# ABOUTME: Configuration loading from moongreet.toml.
# ABOUTME: Parses appearance and behavior settings with wallpaper path resolution.

import tomllib
from contextlib import AbstractContextManager
from dataclasses import dataclass
from importlib.resources import as_file, files
from pathlib import Path

DEFAULT_CONFIG_PATHS = [
    Path("/etc/moongreet/moongreet.toml"),
]


@dataclass
class Config:
    """Greeter configuration loaded from moongreet.toml."""

    background: Path | None = None
    gtk_theme: str | None = None


def load_config(config_path: Path | None = None) -> Config:
    """Load configuration from a TOML file.

    Relative paths in the config are resolved against the config file's directory.
    """
    if config_path is None:
        for path in DEFAULT_CONFIG_PATHS:
            if path.exists():
                config_path = path
                break
        if config_path is None:
            return Config()

    if not config_path.exists():
        return Config()

    try:
        with open(config_path, "rb") as f:
            data = tomllib.load(f)
    except (tomllib.TOMLDecodeError, OSError):
        return Config()

    config = Config()
    appearance = data.get("appearance", {})

    bg = appearance.get("background")
    if bg:
        bg_path = Path(bg)
        if not bg_path.is_absolute():
            bg_path = config_path.parent / bg_path
        config.background = bg_path

    gtk_theme = appearance.get("gtk-theme")
    if gtk_theme:
        config.gtk_theme = gtk_theme

    return config


_PACKAGE_DATA = files("moongreet") / "data"
_DEFAULT_WALLPAPER_PATH = _PACKAGE_DATA / "wallpaper.jpg"


def resolve_wallpaper_path(
    config: Config,
) -> tuple[Path, AbstractContextManager | None]:
    """Resolve the wallpaper path from config or fall back to the package default.

    Returns (path, context_manager). The context_manager is non-None when a
    package resource was extracted to a temporary file — the caller must keep
    it alive and call __exit__ when done.
    """
    if config.background and config.background.exists():
        return config.background, None

    ctx = as_file(_DEFAULT_WALLPAPER_PATH)
    try:
        path = ctx.__enter__()
    except Exception:
        ctx.__exit__(None, None, None)
        raise
    return path, ctx