import cv2

convert_gray_scale_cache = {}


def grayscale(img_test_path):
    global convert_gray_scale_cache

    try:
        if img_test_path in convert_gray_scale_cache.keys():
            pass

        else:
            # read image
            img_test_rgb = cv2.imread(img_test_path)
            # convert to gray scale
            img_test_gray = cv2.cvtColor(img_test_rgb, cv2.COLOR_BGR2GRAY)
            img_test_gray = cv2.resize(img_test_gray, (1024, 1024))
            convert_gray_scale_cache[img_test_path] = img_test_gray

        return convert_gray_scale_cache[img_test_path]

    except:
        print("error during converting to grayscale")
        exit(0)