import sys

from PIL import Image, ImageFilter


def insta_size_no_padding(img):
    w, h = img.size
    new = Image.new(img.mode, (max(w, h), max(w, h)), (255, 255, 255))
    if h >= w:
        new.paste(img, (int((max(w, h) - w) / 2), 0))
    else:
        new.paste(img, (0, int((max(w, h) - h) / 2)))
    return new


def insta_size_padding(img):
    w, h = img.size
    padding_percentage = 0.02
    length = max(w, h)
    padding = int(padding_percentage * length)
    new = Image.new(img.mode, (length + 2 * padding, length + 2 * padding), 0xeeeeee)
    if h >= w:
        new.paste(img, (int((length + 2 * padding - w) / 2), padding))
    else:
        new.paste(img, (padding, int((length + 2 * padding - h) / 2)))
    return new


def drop_shadow(image, offset=(5, 5), background=0xffffff, shadow=0x444444, border=8, iterations=50):
    """
    Add a gaussian blur drop shadow to an image.

    image       - The image to overlay on top of the shadow.
    offset      - Offset of the shadow from the image as an (x,y) tuple.  Can be
                  positive or negative.
    background  - Background colour behind the image.
    shadow      - Shadow colour (darkness).
    border      - Width of the border around the image.  This must be wide
                  enough to account for the blurring of the shadow.
    iterations  - Number of times to apply the filter.  More iterations
                  produce a more blurred shadow, but increase processing time.
    """

    # Create the backdrop image -- a box in the background colour with a
    # shadow on it.
    total_width = image.size[0] + abs(offset[0]) + 2 * border
    total_height = image.size[1] + abs(offset[1]) + 2 * border
    back = Image.new(image.mode, (total_width, total_height), background)

    shadow_image = Image.new(image.mode, (image.size[0], image.size[1]), shadow)

    # Place the shadow, taking into account the offset from the image
    shadow_left = border + max(offset[0], 0)
    shadow_top = border + max(offset[1], 0)
    back.paste(shadow_image, (shadow_left, shadow_top))

    # Apply the filter to blur the edges of the shadow.  Since a small kernel
    # is used, the filter must be applied repeatedly to get a decent blur.
    n = 0
    while n < iterations:
        back = back.filter(ImageFilter.BLUR)
        n += 1

    # Paste the input image onto the shadow backdrop
    image_left = border - min(offset[0], 0)
    image_top = border - min(offset[1], 0)
    back.paste(image, (image_left, image_top))

    return back


if __name__ == "__main__":
    if len(sys.argv) <= 1:
        exit(0)
    for file in sys.argv[1:]:
        names = file.split(".")
        if len(names) != 2:
            continue
        try:
            im = Image.open(file)
        except Exception as e:
            print(str(e))
            continue
        result = insta_size_padding(drop_shadow(im, background=0xeeeeee, shadow=0x444444, offset=(20, 20)))
        result.save("{}-square-shadow.{}".format(names[0], names[1]), quality=100)