// Copyright 2017 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 "dawn/dawncpp.h"

#include <gtest/gtest.h>
#include <memory>

// Getting data back from NXT is done in an async manners so all expectations are "deferred"
// until the end of the test. Also expectations use a copy to a MapRead buffer to get the data
// so resources should have the TransferSrc allowed usage bit if you want to add expectations on them.
#define EXPECT_BUFFER_U32_EQ(expected, buffer, offset) \
    AddBufferExpectation(__FILE__, __LINE__, buffer, offset, sizeof(uint32_t), new detail::ExpectEq<uint32_t>(expected))

#define EXPECT_BUFFER_U32_RANGE_EQ(expected, buffer, offset, count) \
    AddBufferExpectation(__FILE__, __LINE__, buffer, offset, sizeof(uint32_t) * count, new detail::ExpectEq<uint32_t>(expected, count))

#define EXPECT_BUFFER_U8_EQ(expected, buffer, offset)                         \
    AddBufferExpectation(__FILE__, __LINE__, buffer, offset, sizeof(uint8_t), \
                         new detail::ExpectEq<uint8_t>(expected))

// Test a pixel of the mip level 0 of a 2D texture.
#define EXPECT_PIXEL_RGBA8_EQ(expected, texture, x, y) \
    AddTextureExpectation(__FILE__, __LINE__, texture, x, y, 1, 1, 0, sizeof(RGBA8), new detail::ExpectEq<RGBA8>(expected))

#define EXPECT_TEXTURE_RGBA8_EQ(expected, texture, x, y, width, height, level) \
    AddTextureExpectation(__FILE__, __LINE__, texture, x, y, width, height, level, sizeof(RGBA8), new detail::ExpectEq<RGBA8>(expected, (width) * (height)))

struct RGBA8 {
    constexpr RGBA8() : RGBA8(0,0,0,0) {}
    constexpr RGBA8(uint8_t r, uint8_t g, uint8_t b, uint8_t a): r(r), g(g), b(b), a(a) {
    }
    bool operator==(const RGBA8& other) const;
    bool operator!=(const RGBA8& other) const;

    uint8_t r, g, b, a;
};
std::ostream& operator<< (std::ostream& stream, const RGBA8& color);

// Backend types used in the NXT_INSTANTIATE_TEST
enum BackendType {
    D3D12Backend,
    MetalBackend,
    OpenGLBackend,
    VulkanBackend,
    NumBackendTypes,
};
std::ostream &operator<<(std::ostream& stream, BackendType backend);

namespace utils {
    class BackendBinding;
}

namespace detail {
    class Expectation;
}

namespace dawn { namespace wire {
    class CommandHandler;
    class TerribleCommandBuffer;
}}  // namespace dawn::wire

class NXTTest : public ::testing::TestWithParam<BackendType> {
  public:
    ~NXTTest();

    void SetUp() override;
    void TearDown() override;

    bool IsD3D12() const;
    bool IsMetal() const;
    bool IsOpenGL() const;
    bool IsVulkan() const;

  protected:
    dawn::Device device;
    dawn::Queue queue;
    dawn::SwapChain swapchain;

    // Helper methods to implement the EXPECT_ macros
    std::ostringstream& AddBufferExpectation(const char* file,
                                             int line,
                                             const dawn::Buffer& buffer,
                                             uint32_t offset,
                                             uint32_t size,
                                             detail::Expectation* expectation);
    std::ostringstream& AddTextureExpectation(const char* file,
                                              int line,
                                              const dawn::Texture& texture,
                                              uint32_t x,
                                              uint32_t y,
                                              uint32_t width,
                                              uint32_t height,
                                              uint32_t level,
                                              uint32_t pixelSize,
                                              detail::Expectation* expectation);

    void WaitABit();

    void SwapBuffersForCapture();

  private:
    // Things used to set up testing through the Wire.
    dawn::wire::CommandHandler* mWireServer = nullptr;
    dawn::wire::CommandHandler* mWireClient = nullptr;
    dawn::wire::TerribleCommandBuffer* mC2sBuf = nullptr;
    dawn::wire::TerribleCommandBuffer* mS2cBuf = nullptr;
    void FlushWire();

    // MapRead buffers used to get data for the expectations
    struct ReadbackSlot {
        dawn::Buffer buffer;
        uint32_t bufferSize;
        const void* mappedData = nullptr;
    };
    std::vector<ReadbackSlot> mReadbackSlots;

    // Maps all the buffers and fill ReadbackSlot::mappedData
    void MapSlotsSynchronously();
    static void SlotMapReadCallback(nxtBufferMapAsyncStatus status,
                                    const void* data,
                                    nxtCallbackUserdata userdata);
    size_t mNumPendingMapOperations = 0;

    // Reserve space where the data for an expectation can be copied
    struct ReadbackReservation {
        dawn::Buffer buffer;
        size_t slot;
        uint32_t offset;
    };
    ReadbackReservation ReserveReadback(uint32_t readbackSize);

    struct DeferredExpectation {
        const char* file;
        int line;
        size_t readbackSlot;
        uint32_t readbackOffset;
        uint32_t size;
        uint32_t rowBytes;
        uint32_t rowPitch;
        detail::Expectation* expectation;
        // https://gcc.gnu.org/bugzilla/show_bug.cgi?id=54316
        // Use unique_ptr because of missing move/copy constructors on std::basic_ostringstream
        std::unique_ptr<std::ostringstream> message;
    };
    std::vector<DeferredExpectation> mDeferredExpectations;

    // Assuming the data is mapped, checks all expectations
    void ResolveExpectations();

    utils::BackendBinding* mBinding = nullptr;
};

// Instantiate the test once for each backend provided after the first argument. Use it like this:
//     NXT_INSTANTIATE_TEST(MyTestFixture, MetalBackend, OpenGLBackend)
#define NXT_INSTANTIATE_TEST(testName, firstParam, ...) \
    const decltype(firstParam) testName##params[] = { firstParam, ##__VA_ARGS__ }; \
    INSTANTIATE_TEST_CASE_P(, testName, \
        testing::ValuesIn(::detail::FilterBackends(testName##params, sizeof(testName##params) / sizeof(firstParam))), \
        testing::PrintToStringParamName());

namespace detail {
    // Helper functions used for NXT_INSTANTIATE_TEST
    bool IsBackendAvailable(BackendType type);
    std::vector<BackendType> FilterBackends(const BackendType* types, size_t numParams);

    // All classes used to implement the deferred expectations should inherit from this.
    class Expectation {
        public:
            virtual ~Expectation() = default;

            // Will be called with the buffer or texture data the expectation should check.
            virtual testing::AssertionResult Check(const void* data, size_t size) = 0;
    };

    // Expectation that checks the data is equal to some expected values.
    template<typename T>
    class ExpectEq : public Expectation {
        public:
            ExpectEq(T singleValue);
            ExpectEq(const T* values, const unsigned int count);

            testing::AssertionResult Check(const void* data, size_t size) override;

        private:
            std::vector<T> mExpected;
    };
    extern template class ExpectEq<uint8_t>;
    extern template class ExpectEq<uint32_t>;
    extern template class ExpectEq<RGBA8>;
}