# app.py - YouTube Downloader API (No UI)
from flask import Flask, request, send_file, jsonify
import yt_dlp
import os
import glob
import uuid
import traceback

app = Flask(__name__)

# Use /tmp (only writable directory on Hugging Face)
DOWNLOAD_FOLDER = "/tmp/downloads"
os.makedirs(DOWNLOAD_FOLDER, exist_ok=True)


@app.route("/", methods=["GET"])
def info():
    return jsonify({
        "api": "/download",
        "method": "POST",
        "body": {"url": "YouTube_URL", "format": "mp3 or mp4"},
        "example": {
            "url": "https://www.youtube.com/watch?v=dQw4w9WgXcQ",
            "format": "mp3"
        }
    })


@app.route("/download", methods=["POST"])
def download():
    data = request.get_json()

    url = data.get("url")
    fmt = (data.get("format") or "").lower().strip()

    if not url:
        return jsonify({"error": "Missing 'url' in request"}), 400
    if fmt not in ["mp3", "mp4"]:
        return jsonify({"error": "Format must be 'mp3' or 'mp4'"}), 400

    job_id = str(uuid.uuid4())[:8]

    # Robust yt-dlp options with retries and delays
    ydl_opts = {
        'format': 'bestaudio/best' if fmt == 'mp3' else 'bestvideo+bestaudio/best',
        'outtmpl': os.path.join(DOWNLOAD_FOLDER, f'{job_id}_%(title)s.%(ext)s'),
        'merge_output_format': 'mp4' if fmt == 'mp4' else None,
        'noplaylist': True,
        'quiet': True,
        'retries': 6,
        'fragment_retries': 10,
        'socket_timeout': 15,
        'http_headers': {
            'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 '
                          '(KHTML, like Gecko) Chrome/120.0 Safari/537.36'
        },
        'sleep_interval': 5,
        'max_sleep_interval': 15,
        'source_address': None,
        'extractor_retries': 3,
    }

    try:
        with yt_dlp.YoutubeDL(ydl_opts) as ydl:
            info = ydl.extract_info(url, download=True)
            title = info.get("title", "media").replace("/", "_").replace("\\", "_")
            ext = "mp3" if fmt == "mp3" else "mp4"

        pattern = os.path.join(DOWNLOAD_FOLDER, f"{job_id}_*.{ext}")
        matches = glob.glob(pattern)

        if not matches:
            return jsonify({"error": "Download completed but file not found."}), 500

        return send_file(
            matches[0],
            as_attachment=True,
            download_name=f"{title}.{ext}"
        )

    except Exception as e:
        tb = ''.join(traceback.format_exception(None, e, e.__traceback__))
        return jsonify({
            "error": str(e),
            "details": tb.splitlines()[-1]  # Show last line of error
        }), 500


# Optional: Health check route
@app.route("/ping", methods=["GET"])
def ping():
    try:
        import socket
        socket.gethostbyname("www.youtube.com")
        return jsonify({"status": "ok", "dns": "resolved"})
    except Exception as e:
        return jsonify({"status": "fail", "dns_error": str(e)})