import os
import json
import yaml
from yt_dlp import YoutubeDL
from Playlist_Updater import update
import re

CONFIG_FILE =  "config.yaml"
NOW_PLAYING_FILE = "/home/media/Music/now_playing.json"
MUSIC_BASE = "/home/media/Music"

with open(CONFIG_FILE, "r") as f:
    config = yaml.safe_load(f)
sources = config.get("sources", {})

if os.path.exists(NOW_PLAYING_FILE):
    with open(NOW_PLAYING_FILE, "r") as f:
        now_playing = json.load(f)
else:
    now_playing = {}

ydl_opts = {
    "quiet": True,
    "extract_flat": True,
    "dump_single_json": True,
    "skip_download": True
}

def sanitize_filename(title):
    return title.replace("/", "-")

pending_files = {}

for name, data in sources.items():
    url = data.get("youtube_url")
    id_cache_file = data.get("id_cache")
    if not url or not id_cache_file:
        continue

    print(f"Processing Playlist: {name}")

    try:
        with open(id_cache_file, "r") as f:
            content = f.read().strip()
            old_ids = set(json.loads(content)) if content else set()            
    except FileNotFoundError:
        old_ids = set()

    with YoutubeDL(ydl_opts) as ydl:
        info = ydl.extract_info(url, download=False)
        new_ids = set(entry["id"] for entry in info["entries"])

    to_add = new_ids - old_ids
    to_remove = old_ids - new_ids

    print(f"To download: {len(to_add)}")
    print(f"To remove: {len(to_remove)}")

    # where new music will be saved
    folder_path = os.path.join(MUSIC_BASE, name.capitalize())
    os.makedirs(folder_path, exist_ok=True)

    # Define download options for yt-dlp
    download_opts = {
        "format": "bestaudio/best",
        "quiet": False,
        "postprocessors": [{
            "key": "FFmpegExtractAudio",
            "preferredcodec": "mp3",
            "preferredquality": "192",
        }]
    }


    if to_add:
        with YoutubeDL({"quiet": True}) as metadata_ydl:
            for vid in to_add:
                try:
                    info = metadata_ydl.extract_info(f"https://youtu.be/{vid}", download=False)
                    title = info.get("title", vid)
                    safe_title = sanitize_filename(title)
                    filename = f"{safe_title} [{vid}]"
                    full_output_path = os.path.join(folder_path, filename)

                    if os.path.exists(full_output_path):
                        print(f"File already downloaded")
                        continue
                    print(f"downloading... {filename}")

                    download_opts["outtmpl"] = full_output_path
                    with YoutubeDL(download_opts) as downloader:
                        downloader.download([f"https://youtu.be/{vid}"])

                except Exception as e:
                    print(f"Failed to process {vid}: {e}")

    currently_playing = now_playing.get(name, "").strip()
    pending_delete = []

    for file in os.listdir(folder_path):
        if not file.endswith(".mp3"):
            continue

        full_path = os.path.join(folder_path, file)

        # Try to match video ID
        match = re.search(r'\[([a-zA-Z0-9_-]{11})\]\.mp3$', file)
        if not match:
            continue

        file_id = match.group(1)

        # Only delete if:
        # - the ID is in the removal list
        # - the file is NOT currently playing
        if file_id in to_remove:
            if file == currently_playing:
                print(f"postponing deletion (still playing): {file}")
                pending_delete.append(file_id)

                pending_files.setdefault(name, []).append(file)
            else:
                print(f"Deleting: {file}")
                os.remove(full_path)       

    with open(id_cache_file, "w") as f:
        json.dump(sorted(new_ids), f, indent=2)
        print(f"Saved updated ID cache: {id_cache_file}")

print("\n🔁 Regenerating .m3u playlists...")
update(skip_files=pending_files)
print("✅ Playlist sync complete.")