#ifndef GF2_MAT_CUH
#define GF2_MAT_CUH

#include "gf2_header.cuh"

#include <random>
#include <vector>
#include <bitset>
// #include <algorithm>

namespace gf2
{
    struct ElimResult
    {
        size_t rank;
        vector<size_t> pivot;
        vector<size_t> swap_row;
    };

    class MatGF2
    {
    public:
        enum MatType
        {
            root,
            window,
            moved,
        };
        // 只能构造root矩阵
        MatGF2(size_t nrows, size_t ncols) : nrows(nrows), ncols(ncols), type(root)
        {
            width = (ncols - 1) / gf2_num + 1;
            rowstride = ((width - 1) / 4 + 1) * 4; // 以32字节（4*64bit）为单位对齐
            CUDA_CHECK(cudaMallocManaged((void **)&data, nrows * rowstride * sizeof(base_t)));
            CUDA_CHECK(cudaMemset(data, 0, nrows * rowstride * sizeof(base_t)));
        }
        // 只能以base_t为单位建立window矩阵
        MatGF2(const MatGF2 &src, size_t begin_ri, size_t begin_wi, size_t end_rj, size_t end_wj) : nrows(end_rj - begin_ri), ncols((end_wj == src.width ? src.ncols : end_wj * gf2_num) - begin_wi * gf2_num), width(end_wj - begin_wi), rowstride(src.rowstride), type(window), data(src.at_base(begin_ri, begin_wi))
        {
            assert(begin_ri < end_rj && end_rj <= src.nrows && begin_wi < end_wj && end_wj <= src.width);
        }
        // 只能拷贝构造root矩阵
        MatGF2(const MatGF2 &m) : MatGF2(m.nrows, m.ncols)
        {
            CUDA_CHECK(cudaMemcpy2D(data, rowstride * sizeof(base_t), m.data, m.rowstride * sizeof(base_t), m.width * sizeof(base_t), nrows, cudaMemcpyDefault));
        }
        MatGF2(MatGF2 &&m) noexcept : nrows(m.nrows), ncols(m.ncols), width(m.width), rowstride(m.rowstride), type(m.type), data(m.data)
        {
            m.type = moved;
            m.data = nullptr;
        }
        MatGF2 &operator=(const MatGF2 &m)
        {
            if (this == &m)
            {
                return *this;
            }
            assert(nrows == m.nrows && ncols == m.ncols);
            CUDA_CHECK(cudaMemcpy2D(data, rowstride * sizeof(base_t), m.data, m.rowstride * sizeof(base_t), m.width * sizeof(base_t), nrows, cudaMemcpyDefault));
            return *this;
        }
        MatGF2 &operator=(MatGF2 &&m) noexcept
        {
            if (this == &m)
            {
                return *this;
            }
            if (type == root)
            {
                CUDA_CHECK(cudaFree(data));
            }
            nrows = m.nrows;
            ncols = m.ncols;
            width = m.width;
            rowstride = m.rowstride;
            type = m.type;
            data = m.data;
            m.type = moved;
            m.data = nullptr;
            return *this;
        }

        ~MatGF2()
        {
            if (type == root)
            {
                CUDA_CHECK(cudaFree(data));
            }
        }

        inline base_t *at_base(size_t r, size_t w) const
        {
            return data + r * rowstride + w;
        }

        void randomize(uint_fast32_t seed)
        {
            assert(type == root);
            static default_random_engine e(seed);
            static uniform_int_distribution<base_t> d;
            base_t lastmask = base_fullmask >> (width * base_len - ncols * gf2_len);
            for (size_t r = 0; r < nrows; r++)
            {
                for (size_t w = 0; w < width; w++)
                {
                    *at_base(r, w) = d(e);
                }
                *at_base(r, width - 1) &= lastmask;
            }
        }

        // 生成随机最简化行阶梯矩阵 前rank_col中选择nrows个主元列
        void randomize(size_t rank_col, uint_fast32_t seed)
        {
            assert(nrows <= rank_col && rank_col <= ncols);
            randomize(seed);
            vector<size_t> pivot(rank_col);
            iota(pivot.begin(), pivot.end(), 0);
            random_shuffle(pivot.begin(), pivot.end());
            pivot.resize(nrows);
            sort(pivot.begin(), pivot.end());

            vector<base_t> pivotmask(width, base_fullmask);
            for (size_t r = 0; r < nrows; r++)
            {
                del(pivotmask[pivot[r] / gf2_num], pivot[r] % gf2_num);
            }

            for (size_t r = 0; r < nrows; r++)
            {
                for (size_t w = 0; w < pivot[r] / gf2_num; w++)
                {
                    *at_base(r, w) = base_zero;
                }
                base_t *now = at_base(r, pivot[r] / gf2_num);
                *now = concat(base_zero, pivot[r] % gf2_num + 1, *now & pivotmask[pivot[r] / gf2_num]);
                set(*now, pivot[r] % gf2_num);
                for (size_t w = pivot[r] / gf2_num + 1; w < rank_col / gf2_num + 1; w++)
                {
                    *at_base(r, w) &= pivotmask[w];
                }
            }
        }

        bool operator==(const MatGF2 &m) const
        {
            if (nrows != m.nrows || ncols != m.ncols)
            {
                return false;
            }
            for (size_t r = 0; r < nrows; r++)
            {
                for (size_t w = 0; w < width; w++)
                {
                    if (*at_base(r, w) != *m.at_base(r, w))
                    {
                        return false;
                    }
                }
            }
            return true;
        }

        bool operator==(const base_t base) const
        {
            for (size_t r = 0; r < nrows; r++)
            {
                for (size_t w = 0; w < width; w++)
                {
                    if (*at_base(r, w) != base)
                    {
                        return false;
                    }
                }
            }
            return true;
        }
        void operator^=(const MatGF2 &m)
        {
            assert(nrows == m.nrows && ncols == m.ncols);
            for (size_t r = 0; r < nrows; r++)
            {
                for (size_t w = 0; w < width; w++)
                {
                    *at_base(r, w) ^= *m.at_base(r, w);
                }
            }
        }
        MatGF2 operator^(const MatGF2 &m) const
        {
            MatGF2 temp(*this);
            temp ^= m;
            return temp;
        }

        void gpu_addmul(const MatGF2 &a, const MatGF2 &b);
        friend MatGF2 gpu_mul(const MatGF2 &a, const MatGF2 &b);

        MatGF2 operator*(const MatGF2 &m) const
        {
            return gpu_mul(*this, m);
        }

        ElimResult gpu_elim();

        friend ostream &operator<<(ostream &out, const MatGF2 &m);

        size_t nrows, ncols, width;

    private:
        MatGF2() : nrows(0), ncols(0), width(0), rowstride(0), type(moved), data(nullptr) {}

        void cpu_swap_row(size_t r1, size_t r2)
        {
            if (r1 == r2)
            {
                return;
            }
            base_t *p1 = at_base(r1, 0);
            base_t *p2 = at_base(r2, 0);
            for (size_t i = 0; i < width; i++)
            {
                base_t temp = p1[i];
                p1[i] = p2[i];
                p2[i] = temp;
            }
        }

        size_t rowstride;
        MatType type;
        base_t *data;
    };

    ostream &operator<<(ostream &out, const MatGF2 &m)
    {
        for (size_t r = 0; r < m.nrows; r++)
        {
            for (size_t w = 0; w < m.width; w++)
            {
                bitset<gf2_num> temp(rev(*m.at_base(r, w)));
                out << temp << " ";
            }
            out << endl;
        }
        return out;
    }
}

#endif