// Copyright 2019 The Dawn Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// 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 <vector>

#include "dawn/tests/perf_tests/DawnPerfTest.h"
#include "dawn/utils/WGPUHelpers.h"

namespace dawn {
namespace {

constexpr unsigned int kNumIterations = 50;

enum class UploadMethod {
    WriteBuffer,
    MappedAtCreation,
};

// Perf delta exists between ranges [0, 1MB] vs [1MB, MAX_SIZE).
// These are sample buffer sizes within each range.
enum class UploadSize {
    BufferSize_1KB = 1 * 1024,
    BufferSize_64KB = 64 * 1024,
    BufferSize_1MB = 1 * 1024 * 1024,

    BufferSize_4MB = 4 * 1024 * 1024,
    BufferSize_16MB = 16 * 1024 * 1024,
};

struct BufferUploadParams : AdapterTestParam {
    BufferUploadParams(const AdapterTestParam& param,
                       UploadMethod uploadMethod,
                       UploadSize uploadSize)
        : AdapterTestParam(param), uploadMethod(uploadMethod), uploadSize(uploadSize) {}

    UploadMethod uploadMethod;
    UploadSize uploadSize;
};

std::ostream& operator<<(std::ostream& ostream, const BufferUploadParams& param) {
    ostream << static_cast<const AdapterTestParam&>(param);

    switch (param.uploadMethod) {
        case UploadMethod::WriteBuffer:
            ostream << "_WriteBuffer";
            break;
        case UploadMethod::MappedAtCreation:
            ostream << "_MappedAtCreation";
            break;
    }

    switch (param.uploadSize) {
        case UploadSize::BufferSize_1KB:
            ostream << "_BufferSize_1KB";
            break;
        case UploadSize::BufferSize_64KB:
            ostream << "_BufferSize_64KB";
            break;
        case UploadSize::BufferSize_1MB:
            ostream << "_BufferSize_1MB";
            break;
        case UploadSize::BufferSize_4MB:
            ostream << "_BufferSize_4MB";
            break;
        case UploadSize::BufferSize_16MB:
            ostream << "_BufferSize_16MB";
            break;
    }

    return ostream;
}

// Test uploading |kBufferSize| bytes of data |kNumIterations| times.
class BufferUploadPerf : public DawnPerfTestWithParams<BufferUploadParams> {
  public:
    BufferUploadPerf()
        : DawnPerfTestWithParams(kNumIterations, 1),
          data(static_cast<size_t>(GetParam().uploadSize)) {}
    ~BufferUploadPerf() override = default;

    void SetUp() override;

  private:
    void Step() override;

    wgpu::Buffer dst;
    std::vector<uint8_t> data;
};

void BufferUploadPerf::SetUp() {
    DawnPerfTestWithParams<BufferUploadParams>::SetUp();

    wgpu::BufferDescriptor desc = {};
    desc.size = data.size();
    desc.usage = wgpu::BufferUsage::CopyDst;

    dst = device.CreateBuffer(&desc);
}

void BufferUploadPerf::Step() {
    switch (GetParam().uploadMethod) {
        case UploadMethod::WriteBuffer: {
            for (unsigned int i = 0; i < kNumIterations; ++i) {
                queue.WriteBuffer(dst, 0, data.data(), data.size());
            }
            // Make sure all WriteBuffer's are flushed.
            queue.Submit(0, nullptr);
            break;
        }

        case UploadMethod::MappedAtCreation: {
            wgpu::BufferDescriptor desc = {};
            desc.size = data.size();
            desc.usage = wgpu::BufferUsage::CopySrc | wgpu::BufferUsage::MapWrite;
            desc.mappedAtCreation = true;

            wgpu::CommandEncoder encoder = device.CreateCommandEncoder();

            for (unsigned int i = 0; i < kNumIterations; ++i) {
                wgpu::Buffer buffer = device.CreateBuffer(&desc);
                memcpy(buffer.GetMappedRange(0, data.size()), data.data(), data.size());
                buffer.Unmap();
                encoder.CopyBufferToBuffer(buffer, 0, dst, 0, data.size());
            }

            wgpu::CommandBuffer commands = encoder.Finish();
            queue.Submit(1, &commands);
            break;
        }
    }
}

TEST_P(BufferUploadPerf, Run) {
    RunTest();
}

DAWN_INSTANTIATE_TEST_P(BufferUploadPerf,
                        {D3D12Backend(), MetalBackend(), OpenGLBackend(), VulkanBackend()},
                        {UploadMethod::WriteBuffer, UploadMethod::MappedAtCreation},
                        {UploadSize::BufferSize_1KB, UploadSize::BufferSize_64KB,
                         UploadSize::BufferSize_1MB, UploadSize::BufferSize_4MB,
                         UploadSize::BufferSize_16MB});

}  // anonymous namespace
}  // namespace dawn