/*
 * Copyright (c) 2017-2018 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.
 */
#pragma once

#include <assert.h>
#include <stdio.h>

#include <algorithm>

#include "arm_gemm.hpp"
#include "utils.hpp"

#include "buffer_manager.hpp"
#include "mergeresults.hpp"
#include "profiler.hpp"
#include "transform.hpp"

// Some macros used to decide how much working space to allocate.
// Round allocations up to the next cache line.
#define ALLOC_ROUND 64
#define ROUND_UP(x) ((((x) + ALLOC_ROUND - 1) / ALLOC_ROUND) * ALLOC_ROUND)

// Implementation of the GemmCommon abstract class.
//
// This implementation interleaves the source matrices in blocks - good for
// larger matrices.
namespace arm_gemm
{
template <typename strategy, typename To, typename Tr>
class GemmInterleaved : public GemmCommon<To, Tr>
{
    typedef typename strategy::operand_type Toi;
    typedef typename strategy::result_type  Tri;

    /* const properties set by constructor */
    const CPUInfo *const _ci;

    const unsigned int _Msize;
    const unsigned int _Nsize;
    const unsigned int _Ksize;

    const bool _trA;
    const bool _trB;

    const Tr _alpha;
    const Tr _beta;

    const unsigned int _maxthreads;
    const bool         _pretransposed;

    /* Blocking info */
    unsigned int _k_block = 0;
    unsigned int _x_block = 0;
    unsigned int _Mround  = 0;

    /* Working space, pretransposed buffer, buffer manager */
    const Toi     *_B_transposed  = nullptr;
    BufferManager *_bm            = nullptr;
    void          *_working_space = nullptr;

    /* We will need to walk through the blocks of B in a few contexts, so
     * factor that out.  */
    class blockwalker
    {
    private:
        /* Loop parameters, we only block up N and K so don't worry about M. */
        const unsigned int _Nsize, _Ksize, _x_block, _k_block;

        /* K and X parameters for current iteration. */
        unsigned int _k0 = 0, _x0 = 0;

        unsigned int _index     = 0;
        bool         _done      = false;
        bool         _newkblock = true;

    public:
        blockwalker(const unsigned int K, const unsigned int k_block, const unsigned int N, const unsigned int x_block)
            : _Nsize(N), _Ksize(K), _x_block(x_block), _k_block(k_block)
        {
        }

        unsigned int xmax()
        {
            return std::min(_x0 + _x_block, _Nsize);
        }

        unsigned int kmax()
        {
            return std::min(_k0 + _k_block, _Ksize);
        }

        /* Advance to the next block, return false at the end. */
        bool advance(void)
        {
            if(_done)
            {
                return false;
            }

            _newkblock = false;
            _x0 += _x_block;
            if(_x0 >= _Nsize)
            {
                _x0 = 0;
                _k0 += _k_block;
                if(_k0 >= _Ksize)
                {
                    _done = true;
                    return false;
                }
                _newkblock = true;
            }
            _index++;

            return true;
        }

        unsigned int k0(void)
        {
            return _k0;
        }
        unsigned int x0(void)
        {
            return _x0;
        }
        unsigned int index(void)
        {
            return _index;
        }
        bool done(void)
        {
            return _done;
        }
        bool newkblock(void)
        {
            return _newkblock;
        }
    };

    // A working size: One of these needed, regardless of thread count.  Divided according to window.
    size_t get_a_working_size() const
    {
        return ROUND_UP(sizeof(Toi) * _k_block * _Mround);
    }

    // B working size: 0, 1 or 3 of these needed depending on pretransposed and threading settings.
    size_t get_b_working_size() const
    {
        return ROUND_UP(sizeof(Toi) * _x_block * _k_block);
    }

    // C working size: One needed per thread.
    size_t get_c_working_size() const
    {
        return ROUND_UP(sizeof(Tri) * _x_block * strategy::out_height);
    }

    // Internal execute function.
    // This supports both the "pretransposed" and "standard" interfaces via the template parameter.
    template <bool pretransposed>
    void execute_internal(unsigned int start, unsigned int end, int threadid)
    {
        profiler prof;
        strategy strat(_ci);

        blockwalker current(_Ksize, _k_block, _Nsize, _x_block);
        blockwalker next = current;

        /* Compute the M values to operate on */
        unsigned int m_0   = start * strategy::out_height;
        unsigned int m_max = std::min(end * strategy::out_height, _Msize);

        /* Make sure we've been set up correctly. */
        if(pretransposed)
        {
            assert(_B_transposed);
        }
        else
        {
            assert(_bm);
        }

        assert(_working_space);
        int8_t *working_space_bytes = reinterpret_cast<int8_t *>(_working_space);

        // Private buffers.  Treat working_space as an array of C buffers (one per thread) first, followed by the (window-divided) A buffer.
        Toi *const a_panel = reinterpret_cast<Toi *>(working_space_bytes + (_maxthreads * get_c_working_size()) + (m_0 * _k_block * sizeof(Toi)));
        Tri *const c_panel = reinterpret_cast<Tri *>(working_space_bytes + (threadid * get_c_working_size()));

        // Shared buffers - these come either from BufferManager or _B_transposed.
        const Toi *b_panel;

        if(pretransposed)
        {
            b_panel = _B_transposed;
        }

        //printf("Starting GEMM loop, x_block=%d, k_block=%d\n", _x_block, _k_block);

        // newkblock() is always true on the first iteration, so this will be set properly on the first loop.
        int kern_k = 0;

        for(; !current.done(); current.advance())
        {
            if(current.newkblock())
            {
                prof(PROFILE_PREPA, ((m_max - m_0) * (current.kmax() - current.k0()) * sizeof(Toi)), [&](void)
                {
                    if(_trA ^ strategy::A_transpose)
                    {
                        Transform<strategy::A_interleave, strategy::A_block, true>(a_panel, this->_Aptr, this->_lda, m_0, m_max, current.k0(), current.kmax());
                    }
                    else
                    {
                        Transform<strategy::A_interleave, strategy::A_block, false>(a_panel, this->_Aptr, this->_lda, m_0, m_max, current.k0(), current.kmax());
                    }
                });

                // Figure out how many "K" the kernel will actually process.
                kern_k = iceildiv(current.kmax() - current.k0(), strategy::k_unroll);
                kern_k *= strat.k_unroll;
            }

            int bblocks = iceildiv(current.xmax() - current.x0(), strategy::out_width);

            if(!pretransposed)
            {
                /* Look ahead to the next block and populate it if necessary.
                 * This avoids the populate operation becoming a bottleneck, and
                 * helps keep the threads synchronized (the first thread to get
                 * here will populate while the rest will advance).
                 *
                 * If we are running single threaded, bm->try_populate() will do
                 * nothing.
                 */
                if(next.advance())
                {
                    _bm->try_populate(next.index(), [&](void *buffer)
                    {
                        prof(PROFILE_PREPB, (next.xmax() - next.x0()) * (next.kmax() - next.k0()) * sizeof(Toi), [&](void)
                        {
                            Toi *b_panel = reinterpret_cast<Toi *>(buffer);
                            if(_trB ^ strategy::B_transpose)
                            {
                                Transform<strategy::B_interleave, strategy::B_block, true>(b_panel, this->_Bptr, this->_ldb, next.x0(), next.xmax(), next.k0(), next.kmax());
                            }
                            else
                            {
                                Transform<strategy::B_interleave, strategy::B_block, false>(b_panel, this->_Bptr, this->_ldb, next.x0(), next.xmax(), next.k0(), next.kmax());
                            }
                        });
                    });
                }

                /* Get the buffer for this iteration from the BufferManager. */
                b_panel = reinterpret_cast<Toi *>(_bm->get(current.index(), [&](void *bpv)
                {
                    prof(PROFILE_PREPB, (current.xmax() - current.x0()) * (current.kmax() - current.k0()) * sizeof(Toi), [&](void)
                    {
                        Toi *b_panel = reinterpret_cast<Toi *>(bpv);
                        if(_trB ^ strategy::B_transpose)
                        {
                            Transform<strategy::B_interleave, strategy::B_block, true>(b_panel, this->_Bptr, this->_ldb, current.x0(), current.xmax(), current.k0(), current.kmax());
                        }
                        else
                        {
                            Transform<strategy::B_interleave, strategy::B_block, false>(b_panel, this->_Bptr, this->_ldb, current.x0(), current.xmax(), current.k0(), current.kmax());
                        }
                    });
                }));
            }

            /* Do the actual work. */
            for(unsigned int y = m_0; y < m_max; y += strategy::out_height)
            {
                unsigned int ymax = std::min(_Msize, y + strategy::out_height);

                prof(PROFILE_KERNEL, (strategy::out_height * bblocks * strategy::out_width * kern_k), [&](void)
                {
                    strat.kernel(a_panel + ((y - m_0) * kern_k), b_panel, c_panel, 1, bblocks, kern_k);
                });
                prof(PROFILE_MERGE, (strategy::out_height * bblocks * strategy::out_width * sizeof(Tr)), [&](void)
                {
                    MergeResults<strategy::out_width, strategy::out_height>(this->_Cptr, c_panel, this->_ldc, y, ymax,
                                                                            current.x0(), current.xmax(), _alpha, (current.k0() == 0 ? _beta : static_cast<Tr>(1)));
                });
            }

            if(pretransposed)
            {
                b_panel += (bblocks * strat.out_width * kern_k);
            }
            else
            {
                _bm->release(current.index());
            }
        }
    }

public:
    GemmInterleaved(GemmInterleaved &) = delete;
    GemmInterleaved &operator=(GemmInterleaved &) = delete;

    /* Constructor */
    GemmInterleaved(const CPUInfo *ci, const unsigned int M, const unsigned int N, const unsigned int K,
                    const bool trA, const bool trB, const Tr alpha, const Tr beta, const int maxthreads,
                    const bool pretransposed)
        : _ci(ci), _Msize(M), _Nsize(N), _Ksize(K), _trA(trA), _trB(trB), _alpha(alpha), _beta(beta), _maxthreads(maxthreads), _pretransposed(pretransposed)
    {
        const unsigned int L1_size = ci->get_L1_cache_size();
        const unsigned int L2_size = ci->get_L2_cache_size();

        assert(maxthreads > 0);

        // Work out blocking parameters

        // k_block: Find out how much of the larger array can be loaded into half the cache.
        // This should account for associative caches.
        _k_block = (L1_size / 2) / (sizeof(Toi) * (std::max(strategy::out_width, strategy::out_height)));

        // Needs to be (at least a single) multiple of the K unroll level.
        _k_block /= strategy::k_unroll;
        _k_block = std::max(_k_block, 1U) * strategy::k_unroll;

        // Now tune to presented problem size; this is how many blocks we need.
        int num_k_blocks = iceildiv(K, _k_block);

        // So divide the space equally into that many blocks.
        _k_block = iceildiv(K, num_k_blocks);

        // And round UP to the K unroll level required.
        _k_block = iceildiv(_k_block, strategy::k_unroll);
        _k_block *= strategy::k_unroll;

        // x_block: Work out how many rows (of length k_block) will fit in the L2
        // Don't allocate more than 90% of the L2 to allow for overheads, and subtract off the L1 contents.
        _x_block = (((L2_size * 9) / 10) - (_k_block * sizeof(Toi) * (strategy::out_width + strategy::out_height))) / (sizeof(Toi) * _k_block);

        // Needs to be (at least a single) multiple of the kernel output width.
        _x_block /= strategy::out_width;
        _x_block = std::max(_x_block, 1U) * strategy::out_width;

        // And tune to the presented problem size.
        int num_x_blocks = iceildiv(N, _x_block);
        _x_block         = iceildiv(N, num_x_blocks);

        _x_block = iceildiv(_x_block, strategy::out_width);
        _x_block *= strategy::out_width;

        // Work out the rounded size of M - needed for some buffers.
        _Mround = iceildiv(M, strategy::out_height);
        _Mround *= strategy::out_height;
    }

    // Interface implementation - Compulsory functions

    // Window size: Only the last thread should do a ragged block, so dole out work in units of out_height */
    unsigned int get_window_size() const override
    {
        // _Mround is a multiple of out_height by definition.
        return _Mround / strategy::out_height;
    }

    // set_nthreads: pass on to buffer manager to avoid it waiting for non-existant threads.
    void set_nthreads(int nthreads) override
    {
        if(_bm)
        {
            _bm->set_nthreads(nthreads);
        }
    }

    // Execute
    void execute(unsigned int start, unsigned int end, int threadid) override
    {
        if(_pretransposed)
        {
            execute_internal<true>(start, end, threadid);
        }
        else
        {
            execute_internal<false>(start, end, threadid);
        }
    }

    // Interface implementation - working space
    size_t get_working_size() const override
    {
        // In all cases, we need one A buffer plus a C buffer per thread.
        size_t size = get_a_working_size() + (get_c_working_size() * _maxthreads);

        // For pretransposed case, there is no working space needed for B.
        // Otherwise, we need a BufferManager.
        if(!_pretransposed)
        {
            size += BufferManager::get_storage_requirement(_maxthreads, get_b_working_size());
        }

        size += 64; // Add on a cache line extra for alignment.

        return size;
    }

    void set_working_space(void *working_space) override
    {
        // Make sure everything ends up cache line aligned
        int8_t *working_space_bytes = reinterpret_cast<int8_t *>(working_space);
        intptr_t working_space_int   = reinterpret_cast<intptr_t>(working_space);

        size_t diff = 0;

        if(working_space_int & 0x3F)
        {
            diff = 0x40 - (working_space_int & 0x3F);
        }

        working_space_bytes += diff;

        if(_pretransposed)
        {
            // Pretransposed case: just set internal pointer to parameter value.
            _working_space = reinterpret_cast<void *>(working_space_bytes);
        }
        else
        {
            // Otherwise, use the first part of the working space for the buffer manager.
            // It's legal to call this again so don't leak a buffer manager if it already existed.
            delete _bm;

            _bm = new BufferManager(_maxthreads, get_b_working_size(), reinterpret_cast<void *>(working_space_bytes));

            working_space_bytes += BufferManager::get_storage_requirement(_maxthreads, get_b_working_size());

            _working_space = reinterpret_cast<void *>(working_space_bytes);
        }
    }

    // Interface implementation - pretransposed
    bool B_is_pretransposed() const override
    {
        return _pretransposed;
    }

    bool B_pretranspose_required() const override
    {
        return _pretransposed && (_B_transposed == nullptr);
    }

    // TODO: this could almost certainly be considerably simpler.
    size_t get_B_pretransposed_array_size() const override
    {
        size_t      total = 0;
        blockwalker current(_Ksize, _k_block, _Nsize, _x_block);

        do
        {
            /* Figure out the size of each block. */
            size_t x_size = (current.xmax() - current.x0());
            size_t k_size = (current.kmax() - current.k0());

            /* Round sizes up as needed. */
            x_size = iceildiv(x_size, strategy::out_width);
            x_size *= strategy::out_width;

            k_size = iceildiv(k_size, strategy::k_unroll);
            k_size *= strategy::k_unroll;

            total += x_size * k_size * sizeof(Toi);
        }
        while(current.advance());

        return total;
    }

    void pretranspose_B_array(void *in_buffer, const To *B, const int ldb) override
    {
        blockwalker current(_Ksize, _k_block, _Nsize, _x_block);
        Toi        *buffer = reinterpret_cast<Toi *>(in_buffer);
        _B_transposed      = buffer;

        do
        {
            /* Figure out the size of each block. */
            size_t x_size = (current.xmax() - current.x0());
            size_t k_size = (current.kmax() - current.k0());

            /* Round sizes up as needed. */
            x_size = iceildiv(x_size, strategy::out_width);
            x_size *= strategy::out_width;

            k_size = iceildiv(k_size, strategy::k_unroll);
            k_size *= strategy::k_unroll;

            if(_trB ^ strategy::B_transpose)
            {
                Transform<strategy::B_interleave, strategy::B_block, true>(buffer, B, ldb, current.x0(), current.xmax(), current.k0(), current.kmax());
            }
            else
            {
                Transform<strategy::B_interleave, strategy::B_block, false>(buffer, B, ldb, current.x0(), current.xmax(), current.k0(), current.kmax());
            }

            buffer += (x_size * k_size);
        }
        while(current.advance());
    }

    ~GemmInterleaved() override
    {
        delete _bm;
    }
};

} // namespace arm_gemm