package net.taler.wallet.kotlin.crypto

abstract class CryptoImpl : Crypto {

    override fun kdf(outputLength: Int, ikm: ByteArray, salt: ByteArray, info: ByteArray): ByteArray {
        return Kdf.kdf(outputLength, ikm, salt, info, { sha256(it) }, { sha512(it) })
    }

    override fun setupRefreshPlanchet(secretSeed: ByteArray, coinNumber: Int): FreshCoin {
        val info = "taler-coin-derivation".encodeToByteArray()
        val salt = coinNumber.toByteArray()
        val out = kdf(64, secretSeed, salt, info)
        val coinPrivateKey = out.copyOfRange(0, 32)
        val bks = out.copyOfRange(32, 64)
        return FreshCoin(eddsaGetPublic(coinPrivateKey), coinPrivateKey, bks)
    }

    private fun Int.toByteArray(): ByteArray {
        val bytes = ByteArray(4)
        bytes[3] = (this and 0xFFFF).toByte()
        bytes[2] = ((this ushr 8) and 0xFFFF).toByte()
        bytes[1] = ((this ushr 16) and 0xFFFF).toByte()
        bytes[0] = ((this ushr 24) and 0xFFFF).toByte()
        return bytes
    }

}