#ifndef GF28_CUH
#define GF28_CUH

#include "header.cuh"

static const set<base_t> irreducible_polynomials_degree_08{0x11b, 0x11d, 0x12b, 0x12d, 0x139, 0x13f, 0x14d, 0x15f, 0x163, 0x165, 0x169, 0x171, 0x177, 0x17b, 0x187, 0x18b, 0x18d, 0x19f, 0x1a3, 0x1a9, 0x1b1, 0x1bd, 0x1c3, 0x1cf, 0x1d7, 0x1dd, 0x1e7, 0x1f3, 0x1f5, 0x1f9};

class GF28
{
public:
    GF28(base_t poly)
    {
        assert(irreducible_polynomials_degree_08.count(poly) == 1);
        this->poly = poly;
        for (size_t x = 0; x < (1 << base_deg); x++)
        {
            mul_table[x][gf28_zero] = gf28_zero;
            for (size_t d = 0; d < base_deg; d++)
            {
                gf28_t val = shift_left(x, d);
                for (size_t y = (1 << d); y < (1 << (d + 1)); y++)
                {
                    mul_table[x][y] = val ^ mul_table[x][y ^ (1 << d)];
                    if (mul_table[x][y] == gf28_one)
                    {
                        inv_table[x] = y;
                    }
                }
            }
        }
        inv_table[gf28_zero] = gf28_zero;
    }

    gf28_t mul(const gf28_t x, const gf28_t y) const
    {
        return mul_table[x][y];
    }

    base_t mul_base(const gf28_t val, const base_t base, const size_t offset = 0) const
    {
        base_t temp = base_zero;
        for (size_t i = offset; i < base_num; i++)
        {
            set8(temp, mul(val, get8(base, i)), i);
        }
        return temp;
    }

    gf28_t inv(gf28_t x)
    {
        return inv_table[x];
    }

    friend ostream &operator<<(ostream &out, const GF28 &gf);

    GF28() = delete;
    GF28(const GF28 &) = delete;
    GF28(GF28 &&) = delete;
    GF28 &operator=(const GF28 &) = delete;
    GF28 &operator=(GF28 &&) = delete;

    gf28_t mul_table[1 << base_deg][1 << base_deg];

private:
    gf28_t shift_left(gf28_t x, size_t d)
    {
        base_t temp = (base_t)x << d;
        for (size_t i = base_deg - 1 + d; i > base_deg - 1; i--)
        {
            if (temp & (1 << i))
            {
                temp ^= poly << (i - base_deg);
            }
        }
        return temp;
    }

    base_t poly;
    gf28_t inv_table[1 << base_deg];
};

ostream &operator<<(ostream &out, const GF28 &gf)
{
    for (size_t x = 0; x < 1 << base_deg; x++)
    {
        for (size_t y = 0; y < 1 << base_deg; y++)
        {
            printf("%02X ", gf.mul_table[x][y]);
        }
        printf("\n");
    }
    return out;
}

#endif