import numpy as np
import cv2
from fastapi import HTTPException


def preprocess_image(file):
    try:
        file.file.seek(0)
        image_bytes = file.file.read()
        nparr = np.frombuffer(image_bytes, np.uint8)
        img = cv2.imdecode(nparr, cv2.IMREAD_COLOR)
        if img is None:
            raise HTTPException(status_code=500, detail="Could not decode image.")

        img = cv2.resize(img, (299, 299))
        img = cv2.cvtColor(img, cv2.COLOR_BGR2RGB)
        img = img / 255.0
        img = np.expand_dims(img, axis=0).astype(np.float32)
        return img

    except HTTPException:
        raise  # Re-raise already defined HTTP errors
    except Exception as e:
        raise HTTPException(
            status_code=500, detail=f"Image preprocessing failed: {str(e)}"
        )