import asyncio  # Built-in, no pip install needed!
from fastapi import FastAPI, UploadFile, File
from cnnmodels import classify_tumor

app = FastAPI(title="Brain Tumor CNN Service")

@app.post("/classify")
async def classify(file: UploadFile = File(...)):
    # 1. This reads the file asynchronously on the Main Event Loop
    image_bytes = await file.read()
    
    # 2. Get the running manager (Event Loop)
    loop = asyncio.get_running_loop()
    
    # 3. Offload the heavy CNN model to the background thread pool
    # None tells Python to use FastAPI's default pool of worker threads
    result = await loop.run_in_executor(None, classify_tumor, image_bytes)
    
    return result