"""Konfiguration laden und validieren."""

from __future__ import annotations

import os
from pathlib import Path
from typing import Any

import yaml

MUSIC_EXTENSIONS = {".mp3", ".wav", ".flac", ".aac", ".ogg"}
VIDEO_EXTENSIONS = {".mp4", ".mov", ".avi", ".mkv"}
IMAGE_EXTENSIONS = {".png", ".jpg", ".jpeg"}

DEFAULTS: dict[str, Any] = {
    "resources": {
        "folder": "./resources",
    },
    "music": {
        "mode": "random",
        "volume_original": 1.0,
        "volume_music": 0.3,
    },
    "videos": {
        "intro": None,
        "outro": None,
        "transitions": False,
    },
    "images": {
        "title_card": None,
        "duration": 3,
    },
    "silence": {
        "threshold_db": -40,
        "min_duration": 0.5,
    },
    "scenes": {
        "threshold": 27.0,
    },
    "output": {
        "format": "mp4",
        "folder": "./output",
    },
}


def _deep_merge(base: dict, override: dict) -> dict:
    """Rekursiv Dictionaries zusammenführen."""
    result = dict(base)
    for key, value in override.items():
        if key in result and isinstance(result[key], dict) and isinstance(value, dict):
            result[key] = _deep_merge(result[key], value)
        else:
            result[key] = value
    return result


def load_config(config_path: str | Path | None = None) -> dict[str, Any]:
    """YAML-Konfiguration laden und mit Standardwerten zusammenführen."""
    config = dict(DEFAULTS)
    if config_path is None:
        return config

    path = Path(config_path)
    if not path.exists():
        raise FileNotFoundError(f"Konfigurationsdatei nicht gefunden: {path}")

    with open(path, encoding="utf-8") as fh:
        user_config = yaml.safe_load(fh) or {}

    return _deep_merge(config, user_config)


def validate_config(config: dict[str, Any]) -> list[str]:
    """Konfiguration prüfen, Warnungen zurückgeben."""
    warnings: list[str] = []

    resources_folder = Path(config["resources"]["folder"])
    if not resources_folder.exists():
        warnings.append(f"Ressourcen-Ordner existiert nicht: {resources_folder}")
    else:
        music_folder = resources_folder / "music"
        if not music_folder.exists():
            warnings.append(f"Musik-Ordner existiert nicht: {music_folder}")
        else:
            music_files = [
                f for f in music_folder.iterdir()
                if f.suffix.lower() in MUSIC_EXTENSIONS
            ]
            if not music_files:
                warnings.append(f"Keine Musikdateien in: {music_folder}")

    vol_orig = config["music"]["volume_original"]
    vol_music = config["music"]["volume_music"]
    if not (0.0 <= vol_orig <= 1.0):
        warnings.append(f"volume_original muss zwischen 0.0 und 1.0 liegen (ist: {vol_orig})")
    if not (0.0 <= vol_music <= 1.0):
        warnings.append(f"volume_music muss zwischen 0.0 und 1.0 liegen (ist: {vol_music})")

    return warnings


def get_resources_folder(config: dict[str, Any]) -> Path:
    return Path(config["resources"]["folder"])


def get_music_files(config: dict[str, Any]) -> list[Path]:
    """Alle Musikdateien aus dem konfigurierten Ordner zurückgeben."""
    music_folder = get_resources_folder(config) / "music"
    if not music_folder.exists():
        return []
    return sorted(
        f for f in music_folder.iterdir()
        if f.suffix.lower() in MUSIC_EXTENSIONS
    )