"""Configuration loading and defaults."""

from __future__ import annotations

import os
import tomllib
from pathlib import Path
from typing import Any, Optional

DEFAULT_CONFIG_NAME = "yt_downloader.toml"
QUALITY_PRESETS = ("best", "1080", "720", "480", "audio")


def default_config_path() -> Path:
    xdg = os.environ.get("XDG_CONFIG_HOME")
    base = Path(xdg) if xdg else Path.home() / ".config"
    return base / "yt-downloader" / DEFAULT_CONFIG_NAME


def _as_bool(value: Any, default: bool) -> bool:
    if value is None:
        return default
    if isinstance(value, bool):
        return value
    return str(value).strip().lower() in ("1", "true", "yes", "on")


class Config:
    """Thin wrapper around the parsed TOML config."""

    def __init__(self, data: dict, path: Path):
        self._data = data
        self.path = path

    # -- download --------------------------------------------------------
    @property
    def out_dir(self) -> Path:
        return Path(self._data.get("download", {}).get("out", "./videos"))

    @property
    def quality(self) -> str:
        q = str(self._data.get("download", {}).get("quality", "best")).lower()
        return q if q in QUALITY_PRESETS else "best"

    @property
    def format_override(self) -> Optional[str]:
        return self._data.get("download", {}).get("format")

    @property
    def cookies_file(self) -> Optional[str]:
        return self._data.get("download", {}).get("cookies_file")

    @property
    def cookies_from_browser(self) -> Optional[str]:
        return self._data.get("download", {}).get("cookies_from_browser")

    # -- vpn ------------------------------------------------------------
    @property
    def vpn_wireguard(self) -> Optional[str]:
        return self._data.get("vpn", {}).get("wireguard")

    @property
    def vpn_namespace(self) -> Optional[str]:
        return self._data.get("vpn", {}).get("namespace")

    @property
    def vpn_interface(self) -> Optional[str]:
        return self._data.get("vpn", {}).get("interface")

    # -- misc -----------------------------------------------------------
    @property
    def dry_run(self) -> bool:
        return _as_bool(self._data.get("global", {}).get("dry_run", False), False)


def load_config(path: Optional[Path | str] = None) -> Config:
    if path is None:
        path = default_config_path()
    path = Path(path)
    if not path.exists():
        raise FileNotFoundError(
            f"Config not found at {path}. Run 'yt-downloader init' first."
        )
    with open(path, "rb") as fh:
        data = tomllib.load(fh)
    return Config(data, path)


def write_default_config(path: Path) -> None:
    path.parent.mkdir(parents=True, exist_ok=True)
    template = """\
# yt-downloader configuration

[global]
dry_run = false                  # when true: plan only, touch nothing

[download]
out = "~/Videos/yt-downloader"   # where videos land
quality = "best"                 # best | 1080 | 720 | 480 | audio
# format = ""                    # raw yt-dlp -f string, overrides quality
# cookies_file = "/path/to/cookies.txt"      # pass your browser cookies (best
# cookies_from_browser = "firefox"           # protection against bot checks;
#                                            # e.g. chromium, firefox, safari)

[vpn]
# wireguard = "~/.config/yt-downloader/mullvad.conf"
#                                # optional: path to a WireGuard (Mullvad) .conf.
#                                # When set, `download` runs inside a dedicated
#                                # network namespace so ONLY yt-dlp traffic goes
#                                # through the VPN. Requires sudo + wireguard-tools.
# namespace = "mullvad"          # optional: network namespace name
# interface = "mv0"              # optional: WireGuard interface name
"""
    path.write_text(template)