"""Music library API — list dirs, list files, move files between folders."""

import os
import shutil

from flask import Blueprint, jsonify, request

from ..config import MUSIC_BASE, FALLBACK_DIR

bp = Blueprint("music", __name__)

AUDIO_EXTENSIONS = {".mp3", ".flac", ".ogg", ".opus", ".m4a", ".wav"}


def _get_folders():
    """Return dict mapping folder name -> absolute path."""
    folders = {}
    if MUSIC_BASE.exists():
        for d in sorted(MUSIC_BASE.iterdir()):
            if d.is_dir():
                folders[d.name] = d
    folders["fallback"] = FALLBACK_DIR
    return folders


def _count_audio_files(directory):
    if not directory.exists():
        return 0
    return sum(
        1 for f in directory.rglob("*")
        if f.is_file() and f.suffix.lower() in AUDIO_EXTENSIONS
    )


def _list_audio_files(directory):
    if not directory.exists():
        return []
    files = []
    for f in sorted(directory.iterdir()):
        if f.is_file() and f.suffix.lower() in AUDIO_EXTENSIONS:
            files.append({
                "name": f.name,
                "size": f.stat().st_size,
            })
    return files


@bp.route("/music")
def list_music():
    dirs = []
    if MUSIC_BASE.exists():
        for d in sorted(MUSIC_BASE.iterdir()):
            if d.is_dir():
                dirs.append({
                    "folder": d.name,
                    "path": str(d),
                    "file_count": _count_audio_files(d),
                })

    fallback_count = _count_audio_files(FALLBACK_DIR)

    return jsonify({
        "directories": dirs,
        "fallback": {
            "path": str(FALLBACK_DIR),
            "file_count": fallback_count,
        },
    })


@bp.route("/music/<folder>/files")
def list_files(folder):
    folders = _get_folders()
    if folder not in folders:
        return jsonify({"error": "Unknown folder"}), 404
    files = _list_audio_files(folders[folder])
    return jsonify({"folder": folder, "files": files})


@bp.route("/music/move", methods=["POST"])
def move_file():
    data = request.get_json()
    src_folder = data.get("from")
    dst_folder = data.get("to")
    filename = data.get("file")

    if not all([src_folder, dst_folder, filename]):
        return jsonify({"error": "Missing from, to, or file"}), 400

    folders = _get_folders()
    if src_folder not in folders or dst_folder not in folders:
        return jsonify({"error": "Unknown folder"}), 404

    if os.sep in filename or "/" in filename or ".." in filename:
        return jsonify({"error": "Invalid filename"}), 400

    src_path = folders[src_folder] / filename
    dst_path = folders[dst_folder] / filename

    if not src_path.exists():
        return jsonify({"error": "File not found"}), 404

    if dst_path.exists():
        return jsonify({"error": "File already exists in destination"}), 409

    dst_path.parent.mkdir(parents=True, exist_ok=True)
    shutil.move(str(src_path), str(dst_path))
    return jsonify({"ok": True, "moved": filename, "from": src_folder, "to": dst_folder})