/*! \file */
/* ************************************************************************
 * Copyright (C) 2021-2022 Advanced Micro Devices, Inc. All rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 * ************************************************************************ */

#include "rocsparse_bsrxmv_spzl.hpp"

template <unsigned int BLOCKSIZE, rocsparse_direction DIR, typename I, typename J>
__device__ void sbsrxmvn_8x8_device(J     mb,
                                    float alpha,
                                    J     size_of_mask,
                                    const J* __restrict__ bsr_mask_ptr,
                                    const I* __restrict__ bsr_row_ptr,
                                    const I* __restrict__ bsr_end_ptr,
                                    const J* __restrict__ bsr_col_ind,
                                    const float* __restrict__ bsr_val,
                                    const float* __restrict__ x,
                                    float beta,
                                    float* __restrict__ y,
                                    rocsparse_index_base idx_base)

{
    static constexpr int block_size    = 8;
    static constexpr int sq_block_size = block_size * block_size;

    int const local_i = threadIdx.x % block_size;
    int const local_j = threadIdx.x / block_size;

    int row = blockIdx.x * blockDim.y + threadIdx.y;
    if(bsr_mask_ptr != nullptr)
    {
        row = bsr_mask_ptr[row] - idx_base;
    }

    if((row < mb) && (local_j < block_size))
    {
        const int global_row = local_i + row * block_size;

        const I offset_begin = bsr_row_ptr[row] - idx_base;
        const I offset_end   = (bsr_end_ptr == nullptr) ? (bsr_row_ptr[row + 1] - idx_base)
                                                        : (bsr_end_ptr[row] - idx_base);

        float fk = static_cast<float>(0);
        if(DIR == rocsparse_direction_row)
        {
            I offset = offset_begin;
            bsr_val += int64_t(sq_block_size) * offset;
            bsr_val += local_j + local_i * block_size;
#pragma unroll 4
            for(; offset < offset_end; offset++)
            {
                const J jam0 = bsr_col_ind[offset] - idx_base;
                fk           = rocsparse_fma(*bsr_val, x[local_j + jam0 * block_size], fk);
                bsr_val += sq_block_size;
            }
        }
        else
        {
            I offset = offset_begin;
            bsr_val += int64_t(sq_block_size) * offset;
            bsr_val += local_i + local_j * block_size;
#pragma unroll 4
            for(; offset < offset_end; offset++)
            {
                const J jam0 = bsr_col_ind[offset] - idx_base;
                fk           = rocsparse_fma(*bsr_val, x[local_j + jam0 * block_size], fk);
                bsr_val += sq_block_size;
            }
        }

        // Reduction along the subcolumns, threads with l=0 hold the complete sum
        float f1 = fk;
#pragma unroll 7
        for(int s = 1; s < 8; ++s)
            f1 = f1 + __shfl(fk, local_i + s * block_size, 64);

        f1 = beta * y[global_row] + alpha * f1;
        if(local_j == 0)
        {
            y[global_row] = f1;
        }
    }
}

template <unsigned int BLOCKSIZE, rocsparse_direction DIR, typename I, typename J, typename U>
__launch_bounds__(BLOCKSIZE) ROCSPARSE_KERNEL
    void sbsrxmvn_8x8_kernel(J mb,
                             U alpha_device_host,
                             J size_of_mask,
                             const J* __restrict__ bsr_mask_ptr,
                             const I* __restrict__ bsr_row_ptr,
                             const I* __restrict__ bsr_end_ptr,
                             const J* __restrict__ bsr_col_ind,
                             const float* __restrict__ bsr_val,
                             const float* __restrict__ x,
                             U beta_device_host,
                             float* __restrict__ y,
                             rocsparse_index_base idx_base)
{
    auto alpha = load_scalar_device_host(alpha_device_host);
    auto beta  = load_scalar_device_host(beta_device_host);
    if(alpha != static_cast<float>(0) || beta != static_cast<float>(1))
    {
        sbsrxmvn_8x8_device<BLOCKSIZE, DIR>(mb,
                                            alpha,
                                            size_of_mask,
                                            bsr_mask_ptr,
                                            bsr_row_ptr,
                                            bsr_end_ptr,
                                            bsr_col_ind,
                                            bsr_val,
                                            x,
                                            beta,
                                            y,
                                            idx_base);
    }
}

// BSRXMV kernel for BSR block dimension of 8
template <unsigned int BLOCKSIZE, typename T, typename I, typename J>
__device__ void bsrxmvn_8x8_device(J                   mb,
                                   rocsparse_direction dir,
                                   T                   alpha,
                                   J                   size_of_mask,
                                   const J* __restrict__ bsr_mask_ptr,
                                   const I* __restrict__ bsr_row_ptr,
                                   const I* __restrict__ bsr_end_ptr,
                                   const J* __restrict__ bsr_col_ind,
                                   const T* __restrict__ bsr_val,
                                   const T* __restrict__ x,
                                   T beta,
                                   T* __restrict__ y,
                                   rocsparse_index_base idx_base)
{
    // BSR block dimension
    static constexpr int BSRDIM   = 8;
    static constexpr int SQBSRDIM = BSRDIM * BSRDIM;

    // BSR block lane id
    J lid = hipThreadIdx_x % BSRDIM;

    // Offset into x vector
    J idx = (dir == rocsparse_direction_column) ? ((hipThreadIdx_x / BSRDIM) % BSRDIM) : lid;

    // Number of BSR blocks processed at the same time
    const unsigned int NBLOCKS = BLOCKSIZE / SQBSRDIM;

    // Each thread block processes a single BSR row
    J row = hipBlockIdx_x;

    if(bsr_mask_ptr != nullptr)
    {
        row = bsr_mask_ptr[row] - idx_base;
    }

    // BSR row entry and exit point
    I row_begin = bsr_row_ptr[row] - idx_base;
    I row_end   = (bsr_end_ptr == nullptr) ? (bsr_row_ptr[row + 1] - idx_base)
                                           : (bsr_end_ptr[row] - idx_base);

    // BSR block row accumulator
    T sum = static_cast<T>(0);

    // Loop over all BSR blocks in the current row where each lane
    // processes a BSR block value
    bsr_val += size_t(row_begin) * SQBSRDIM + hipThreadIdx_x;
    I j = row_begin;
    for(; j < row_end; j += NBLOCKS)
    {
        I k = j + hipThreadIdx_x / (BSRDIM * BSRDIM);

        // Do not exceed the row
        if(k < row_end)
        {
            // Column index into x vector
            J col = (bsr_col_ind[k] - idx_base) * BSRDIM;

            // Compute the sum of the two rows within the BSR blocks of the current
            // BSR row
            sum = rocsparse_fma(*bsr_val, x[col + idx], sum);
        }
        bsr_val += NBLOCKS * SQBSRDIM;
    }

    // Accumulate each row sum of the BSR block
    __shared__ T sdata[SQBSRDIM * NBLOCKS];

    sdata[hipThreadIdx_x] = sum;

    __syncthreads();

    if(dir == rocsparse_direction_column)
    {
        if(hipThreadIdx_x < BSRDIM * 8)
            sdata[hipThreadIdx_x] += sdata[hipThreadIdx_x + BSRDIM * 8];
        __threadfence_block();
        if(hipThreadIdx_x < BSRDIM * 4)
            sdata[hipThreadIdx_x] += sdata[hipThreadIdx_x + BSRDIM * 4];
        __threadfence_block();
        if(hipThreadIdx_x < BSRDIM * 2)
            sdata[hipThreadIdx_x] += sdata[hipThreadIdx_x + BSRDIM * 2];
        __threadfence_block();
        if(hipThreadIdx_x < BSRDIM * 1)
            sum = sdata[hipThreadIdx_x] + sdata[hipThreadIdx_x + BSRDIM * 1];
    }
    else
    {
        // Accumulate the row sum for different blocks
        if(hipThreadIdx_x < BSRDIM * BSRDIM)
            sdata[hipThreadIdx_x] += sdata[hipThreadIdx_x + BSRDIM * BSRDIM];
        __syncthreads();

        // Reduce the intra block row sum
        if(lid < 4)
            sdata[hipThreadIdx_x] += sdata[hipThreadIdx_x + 4];
        __threadfence_block();
        if(lid < 2)
            sdata[hipThreadIdx_x] += sdata[hipThreadIdx_x + 2];
        __threadfence_block();

        // Final reduction
        if(hipThreadIdx_x < BSRDIM)
            sum = sdata[hipThreadIdx_x * BSRDIM] + sdata[hipThreadIdx_x * BSRDIM + 1];
    }

    // First 8 threads write row sums to global memory
    if(hipThreadIdx_x < BSRDIM)
    {
        if(beta != static_cast<T>(0))
        {
            y[row * BSRDIM + hipThreadIdx_x]
                = rocsparse_fma(beta, y[row * BSRDIM + hipThreadIdx_x], alpha * sum);
        }
        else
        {
            y[row * BSRDIM + hipThreadIdx_x] = alpha * sum;
        }
    }
}

template <unsigned int BLOCKSIZE, typename T, typename I, typename J, typename U>
__launch_bounds__(BLOCKSIZE) ROCSPARSE_KERNEL
    void bsrxmvn_8x8_kernel(J                   mb,
                            rocsparse_direction dir,
                            U                   alpha_device_host,
                            J                   size_of_mask,
                            const J* __restrict__ bsr_mask_ptr,
                            const I* __restrict__ bsr_row_ptr,
                            const I* __restrict__ bsr_end_ptr,
                            const J* __restrict__ bsr_col_ind,
                            const T* __restrict__ bsr_val,
                            const T* __restrict__ x,
                            U beta_device_host,
                            T* __restrict__ y,
                            rocsparse_index_base idx_base)
{
    auto alpha = load_scalar_device_host(alpha_device_host);
    auto beta  = load_scalar_device_host(beta_device_host);
    if(alpha != static_cast<T>(0) || beta != static_cast<T>(1))
    {
        bsrxmvn_8x8_device<BLOCKSIZE>(mb,
                                      dir,
                                      alpha,
                                      size_of_mask,
                                      bsr_mask_ptr,
                                      bsr_row_ptr,
                                      bsr_end_ptr,
                                      bsr_col_ind,
                                      bsr_val,
                                      x,
                                      beta,
                                      y,
                                      idx_base);
    }
}

template <typename T>
struct kernels_type_dispatch
{
    template <typename I, typename J, typename U>
    static void bsrxmvn_8x8(rocsparse_handle     handle,
                            rocsparse_direction  dir,
                            J                    mb,
                            I                    nnzb,
                            U                    alpha_device_host,
                            J                    size_of_mask,
                            const J*             bsr_mask_ptr,
                            const I*             bsr_row_ptr,
                            const I*             bsr_end_ptr,
                            const J*             bsr_col_ind,
                            const T*             bsr_val,
                            const T*             x,
                            U                    beta_device_host,
                            T*                   y,
                            rocsparse_index_base base)
    {
        const J size = (bsr_mask_ptr == nullptr) ? mb : size_of_mask;
        hipLaunchKernelGGL((bsrxmvn_8x8_kernel<128>),
                           dim3(size),
                           dim3(128),
                           0,
                           handle->stream,
                           mb,
                           dir,
                           alpha_device_host,
                           size_of_mask,
                           bsr_mask_ptr,
                           bsr_row_ptr,
                           bsr_end_ptr,
                           bsr_col_ind,
                           bsr_val,
                           x,
                           beta_device_host,
                           y,
                           base);
    }
};

template <>
struct kernels_type_dispatch<float>
{
    template <typename I, typename J, typename U>
    static void bsrxmvn_8x8(rocsparse_handle     handle,
                            rocsparse_direction  dir,
                            J                    mb,
                            I                    nnzb,
                            U                    alpha_device_host,
                            J                    size_of_mask,
                            const J*             bsr_mask_ptr,
                            const I*             bsr_row_ptr,
                            const I*             bsr_end_ptr,
                            const J*             bsr_col_ind,
                            const float*         bsr_val,
                            const float*         x,
                            U                    beta_device_host,
                            float*               y,
                            rocsparse_index_base base)
    {

        const int wsize = handle->wavefront_size;
        if(wsize == 32)
        {
            const J size = (bsr_mask_ptr == nullptr) ? mb : size_of_mask;
            hipLaunchKernelGGL((bsrxmvn_8x8_kernel<128>),
                               dim3(size),
                               dim3(128),
                               0,
                               handle->stream,
                               mb,
                               dir,
                               alpha_device_host,
                               size_of_mask,
                               bsr_mask_ptr,
                               bsr_row_ptr,
                               bsr_end_ptr,
                               bsr_col_ind,
                               bsr_val,
                               x,
                               beta_device_host,
                               y,
                               base);
        }
        else
        {
            static constexpr int nthreads_per_warp = 64;
            static constexpr int nwarps_per_block  = 4;
            const J              size              = (bsr_mask_ptr == nullptr) ? mb : size_of_mask;

            dim3 const block2d_dim(nthreads_per_warp, nwarps_per_block);
            dim3 const grid1d_dim((size - 1) / nwarps_per_block + 1);

            if(rocsparse_direction_row == dir)
            {
                hipLaunchKernelGGL((sbsrxmvn_8x8_kernel<nthreads_per_warp * nwarps_per_block,
                                                        rocsparse_direction_row>),
                                   grid1d_dim,
                                   block2d_dim,
                                   0,
                                   handle->stream,
                                   mb,
                                   alpha_device_host,
                                   size_of_mask,
                                   bsr_mask_ptr,
                                   bsr_row_ptr,
                                   bsr_end_ptr,
                                   bsr_col_ind,
                                   bsr_val,
                                   x,
                                   beta_device_host,
                                   y,
                                   base);
            }
            else
            {
                hipLaunchKernelGGL((sbsrxmvn_8x8_kernel<nthreads_per_warp * nwarps_per_block,
                                                        rocsparse_direction_column>),
                                   grid1d_dim,
                                   block2d_dim,
                                   0,
                                   handle->stream,
                                   mb,
                                   alpha_device_host,
                                   size_of_mask,
                                   bsr_mask_ptr,
                                   bsr_row_ptr,
                                   bsr_end_ptr,
                                   bsr_col_ind,
                                   bsr_val,
                                   x,
                                   beta_device_host,
                                   y,
                                   base);
            }
        }
    }
};

template <typename T, typename I, typename J, typename U>
void bsrxmvn_8x8(rocsparse_handle     handle,
                 rocsparse_direction  dir,
                 J                    mb,
                 I                    nnzb,
                 U                    alpha_device_host,
                 J                    size_of_mask,
                 const J*             bsr_mask_ptr,
                 const I*             bsr_row_ptr,
                 const I*             bsr_end_ptr,
                 const J*             bsr_col_ind,
                 const T*             bsr_val,
                 const T*             x,
                 U                    beta_device_host,
                 T*                   y,
                 rocsparse_index_base base)
{
    kernels_type_dispatch<T>::template bsrxmvn_8x8<I, J, U>(handle,
                                                            dir,
                                                            mb,
                                                            nnzb,
                                                            alpha_device_host,
                                                            size_of_mask,
                                                            bsr_mask_ptr,
                                                            bsr_row_ptr,
                                                            bsr_end_ptr,
                                                            bsr_col_ind,
                                                            bsr_val,
                                                            x,
                                                            beta_device_host,
                                                            y,
                                                            base);
}

//
// INSTANTIATE.
//
#define INSTANTIATE(T, I, J)                                          \
    template void bsrxmvn_8x8(rocsparse_handle     handle,            \
                              rocsparse_direction  dir,               \
                              J                    mb,                \
                              I                    nnzb,              \
                              const T*             alpha_device_host, \
                              J                    size_of_mask,      \
                              const J*             bsr_mask_ptr,      \
                              const I*             bsr_row_ptr,       \
                              const I*             bsr_end_ptr,       \
                              const J*             bsr_col_ind,       \
                              const T*             bsr_val,           \
                              const T*             x,                 \
                              const T*             beta_device_host,  \
                              T*                   y,                 \
                              rocsparse_index_base base);             \
    template void bsrxmvn_8x8(rocsparse_handle     handle,            \
                              rocsparse_direction  dir,               \
                              J                    mb,                \
                              I                    nnzb,              \
                              T                    alpha_device_host, \
                              J                    size_of_mask,      \
                              const J*             bsr_mask_ptr,      \
                              const I*             bsr_row_ptr,       \
                              const I*             bsr_end_ptr,       \
                              const J*             bsr_col_ind,       \
                              const T*             bsr_val,           \
                              const T*             x,                 \
                              T                    beta_device_host,  \
                              T*                   y,                 \
                              rocsparse_index_base base)

INSTANTIATE(float, int32_t, int32_t);
INSTANTIATE(double, int32_t, int32_t);
INSTANTIATE(rocsparse_float_complex, int32_t, int32_t);
INSTANTIATE(rocsparse_double_complex, int32_t, int32_t);

INSTANTIATE(float, int64_t, int32_t);
INSTANTIATE(double, int64_t, int32_t);
INSTANTIATE(rocsparse_float_complex, int64_t, int32_t);
INSTANTIATE(rocsparse_double_complex, int64_t, int32_t);

INSTANTIATE(float, int64_t, int64_t);
INSTANTIATE(double, int64_t, int64_t);
INSTANTIATE(rocsparse_float_complex, int64_t, int64_t);
INSTANTIATE(rocsparse_double_complex, int64_t, int64_t);

#undef INSTANTIATE
