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

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)

# Job storage (in production, use Redis or database)
jobs = {}


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, job_id: str):
    """Download YouTube video and convert to MP3 at 320kbps."""
    jobs[job_id]['status'] = 'downloading'
    jobs[job_id]['progress'] = 'Downloading video from YouTube...'

    cookies_file = 'cookies.txt'
    has_cookies = os.path.isfile(cookies_file)

    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,
        'cookiefile': cookies_file if has_cookies else None,
        'nocheckcertificate': True,
        'geo_bypass': True,
        'age_limit': None,
        '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_args': {
            'youtube': {
                'player_client': ['android', 'web'],
                'player_skip': ['webpage', 'configs'],
            }
        },
        'postprocessors': [{
            'key': 'FFmpegExtractAudio',
            'preferredcodec': 'mp3',
            'preferredquality': '320',
        }],
        '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)

    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}")

    jobs[job_id]['progress'] = 'Download complete. Processing audio...'
    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

        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}")

    entries.sort(key=lambda x: x[0])
    return entries


def split_audio(mp3_path: str, entries: list, album: str, artist: str, output_dir: str, job_id: str):
    """Split audio file into tracks based on setlist entries."""
    jobs[job_id]['status'] = 'splitting'
    jobs[job_id]['progress'] = 'Loading audio file...'

    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):
        jobs[job_id]['progress'] = f'Processing track {idx}/{len(entries)}: {title}'

        end_ms = entries[idx][0] if idx < len(entries) else total_ms
        filename = f"{idx:02d} - {sanitize(title)}.mp3"
        filepath = os.path.join(output_dir, filename)

        if os.path.isfile(filepath):
            track_results.append({'filename': filename, 'status': 'skipped'})
            skipped_count += 1
            continue

        segment = audio[start_ms:end_ms]
        segment.export(filepath, format='mp3', bitrate='320k')

        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}", flush=True)

        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)
    except (subprocess.CalledProcessError, FileNotFoundError):
        pass


def process_job(job_id: str, url: str, artist: str, album: str, setlist_text: str):
    """Background job processor."""
    try:
        album_sanitized = sanitize(album)
        output_dir = os.path.join(DOWNLOAD_FOLDER, album_sanitized)

        if not os.path.exists(output_dir):
            os.makedirs(output_dir, exist_ok=True)

        # Download audio
        mp3_path, info = download_youtube_audio(url, DOWNLOAD_FOLDER, job_id)

        # Single song mode or split mode
        if not setlist_text:
            jobs[job_id]['status'] = 'processing'
            jobs[job_id]['progress'] = 'Creating single track...'

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

            if os.path.isfile(filepath):
                os.remove(mp3_path)
                track_results = [{'filename': filename, 'status': 'skipped'}]
                created_count = 0
                skipped_count = 1
            else:
                audio = AudioSegment.from_file(mp3_path)
                audio.export(filepath, format='mp3', bitrate='320k')

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

                os.remove(mp3_path)
                track_results = [{'filename': filename, 'status': 'created'}]
                created_count = 1
                skipped_count = 0
        else:
            # Split mode
            entries = parse_setlist(setlist_text)
            if not entries:
                raise ValueError('No valid tracks found in setlist')

            track_results, created_count, skipped_count = split_audio(
                mp3_path, entries, album, artist, output_dir, job_id
            )
            os.remove(mp3_path)

        # Set permissions
        set_permissions(output_dir)

        # Update job with results
        jobs[job_id]['status'] = 'completed'
        jobs[job_id]['progress'] = 'Processing complete!'
        jobs[job_id]['result'] = {
            '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"Job {job_id} failed: {str(e)}", flush=True)
        import traceback
        traceback.print_exc()

        jobs[job_id]['status'] = 'failed'
        jobs[job_id]['error'] = str(e)


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


@app.route('/split', methods=['POST'])
def split_concert():
    """Submit a split job and return job ID immediately."""
    try:
        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()

        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

        # Create job
        job_id = str(uuid.uuid4())
        jobs[job_id] = {
            'status': 'queued',
            'progress': 'Job queued...',
            'created_at': datetime.now().isoformat(),
            'url': url,
            'artist': artist,
            'album': album
        }

        # Start background thread
        thread = threading.Thread(
            target=process_job,
            args=(job_id, url, artist, album, setlist_text)
        )
        thread.daemon = True
        thread.start()

        print(f"✓ Job {job_id} created and started", flush=True)

        return jsonify({
            'success': True,
            'job_id': job_id
        })

    except Exception as e:
        print(f"Error creating job: {str(e)}", flush=True)
        return jsonify({'error': str(e)}), 500


@app.route('/status/<job_id>', methods=['GET'])
def get_status(job_id):
    """Get job status and results."""
    if job_id not in jobs:
        return jsonify({'error': 'Job not found'}), 404

    job = jobs[job_id]
    response = {
        'status': job['status'],
        'progress': job.get('progress', '')
    }

    if job['status'] == 'completed':
        response['result'] = job.get('result', {})
    elif job['status'] == 'failed':
        response['error'] = job.get('error', 'Unknown error')

    return jsonify(response)


if __name__ == '__main__':
    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}", flush=True)
    print(f"Music directory: {DOWNLOAD_FOLDER}", flush=True)

    app.run(host="0.0.0.0", port=port, debug=debug, threaded=True)