import { galoisMultiplyBy2 } from './mixColumns'

const galoisMultiplyBy9 = (value: number): number => {
  return galoisMultiplyBy2(galoisMultiplyBy2(galoisMultiplyBy2(value))) ^ value
}

const galoisMultiplyBy11 = (value: number): number => {
  return galoisMultiplyBy2(galoisMultiplyBy2(galoisMultiplyBy2(value)) ^ value) ^ value
}

const galoisMultiplyBy13 = (value: number): number => {
  return galoisMultiplyBy2(galoisMultiplyBy2(galoisMultiplyBy2(value) ^ value)) ^ value
}

const galoisMultiplyBy14 = (value: number): number => {
  return galoisMultiplyBy2(galoisMultiplyBy2(galoisMultiplyBy2(value) ^ value) ^ value)
}

const clampToByte = (value: number): number => {
  return value & 0xFF
}

export const invMixColumns = (state: number[][]): number[][] => {
  const result: number[][] = [
    [0, 0, 0, 0],
    [0, 0, 0, 0],
    [0, 0, 0, 0],
    [0, 0, 0, 0]
  ]

  for (let col = 0; col < 4; col++) {
    result[0][col] = clampToByte(galoisMultiplyBy14(state[0][col]) ^ galoisMultiplyBy11(state[1][col]) ^ galoisMultiplyBy13(state[2][col]) ^ galoisMultiplyBy9(state[3][col]))
    result[1][col] = clampToByte(galoisMultiplyBy9(state[0][col]) ^ galoisMultiplyBy14(state[1][col]) ^ galoisMultiplyBy11(state[2][col]) ^ galoisMultiplyBy13(state[3][col]))
    result[2][col] = clampToByte(galoisMultiplyBy13(state[0][col]) ^ galoisMultiplyBy9(state[1][col]) ^ galoisMultiplyBy14(state[2][col]) ^ galoisMultiplyBy11(state[3][col]))
    result[3][col] = clampToByte(galoisMultiplyBy11(state[0][col]) ^ galoisMultiplyBy13(state[1][col]) ^ galoisMultiplyBy9(state[2][col]) ^ galoisMultiplyBy14(state[3][col]))
  }

  return result
}