import os
import argparse
import glob
import operator
from shutil import rmtree
from PIL import Image

parser = argparse.ArgumentParser()
parser.add_argument('--step', default=256, type=int)
parser.add_argument('--overlap', default=4, type=int)
parser.add_argument('--scale', default=4, type=int)
parser.add_argument('cmd', metavar='crop', help='Command')
parser.add_argument('dir', metavar='dir', help='Directory to process')
args = parser.parse_args()

def crop_dir():
    step = args.step - args.overlap
    files = glob.glob('{}/*.png'.format(args.dir))
    img = Image.open(files[0])
    width, height = img.size
    print("{}x{} {}".format(width, height, step))
    for x in range(0, width, step):
        for y in range(0, height, step):
            w = min(args.step, width - x)
            h = min(args.step, height - y)
            crop_dir = "{}/crop_{}_{}_{}_{}".format(args.dir, x, y, w, h)
            if os.path.exists(crop_dir):
                rmtree(crop_dir)
            os.makedirs(crop_dir)

    for raw_fn in files:
        img = Image.open(raw_fn)
        fn = os.path.basename(raw_fn)
        for x in range(0, width, step):
            for y in range(0, height, step):
                w = min(args.step, width - x)
                h = min(args.step, height - y)
                crop_dir = "{}/crop_{}_{}_{}_{}".format(args.dir, x, y, w, h)
                print("{}x{} {}x{}".format(x, y, w, h))
                crop = img.crop((x, y, x + w, y + h))
                crop.save("{}/{}".format(crop_dir, fn))

def split_crop_dir(fn):
    crop, x, y, w, h = os.path.basename(fn).split("_")
    return int(x), int(y), int(w), int(h)

def create_mask(overlap, x, y, w, h):
    mask_img = Image.new('L', (w, h,), "white")
    mask = mask_img.load()
    if x > 0:
        for i in range(0, overlap, 1):
            for j in range(0, h, 1):
                mask[i, j] = (int((i / overlap) * mask[i, j]),)
    if y > 0:
        for i in range(0, w, 1):
            for j in range(0, overlap, 1):
                mask[i, j] = (int((i / overlap) * mask[i, j]),)
    return mask_img

def merge_dir():
    overlap = args.overlap * args.scale
    crop_dirs = glob.glob("{}/crop_*".format(args.dir))
    merge_dir = "{}/merged".format(args.dir)
    os.makedirs(merge_dir, exist_ok=True)
    ww = 0
    hh = 0
    masks = {}
    crop_dir_list = []
    widths = []
    heights = []
    for crop_dir in crop_dirs:
        x, y, w, h = split_crop_dir(crop_dir)
        # print("{} {} {} {}".format(x, y, w, h))
        if x not in widths:
            overlap = args.overlap
            if x == 0:
                overlap = 0
            ww += (w - overlap) * args.scale
            widths.append(x)
        if y not in heights:
            overlap = args.overlap
            if x == 0:
                overlap = 0
            hh += (h - overlap) * args.scale
            heights.append(y)
        # print(w, h)
        mask = create_mask(overlap, x, y, w * args.scale, h * args.scale)
        masks[os.path.basename(crop_dir)] = mask
        crop_dir_list.append((x, y, w, h,))
    crop_dir_list = sorted(crop_dir_list, key=operator.itemgetter(0, 1))

    print("{}x{}".format(ww, hh))

    files = sorted(glob.glob("{}/*.png".format(crop_dirs[0])))
    for file in files:
        fn = os.path.basename(file)
        print(fn)
        canvas = Image.new('RGB', (ww, hh,))
        for crop_dir_tuple in crop_dir_list:
            x, y, w, h = crop_dir_tuple
            crop_dir = "crop_{}_{}_{}_{}".format(x, y, w, h)
            image = Image.open("{}/{}/{}".format(args.dir, crop_dir, fn))
            mask = masks[crop_dir]
            canvas.paste(image, (x * args.scale, y * args.scale,), mask)
        canvas.save("{}/{}".format(merge_dir, fn))

if __name__ == "__main__":
    if args.cmd == 'crop':
        crop_dir()
    else:
        merge_dir()