from pathlib import Path  
import argparse
from PIL import Image, ImageOps, ImageEnhance

if __name__ == "__main__":
    # get opt
    parser = argparse.ArgumentParser()
    parser.add_argument("img", help="input img file name", type=str)
    group = parser.add_mutually_exclusive_group()
    group.add_argument("-g", "--gray", help="convert color img to gray", action="store_true")
    group.add_argument("-i", "--invert", help="invert color img", action="store_true")
    group.add_argument("-t", "--threshold", help="to produce a black and white image", action="store_true")
    parser.add_argument("-o", "--output", help="output img file name", type=str, default="output.png")
    args = parser.parse_args()

    if args.gray:
        img = Image.open(args.img)  
        img_gray = img.convert('L')   
        img_gray.save(args.output)
    elif args.invert:
        img = Image.open(args.img)  
        img_invert = ImageOps.invert(img)   
        img_invert.save(args.output)
    elif args.threshold:
        img = Image.open(args.img)   
        img_gray = img.convert('L')  
        enhancer = ImageEnhance.Contrast(img_gray)  
        img_gray = enhancer.enhance(2)   
        img_bw = img_gray.point(lambda x: 0 if x < 128 else 255, '1')  
        img_bw.save(args.output)
    else:
        print("Please run scripts with -g or -i or -t")