//
// MIT license
// Copyright (C) 2024 Intel Corporation
// SPDX-License-Identifier: MIT
//

//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//

#ifndef GGML_SYCL_GEMM_HPP
#define GGML_SYCL_GEMM_HPP

#include "ggml-sycl.h"

#if GGML_SYCL_DNNL

#include "dnnl.hpp"
#include "dnnl_sycl.hpp"

class DnnlGemmWrapper {
public:
    using dt = dnnl::memory::data_type;
    using tag = dnnl::memory::format_tag;

    template<typename T>
    static constexpr dt to_dt() {
        if constexpr (std::is_same_v<T, float>) return dt::f32;
        else if constexpr (std::is_same_v<T, sycl::half>) return dt::f16;
        else static_assert(0);
    }

    // matrix A has m rows, k columns
    // matrix B has k rows, n columns
    // nra - number of elements to skip when moving into next row in A
    // nrb - number of elements to skip when moving into next row in B
    // nca - number of elements to skip when moving into next column in A
    // ncb - number of elements to skip when moving into next column in B
    // stride_a - number of elements to skip when moving to next A matrix
    // stride_b - number of elements to skip when moving to next B matrix
    // batches_a - number of A matrices
    // batches_b - number of B matrices
    static void gemm(ggml_backend_sycl_context & ctx, int m, int n, int k,
        const void * a, dt at, dnnl_dim_t nra, dnnl_dim_t nca, dnnl_dim_t stride_a,
        const void * b, dt bt, dnnl_dim_t nrb, dnnl_dim_t ncb, dnnl_dim_t stride_b,
        void * c, dt ct, const queue_ptr & q, dnnl_dim_t batches_a, dnnl_dim_t batches_b) {

        auto stream = ctx.stream_dnnl(q);
        auto eng = ctx.engine_dnnl(q);

        // { # strides, # rows, # columns }
        dnnl::memory::dims a_dims = { batches_a, m, k };
        dnnl::memory::dims b_dims = { batches_b, k, n };
        dnnl::memory::dims c_dims = { std::max(batches_a, batches_b), m, n };

        // { # elements to skip to next stride, # elements to skip to next row, # elements to skip to next column }
        dnnl::memory::dims a_strides = { stride_a, nra, nca };
        dnnl::memory::dims b_strides = { stride_b, nrb, ncb };

        const auto a_in_md = dnnl::memory::desc(a_dims, at, a_strides);
        const auto b_in_md = dnnl::memory::desc(b_dims, bt, b_strides);
        const auto c_md    = dnnl::memory::desc(c_dims, ct, tag::abc);

        dnnl::primitive_attr primitive_attr;
        primitive_attr.set_scratchpad_mode(dnnl::scratchpad_mode::user);
#ifdef GGML_SYCL_F16
        primitive_attr.set_fpmath_mode(dnnl::fpmath_mode::f16);
#endif

        auto a_mem = dnnl::memory(a_in_md, eng, const_cast<void*>(a));
        auto b_mem = dnnl::memory(b_in_md, eng, const_cast<void*>(b));
        auto matmul_pd = dnnl::matmul::primitive_desc(eng, a_in_md, b_in_md, c_md, primitive_attr);
        auto c_mem = dnnl::memory(matmul_pd.dst_desc(), eng, c);

        auto scratchpad_md = matmul_pd.scratchpad_desc();
        auto scratchpad_mem = ctx.get_scratchpad_mem(scratchpad_md, eng, q);
        auto matmul_prim = dnnl::matmul(matmul_pd);

        std::unordered_map<int, dnnl::memory> matmul_args;
        matmul_args.insert({ DNNL_ARG_SRC, a_mem });
        matmul_args.insert({ DNNL_ARG_WEIGHTS, b_mem });
        matmul_args.insert({ DNNL_ARG_DST, c_mem });
        matmul_args.insert({ DNNL_ARG_SCRATCHPAD, scratchpad_mem });

        matmul_prim.execute(stream, matmul_args);
    }

    // matrices A and B are column major, both having k rows
    // matrix A has m column, matrix B has n columns
    // output: column major matrix C = A transposed * B
    static void row_gemm(ggml_backend_sycl_context & ctx, int m, int n, int k,
        const void * a, dt at, const void * b, dt bt, void * c, dt ct, const queue_ptr & q) {

        gemm(ctx, m, n, k, a, at, k, 1, k * m, b, bt, 1, k, n * k, c, ct, q, 1, 1);
    }
};

#endif

#endif // GGML_SYCL_GEMM_HPP