export const galoisMultiplyBy2 = (value: number): number => {
  return (value << 1) ^ ((value & 0x80) ? 0x1b : 0x00)
}

export const galoisMultiplyBy3 = (value: number): number => {
  return galoisMultiplyBy2(value) ^ value
}

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

export const mixColumns = (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(galoisMultiplyBy2(state[0][col]) ^ galoisMultiplyBy3(state[1][col]) ^ state[2][col] ^ state[3][col])
    result[1][col] = clampToByte(state[0][col] ^ galoisMultiplyBy2(state[1][col]) ^ galoisMultiplyBy3(state[2][col]) ^ state[3][col])
    result[2][col] = clampToByte(state[0][col] ^ state[1][col] ^ galoisMultiplyBy2(state[2][col]) ^ galoisMultiplyBy3(state[3][col]))
    result[3][col] = clampToByte(galoisMultiplyBy3(state[0][col]) ^ state[1][col] ^ state[2][col] ^ galoisMultiplyBy2(state[3][col]))
  }

  return result
}