import math
from typing import List
from tabulate import tabulate

def matmul(matrix_a:List[List[float]], matrix_b:List[List[float]]) -> List[List[float]]:
    """
    calculates matrix multiplication with 2 matrices
    :param matrix_a: the first matrix
    :param matrix_b: the second matrix
    :return: the product of 2 matrices
    """
    a_rows = len(matrix_a)
    a_columns = len(matrix_a[0])
    b_rows = len(matrix_b)
    b_columns = len(matrix_b[0])
    if not a_columns == b_rows:
        raise ValueError("Matrices not valid")
    result = []
    for i in range(a_rows):
        line = []
        for j in range(b_columns):
            elem = 0
            for k in range(a_columns):
                elem += matrix_a[i][k] * matrix_b[k][j]
            line.append(elem)
        result.append(line)
    return result

def transpose(matrix:List[List[int]]) -> List[List[int]]:
    """
    transposes the matrix
    :param matrix: the matrix
    :return: the transpose of the matrix
    """
    if not matrix:
        raise ValueError("Matrices not valid")
    rows = len(matrix)
    cols = len(matrix[0])
    #for i in matrix:
     #   if rows != cols:
      #      raise ValueError("Matrices not valid")
    result = []
    for i in range(cols):
        line = []
        for j in range(rows):
            line.append(matrix[j][i])
        result.append(line)
    return result


def rot_2D(angle: float) -> List[List[float]]:
    rot_matrix = [[math.cos(angle), -math.sin(angle)],
                  [math.sin(angle), math.cos(angle)]]
    return rot_matrix


if __name__ == "__main__":

    # ich habe alles selbst programmiert

    matrix_a =  [    [3, 4, -1, 4],
                    [-2, 2, 5, 1]
                ]
    matrix_b =  [   [1, 3, -2],
                    [2, 5, 1],
                    [-1, 4, -4],
                    [2, 3, 6]
                ]

    matrix_c = matmul(matrix_a, matrix_b)
    print("Ergebnis C = A * B:")
    for row in matrix_c:
        print(row)

    matrix = [
        [1, 2, 3],
        [4, 5, 6]
    ]
    new_matrix = transpose(matrix)
    print("transposed matrix:")
    for row in new_matrix:
        print(row)

    #empty_matrix = []
    #transpose(empty_matrix)

    theta = math.pi / 2
    R = rot_2D(theta)
    print("Rotatiosnmatrix für 90 Grad:")
    print(R)

    p = [[1, 0]]
    rotated = matmul(p, R)
    print("rotated matrix:")
    print(rotated)

    print("Matrix A:")
    print(tabulate(matrix_a))