package.scala

package com.wavesplatform

import java.lang.reflect.Constructor

import com.wavesplatform.account.{PrivateKey, PublicKey}
import com.wavesplatform.common.state.ByteStr
import com.wavesplatform.lang.ValidationError
import com.wavesplatform.transaction.TxValidationError.GenericError
import com.wavesplatform.utils._
import org.whispersystems.curve25519.OpportunisticCurve25519Provider

import scala.util.Try

package object crypto extends ScorexLogging {
  // Constants
  val SignatureLength: Int = Curve25519.SignatureLength
  val KeyLength: Int       = Curve25519.KeyLength
  val DigestLength: Int    = 32

  // Additional provider
  private val provider: OpportunisticCurve25519Provider = {
    val constructor = classOf[OpportunisticCurve25519Provider].getDeclaredConstructors.head
      .asInstanceOf[Constructor[OpportunisticCurve25519Provider]]
    constructor.setAccessible(true)
    val p = constructor.newInstance()
    log.info(s"Native provider used: ${p.isNative}")
    p
  }

  // Digests
  def fastHash(m: Array[Byte]): Array[Byte]   = Blake2b256.hash(m)
  def fastHash(s: String): Array[Byte]        = fastHash(s.utf8Bytes)
  def secureHash(m: Array[Byte]): Array[Byte] = Keccak256.hash(Blake2b256.hash(m))
  def secureHash(s: String): Array[Byte]      = secureHash(s.utf8Bytes)

  // Signatures
  def sign(account: PrivateKey, message: Array[Byte]): ByteStr =
    ByteStr(Curve25519.sign(account.arr, message))

  def signVRF(account: PrivateKey, message: Array[Byte]): ByteStr =
    ByteStr(provider.calculateVrfSignature(provider.getRandom(DigestLength), account.arr, message))

  def verify(signature: ByteStr, message: Array[Byte], publicKey: PublicKey): Boolean =
    Curve25519.verify(signature.arr, message, publicKey.arr)

  def verifyVRF(signature: ByteStr, message: Array[Byte], publicKey: PublicKey): Either[ValidationError, ByteStr] =
    Try(ByteStr(provider.verifyVrfSignature(publicKey.arr, message, signature.arr))).toEither.left
      .map(_ => GenericError("Could not verify VRF proof"))

  // see
  // https://github.com/jedisct1/libsodium/blob/ab4ab23d5744a8e060864a7cec1a7f9b059f9ddd/src/libsodium/crypto_scalarmult/curve25519/ref10/x25519_ref10.c#L17
  // https://boringssl.googlesource.com/boringssl/+/master/third_party/wycheproof_testvectors/x25519_test.json
  private[this] val BlacklistedKeys: Array[Array[Byte]] = Array(
    // 0 (order 4)
    Array(0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
      0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00),
    // 1 (order 1)
    Array(0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
      0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00),
    // 325606250916557431795983626356110631294008115727848805560023387167927233504 (order 8)
    Array(0xe0, 0xeb, 0x7a, 0x7c, 0x3b, 0x41, 0xb8, 0xae, 0x16, 0x56, 0xe3, 0xfa, 0xf1, 0x9f, 0xc4, 0x6a, 0xda, 0x09, 0x8d, 0xeb, 0x9c, 0x32, 0xb1,
      0xfd, 0x86, 0x62, 0x05, 0x16, 0x5f, 0x49, 0xb8, 0x00),
    // 39382357235489614581723060781553021112529911719440698176882885853963445705823 (order 8)
    Array(0x5f, 0x9c, 0x95, 0xbc, 0xa3, 0x50, 0x8c, 0x24, 0xb1, 0xd0, 0xb1, 0x55, 0x9c, 0x83, 0xef, 0x5b, 0x04, 0x44, 0x5c, 0xc4, 0x58, 0x1c, 0x8e,
      0x86, 0xd8, 0x22, 0x4e, 0xdd, 0xd0, 0x9f, 0x11, 0x57),
    // p-1 (order 2)
    Array(0xec, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
      0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x7f),
    // p (=0, order 4)
    Array(0xed, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
      0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x7f),
    // p+1 (=1, order 1)
    Array(0xee, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
      0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x7f)
  ).map(_.map(_.toByte))

  def isWeakPublicKey(publicKey: Array[Byte]): Boolean =
    BlacklistedKeys.exists { wk =>
      publicKey.view.init.iterator.sameElements(wk.view.init) &&
      (publicKey.last == wk.last || (publicKey.last & 0xff) == wk.last + 0x80)
    }
}