import subprocess
import logging
from dataclasses import dataclass, field
from pathlib import Path
from typing import Optional

logger = logging.getLogger(__name__)

PACMAN_LOCK = Path("/var/lib/pacman/db.lck")


@dataclass
class Package:
    name: str
    old_version: str
    new_version: str


@dataclass
class InstallResult:
    success: bool
    installed: list = field(default_factory=list)
    failed: list = field(default_factory=list)
    error: Optional[str] = None


def is_pacman_locked() -> bool:
    return PACMAN_LOCK.exists()


def check_updates() -> list[Package]:
    """Vérifie les mises à jour disponibles via checkupdates (sans droits root)."""
    result = subprocess.run(
        ["checkupdates"],
        capture_output=True, text=True, timeout=120
    )
    packages = []
    for line in result.stdout.strip().splitlines():
        parts = line.split()
        # Format attendu : "nom ancienne_version -> nouvelle_version"
        if len(parts) >= 4 and parts[2] == "->":
            packages.append(Package(
                name=parts[0],
                old_version=parts[1],
                new_version=parts[3],
            ))
    return packages


def download_packages(names: list[str]) -> bool:
    """Télécharge les paquets dans le cache sans les installer."""
    if not names:
        return True
    result = subprocess.run(
        ["pacman", "-Syw", "--noconfirm", "--noprogressbar"] + names,
        capture_output=True, text=True, timeout=600
    )
    if result.returncode != 0:
        logger.error(f"Téléchargement échoué : {result.stderr[-500:]}")
        return False
    return True


def sync_db() -> bool:
    """Synchronise la base de données des paquets."""
    result = subprocess.run(
        ["pacman", "-Sy", "--noconfirm"],
        capture_output=True, text=True, timeout=120
    )
    return result.returncode == 0


def install_packages(names: list[str]) -> InstallResult:
    """Installe des paquets spécifiques depuis le cache."""
    if not names:
        return InstallResult(success=True)

    result = subprocess.run(
        ["pacman", "-S", "--noconfirm", "--needed", "--noprogressbar"] + names,
        capture_output=True, text=True, timeout=600
    )

    if result.returncode == 0:
        return InstallResult(success=True, installed=names)
    else:
        return InstallResult(
            success=False,
            failed=names,
            error=result.stderr[-800:],
        )


def upgrade_cached_packages(expected_names: list[str]) -> InstallResult:
    """Installe toutes les mises à jour présentes dans le cache pacman.

    Utilisé à l'extinction pour éviter les échecs de dépendances liés aux
    mises à jour partielles : pacman -Su installe l'ensemble cohérent des
    paquets déjà téléchargés plutôt qu'une liste isolée.
    """
    if not expected_names:
        return InstallResult(success=True)

    result = subprocess.run(
        ["pacman", "-Su", "--noconfirm", "--noprogressbar"],
        capture_output=True, text=True, timeout=600
    )

    if result.returncode == 0:
        return InstallResult(success=True, installed=expected_names)
    else:
        return InstallResult(
            success=False,
            failed=expected_names,
            error=result.stderr[-800:],
        )