package com.infendro.hash.blake

import com.infendro.bytearray.toUByteArray
import com.infendro.bytearray.toUIntArray
import com.infendro.hash.HashFunction

object `Blake-224` : HashFunction() {
    override val bytes: Int
        get() = 28

    override val block: Int
        get() = 64

    private val initial = uintArrayOf(
        0xc1059ed8U, 0x367cd507U,
        0x3070dd17U, 0xf70e5939U,
        0xffc00b31U, 0x68581511U,
        0x64f98fa7U, 0xbefa4fa4U,
    )

    private val c = uintArrayOf(
        0x243f6a88U, 0x85a308d3U,
        0x13198a2eU, 0x03707344U,
        0xa4093822U, 0x299f31d0U,
        0x082efa98U, 0xec4e6c89U,
        0x452821e6U, 0x38d01377U,
        0xbe5466cfU, 0x34e90c6cU,
        0xc0ac29b7U, 0xc97c50ddU,
        0x3f84d5b5U, 0xb5470917U,
    )

    private 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),
    )

    override fun hash(value: UByteArray): UByteArray {
        val l = value.size.toULong() * 8UL
        val h = initial.copyOf()
        var t = 0U

        val blocks = pad(value)
            .chunked(64) { it.toUByteArray() }
        for (block in blocks) {
            t += minOf(l - t, 512UL).toUInt()
            compress(h, block, t)
        }

        return h.sliceArray(0..6).toUByteArray()
    }

    private fun pad(
        value: UByteArray,
    ): UByteArray {
        val l = value.size.toULong() * 8UL
        return buildList {
            addAll(value)
            add(0x80U)
            while (size % 64 != 56) {
                add(0x00U)
            }
            addAll(l.toUByteArray())
        }.toUByteArray()
    }

    private fun compress(
        h: UIntArray,
        block: UByteArray,
        t: UInt,
    ) {
        val m = block.toUIntArray()
        val v = UIntArray(16)
        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(14) { 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..7) {
            h[i] = h[i] xor v[i] xor v[i + 8]
        }
    }

    private fun g(
        v: UIntArray,
        a: Int,
        b: Int,
        c: Int,
        d: Int,
        x: UInt,
        y: UInt,
    ) {
        v[a] += v[b] + x
        v[d] = (v[d] xor v[a]).rotateRight(16)
        v[c] += v[d]
        v[b] = (v[b] xor v[c]).rotateRight(12)
        v[a] += v[b] + y
        v[d] = (v[d] xor v[a]).rotateRight(8)
        v[c] += v[d]
        v[b] = (v[b] xor v[c]).rotateRight(7)
    }
}