package ixee.cryptopals.utils

import ixee.cryptopals.utils.crypto._
import javax.crypto.Cipher
import javax.crypto.spec.SecretKeySpec

object CryptoUtils {

  def pkcs7pad(s: Seq[Byte], blockSize: Int): Seq[Byte] = {
    val padLength = blockSize - (s.length % blockSize)
    s ++ Stream.continually(padLength.toByte).take(padLength)
  }

  def cbcDecryptInstance(cipherPrim: String, key: Seq[Byte], iv: Seq[Byte]): CBCDecrypter = {
    val keySpec = new SecretKeySpec(key.toArray, cipherPrim)
    val cipher = Cipher.getInstance(s"$cipherPrim/ECB/NoPadding")
    cipher.init(Cipher.DECRYPT_MODE, keySpec)
    new CBCDecrypter(cipher, iv)
  }

  def cbcEncryptInstance(cipherPrim: String, key: Seq[Byte], iv: Seq[Byte]): CBCEncrypter = {
    val keySpec = new SecretKeySpec(key.toArray, cipherPrim)
    val cipher = Cipher.getInstance(s"$cipherPrim/ECB/NoPadding")
    cipher.init(Cipher.ENCRYPT_MODE, keySpec)
    new CBCEncrypter(cipher, iv)
  }
}