Kirjainlaatikko ohj1 MOOC 2022

# populates a dict with 0-25 key and A-Z values
def generate_letters(letters:dict):
    key = 0
    for i in range(65,91): # A-Z
        letters[key] = chr(i)
        key += 1

# renders 1/4 of the square shape, example below:
# CCC
# CBB
# CBA
# == all we need to render the whole shape later
def construct_shape(shape: dict, letters:dict, layers: int):
    dist_from_x = layers-1

    for i in range(layers):
        #initialize a blank key-value to avoid key errors
        shape[i] = ""

        # first row
        if i == 0:
             shape[i] = letters[layers-1] * (layers)

        # middle row
        elif i == layers-1:
            middle = 1
            # first left to middle letter
            while middle <= layers:
                shape[i] += letters[layers-middle]
                middle += 1
            middle -= 1

        # rows in between
        else:
            dist_from_x -= 1
            temp = layers-1
            for val in range(layers, 0, -1):
                shape[i] += letters[temp]
                if temp > dist_from_x:
                    temp -=1

# copies the left top quadrant (1/4) characters to left bottom.
# then copies the left side charaters to the right side
# function has probably a bad name, i don't even know what it means
def transpose(matrix: dict, layers: int):
    # read from top to middle, and write from middle to bottom
    original_key = layers-2
    new_key = layers
    while original_key > -1:
        matrix[new_key] = matrix[original_key]
        new_key += 1
        original_key -= 1

    # reverse the string and add it to the previous string
    for key, row in matrix.items():
        last_char = int(-layers-1)
        matrix[key] += row[-2:last_char:-1]

# prints the final shape to terminal
def print_shape(shape: dict):
    for key, row in shape.items():
        print(row)

def main():
    letters = {}
    shape = {}
    layers = int(input("Kerrokset:"))

    generate_letters(letters)
    construct_shape(shape, letters, layers) # create 1/4 of shape
    transpose(shape, layers)   # flip & transform to fill the whole pattern
    print_shape(shape) # print final result

main()