"""
image.py, by chaynes@indiana.edu

A PIL.Image module wrapper for CSCI A201.
"""

import PIL.Image

def read(file_name):
    """Read an image from the named file and return it as a matrix of (r,g,b)
    pixel tuples, or raise 'Bad image type' if it is not a suitable image type.
    JPEG is a suitable type, while GIF and PNG are not.
    """
    def make_matrix(lst, numCols):
        matrix = []
        for i in range(0, len(lst), numCols):
            matrix.append(lst[i : i+numCols])
        return matrix
    WIDTH_INDEX = 0
    im = PIL.Image.open(file_name)
    imageData = list(im.getdata())
    if not isinstance(imageData[0], tuple) or not len(imageData[0]) == 3:
        raise 'Bad image type', file_name
    return make_matrix(imageData, im.size[WIDTH_INDEX])

def new(matrix):
    """Return an image object made from the (r,g,b) pixel tuples in matrix.
    Two image object methods:
        show() displays the image in a window
        save(str) saves the image in a jpeg file named by the string
    """
    def flatten_matrix(matrix):
        width = len(matrix[0])
        lst = []
        for index in range(len(matrix)):
            row = matrix[index]
            if width != len(row):
                raise 'Matrix is ragged (rows not all of the same length)'
            lst = lst + row
        return lst
    width = len(matrix[0])
    height = len(matrix)
    im = PIL.Image.new('RGB', (width, height))
    im.putdata(flatten_matrix(matrix))
    return im