from flask import Flask, render_template, request, jsonify, send_file
from werkzeug.exceptions import HTTPException
import os
import subprocess
import uuid

app = Flask(__name__)
app.config['UPLOAD_FOLDER'] = 'uploads'
app.config['OUTPUT_FOLDER'] = 'outputs'
app.config['MAX_CONTENT_LENGTH'] = 100 * 1024 * 1024  # 100MB limit to prevent server overload

os.makedirs(app.config['UPLOAD_FOLDER'], exist_ok=True)
os.makedirs(app.config['OUTPUT_FOLDER'], exist_ok=True)

import shutil
import time
import traceback

# Check if ffmpeg is installed
FFMPEG_AVAILABLE = shutil.which('ffmpeg') is not None

def cleanup_old_files():
    """Cleanup files older than 1 hour"""
    try:
        now = time.time()
        for folder in [app.config['UPLOAD_FOLDER'], app.config['OUTPUT_FOLDER']]:
            if not os.path.exists(folder):
                continue
            for filename in os.listdir(folder):
                filepath = os.path.join(folder, filename)
                # Remove if older than 1 hour
                if os.path.isfile(filepath) and os.path.getmtime(filepath) < now - 3600:
                    try:
                        os.remove(filepath)
                    except Exception:
                        pass
    except Exception:
        pass

@app.errorhandler(500)
def internal_error(error):
    return jsonify({
        "error": "服务器内部错误 (Internal Server Error)",
        "details": str(error),
        "trace": traceback.format_exc(),
        "suggestion": "请尝试上传较小的文件，或检查文件格式是否正确。"
    }), 500

@app.errorhandler(413)
def request_entity_too_large(error):
    return jsonify({
        "error": "文件过大 (File Too Large)",
        "details": "上传的文件超过了服务器限制 (100MB)。"
    }), 413

@app.errorhandler(Exception)
def handle_exception(e):
    # Pass through HTTP errors
    if isinstance(e, HTTPException):
        return e
    
    # Log the full traceback
    print("Error occurred:")
    traceback.print_exc()
    
    # Now you're handling non-HTTP exceptions only
    return jsonify({
        "error": "Unexpected Error",
        "details": str(e),
        "trace": traceback.format_exc() # Return trace to client for debugging
    }), 500

@app.route('/')
def index():
    return render_template('index.html', ffmpeg_available=FFMPEG_AVAILABLE)

@app.route('/convert', methods=['POST'])
def convert():
    cleanup_old_files()
    
    if 'video' not in request.files:
        return jsonify({"error": "No video file"}), 400
    
    video = request.files['video']
    filename = str(uuid.uuid4())
    input_path = os.path.join(app.config['UPLOAD_FOLDER'], filename + '.webm')
    output_path = os.path.join(app.config['OUTPUT_FOLDER'], filename + '.mp4')
    
    try:
        video.save(input_path)
        
        if not FFMPEG_AVAILABLE:
            return jsonify({"error": "FFmpeg not installed on server", "fallback": True}), 503

        # FFmpeg conversion
        # -vf "pad=ceil(iw/2)*2:ceil(ih/2)*2" ensures dimensions are even for libx264
        # -pix_fmt yuv420p is often required for broad compatibility
        # Added -movflags +faststart for better web playback
        cmd = [
            'ffmpeg', '-y', '-i', input_path,
            '-c:v', 'libx264', '-preset', 'fast', '-crf', '23',
            '-pix_fmt', 'yuv420p',
            '-c:a', 'aac', '-b:a', '192k',
            '-vf', 'pad=ceil(iw/2)*2:ceil(ih/2)*2', 
            '-movflags', '+faststart',
            output_path
        ]
        
        # Log command for debugging
        print(f"Running command: {' '.join(cmd)}")
        
        subprocess.run(cmd, check=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
        return jsonify({"url": f"/download/{filename}.mp4"})
        
    except subprocess.CalledProcessError as e:
        print(f"FFmpeg Error: {e.stderr.decode() if e.stderr else str(e)}")
        return jsonify({"error": "Conversion failed", "details": str(e)}), 500
    except Exception as e:
        print(f"General Error: {str(e)}")
        return jsonify({"error": "Internal server error", "details": str(e)}), 500
    finally:
        # Cleanup input
        if os.path.exists(input_path):
            try:
                os.remove(input_path)
            except:
                pass

@app.route('/download/<filename>')
def download_file(filename):
    return send_file(os.path.join(app.config['OUTPUT_FOLDER'], filename), as_attachment=True)


if __name__ == '__main__':
    app.run(host='0.0.0.0', port=7860)