *apkbuild["subpackages"].values()]
    for apkbuild_pkg in apkbuild_pkgs:
        if not apkbuild_pkg:
            continue

        # Provides (cut off before equals sign for entries like
        # "mkbootimg=0.0.1")
        for provides_i in apkbuild_pkg["provides"]:
            # Ignore provides without version, they shall never be
            # automatically selected
            if "=" not in provides_i:
                continue

            if package == provides_i.split("=", 1)[0]:
                return True

    return False


def find(package: str, must_exist=True) -> Path:
    """Find the aport path that provides a certain subpackage.

    If you want the parsed APKBUILD instead, use pmb.helpers.pmaports.get().

    :param must_exist: Raise an exception, when not found
    :returns: the full path to the aport folder
    """
    # Try to get a cached result first (we assume that the aports don't change
    # in one pmbootstrap call)
    ret: Optional[Path] = None
    if package in pmb.helpers.other.cache["find_aport"]:
        ret = pmb.helpers.other.cache["find_aport"][package]
    else:
        # Sanity check
        if "*" in package:
            raise RuntimeError("Invalid pkgname: " + package)

        # Try to find an APKBUILD with the exact pkgname we are looking for
        path = _find_apkbuilds().get(package)
        if path:
            ret = path.parent
        else:
            # No luck, take a guess what APKBUILD could have the package we are
            # looking for as subpackage
            guess = guess_main(package)
            if guess:
                # Parse the APKBUILD and verify if the guess was right
                if _find_package_in_apkbuild(package, guess / "APKBUILD"):
                    ret = guess
                else:
                    # Otherwise parse all APKBUILDs (takes time!), is the
                    # package we are looking for a subpackage of any of those?
                    for path_current in _find_apkbuilds().values():
                        if _find_package_in_apkbuild(package, path_current):
                            ret = path_current.parent
                            break

                # If we still didn't find anything, as last resort: assume our
                # initial guess was right and the APKBUILD parser just didn't
                # find the subpackage in there because it is behind shell logic
                # that we don't parse.
                if not ret:
                    ret = guess

    # Crash when necessary
    if ret is None:
        raise RuntimeError("Could not find aport for package: " +
                           package)

    # Save result in cache
    pmb.helpers.other.cache["find_aport"][package] = ret
    return ret


def find_optional(package: str) -> Optional[Path]:
    try:
        return find(package)
    except RuntimeError:
        return None


def get(pkgname, must_exist=True, subpackages=True):
    """Find and parse an APKBUILD file.

    Run 'pmbootstrap apkbuild_parse hello-world' for a full output example.
    Relevant variables are defined in pmb.config.apkbuild_attributes.

    :param pkgname: the package name to find
    :param must_exist: raise an exception when it can't be found
    :param subpackages: also search for subpackages with the specified
        names (slow! might need to parse all APKBUILDs to find it)

    :returns: relevant variables from the APKBUILD as dictionary, e.g.:
                  { "pkgname": "hello-world",
                  "arch": ["all"],
                  "pkgrel": "4",
                  "pkgrel": "1",
                  "options": [],
                  ... }
    """
    pkgname = pmb.helpers.package.remove_operators(pkgname)
    if subpackages:
        aport = find_optional(pkgname)
        if aport:
            return pmb.parse.apkbuild(aport / "APKBUILD")
        elif must_exist:
            raise RuntimeError("Could not find APKBUILD for package:"
                               f" {pkgname}")
    else:
        path = _find_apkbuilds().get(pkgname)
        if path:
            return pmb.parse.apkbuild(path)
        if must_exist:
            raise RuntimeError("Could not find APKBUILD for package:"
                               f" {pkgname}")

    return None


def find_providers( provide):
    """Search for providers of the specified (virtual) package in pmaports.

    Note: Currently only providers from a single APKBUILD are returned.

    :param provide: the (virtual) package to search providers for
    :returns: tuple list (pkgname, apkbuild_pkg) with providers, sorted by
              provider_priority. The provider with the highest priority
              (which would be selected by default) comes first.
    """

    providers = {}

    apkbuild = get(provide)
    for subpkgname, subpkg in apkbuild["subpackages"].items():
        for provides in subpkg["provides"]:
            # Strip provides version (=$pkgver-r$pkgrel)
            if provides.split("=", 1)[0] == provide:
                providers[subpkgname] = subpkg

    return sorted(providers.items(), reverse=True,
                  key=lambda p: p[1].get('provider_priority', 0))


# FIXME (#2324): split into an _optional variant or drop must_exist
def get_repo(pkgname, must_exist=True) -> Optional[str]:
    """Get the repository folder of an aport.

    :pkgname: package name
    :must_exist: raise an exception when it can't be found
    :returns: a string like "main", "device", "cross", ...
                  or None when the aport could not be found
    """
    aport: Optional[Path]
    if must_exist:
        aport = find(pkgname)
    else:
        aport = find_optional(pkgname)
    if not aport:
        return None
    return aport.parent.name


def check_arches(arches, arch):
    """Check if building for a certain arch is allowed.

    :param arches: list of all supported arches, as it can be found in the
        arch="" line of APKBUILDS (including all, noarch, !arch, ...).
        For example: ["x86_64", "x86", "!armhf"]

    :param arch: the architecture to check for

    :returns: True when building is allowed, False otherwise
    """
    if "!" + arch in arches:
        return False
    for value in [arch, "all", "noarch"]:
        if value in arches:
            return True
    return False


def get_channel_new(channel: str) -> str:
    """Translate legacy channel names to the new ones.

    Legacy names are still supported for compatibility with old branches (pmb#2015).
    :param channel: name as read from pmaports.cfg or channels.cfg, like "edge", "v21.03" etc.,
    or potentially a legacy name like "stable".

    :returns: name in the new format, e.g. "edge" or "v21.03"
    """
    legacy_cfg = pmb.config.pmaports_channels_legacy
    if channel in legacy_cfg:
        ret = legacy_cfg[channel]
        logging.verbose(f"Legacy channel '{channel}' translated to '{ret}'")
        return ret
    return channel