#!/usr/bin/env python3
"""
Flask server for YouTube Concert Splitter
Downloads YouTube videos and splits them into tracks based on a setlist.
"""
from flask import Flask, request, render_template, jsonify
import os
import re
import subprocess
import yt_dlp
from pydub import AudioSegment
from mutagen.easyid3 import EasyID3

app = Flask(__name__)
app.secret_key = os.environ.get('SECRET_KEY', 'your_secret_key_here_change_this')

# Configuration
DOWNLOAD_FOLDER = os.environ.get('DOWNLOAD_FOLDER', 'youtube')
os.makedirs(DOWNLOAD_FOLDER, exist_ok=True)


def sanitize(s: str) -> str:
    """Sanitize string for use as filename."""
    s = s.strip()
    s = re.sub(r'[\\/:"*?<>|]+', '', s)
    s = re.sub(r"[^A-Za-z0-9 _\-]", '_', s)
    return s


def parse_timestamp(ts: str) -> int:
    """Parse timestamp string (HH:MM:SS or MM:SS) to milliseconds."""
    parts = ts.strip().split(':')
    try:
        if len(parts) == 3:
            h, m, s = parts
        elif len(parts) == 2:
            h = 0
            m, s = parts
        else:
            raise ValueError(f"Invalid timestamp format: '{ts}'")
        return (int(h) * 3600 + int(m) * 60 + int(s)) * 1000
    except ValueError as e:
        raise ValueError(f"Cannot parse timestamp '{ts}': {e}")


def download_youtube_audio(url: str, output_folder: str):
    """Download YouTube video and convert to MP3 at 320kbps with enhanced anti-blocking measures."""

    # Check if cookies file exists
    cookies_file = 'cookies.txt'
    has_cookies = os.path.isfile(cookies_file)
    if has_cookies:
        print(f"✓ Using cookies from {cookies_file}")
    else:
        print("⚠️  No cookies.txt found - download may fail for some videos")
        print("   See COOKIES_INSTRUCTIONS.txt for how to add cookies")

    # Enhanced options to bypass YouTube restrictions
    ydl_opts = {
        'format': 'bestaudio/best',
        'outtmpl': f'{output_folder}/%(title)s.%(ext)s',
        'noplaylist': True,
        'quiet': False,
        'no_warnings': False,
        'extract_flat': False,
        'ignoreerrors': False,

        # Use cookies if available
        'cookiefile': cookies_file if has_cookies else None,

        # Anti-blocking measures
        'nocheckcertificate': True,
        'geo_bypass': True,
        'age_limit': None,

        # Better headers to mimic a real browser
        'http_headers': {
            'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36',
            'Accept': 'text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8',
            'Accept-Language': 'en-us,en;q=0.5',
            'Accept-Encoding': 'gzip,deflate',
            'Accept-Charset': 'ISO-8859-1,utf-8;q=0.7,*;q=0.7',
            'Connection': 'keep-alive',
        },

        # Extractor specific arguments for YouTube
        'extractor_args': {
            'youtube': {
                'player_client': ['android', 'web'],
                'player_skip': ['webpage', 'configs'],
            }
        },

        # Post-processing
        'postprocessors': [{
            'key': 'FFmpegExtractAudio',
            'preferredcodec': 'mp3',
            'preferredquality': '320',
        }],

        # Retry options
        'retries': 10,
        'fragment_retries': 10,
        'skip_unavailable_fragments': True,
    }

    with yt_dlp.YoutubeDL(ydl_opts) as ydl:
        info = ydl.extract_info(url, download=True)
        base_name = ydl.prepare_filename(info)

    # Determine the actual MP3 filename
    mp3_path = os.path.splitext(base_name)[0] + '.mp3'

    if not os.path.isfile(mp3_path):
        raise FileNotFoundError(f"Downloaded MP3 not found: {mp3_path}")

    return mp3_path, info


def parse_setlist(setlist_text: str):
    """Parse setlist text into list of (timestamp_ms, title) tuples."""
    entries = []
    lines = setlist_text.strip().split('\n')

    for line in lines:
        line = line.strip()
        if not line:
            continue

        # Match pattern: "TIMESTAMP TITLE"
        m = re.match(r"(\d+:\d+(?::\d+)?)\s+(.+)", line)
        if not m:
            raise ValueError(f"Invalid setlist line format: '{line}'")

        ts, title = m.groups()
        try:
            timestamp_ms = parse_timestamp(ts)
            entries.append((timestamp_ms, title.strip()))
        except ValueError as e:
            raise ValueError(f"Error parsing line '{line}': {e}")

    # Sort by timestamp
    entries.sort(key=lambda x: x[0])
    return entries


def split_audio(mp3_path: str, entries: list, album: str, artist: str, output_dir: str):
    """
    Split audio file into tracks based on setlist entries.
    Skip tracks that already exist.
    Returns list of track info with status (created or skipped).
    """
    print(f"Loading audio file: {mp3_path}")
    audio = AudioSegment.from_file(mp3_path)
    total_ms = len(audio)

    track_results = []
    created_count = 0
    skipped_count = 0

    for idx, (start_ms, title) in enumerate(entries, start=1):
        # Determine end time
        end_ms = entries[idx][0] if idx < len(entries) else total_ms

        # Create filename
        filename = f"{idx:02d} - {sanitize(title)}.mp3"
        filepath = os.path.join(output_dir, filename)

        # Check if file already exists
        if os.path.isfile(filepath):
            print(f"Skipping track {idx}/{len(entries)}: {filename} (already exists)")
            track_results.append({
                'filename': filename,
                'status': 'skipped'
            })
            skipped_count += 1
            continue

        # Extract and export segment
        print(f"Creating track {idx}/{len(entries)}: {filename}")
        segment = audio[start_ms:end_ms]

        # Export with 320kbps
        segment.export(filepath, format='mp3', bitrate='320k')

        # Add ID3 tags
        try:
            tags = EasyID3(filepath)
            tags['title'] = title
            tags['album'] = album
            tags['artist'] = artist
            tags['tracknumber'] = str(idx)
            tags.save()
        except Exception as e:
            print(f"Warning: Could not add ID3 tags to {filename}: {e}")

        track_results.append({
            'filename': filename,
            'status': 'created'
        })
        created_count += 1

    return track_results, created_count, skipped_count


def set_permissions(directory: str):
    """Set directory permissions to 775 recursively."""
    try:
        subprocess.run(['chmod', '-R', '775', directory], check=True)
        print(f"Set permissions 775 on {directory}")
    except subprocess.CalledProcessError as e:
        print(f"Warning: Could not set permissions: {e}")
    except FileNotFoundError:
        print("Warning: chmod command not found (might be on Windows)")


@app.route('/')
def index():
    """Render the main page."""
    return render_template('index.html')


@app.route('/split', methods=['POST'])
def split_concert():
     """Handle the split request."""
     try:
         # Get form data
         url = request.form.get('youtube_url', '').strip()
         artist = request.form.get('artist', '').strip()
         album = request.form.get('album', '').strip()
         setlist_text = request.form.get('setlist', '').strip()

         # Validate required inputs (setlist is OPTIONAL)
         if not url:
             return jsonify({'error': 'No YouTube URL provided'}), 400

         if not artist:
             return jsonify({'error': 'No artist name provided'}), 400

         if not album:
             return jsonify({'error': 'No album name provided'}), 400

         # Sanitize album for directory name
         album_sanitized = sanitize(album)

         # Create output directory directly in DOWNLOAD_FOLDER
         output_dir = os.path.join(DOWNLOAD_FOLDER, album_sanitized)

         # Create directory only if it doesn't exist
         if not os.path.exists(output_dir):
             os.makedirs(output_dir, exist_ok=True)
             print(f"✓ Created album directory: {output_dir}")
         else:
             print(f"✓ Album directory already exists: {output_dir}")

         # Download audio
         print(f"Downloading audio from: {url}")
         mp3_path, info = download_youtube_audio(url, DOWNLOAD_FOLDER)

         # DECISION POINT: Empty setlist = Single song mode
         if not setlist_text:
             print("📀 Single song mode: No setlist provided")

             # Use video title as track name
             track_title = info.get('title', 'Unknown Track')
             filename = f"01 - {sanitize(track_title)}.mp3"
             filepath = os.path.join(output_dir, filename)

             # Check if file already exists
             if os.path.isfile(filepath):
                 print(f"⊘ Track already exists: {filename}")
                 os.remove(mp3_path)  # Clean up downloaded file

                 track_results = [{
                     'filename': filename,
                     'status': 'skipped'
                 }]
                 created_count = 0
                 skipped_count = 1
             else:
                 # Move and rename the file (no splitting needed)
                 print(f"✓ Creating single track: {filename}")

                 # Load audio to re-export with proper tags
                 audio = AudioSegment.from_file(mp3_path)
                 audio.export(filepath, format='mp3', bitrate='320k')

                 # Add ID3 tags
                 try:
                     tags = EasyID3(filepath)
                     tags['title'] = track_title
                     tags['album'] = album
                     tags['artist'] = artist
                     tags['tracknumber'] = '1'
                     tags.save()
                     print(f"✓ Added ID3 tags")
                 except Exception as e:
                     print(f"⚠️  Warning: Could not add ID3 tags: {e}")

                 # Clean up original
                 os.remove(mp3_path)

                 track_results = [{
                     'filename': filename,
                     'status': 'created'
                 }]
                 created_count = 1
                 skipped_count = 0

         else:
             # SPLIT MODE: Parse setlist and split audio
             print(f"✂️  Split mode: Processing setlist with {len(setlist_text.splitlines())} lines")

             # Parse setlist for splitting
             try:
                 entries = parse_setlist(setlist_text)
             except ValueError as e:
                 os.remove(mp3_path)  # Clean up downloaded file
                 return jsonify({'error': f'Setlist parsing error: {str(e)}'}), 400

             if not entries:
                 os.remove(mp3_path)  # Clean up downloaded file
                 return jsonify({'error': 'No valid tracks found in setlist'}), 400

             # Split audio into tracks (skipping existing ones)
             print(f"Splitting into {len(entries)} tracks...")
             track_results, created_count, skipped_count = split_audio(
                 mp3_path, entries, album, artist, output_dir
             )

             # Clean up original MP3
             print(f"Removing original file: {mp3_path}")
             os.remove(mp3_path)

         # Set permissions
         set_permissions(output_dir)

         # Return success response with detailed track information
         return jsonify({
             'success': True,
             'album': album,
             'artist': artist,
             'total_tracks': len(track_results),
             'created_count': created_count,
             'skipped_count': skipped_count,
             'tracks': track_results,
             'output_dir': output_dir
         })

     except Exception as e:
         print(f"❌ Error: {str(e)}")
         import traceback
         traceback.print_exc()
         return jsonify({'error': str(e)}), 500

if __name__ == '__main__':
    # Get configuration from environment variables
    host = os.environ.get('FLASK_HOST', '0.0.0.0')
    port = int(os.environ.get('FLASK_PORT', 5000))
    debug = os.environ.get('FLASK_DEBUG', 'False').lower() == 'true'

    print(f"Starting YouTube Concert Splitter on {host}:{port}")
    print(f"Music directory: {DOWNLOAD_FOLDER}")

    # Run on all interfaces, configurable port
#     app.run(host=host, port=port, debug=debug)
    app.run(host="0.0.0.0", port=port, debug=debug)