/*
 * Copyright (c) 2018-2019 ARM Limited.
 *
 * SPDX-License-Identifier: MIT
 *
 * 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.
 */
#ifndef __ARM_COMPUTE_NEGEMMINTERLEAVEDTRANSFORMAWRAPPER_H__
#define __ARM_COMPUTE_NEGEMMINTERLEAVEDTRANSFORMAWRAPPER_H__

#include "arm_compute/core/CPP/CPPTypes.h"
#include "arm_compute/core/Helpers.h"
#include "arm_compute/core/ITensor.h"
#include "arm_compute/core/NEON/kernels/assembly/INEGEMMWrapperKernel.h"
#include "arm_compute/core/Utils.h"
#include "arm_compute/core/Validate.h"
#include "arm_compute/core/Window.h"
#include "arm_compute/core/WindowIterator.h"

namespace arm_compute
{
class ITensor;

/** Unit of work for @ref NEGEMMInterleavedTransformAWrapper to process */
struct TransformAWorkload
{
    /** Constructor
     *
     * @param[in] k0    First value to process along the K dimension.
     * @param[in] kmax  Last value to process along the K dimension.
     * @param[in] multi Multi index.
     */
    TransformAWorkload(unsigned int k0, unsigned int kmax, unsigned int multi)
        : _k0(k0), _kmax(kmax), _multi(multi)
    {
    }
    unsigned int _k0;    /**< First value to process along the K dimension. */
    unsigned int _kmax;  /**< Last value to process along the K dimension. */
    unsigned int _multi; /**< Multi index. */
};

/** Equivalent to arm_gemm::GemmInterleaved's Transform<strategy::A_interleave, strategy::A_block but using Compute Library types.
 *
 * Note: Each workload converts a different slice of a and writes it to transformed_a (Which can store only one slice at the time), therefore the workloads' execution should be interleaved with other workloads that make use of their result.
 */
class NEGEMMInterleavedTransformAWrapper
{
public:
    /** Transform the block at the given coordinates
     *
     * @param[in] wl           Workload to process.
     * @param[in] info         Information about the current thread.
     * @param[in] batch_window Window containing iteration information for the M and batch dimensions.
     * @param[in] start_offset Offset relative to the beginning of batch_window to start the processing from.
     * @param[in] end_offset   Offset relative to the beginning of batch_window to stop the processing.
     */
    virtual void transform(const TransformAWorkload &wl, const ThreadInfo &info, const Window &batch_window, const Coordinates &start_offset, const Coordinates &end_offset) = 0;
    /** Generate an array of workloads
     *
     * @param[out] workloads Container to store the generated workloads.
     */
    virtual void create_workloads(std::vector<TransformAWorkload> &workloads) = 0;
    /** Default destructor */
    virtual ~NEGEMMInterleavedTransformAWrapper() = default;
};

/** Type specialisations of @ref NEGEMMInterleavedTransformAWrapper */
template <typename strategy>
class NEGEMMInterleavedTransformAWrapperTemplate : public NEGEMMInterleavedTransformAWrapper
{
public:
    /** Configure the reshape A routine.
     *
     * @param[in]  a                   Input matrix A.
     * @param[out] transformed_a       Reshaped matrix A.
     * @param[in]  transpose_a         Also transpose A ?
     * @param[in]  reinterpret_a_as_3d Re-interpret as 3D ?
     * @param[in]  block_walker        Window representing the layout of the matrix's blocks
     * @param[in]  params              M, N, K sizes.
     */
    void configure(const ITensor *a, ITensor *transformed_a, bool transpose_a, bool reinterpret_a_as_3d, const Window &block_walker, const INEGEMMWrapperKernel::Params &params)
    {
        _a                   = a;
        _transformed_a       = transformed_a;
        _transpose_a         = transpose_a;
        _reinterpret_a_as_3d = reinterpret_a_as_3d;
        _Ksize               = params.K;
        _Msize               = params.M;
        _k_multi_window      = block_walker.shift_dimensions(1); // block_walker contains (M,K,Multi) --> shift by 1 to get rid of the "M" dimension
    }

    // Inherited methods overridden:
    void transform(const TransformAWorkload &wl, const ThreadInfo &info, const Window &batch_window, const Coordinates &start_offset, const Coordinates &end_offset) override
    {
        strategy                                        strat(info.cpu_info);
        TensorAccessor<typename strategy::operand_type> a(*_a);
        TensorAccessor<typename strategy::operand_type> transformed_a(*_transformed_a);

        // Handle 3d input re-interpretation
        if(_reinterpret_a_as_3d)
        {
            Strides a_strides_as_3d = _a->info()->strides_in_bytes();
            a_strides_as_3d.remove(Window::DimZ);
            a.set_strides(a_strides_as_3d);
        }

        unsigned int last_m = 0;
        //TODO: Create a new iterate_1D( DimY);
        int  last_y          = -1;
        auto window_iterator = arm_compute::create_window_iterator(batch_window, start_offset, end_offset, [&](const Coordinates & id)
        {
            if(id.y() != last_y)
            {
                last_y               = id.y();
                unsigned int batch   = id.y();
                unsigned int first_m = id.x();

                if(first_m >= last_m)
                    return;

                strat.transforms.PrepareA(transformed_a(0, first_m, batch),
                                          a(0, 0, batch, wl._multi),
                                          a.stride(1), first_m, last_m, wl._k0, wl._kmax, _transpose_a);
            }
        });
        auto on_new_row_size = [&](unsigned int, unsigned int end)
        {
            last_m = std::min(end, _Msize);
        };
        window_iterator.iterate_2D(on_new_row_size);
    }
    void create_workloads(std::vector<TransformAWorkload> &workloads) override
    {
        execute_window_loop(_k_multi_window, [&](const Coordinates & id)
        {
            const unsigned int k0    = id.x();
            const unsigned int multi = id.y();
            const unsigned int kmax  = std::min(k0 + _k_multi_window.x().step(), _Ksize);

            workloads.push_back(TransformAWorkload(k0, kmax, multi));
        });
    }

private:
    const ITensor *_a
    {
        nullptr
    };
    ITensor     *_transformed_a{ nullptr };
    unsigned int _Msize{ 0 };
    unsigned int _Ksize{ 0 };
    bool         _transpose_a{ false };
    bool         _reinterpret_a_as_3d{ false };
    Window       _k_multi_window{};
};
} // namespace arm_compute
#endif /* __ARM_COMPUTE_NEGEMMINTERLEAVEDTRANSFORMAWRAPPER_H__ */