package com.infendro.hash.blake

import com.infendro.bytes.bytearray.copyInto
import com.infendro.bytes.longarray.copyInto
import com.infendro.hash.HashFunction

class `Blake-512` : HashFunction(64, 128) {
    private val h = initial.copyOf()

    private val m = LongArray(16)
    private val v = LongArray(16)

    override fun reset() {
        super.reset()
        initial.copyInto(h)
    }

    override fun process() = compress(buffer.value, length * 8L)

    private fun finalize() {
        buffer.append(0x80.toByte())
        if (buffer.free < 17) {
            process()
            buffer.reset()
        }
        buffer.jumpTo(111)
        buffer.append(0x01.toByte())
        buffer.append(0L)
        buffer.append(length * 8L)

        process()
    }

    override fun digestInto(destination: ByteArray, destinationOffset: Int) {
        finalize()
        h.copyInto(destination, destinationOffset)
        reset()
    }

    private fun compress(block: ByteArray, t: Long) {
        block.copyInto(m)
        for (i in 0..<8) v[i] = h[i]
        for (i in 0..<4) v[i + 8] = c[i]
        for (i in 0..<2) v[i + 12] = c[i + 4] xor t
        for (i in 0..<2) v[i + 14] = c[i + 6]

        repeat(16) { r ->
            val s = sigma[r % 10]

            g(v, 0, 4, 8, 12, m[s[0]] xor c[s[1]], m[s[1]] xor c[s[0]])
            g(v, 1, 5, 9, 13, m[s[2]] xor c[s[3]], m[s[3]] xor c[s[2]])
            g(v, 2, 6, 10, 14, m[s[4]] xor c[s[5]], m[s[5]] xor c[s[4]])
            g(v, 3, 7, 11, 15, m[s[6]] xor c[s[7]], m[s[7]] xor c[s[6]])

            g(v, 0, 5, 10, 15, m[s[8]] xor c[s[9]], m[s[9]] xor c[s[8]])
            g(v, 1, 6, 11, 12, m[s[10]] xor c[s[11]], m[s[11]] xor c[s[10]])
            g(v, 2, 7, 8, 13, m[s[12]] xor c[s[13]], m[s[13]] xor c[s[12]])
            g(v, 3, 4, 9, 14, m[s[14]] xor c[s[15]], m[s[15]] xor c[s[14]])
        }

        for (i in 0..<8) {
            h[i] = h[i] xor v[i] xor v[i + 8]
        }
    }

    private fun g(v: LongArray, a: Int, b: Int, c: Int, d: Int, x: Long, y: Long) {
        v[a] += v[b] + x
        v[d] = (v[d] xor v[a]).rotateRight(32)
        v[c] += v[d]
        v[b] = (v[b] xor v[c]).rotateRight(25)
        v[a] += v[b] + y
        v[d] = (v[d] xor v[a]).rotateRight(16)
        v[c] += v[d]
        v[b] = (v[b] xor v[c]).rotateRight(11)
    }

    companion object {
        private val initial = longArrayOf(
            +0x6a09e667f3bcc908L, -0x4498517a7b3558c5L,
            +0x3c6ef372fe94f82bL, -0x5ab00ac5a0e2c90fL,
            +0x510e527fade682d1L, -0x64fa9773d4c193e1L,
            +0x1f83d9abfb41bd6bL, +0x5be0cd19137e2179L,
        )

        internal val c = longArrayOf(
            +0x243f6a8885a308d3L, +0x13198a2e03707344L,
            -0x5bf6c7ddd660ce30L, +0x082efa98ec4e6c89L,
            +0x452821e638d01377L, -0x41ab9930cb16f394L,
            -0x3f53d6483683af23L, +0x3f84d5b5b5470917L,
            -0x6de92a26768604e5L, -0x2ecef45967204a54L,
            +0x2ffd72dbd01adfb7L, -0x471e501295d9816aL,
            -0x45836fba0ed38067L, +0x24a19947b3916cf7L,
            +0x0801f2e2858efc16L, +0x636920d871574e69L,
        )

        internal val sigma = arrayOf(
            intArrayOf(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15),
            intArrayOf(14, 10, 4, 8, 9, 15, 13, 6, 1, 12, 0, 2, 11, 7, 5, 3),
            intArrayOf(11, 8, 12, 0, 5, 2, 15, 13, 10, 14, 3, 6, 7, 1, 9, 4),
            intArrayOf(7, 9, 3, 1, 13, 12, 11, 14, 2, 6, 5, 10, 4, 0, 15, 8),
            intArrayOf(9, 0, 5, 7, 2, 4, 10, 15, 14, 1, 11, 12, 6, 8, 3, 13),
            intArrayOf(2, 12, 6, 10, 0, 11, 8, 3, 4, 13, 7, 5, 15, 14, 1, 9),
            intArrayOf(12, 5, 1, 15, 14, 13, 4, 10, 0, 7, 6, 3, 9, 2, 8, 11),
            intArrayOf(13, 11, 7, 14, 12, 1, 3, 9, 5, 0, 15, 4, 8, 6, 2, 10),
            intArrayOf(6, 15, 14, 9, 11, 3, 0, 8, 12, 2, 13, 7, 1, 4, 10, 5),
            intArrayOf(10, 2, 8, 4, 7, 6, 1, 5, 15, 11, 9, 14, 3, 12, 13, 0),
        )
    }
}