import argparse
import os
import sys

from pathlib import Path
import json

from karaoke_downloader.downloader import KaraokeDownloader

# Constants
DEFAULT_FUZZY_THRESHOLD = 85
DEFAULT_LATEST_PER_CHANNEL_LIMIT = 5
DEFAULT_DISPLAY_LIMIT = 10
DEFAULT_CACHE_DURATION_HOURS = 24


def main():
    parser = argparse.ArgumentParser(
        description="Karaoke Video Downloader - Download YouTube playlists and channel videos for karaoke",
        formatter_class=argparse.RawDescriptionHelpFormatter,
        epilog="""
Examples:
  python download_karaoke.py https://www.youtube.com/playlist?list=XYZ
  python download_karaoke.py https://www.youtube.com/@SingKingKaraoke/videos
  python download_karaoke.py --file data/channels.txt
  python download_karaoke.py --reset-channel SingKingKaraoke --delete-files
        """,
    )
    parser.add_argument(
        "url", nargs="?", help="YouTube playlist or channel URL to download"
    )
    parser.add_argument(
        "--file",
        "-f",
        help="Text file containing playlist or channel URLs (one per line)",
    )
    parser.add_argument(
        "--status",
        "-s",
        action="store_true",
        help="Show download status and statistics",
    )
    parser.add_argument(
        "--report",
        "-r",
        metavar="PLAYLIST_ID",
        help="Generate a detailed report for a specific playlist",
    )
    parser.add_argument(
        "--sync",
        "--sync-only",
        action="store_true",
        help="Only sync playlist without downloading (update tracking)",
    )
    parser.add_argument(
        "--cleanup", action="store_true", help="Clean up orphaned tracking entries"
    )
    parser.add_argument(
        "--resolution",
        "--res",
        choices=["480p", "720p", "1080p", "1440p", "2160p"],
        default="720p",
        help="Preferred video resolution (default: 720p)",
    )
    parser.add_argument(
        "--limit",
        "-l",
        type=int,
        help="Limit the number of videos to download (e.g., --limit 10)",
    )
    parser.add_argument(
        "--refresh",
        "--force-refresh",
        action="store_true",
        help="Force refresh channel cache (ignore cached data)",
    )
    parser.add_argument(
        "--cache-info", action="store_true", help="Show channel cache information"
    )
    parser.add_argument(
        "--clear-cache",
        metavar="CHANNEL_ID",
        nargs="?",
        const="all",
        help="Clear cache for specific channel or all channels (use --clear-cache all)",
    )
    parser.add_argument(
        "--cache-duration",
        type=int,
        metavar="HOURS",
        help="Set cache duration in hours (default: 24)",
    )
    parser.add_argument(
        "--songlist-priority",
        action="store_true",
        help="Prioritize downloads based on data/songList.json (default: enabled)",
    )
    parser.add_argument(
        "--no-songlist-priority",
        action="store_true",
        help="Disable songlist prioritization",
    )
    parser.add_argument(
        "--generate-unmatched-report",
        action="store_true",
        help="Generate a report of songs that couldn't be found in any channel (runs after downloads)",
    )
    parser.add_argument(
        "--show-pagination",
        action="store_true",
        help="Show page-by-page progress when downloading channel video lists (slower but more detailed)",
    )
    parser.add_argument(
        "--parallel-channels",
        action="store_true",
        help="Enable parallel channel scanning for faster channel processing (scans multiple channels simultaneously)",
    )
    parser.add_argument(
        "--channel-workers",
        type=int,
        default=3,
        help="Number of parallel channel scanning workers (default: 3, max: 10)",
    )
    parser.add_argument(
        "--songlist-only",
        action="store_true",
        help="Only download songs that are in the songlist (skip all others)",
    )
    parser.add_argument(
        "--songlist-focus",
        nargs="+",
        metavar="PLAYLIST_TITLE",
        help='Focus on specific playlists by title (e.g., --songlist-focus "2025 - Apple Top 50" "2024 - Billboard Hot 100")',
    )
    parser.add_argument(
        "--songlist-file",
        metavar="FILE_PATH",
        help="Custom songlist file path to use with --songlist-focus (default: data/songList.json)",
    )
    parser.add_argument(
        "--force",
        action="store_true",
        help="Force download from channels regardless of whether songs are already downloaded, on server, or marked as duplicates",
    )
    parser.add_argument(
        "--songlist-status",
        action="store_true",
        help="Show songlist download status and statistics",
    )
    parser.add_argument(
        "--reset-channel",
        metavar="CHANNEL_NAME",
        help="Reset all tracking and files for a channel",
    )
    parser.add_argument(
        "--reset-songlist",
        action="store_true",
        help="When used with --reset-channel, also reset songlist songs for this channel",
    )
    parser.add_argument(
        "--reset-songlist-all",
        action="store_true",
        help="Reset all songlist tracking and delete all songlist-downloaded files (global)",
    )
    parser.add_argument(
        "--clear-server-duplicates",
        action="store_true",
        help="Clear server duplicates tracking (allows re-checking songs against server)",
    )
    parser.add_argument(
        "--version", "-v", action="version", version="Karaoke Playlist Downloader v1.0"
    )
    parser.add_argument(
        "--force-download-plan",
        action="store_true",
        help="Force refresh the download plan cache (re-scan all channels for matches)",
    )
    parser.add_argument(
        "--latest-per-channel",
        action="store_true",
        help="Download the latest N videos from each channel (use with --limit)",
    )
    parser.add_argument(
        "--fuzzy-match",
        action="store_true",
        help="Enable fuzzy matching for songlist-to-video matching (uses rapidfuzz if available)",
    )
    parser.add_argument(
        "--fuzzy-threshold",
        type=int,
        default=DEFAULT_FUZZY_THRESHOLD,
        help=f"Fuzzy match threshold (0-100, default {DEFAULT_FUZZY_THRESHOLD})",
    )
    parser.add_argument(
        "--parallel",
        action="store_true",
        help="Enable parallel downloads for improved speed (3-5x faster for large batches)",
    )
    parser.add_argument(
        "--workers",
        type=int,
        default=3,
        help="Number of parallel download workers (default: 3, max: 10)",
    )
    parser.add_argument(
        "--generate-songlist",
        nargs="+",
        metavar="DIRECTORY",
        help="Generate song list from MP4 files with ID3 tags in specified directories",
    )
    parser.add_argument(
        "--no-append-songlist",
        action="store_true",
        help="Create a new song list instead of appending when using --generate-songlist",
    )
    args = parser.parse_args()

    # Validate workers argument
    if args.workers < 1 or args.workers > 10:
        print("❌ Error: --workers must be between 1 and 10")
        sys.exit(1)

    # Validate channel workers argument
    if args.channel_workers < 1 or args.channel_workers > 10:
        print("❌ Error: --channel-workers must be between 1 and 10")
        sys.exit(1)

    yt_dlp_path = Path("downloader/yt-dlp.exe")
    if not yt_dlp_path.exists():
        print("❌ Error: yt-dlp.exe not found in downloader/ directory")
        print("Please ensure yt-dlp.exe is present in the downloader/ folder")
        sys.exit(1)

    downloader = KaraokeDownloader()
    
    # Set parallel download options
    if args.parallel:
        downloader.enable_parallel_downloads = True
        downloader.parallel_workers = args.workers
        print(f"⚡ Parallel downloads enabled with {args.workers} workers")
    else:
        downloader.enable_parallel_downloads = False
        print("🐌 Sequential downloads enabled")
    
    if args.limit:
        downloader.download_limit = args.limit
        print(f"🎯 Download limit set to: {args.limit} videos")
    if args.no_songlist_priority:
        downloader.use_songlist_priority = False
        print("🎯 Songlist prioritization disabled")
    else:
        downloader.use_songlist_priority = True
        print("🎯 Songlist prioritization enabled")
    if args.songlist_only:
        downloader.songlist_only = True
        print("🎯 Songlist-only mode enabled (will only download songlist songs)")

    if args.songlist_focus:
        downloader.songlist_focus_titles = args.songlist_focus
        downloader.songlist_only = True  # Enable songlist-only mode when focusing
        args.songlist_only = True  # Also set the args flag to ensure CLI logic works
        print(
            f"🎯 Songlist focus mode enabled for playlists: {', '.join(args.songlist_focus)}"
        )
    if args.songlist_file:
        downloader.songlist_file_path = args.songlist_file
        print(f"📁 Using custom songlist file: {args.songlist_file}")
    if args.force:
        downloader.force_download = True
        print("💪 Force mode enabled - will download regardless of existing files or server duplicates")
    if args.resolution != "720p":
        downloader.config_manager.update_resolution(args.resolution)

    # --- NEW: Reset channel CLI command ---
    if args.reset_channel:
        downloader.reset_channel_downloads(
            args.reset_channel,
            reset_songlist=args.reset_songlist,
            delete_files=True,  # Always delete files if they exist
        )
        sys.exit(0)
    # --- END NEW ---

    # --- NEW: If no URL or file is provided, but --songlist-only is set, use all channels in data/channels.txt ---
    if (args.songlist_only or args.songlist_focus) and not args.url and not args.file:
        channels_file = Path("data/channels.txt")
        if channels_file.exists():
            args.file = str(channels_file)
            print(
                "📋 No URL or --file provided, defaulting to all channels in data/channels.txt for songlist mode."
            )
        else:
            print(
                "❌ No URL, --file, or data/channels.txt found. Please provide a channel URL or a file with channel URLs."
            )
            sys.exit(1)
    # --- END NEW ---

    if args.reset_songlist_all:
        from karaoke_downloader.downloader import reset_songlist_all

        reset_songlist_all()
        print("✅ All songlist tracking and files have been reset.")
        sys.exit(0)

    if args.clear_server_duplicates:
        from karaoke_downloader.server_manager import save_server_duplicates_tracking

        save_server_duplicates_tracking({})
        print("✅ Server duplicates tracking has been cleared.")
        print("ℹ️  Songs will be re-checked against the server on next run.")
        sys.exit(0)

    if args.generate_songlist:
        from karaoke_downloader.songlist_generator import SongListGenerator

        print("🎵 Generating song list from MP4 files with ID3 tags...")
        generator = SongListGenerator()
        try:
            generator.generate_songlist_from_multiple_directories(
                args.generate_songlist,
                append=not args.no_append_songlist
            )
            print("✅ Song list generation completed successfully!")
        except Exception as e:
            print(f"❌ Error generating song list: {e}")
            sys.exit(1)
        sys.exit(0)

    if args.status:
        stats = downloader.tracker.get_statistics()
        print("🎤 Karaoke Downloader Status")
        print("=" * 40)
        print(f"Total Songs: {stats['total_songs']}")
        print(f"Total Playlists: {stats['total_playlists']}")
        print(f"Downloaded Songs: {stats['downloaded_songs']}")
        print(f"Failed Songs: {stats['failed_songs']}")
        print(f"Partial Downloads: {stats['partial_songs']}")
        print(f"Total Size: {stats['total_size_mb']} MB")
        print(f"Last Updated: {stats['last_updated']}")
        sys.exit(0)
    elif args.cache_info:
        cache_info = downloader.tracker.get_cache_info()
        print("💾 Channel Cache Information")
        print("=" * 40)
        print(f"Total Channels: {cache_info['total_channels']}")
        print(f"Total Cached Videos: {cache_info['total_cached_videos']}")
        print(f"Cache Duration: {cache_info['cache_duration_hours']} hours")
        print(f"Last Updated: {cache_info['last_updated']}")
        sys.exit(0)
    elif args.clear_cache:
        if args.clear_cache == "all":
            downloader.tracker.clear_channel_cache()
            print("🧹 Cleared all channel caches")
        else:
            downloader.tracker.clear_channel_cache(args.clear_cache)
            print(f"🧹 Cleared cache for channel: {args.clear_cache}")
        sys.exit(0)
    elif args.cache_duration:
        downloader.tracker.set_cache_duration(args.cache_duration)
        print(f"⏰ Cache duration set to {args.cache_duration} hours")
        sys.exit(0)
    elif args.report:
        report = downloader.tracker.export_playlist_report(args.report)
        print(report)
        sys.exit(0)
    elif args.cleanup:
        orphaned = downloader.tracker.cleanup_orphaned_files(downloader.downloads_dir)
        print(f"🧹 Cleaned up {len(orphaned)} orphaned tracking entries")
        sys.exit(0)
    elif args.songlist_status:
        songlist = downloader._load_songlist()
        tracking = downloader.songlist_tracking
        print("📋 Songlist Download Status")
        print("=" * 40)
        print(f"Total songs in list: {len(songlist)}")
        print(f"Songs downloaded: {len(tracking)}")
        print(f"Songs remaining: {len(songlist) - len(tracking)}")
        print(f"Progress: {(len(tracking) / len(songlist) * 100):.1f}%")
        if tracking:
            print(f"\n📁 Downloaded songs:")
            for key, info in list(tracking.items())[:10]:
                print(
                    f"   • {info['artist']} - {info['title']} (from {info['channel']})"
                )
            if len(tracking) > 10:
                print(f"   ... and {len(tracking) - 10} more")
        sys.exit(0)
    elif args.songlist_only or args.songlist_focus:
        # Use provided file or default to data/channels.txt
        channel_file = args.file if args.file else "data/channels.txt"
        if not os.path.exists(channel_file):
            print(f"❌ Channel file not found: {channel_file}")
            sys.exit(1)
        with open(channel_file, "r", encoding="utf-8") as f:
            channel_urls = [
                line.strip()
                for line in f
                if line.strip() and not line.strip().startswith("#")
            ]
        limit = args.limit if args.limit else None
        success = downloader.download_songlist_across_channels(
            channel_urls,
            limit=args.limit,
            force_refresh_download_plan=args.force_download_plan if hasattr(args, "force_download_plan") else False,
            fuzzy_match=args.fuzzy_match,
            fuzzy_threshold=args.fuzzy_threshold,
            force_download=args.force,
            show_pagination=args.show_pagination,
            parallel_channels=args.parallel_channels,
            max_channel_workers=args.channel_workers,
        )
    elif args.latest_per_channel:
        # Use provided file or default to data/channels.txt
        channel_file = args.file if args.file else "data/channels.txt"
        if not os.path.exists(channel_file):
            print(f"❌ Channel file not found: {channel_file}")
            sys.exit(1)
        with open(channel_file, "r", encoding="utf-8") as f:
            channel_urls = [
                line.strip()
                for line in f
                if line.strip() and not line.strip().startswith("#")
            ]
        limit = args.limit if args.limit else DEFAULT_LATEST_PER_CHANNEL_LIMIT
        force_refresh_download_plan = (
            args.force_download_plan if hasattr(args, "force_download_plan") else False
        )
        fuzzy_match = args.fuzzy_match if hasattr(args, "fuzzy_match") else False
        fuzzy_threshold = (
            args.fuzzy_threshold
            if hasattr(args, "fuzzy_threshold")
            else DEFAULT_FUZZY_THRESHOLD
        )
        success = downloader.download_latest_per_channel(
            channel_urls,
            limit=limit,
            force_refresh_download_plan=force_refresh_download_plan,
            fuzzy_match=fuzzy_match,
            fuzzy_threshold=fuzzy_threshold,
            force_download=args.force,
        )
    elif args.url:
        success = downloader.download_channel_videos(
            args.url, force_refresh=args.refresh
        )
    else:
        parser.print_help()
        sys.exit(1)
    
    # Generate unmatched report if requested (additive feature)
    if args.generate_unmatched_report:
        from karaoke_downloader.download_planner import generate_unmatched_report, build_download_plan
        from karaoke_downloader.songlist_manager import load_songlist
        
        print("\n🔍 Generating unmatched songs report...")
        
        # Load songlist based on focus mode
        if args.songlist_focus:
            # Load focused playlists
            songlist_file_path = args.songlist_file if args.songlist_file else "data/songList.json"
            songlist_file = Path(songlist_file_path)
            if not songlist_file.exists():
                print(f"⚠️ Songlist file not found: {songlist_file_path}")
            else:
                try:
                    with open(songlist_file, "r", encoding="utf-8") as f:
                        raw_data = json.load(f)

                    # Filter playlists by title
                    focused_playlists = []
                    for playlist in raw_data:
                        playlist_title = playlist.get("title", "")
                        if playlist_title in args.songlist_focus:
                            focused_playlists.append(playlist)

                    if focused_playlists:
                        # Flatten the focused playlists into songs
                        focused_songs = []
                        seen = set()
                        for playlist in focused_playlists:
                            if "songs" in playlist:
                                for song in playlist["songs"]:
                                    if "artist" in song and "title" in song:
                                        artist = song["artist"].strip()
                                        title = song["title"].strip()
                                        key = f"{artist.lower()}_{title.lower()}"
                                        if key in seen:
                                            continue
                                        seen.add(key)
                                        focused_songs.append(
                                            {
                                                "artist": artist,
                                                "title": title,
                                                "position": song.get("position", 0),
                                            }
                                        )

                        songlist = focused_songs
                    else:
                        print(f"⚠️ No playlists found matching: {', '.join(args.songlist_focus)}")
                        songlist = []

                except (json.JSONDecodeError, FileNotFoundError) as e:
                    print(f"⚠️ Could not load songlist for report: {e}")
                    songlist = []
        else:
            # Load all songs from songlist
            songlist_path = args.songlist_file if args.songlist_file else "data/songList.json"
            songlist = load_songlist(songlist_path)
        
        if songlist:
            # Load channel URLs
            channel_file = args.file if args.file else "data/channels.txt"
            if os.path.exists(channel_file):
                with open(channel_file, "r", encoding='utf-8') as f:
                    channel_urls = [
                        line.strip()
                        for line in f
                        if line.strip() and not line.strip().startswith("#")
                    ]
                
                print(f"📋 Analyzing {len(songlist)} songs against {len(channel_urls)} channels...")
                
                # Build download plan to get unmatched songs
                fuzzy_match = args.fuzzy_match if hasattr(args, "fuzzy_match") else False
                fuzzy_threshold = (
                    args.fuzzy_threshold
                    if hasattr(args, "fuzzy_threshold")
                    else DEFAULT_FUZZY_THRESHOLD
                )
                
                try:
                    download_plan, unmatched = build_download_plan(
                        channel_urls,
                        songlist,
                        downloader.tracker,
                        downloader.yt_dlp_path,
                        fuzzy_match=fuzzy_match,
                        fuzzy_threshold=fuzzy_threshold,
                    )
                    
                    if unmatched:
                        report_file = generate_unmatched_report(unmatched)
                        print(f"\n📋 Unmatched songs report generated successfully!")
                        print(f"📁 Report saved to: {report_file}")
                        print(f"📊 Summary: {len(download_plan)} songs found, {len(unmatched)} songs not found")
                        print(f"\n🔍 First 10 unmatched songs:")
                        for i, song in enumerate(unmatched[:10], 1):
                            print(f"   {i:2d}. {song['artist']} - {song['title']}")
                        if len(unmatched) > 10:
                            print(f"   ... and {len(unmatched) - 10} more songs")
                    else:
                        print(f"\n✅ All {len(songlist)} songs were found in the channels!")
                        
                except Exception as e:
                    print(f"❌ Error generating report: {e}")
            else:
                print(f"❌ Channel file not found: {channel_file}")
        else:
            print("❌ No songlist available for report generation")
    
    # If no download command was specified but generate-unmatched-report was used, exit here
    if not any([args.songlist_only, args.songlist_focus, args.latest_per_channel, args.url]):
        if args.generate_unmatched_report:
            sys.exit(0)
        else:
            parser.print_help()
            sys.exit(1)
    
    downloader.tracker.force_save()
    if success:
        print("\n🎤 All downloads completed successfully!")
        sys.exit(0)
    else:
        print("\n⚠️ Some downloads may have failed. Check the logs for details.")
        sys.exit(1)