import json
import os
import asyncio

video_path = params_kw.get('video_path', '')
subtitle_path = params_kw.get('subtitle_path', '')
output_name = params_kw.get('output_name', 'subtitled_output')

output_dir = os.path.join('/tmp/ffmpeg_output', output_name)
os.makedirs(output_dir, exist_ok=True)

output_path = os.path.join(output_dir, 'output.mp4')

try:
    if not video_path or not subtitle_path:
        result = json.dumps({"status": "error", "error": "video_path and subtitle_path are required"})
    elif not os.path.isfile(video_path):
        result = json.dumps({"status": "error", "error": f"Video file not found: {video_path}"})
    elif not os.path.isfile(subtitle_path):
        result = json.dumps({"status": "error", "error": f"Subtitle file not found: {subtitle_path}"})
    else:
        proc = await asyncio.create_subprocess_exec(
            'ffmpeg', '-y',
            '-i', video_path,
            '-vf', f"ass={subtitle_path}",
            '-c:v', 'libx264', '-c:a', 'copy',
            output_path,
            stdout=asyncio.subprocess.PIPE,
            stderr=asyncio.subprocess.PIPE
        )
        stdout, stderr = await proc.communicate()

        if proc.returncode == 0:
            result = json.dumps({"status": "success", "output_path": output_path})
        else:
            result = json.dumps({"status": "error", "error": stderr.decode()})

except Exception as e:
    result = json.dumps({"status": "error", "error": str(e)})

return result