// 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 "tests/unittests/validation/ValidationTest.h"

#include "common/Constants.h"
#include "utils/ComboRenderPipelineDescriptor.h"
#include "utils/WGPUHelpers.h"

#include <sstream>

class RenderPipelineValidationTest : public ValidationTest {
    protected:
        void SetUp() override {
            ValidationTest::SetUp();

            vsModule = utils::CreateShaderModule(device, utils::SingleShaderStage::Vertex, R"(
                #version 450
                void main() {
                    gl_Position = vec4(0.0, 0.0, 0.0, 1.0);
                })");

            fsModule = utils::CreateShaderModule(device, utils::SingleShaderStage::Fragment, R"(
                #version 450
                layout(location = 0) out vec4 fragColor;
                void main() {
                    fragColor = vec4(0.0, 1.0, 0.0, 1.0);
                })");
        }

        wgpu::ShaderModule vsModule;
        wgpu::ShaderModule fsModule;
};

// Test cases where creation should succeed
TEST_F(RenderPipelineValidationTest, CreationSuccess) {
    {
        utils::ComboRenderPipelineDescriptor descriptor(device);
        descriptor.vertexStage.module = vsModule;
        descriptor.cFragmentStage.module = fsModule;

        device.CreateRenderPipeline(&descriptor);
    }
    {
        // Vertex input should be optional
        utils::ComboRenderPipelineDescriptor descriptor(device);
        descriptor.vertexStage.module = vsModule;
        descriptor.cFragmentStage.module = fsModule;
        descriptor.vertexInput = nullptr;

        device.CreateRenderPipeline(&descriptor);
    }
    {
        // Rasterization state should be optional
        utils::ComboRenderPipelineDescriptor descriptor(device);
        descriptor.vertexStage.module = vsModule;
        descriptor.cFragmentStage.module = fsModule;
        descriptor.rasterizationState = nullptr;
        device.CreateRenderPipeline(&descriptor);
    }
}

// Tests that at least one color state is required.
TEST_F(RenderPipelineValidationTest, ColorStateRequired) {
    {
        // This one succeeds because attachment 0 is the color attachment
        utils::ComboRenderPipelineDescriptor descriptor(device);
        descriptor.vertexStage.module = vsModule;
        descriptor.cFragmentStage.module = fsModule;
        descriptor.colorStateCount = 1;

        device.CreateRenderPipeline(&descriptor);
    }

    {  // Fail because lack of color states (and depth/stencil state)
        utils::ComboRenderPipelineDescriptor descriptor(device);
        descriptor.vertexStage.module = vsModule;
        descriptor.cFragmentStage.module = fsModule;
        descriptor.colorStateCount = 0;

        ASSERT_DEVICE_ERROR(device.CreateRenderPipeline(&descriptor));
    }
}

// Tests that the color formats must be renderable.
TEST_F(RenderPipelineValidationTest, NonRenderableFormat) {
    {
        // Succeeds because RGBA8Unorm is renderable
        utils::ComboRenderPipelineDescriptor descriptor(device);
        descriptor.vertexStage.module = vsModule;
        descriptor.cFragmentStage.module = fsModule;
        descriptor.cColorStates[0].format = wgpu::TextureFormat::RGBA8Unorm;

        device.CreateRenderPipeline(&descriptor);
    }

    {
        // Fails because RG11B10Float is non-renderable
        utils::ComboRenderPipelineDescriptor descriptor(device);
        descriptor.vertexStage.module = vsModule;
        descriptor.cFragmentStage.module = fsModule;
        descriptor.cColorStates[0].format = wgpu::TextureFormat::RG11B10Float;

        ASSERT_DEVICE_ERROR(device.CreateRenderPipeline(&descriptor));
    }
}

// Tests that the format of the color state descriptor must match the output of the fragment shader.
TEST_F(RenderPipelineValidationTest, FragmentOutputFormatCompatibility) {
    constexpr uint32_t kNumTextureFormatBaseType = 3u;
    std::array<const char*, kNumTextureFormatBaseType> kVecPreFix = {{"", "i", "u"}};
    std::array<wgpu::TextureFormat, kNumTextureFormatBaseType> kColorFormats = {
        {wgpu::TextureFormat::RGBA8Unorm, wgpu::TextureFormat::RGBA8Sint,
         wgpu::TextureFormat::RGBA8Uint}};

    for (size_t i = 0; i < kNumTextureFormatBaseType; ++i) {
        for (size_t j = 0; j < kNumTextureFormatBaseType; ++j) {
            utils::ComboRenderPipelineDescriptor descriptor(device);
            descriptor.vertexStage.module = vsModule;
            descriptor.cColorStates[0].format = kColorFormats[j];

            std::ostringstream stream;
            stream << R"(
                #version 450
                layout(location = 0) out )"
                   << kVecPreFix[i] << R"(vec4 fragColor;
                void main() {
                })";
            descriptor.cFragmentStage.module = utils::CreateShaderModule(
                device, utils::SingleShaderStage::Fragment, stream.str().c_str());

            if (i == j) {
                device.CreateRenderPipeline(&descriptor);
            } else {
                ASSERT_DEVICE_ERROR(device.CreateRenderPipeline(&descriptor));
            }
        }
    }
}

/// Tests that the sample count of the render pipeline must be valid.
TEST_F(RenderPipelineValidationTest, SampleCount) {
    {
        utils::ComboRenderPipelineDescriptor descriptor(device);
        descriptor.vertexStage.module = vsModule;
        descriptor.cFragmentStage.module = fsModule;
        descriptor.sampleCount = 4;

        device.CreateRenderPipeline(&descriptor);
    }

    {
        utils::ComboRenderPipelineDescriptor descriptor(device);
        descriptor.vertexStage.module = vsModule;
        descriptor.cFragmentStage.module = fsModule;
        descriptor.sampleCount = 3;

        ASSERT_DEVICE_ERROR(device.CreateRenderPipeline(&descriptor));
    }
}

// Tests that the sample count of the render pipeline must be equal to the one of every attachments
// in the render pass.
TEST_F(RenderPipelineValidationTest, SampleCountCompatibilityWithRenderPass) {
    constexpr uint32_t kMultisampledCount = 4;
    constexpr wgpu::TextureFormat kColorFormat = wgpu::TextureFormat::RGBA8Unorm;
    constexpr wgpu::TextureFormat kDepthStencilFormat = wgpu::TextureFormat::Depth24PlusStencil8;

    wgpu::TextureDescriptor baseTextureDescriptor;
    baseTextureDescriptor.size.width = 4;
    baseTextureDescriptor.size.height = 4;
    baseTextureDescriptor.size.depth = 1;
    baseTextureDescriptor.arrayLayerCount = 1;
    baseTextureDescriptor.mipLevelCount = 1;
    baseTextureDescriptor.dimension = wgpu::TextureDimension::e2D;
    baseTextureDescriptor.usage = wgpu::TextureUsage::OutputAttachment;

    utils::ComboRenderPipelineDescriptor nonMultisampledPipelineDescriptor(device);
    nonMultisampledPipelineDescriptor.sampleCount = 1;
    nonMultisampledPipelineDescriptor.vertexStage.module = vsModule;
    nonMultisampledPipelineDescriptor.cFragmentStage.module = fsModule;
    wgpu::RenderPipeline nonMultisampledPipeline =
        device.CreateRenderPipeline(&nonMultisampledPipelineDescriptor);

    nonMultisampledPipelineDescriptor.colorStateCount = 0;
    nonMultisampledPipelineDescriptor.depthStencilState =
        &nonMultisampledPipelineDescriptor.cDepthStencilState;
    wgpu::RenderPipeline nonMultisampledPipelineWithDepthStencilOnly =
        device.CreateRenderPipeline(&nonMultisampledPipelineDescriptor);

    utils::ComboRenderPipelineDescriptor multisampledPipelineDescriptor(device);
    multisampledPipelineDescriptor.sampleCount = kMultisampledCount;
    multisampledPipelineDescriptor.vertexStage.module = vsModule;
    multisampledPipelineDescriptor.cFragmentStage.module = fsModule;
    wgpu::RenderPipeline multisampledPipeline =
        device.CreateRenderPipeline(&multisampledPipelineDescriptor);

    multisampledPipelineDescriptor.colorStateCount = 0;
    multisampledPipelineDescriptor.depthStencilState =
        &multisampledPipelineDescriptor.cDepthStencilState;
    wgpu::RenderPipeline multisampledPipelineWithDepthStencilOnly =
        device.CreateRenderPipeline(&multisampledPipelineDescriptor);

    // It is not allowed to use multisampled render pass and non-multisampled render pipeline.
    {
        {
            wgpu::TextureDescriptor textureDescriptor = baseTextureDescriptor;
            textureDescriptor.format = kColorFormat;
            textureDescriptor.sampleCount = kMultisampledCount;
            wgpu::Texture multisampledColorTexture = device.CreateTexture(&textureDescriptor);
            utils::ComboRenderPassDescriptor renderPassDescriptor(
                {multisampledColorTexture.CreateView()});

            wgpu::CommandEncoder encoder = device.CreateCommandEncoder();
            wgpu::RenderPassEncoder renderPass = encoder.BeginRenderPass(&renderPassDescriptor);
            renderPass.SetPipeline(nonMultisampledPipeline);
            renderPass.EndPass();

            ASSERT_DEVICE_ERROR(encoder.Finish());
        }

        {
            wgpu::TextureDescriptor textureDescriptor = baseTextureDescriptor;
            textureDescriptor.sampleCount = kMultisampledCount;
            textureDescriptor.format = kDepthStencilFormat;
            wgpu::Texture multisampledDepthStencilTexture =
                device.CreateTexture(&textureDescriptor);
            utils::ComboRenderPassDescriptor renderPassDescriptor(
                {}, multisampledDepthStencilTexture.CreateView());

            wgpu::CommandEncoder encoder = device.CreateCommandEncoder();
            wgpu::RenderPassEncoder renderPass = encoder.BeginRenderPass(&renderPassDescriptor);
            renderPass.SetPipeline(nonMultisampledPipelineWithDepthStencilOnly);
            renderPass.EndPass();

            ASSERT_DEVICE_ERROR(encoder.Finish());
        }
    }

    // It is allowed to use multisampled render pass and multisampled render pipeline.
    {
        {
            wgpu::TextureDescriptor textureDescriptor = baseTextureDescriptor;
            textureDescriptor.format = kColorFormat;
            textureDescriptor.sampleCount = kMultisampledCount;
            wgpu::Texture multisampledColorTexture = device.CreateTexture(&textureDescriptor);
            utils::ComboRenderPassDescriptor renderPassDescriptor(
                {multisampledColorTexture.CreateView()});

            wgpu::CommandEncoder encoder = device.CreateCommandEncoder();
            wgpu::RenderPassEncoder renderPass = encoder.BeginRenderPass(&renderPassDescriptor);
            renderPass.SetPipeline(multisampledPipeline);
            renderPass.EndPass();

            encoder.Finish();
        }

        {
            wgpu::TextureDescriptor textureDescriptor = baseTextureDescriptor;
            textureDescriptor.sampleCount = kMultisampledCount;
            textureDescriptor.format = kDepthStencilFormat;
            wgpu::Texture multisampledDepthStencilTexture =
                device.CreateTexture(&textureDescriptor);
            utils::ComboRenderPassDescriptor renderPassDescriptor(
                {}, multisampledDepthStencilTexture.CreateView());

            wgpu::CommandEncoder encoder = device.CreateCommandEncoder();
            wgpu::RenderPassEncoder renderPass = encoder.BeginRenderPass(&renderPassDescriptor);
            renderPass.SetPipeline(multisampledPipelineWithDepthStencilOnly);
            renderPass.EndPass();

            encoder.Finish();
        }
    }

    // It is not allowed to use non-multisampled render pass and multisampled render pipeline.
    {
        {
            wgpu::TextureDescriptor textureDescriptor = baseTextureDescriptor;
            textureDescriptor.format = kColorFormat;
            textureDescriptor.sampleCount = 1;
            wgpu::Texture nonMultisampledColorTexture = device.CreateTexture(&textureDescriptor);
            utils::ComboRenderPassDescriptor nonMultisampledRenderPassDescriptor(
                {nonMultisampledColorTexture.CreateView()});

            wgpu::CommandEncoder encoder = device.CreateCommandEncoder();
            wgpu::RenderPassEncoder renderPass =
                encoder.BeginRenderPass(&nonMultisampledRenderPassDescriptor);
            renderPass.SetPipeline(multisampledPipeline);
            renderPass.EndPass();

            ASSERT_DEVICE_ERROR(encoder.Finish());
        }

        {
            wgpu::TextureDescriptor textureDescriptor = baseTextureDescriptor;
            textureDescriptor.sampleCount = 1;
            textureDescriptor.format = kDepthStencilFormat;
            wgpu::Texture multisampledDepthStencilTexture =
                device.CreateTexture(&textureDescriptor);
            utils::ComboRenderPassDescriptor renderPassDescriptor(
                {}, multisampledDepthStencilTexture.CreateView());

            wgpu::CommandEncoder encoder = device.CreateCommandEncoder();
            wgpu::RenderPassEncoder renderPass = encoder.BeginRenderPass(&renderPassDescriptor);
            renderPass.SetPipeline(multisampledPipelineWithDepthStencilOnly);
            renderPass.EndPass();

            ASSERT_DEVICE_ERROR(encoder.Finish());
        }
    }
}