"""Utility functions for image manipulation."""

import hashlib

from PIL import Image


def transform(input_filename, width, height, output_format, output_filename):
    """Modify image on disk.

    Args:
        input_filename (str): file on disk to modify
        width (int): resize width
        height (int): resize height
        output_format (str): result image encoding
        output_filename (str): file on disk to save results

    Returns:
        None
    """
    with Image.open(input_filename) as im:
        resized = im.resize((width, height))
        resized.save(output_filename, output_format)


def analyze(input_filename):
    """Gather data about an image on disk.

    Args:
      input_filename (str): file on disk to analyze

    Returns:
        tuple:
            0 (str): MD5 digest of file contents
            1 (int): width of image
            2 (int): height of image
    """
    with Image.open(input_filename) as im:
        (width, height) = im.size

    # don't use im.tobytes() with compressed images
    # https://pillow.readthedocs.io/en/stable/reference/Image.html#PIL.Image.Image.tobytes
    md5 = hashlib.md5(open(input_filename, 'rb').read()).hexdigest()
    return (
        md5,
        width,
        height
    )