// Tencent is pleased to support the open source community by making ncnn available.
//
// Copyright (C) 2017 THL A29 Limited, a Tencent company. All rights reserved.
//
// Licensed under the BSD 3-Clause License (the "License"); you may not use this file except
// in compliance with the License. You may obtain a copy of the License at
//
// https://opensource.org/licenses/BSD-3-Clause
//
// Unless required by applicable law or agreed to in writing, software distributed
// under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
// CONDITIONS OF ANY KIND, either express or implied. See the License for the
// specific language governing permissions and limitations under the License.

#include "reshape.h"

namespace ncnn {

DEFINE_LAYER_CREATOR(Reshape)

Reshape::Reshape()
{
    one_blob_only = true;
    support_inplace = false;
    support_vulkan = true;

#if NCNN_VULKAN
    pipeline_reshape = 0;
    pipeline_reshape_pack4 = 0;
    pipeline_reshape_pack1to4 = 0;
    pipeline_reshape_pack4to1 = 0;
#endif // NCNN_VULKAN
}

int Reshape::load_param(const ParamDict& pd)
{
    w = pd.get(0, -233);
    h = pd.get(1, -233);
    c = pd.get(2, -233);
    permute = pd.get(3, 0);

    ndim = 3;
    if (c == -233)
        ndim = 2;
    if (h == -233)
        ndim = 1;
    if (w == -233)
        ndim = 0;

    return 0;
}

int Reshape::forward(const Mat& bottom_blob, Mat& top_blob, const Option& opt) const
{
    size_t elemsize = bottom_blob.elemsize;
    int total = bottom_blob.w * bottom_blob.h * bottom_blob.c;

    if (ndim == 1)
    {
        int _w = w;

        if (_w == 0)
            _w = bottom_blob.w;

        if (_w == -1)
            _w = total;

        if (permute == 1)
        {
            top_blob.create(_w, elemsize, opt.blob_allocator);
            if (top_blob.empty())
                return -100;

            // c-h-w to h-w-c
            float* ptr = top_blob;
            for (int i=0; i<bottom_blob.h; i++)
            {
                for (int j=0; j<bottom_blob.w; j++)
                {
                    for (int p=0; p<bottom_blob.c; p++)
                    {
                        const float* bptr = bottom_blob.channel(p);
                        *ptr++ = bptr[i*bottom_blob.w + j];
                    }
                }
            }
        }
        else
        {
            top_blob = bottom_blob.reshape(_w, opt.blob_allocator);
        }
    }
    else if (ndim == 2)
    {
        int _w = w;
        int _h = h;

        if (_w == 0)
            _w = bottom_blob.w;
        if (_h == 0)
            _h = bottom_blob.h;

        if (_w == -1)
            _w = total / _h;
        if (_h == -1)
            _h = total / _w;

        top_blob = bottom_blob.reshape(_w, _h, opt.blob_allocator);
    }
    else if (ndim == 3)
    {
        int _w = w;
        int _h = h;
        int _c = c;

        if (_w == 0)
            _w = bottom_blob.w;
        if (_h == 0)
            _h = bottom_blob.h;
        if (_c == 0)
            _c = bottom_blob.c;

        if (_w == -1)
            _w = total / _c / _h;
        if (_h == -1)
            _h = total / _c / _w;
        if (_c == -1)
            _c = total / _h / _w;

        top_blob = bottom_blob.reshape(_w, _h, _c, opt.blob_allocator);
    }

    if (top_blob.empty())
        return -100;

    return 0;
}

#if NCNN_VULKAN
int Reshape::create_pipeline()
{
    std::vector<vk_specialization_type> specializations(1);
    specializations[0].i = ndim;

    // pack1
    {
        pipeline_reshape = new Pipeline(vkdev);
        pipeline_reshape->set_optimal_local_size_xyz();
        pipeline_reshape->create("reshape", specializations, 2, 10);
    }

    // pack4
    {
        pipeline_reshape_pack4 = new Pipeline(vkdev);
        pipeline_reshape_pack4->set_optimal_local_size_xyz();
        pipeline_reshape_pack4->create("reshape_pack4", specializations, 2, 10);
    }

    // pack1to4
    {
        pipeline_reshape_pack1to4 = new Pipeline(vkdev);
        pipeline_reshape_pack1to4->set_optimal_local_size_xyz();
        pipeline_reshape_pack1to4->create("reshape_pack1to4", specializations, 2, 10);
    }

    // pack4to1
    {
        pipeline_reshape_pack4to1 = new Pipeline(vkdev);
        pipeline_reshape_pack4to1->set_optimal_local_size_xyz();
        pipeline_reshape_pack4to1->create("reshape_pack4to1", specializations, 2, 10);
    }

    return 0;
}

int Reshape::destroy_pipeline()
{
    delete pipeline_reshape;
    pipeline_reshape = 0;

    delete pipeline_reshape_pack4;
    pipeline_reshape_pack4 = 0;

    delete pipeline_reshape_pack1to4;
    pipeline_reshape_pack1to4 = 0;

    delete pipeline_reshape_pack4to1;
    pipeline_reshape_pack4to1 = 0;

    return 0;
}

int Reshape::forward(const VkMat& bottom_blob, VkMat& top_blob, VkCompute& cmd, const Option& opt) const
{
    int dims = bottom_blob.dims;
    size_t elemsize = bottom_blob.elemsize;
    int packing = bottom_blob.packing;
    int out_packing;

    int total = bottom_blob.w * bottom_blob.h * bottom_blob.c * packing;

    if (ndim == 1)
    {
        int _w = w;

        if (_w == 0)
            _w = dims == 1 ? bottom_blob.w * packing : bottom_blob.w;

        if (_w == -1)
            _w = total;

        // TODO permute support

        out_packing = _w % 4 == 0 ? 4 : 1;
        size_t out_elemsize = elemsize / packing * out_packing;

        if (dims == 1 && bottom_blob.w == _w && packing == out_packing)
        {
            top_blob = bottom_blob;
            return 0;
        }

        top_blob.create(_w / out_packing, out_elemsize, out_packing, opt.blob_vkallocator, opt.staging_vkallocator);
    }
    else if (ndim == 2)
    {
        int _w = w;
        int _h = h;

        if (_w == 0)
            _w = dims == 1 ? bottom_blob.w * packing : bottom_blob.w;
        if (_h == 0)
            _h = dims == 2 ? bottom_blob.h * packing : bottom_blob.h;

        if (_w == -1)
            _w = total / _h;
        if (_h == -1)
            _h = total / _w;

        out_packing = _h % 4 == 0 ? 4 : 1;
        size_t out_elemsize = elemsize / packing * out_packing;

        if (dims == 2 && bottom_blob.h == _h && packing == out_packing)
        {
            top_blob = bottom_blob;
            return 0;
        }

        top_blob.create(_w, _h / out_packing, out_elemsize, out_packing, opt.blob_vkallocator, opt.staging_vkallocator);
    }
    else // if (ndim == 3)
    {
        int _w = w;
        int _h = h;
        int _c = c;

        if (_w == 0)
            _w = dims == 1 ? bottom_blob.w * packing : bottom_blob.w;
        if (_h == 0)
            _h = dims == 2 ? bottom_blob.h * packing : bottom_blob.h;
        if (_c == 0)
            _c = dims == 3 ? bottom_blob.c * packing : bottom_blob.c;

        if (_w == -1)
            _w = total / _c / _h;
        if (_h == -1)
            _h = total / _c / _w;
        if (_c == -1)
            _c = total / _h / _w;

        out_packing = _c % 4 == 0 ? 4 : 1;
        size_t out_elemsize = elemsize / packing * out_packing;

        if (dims == 3 && bottom_blob.c == _c && packing == out_packing)
        {
            top_blob = bottom_blob;
            top_blob.w = _w;
            top_blob.h = _h;
            return 0;
        }

        top_blob.create(_w, _h, _c / out_packing, out_elemsize, out_packing, opt.blob_vkallocator, opt.staging_vkallocator);
    }

    if (top_blob.empty())
        return -100;

//     fprintf(stderr, "Reshape::forward %p %p\n", bottom_blob.buffer(), top_blob.buffer());

    std::vector<VkMat> bindings(2);
    bindings[0] = bottom_blob;
    bindings[1] = top_blob;

    std::vector<vk_constant_type> constants(10);
    constants[0].i = bottom_blob.dims;
    constants[1].i = bottom_blob.w;
    constants[2].i = bottom_blob.h;
    constants[3].i = bottom_blob.c;
    constants[4].i = bottom_blob.cstep;
    constants[5].i = top_blob.dims;
    constants[6].i = top_blob.w;
    constants[7].i = top_blob.h;
    constants[8].i = top_blob.c;
    constants[9].i = top_blob.cstep;

    const Pipeline* pipeline = 0;
    if (packing == 1 && out_packing == 1)
    {
        pipeline = pipeline_reshape;
    }
    else if (packing == 4 && out_packing == 4)
    {
        pipeline = pipeline_reshape_pack4;
    }
    else if (packing == 1 && out_packing == 4)
    {
        pipeline = pipeline_reshape_pack1to4;
    }
    else if (packing == 4 && out_packing == 1)
    {
        pipeline = pipeline_reshape_pack4to1;
    }

    // record
    cmd.record_prepare_compute_barrier(bottom_blob);
    cmd.record_prepare_compute_barrier(top_blob);
    if (packing == 4 && out_packing == 1)
    {
        cmd.record_pipeline(pipeline, bindings, constants, bottom_blob);
    }
    else
    {
        cmd.record_pipeline(pipeline, bindings, constants, top_blob);
    }

    return 0;
}
#endif // NCNN_VULKAN

} // namespace ncnn