#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include "hash.h"
#include <string.h>
#include <assert.h>
#include "int-util.h"
#include "crypto-ops.h"

#ifndef ROTL64
#define ROTL64(x, y) (((x) << (y)) | ((x) >> (64 - (y))))
#endif

static void local_abort(const char *msg) {
    fprintf(stderr, "%s\n", msg);
#ifdef NDEBUG
    _exit(1);
#else
    abort();
#endif
}

typedef uint64_t state_t[25];

void hash_to_scalar(const uint8_t *in, size_t inlen, uint8_t *md, int mdlen) {
    keccak(in, inlen, md, mdlen);
    sc_reduce32(md);
}

// Hash a key to p3 representation
void hash_to_p3(ge_p3 *hash8_p3, const uint8_t *in, size_t inlen) {
    uint8_t md[32];
    keccak(in, 32, md, inlen);
    ge_p2 hash_p2;

    ge_fromfe_frombytes_vartime(&hash_p2, in);
    ge_p1p1 hash8_p1p1;
    ge_mul8(&hash8_p1p1, &hash_p2);
    ge_p1p1_to_p3(hash8_p3, &hash8_p1p1);
}

const uint64_t keccakf_rndc[24] =
        {
                0x0000000000000001, 0x0000000000008082, 0x800000000000808a,
                0x8000000080008000, 0x000000000000808b, 0x0000000080000001,
                0x8000000080008081, 0x8000000000008009, 0x000000000000008a,
                0x0000000000000088, 0x0000000080008009, 0x000000008000000a,
                0x000000008000808b, 0x800000000000008b, 0x8000000000008089,
                0x8000000000008003, 0x8000000000008002, 0x8000000000000080,
                0x000000000000800a, 0x800000008000000a, 0x8000000080008081,
                0x8000000000008080, 0x0000000080000001, 0x8000000080008008
        };

const int keccakf_rotc[24] =
        {
                1, 3, 6, 10, 15, 21, 28, 36, 45, 55, 2, 14,
                27, 41, 56, 8, 25, 43, 62, 18, 39, 61, 20, 44
        };

const int keccakf_piln[24] =
        {
                10, 7, 11, 17, 18, 3, 5, 16, 8, 21, 24, 4,
                15, 23, 19, 13, 12, 2, 20, 14, 22, 9, 6, 1
        };


void keccakf(uint64_t st[25], int rounds) {
    int i, j, round;
    uint64_t t, bc[5];

    for (round = 0; round < rounds; round++) {

        // Theta
        for (i = 0; i < 5; i++)
            bc[i] = st[i] ^ st[i + 5] ^ st[i + 10] ^ st[i + 15] ^ st[i + 20];

        for (i = 0; i < 5; i++) {
            t = bc[(i + 4) % 5] ^ ROTL64(bc[(i + 1) % 5], 1);
            for (j = 0; j < 25; j += 5)
                st[j + i] ^= t;
        }

        // Rho Pi
        t = st[1];
        for (i = 0; i < 24; i++) {
            j = keccakf_piln[i];
            bc[0] = st[j];
            st[j] = ROTL64(t, keccakf_rotc[i]);
            t = bc[0];
        }

        //  Chi
        for (j = 0; j < 25; j += 5) {
            for (i = 0; i < 5; i++)
                bc[i] = st[j + i];
            for (i = 0; i < 5; i++)
                st[j + i] ^= (~bc[(i + 1) % 5]) & bc[(i + 2) % 5];
        }

        //  Iota
        st[0] ^= keccakf_rndc[round];
    }
}

void keccak(const uint8_t *in, size_t inlen, uint8_t *md, int mdlen) {
    state_t st;
    uint8_t temp[144];
    size_t i, rsiz, rsizw;

    static_assert(HASH_DATA_AREA <= sizeof(temp), "Bad keccak preconditions");
    if (mdlen <= 0 || (mdlen > 100 && sizeof(st) != (size_t) mdlen)) {
        local_abort("Bad keccak use");
    }

    rsiz = sizeof(state_t) == mdlen ? HASH_DATA_AREA : 200 - 2 * mdlen;
    rsizw = rsiz / 8;

    memset(st, 0, sizeof(st));

    for ( ; inlen >= rsiz; inlen -= rsiz, in += rsiz) {
        for (i = 0; i < rsizw; i++) {
            uint64_t ina;
            memcpy(&ina, in + i * 8, 8);
            st[i] ^= swap64le(ina);
        }
        keccakf(st, KECCAK_ROUNDS);
    }

    // last block and padding
    if (inlen + 1 >= sizeof(temp) || inlen > rsiz || rsiz - inlen + inlen + 1 >= sizeof(temp) || rsiz == 0 || rsiz - 1 >= sizeof(temp) || rsizw * 8 > sizeof(temp)) {
        local_abort("Bad keccak use");
    }

    if (inlen > 0)
        memcpy(temp, in, inlen);
    temp[inlen++] = 1;
    memset(temp + inlen, 0, rsiz - inlen);
    temp[rsiz - 1] |= 0x80;

    for (i = 0; i < rsizw; i++)
        st[i] ^= swap64le(((uint64_t *) temp)[i]);

    keccakf(st, KECCAK_ROUNDS);

    if (((size_t) mdlen % sizeof(uint64_t)) != 0) {
        local_abort("Bad keccak use");
    }
    memcpy_swap64le(md, st, mdlen / sizeof(uint64_t));
}

uint64_t load_3(const unsigned char *in) {
    uint64_t result;
    result = (uint64_t) in[0];
    result |= ((uint64_t) in[1]) << 8;
    result |= ((uint64_t) in[2]) << 16;
    return result;
}

uint64_t load_4(const unsigned char *in) {
    uint64_t result;
    result = (uint64_t) in[0];
    result |= ((uint64_t) in[1]) << 8;
    result |= ((uint64_t) in[2]) << 16;
    result |= ((uint64_t) in[3]) << 24;
    return result;
}


void sc_reduce32(unsigned char *s) {
    int64_t s0 = 2097151 & load_3(s);
    int64_t s1 = 2097151 & (load_4(s + 2) >> 5);
    int64_t s2 = 2097151 & (load_3(s + 5) >> 2);
    int64_t s3 = 2097151 & (load_4(s + 7) >> 7);
    int64_t s4 = 2097151 & (load_4(s + 10) >> 4);
    int64_t s5 = 2097151 & (load_3(s + 13) >> 1);
    int64_t s6 = 2097151 & (load_4(s + 15) >> 6);
    int64_t s7 = 2097151 & (load_3(s + 18) >> 3);
    int64_t s8 = 2097151 & load_3(s + 21);
    int64_t s9 = 2097151 & (load_4(s + 23) >> 5);
    int64_t s10 = 2097151 & (load_3(s + 26) >> 2);
    int64_t s11 = (load_4(s + 28) >> 7);
    int64_t s12 = 0;
    int64_t carry0;
    int64_t carry1;
    int64_t carry2;
    int64_t carry3;
    int64_t carry4;
    int64_t carry5;
    int64_t carry6;
    int64_t carry7;
    int64_t carry8;
    int64_t carry9;
    int64_t carry10;
    int64_t carry11;

    carry0 = (s0 + (1 << 20)) >> 21;
    s1 += carry0;
    s0 -= carry0 << 21;
    carry2 = (s2 + (1 << 20)) >> 21;
    s3 += carry2;
    s2 -= carry2 << 21;
    carry4 = (s4 + (1 << 20)) >> 21;
    s5 += carry4;
    s4 -= carry4 << 21;
    carry6 = (s6 + (1 << 20)) >> 21;
    s7 += carry6;
    s6 -= carry6 << 21;
    carry8 = (s8 + (1 << 20)) >> 21;
    s9 += carry8;
    s8 -= carry8 << 21;
    carry10 = (s10 + (1 << 20)) >> 21;
    s11 += carry10;
    s10 -= carry10 << 21;

    carry1 = (s1 + (1 << 20)) >> 21;
    s2 += carry1;
    s1 -= carry1 << 21;
    carry3 = (s3 + (1 << 20)) >> 21;
    s4 += carry3;
    s3 -= carry3 << 21;
    carry5 = (s5 + (1 << 20)) >> 21;
    s6 += carry5;
    s5 -= carry5 << 21;
    carry7 = (s7 + (1 << 20)) >> 21;
    s8 += carry7;
    s7 -= carry7 << 21;
    carry9 = (s9 + (1 << 20)) >> 21;
    s10 += carry9;
    s9 -= carry9 << 21;
    carry11 = (s11 + (1 << 20)) >> 21;
    s12 += carry11;
    s11 -= carry11 << 21;

    s0 += s12 * 666643;
    s1 += s12 * 470296;
    s2 += s12 * 654183;
    s3 -= s12 * 997805;
    s4 += s12 * 136657;
    s5 -= s12 * 683901;
    s12 = 0;

    carry0 = s0 >> 21;
    s1 += carry0;
    s0 -= carry0 << 21;
    carry1 = s1 >> 21;
    s2 += carry1;
    s1 -= carry1 << 21;
    carry2 = s2 >> 21;
    s3 += carry2;
    s2 -= carry2 << 21;
    carry3 = s3 >> 21;
    s4 += carry3;
    s3 -= carry3 << 21;
    carry4 = s4 >> 21;
    s5 += carry4;
    s4 -= carry4 << 21;
    carry5 = s5 >> 21;
    s6 += carry5;
    s5 -= carry5 << 21;
    carry6 = s6 >> 21;
    s7 += carry6;
    s6 -= carry6 << 21;
    carry7 = s7 >> 21;
    s8 += carry7;
    s7 -= carry7 << 21;
    carry8 = s8 >> 21;
    s9 += carry8;
    s8 -= carry8 << 21;
    carry9 = s9 >> 21;
    s10 += carry9;
    s9 -= carry9 << 21;
    carry10 = s10 >> 21;
    s11 += carry10;
    s10 -= carry10 << 21;
    carry11 = s11 >> 21;
    s12 += carry11;
    s11 -= carry11 << 21;

    s0 += s12 * 666643;
    s1 += s12 * 470296;
    s2 += s12 * 654183;
    s3 -= s12 * 997805;
    s4 += s12 * 136657;
    s5 -= s12 * 683901;

    carry0 = s0 >> 21;
    s1 += carry0;
    s0 -= carry0 << 21;
    carry1 = s1 >> 21;
    s2 += carry1;
    s1 -= carry1 << 21;
    carry2 = s2 >> 21;
    s3 += carry2;
    s2 -= carry2 << 21;
    carry3 = s3 >> 21;
    s4 += carry3;
    s3 -= carry3 << 21;
    carry4 = s4 >> 21;
    s5 += carry4;
    s4 -= carry4 << 21;
    carry5 = s5 >> 21;
    s6 += carry5;
    s5 -= carry5 << 21;
    carry6 = s6 >> 21;
    s7 += carry6;
    s6 -= carry6 << 21;
    carry7 = s7 >> 21;
    s8 += carry7;
    s7 -= carry7 << 21;
    carry8 = s8 >> 21;
    s9 += carry8;
    s8 -= carry8 << 21;
    carry9 = s9 >> 21;
    s10 += carry9;
    s9 -= carry9 << 21;
    carry10 = s10 >> 21;
    s11 += carry10;
    s10 -= carry10 << 21;

    s[0] = s0 >> 0;
    s[1] = s0 >> 8;
    s[2] = (s0 >> 16) | (s1 << 5);
    s[3] = s1 >> 3;
    s[4] = s1 >> 11;
    s[5] = (s1 >> 19) | (s2 << 2);
    s[6] = s2 >> 6;
    s[7] = (s2 >> 14) | (s3 << 7);
    s[8] = s3 >> 1;
    s[9] = s3 >> 9;
    s[10] = (s3 >> 17) | (s4 << 4);
    s[11] = s4 >> 4;
    s[12] = s4 >> 12;
    s[13] = (s4 >> 20) | (s5 << 1);
    s[14] = s5 >> 7;
    s[15] = (s5 >> 15) | (s6 << 6);
    s[16] = s6 >> 2;
    s[17] = s6 >> 10;
    s[18] = (s6 >> 18) | (s7 << 3);
    s[19] = s7 >> 5;
    s[20] = s7 >> 13;
    s[21] = s8 >> 0;
    s[22] = s8 >> 8;
    s[23] = (s8 >> 16) | (s9 << 5);
    s[24] = s9 >> 3;
    s[25] = s9 >> 11;
    s[26] = (s9 >> 19) | (s10 << 2);
    s[27] = s10 >> 6;
    s[28] = (s10 >> 14) | (s11 << 7);
    s[29] = s11 >> 1;
    s[30] = s11 >> 9;
    s[31] = s11 >> 17;
}