import os
import json
from app.config import settings

def ensure_smart_playlist(playlist_name: str = "Моя Волна") -> str:
    """Ensure Navidrome .nsp Smart Playlist exists in library."""
    playlists_dir = os.path.join(settings.MUSIC_DIR, "playlists")
    os.makedirs(playlists_dir, exist_ok=True)
    
    nsp_path = os.path.join(playlists_dir, f"{playlist_name}.nsp")
    
    # Path inside Navidrome is relative to /music
    nsp_content = {
        "all": [
            {
                "path": {
                    "contains": "AI Recommendations/Моя Волна"
                }
            }
        ],
        "sort": "random",
        "limit": 100
    }
    
    with open(nsp_path, "w", encoding="utf-8") as f:
        json.dump(nsp_content, f, ensure_ascii=False, indent=2)

    # Also generate M3U8 playlist at music root for universal Subsonic auto-import
    wave_dir = os.path.join(settings.MUSIC_DIR, "AI Recommendations", "Моя Волна")
    m3u_path = os.path.join(settings.MUSIC_DIR, f"{playlist_name}.m3u8")
    
    lines = ["#EXTM3U\n"]
    if os.path.exists(wave_dir):
        for f in sorted(os.listdir(wave_dir)):
            if f.lower().endswith(".mp3"):
                lines.append(f"#EXTINF:-1,{os.path.splitext(f)[0]}\n")
                lines.append(f"AI Recommendations/Моя Волна/{f}\n")

    with open(m3u_path, "w", encoding="utf-8") as f:
        f.writelines(lines)
        
    return nsp_path