import cv2
import numpy as np
import os
import argparse


parser = argparse.ArgumentParser(
    description="""Takes in a path to a  directory
of images and stacks them into a star trail image."""
)
parser.add_argument("path", help="Path to a directory containing images of stars")

parser.add_argument("--name", help="Name of output file")

args = parser.parse_args()
path = args.path
name = args.name

if name is None:
    name = "out.jpg"

im, prev = None, None
for file in os.listdir(path):
    if os.path.splitext(file)[1].lower() == ".jpg":
        curr = cv2.imread(path + file)
        if im is None:
            im = curr
        else:
            im = np.maximum(im, curr)

    cv2.imwrite(name, im)