from fastapi import FastAPI, File, UploadFile, Form
from fastapi.responses import FileResponse
import tempfile
import shutil
import os

app = FastAPI()

@app.post("/merge")
async def merge_endpoint(
    files: list[UploadFile] = File(...),
    orig_vol: float = Form(1.0),
    music_vol: float = Form(0.5),
):
    temp_dir = tempfile.mkdtemp()
    try:
        saved_files = []
        # Save uploaded files to disk
        for upload_file in files:
            file_path = os.path.join(temp_dir, upload_file.filename)
            with open(file_path, "wb") as out_file:
                content = await upload_file.read()
                out_file.write(content)
            saved_files.append(file_path)

        # Your merge logic here
        # For demo: just return first uploaded file as "merged" output
        if not saved_files:
            return {"error": "No files uploaded"}

        output_path = saved_files[0]

        # Return the merged file (video or audio)
        return FileResponse(output_path, media_type="application/octet-stream", filename="merged_output")

    finally:
        # Cleanup temp_dir after response is sent
        shutil.rmtree(temp_dir)