/*
 * Copyright 2023 Google LLC
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#ifndef skgpu_graphite_VulkanGraphicsPipeline_DEFINED
#define skgpu_graphite_VulkanGraphicsPipeline_DEFINED

#include "include/core/SkRefCnt.h"
#include "include/core/SkSpan.h"
#include "include/gpu/vk/VulkanTypes.h"
#include "include/private/SkTArray.h"
#include "src/gpu/Blend.h"
#include "src/gpu/graphite/Attribute.h"
#include "src/gpu/graphite/DrawTypes.h"
#include "src/gpu/graphite/GraphicsPipeline.h"
#include "src/gpu/graphite/Renderer.h"
#include "src/gpu/graphite/vk/VulkanGraphiteUtils.h"
#include "src/gpu/graphite/vk/VulkanSampler.h"

namespace SkSL {
    class Compiler;
}

namespace skgpu::graphite {

class Attribute;
class GraphicsPipelineDesc;
class RuntimeEffectDictionary;
class VulkanResourceProvider;
class VulkanSharedContext;
struct RenderPassDesc;
class TextureInfo;
class VulkanRenderPass;

// VulkanProgramInfo owns the underlying vulkan objects and are deleted automatically.
class VulkanProgramInfo {
public:
    ~VulkanProgramInfo();

    static std::unique_ptr<VulkanProgramInfo> Make(const VulkanSharedContext* sharedContext) {
        SkASSERT(sharedContext);
        return std::unique_ptr<VulkanProgramInfo>(new VulkanProgramInfo(sharedContext));
    }

    VkShaderModule vs() const { return fVS; }
    VkShaderModule fs() const { return fFS; }
    VkPipelineLayout layout() const { return fLayout; }

    // Relinquishes ownership of the VkPipelineLayout and no longer holds a pointer to it.
    VkPipelineLayout releaseLayout() {
        VkPipelineLayout layout = fLayout;
        fLayout = VK_NULL_HANDLE;
        return layout;
    }

    // The modules and layout can be set at most once
    bool setVertexShader(VkShaderModule vs) {
        SkASSERT(fVS == VK_NULL_HANDLE);
        fVS = vs;
        return fVS != VK_NULL_HANDLE;
    }
    bool setFragmentShader(VkShaderModule fs) {
        SkASSERT(fFS == VK_NULL_HANDLE);
        fFS = fs;
        return fFS != VK_NULL_HANDLE;
    }
    bool setLayout(VkPipelineLayout layout) {
        SkASSERT(fLayout == VK_NULL_HANDLE);
        fLayout = layout;
        return fLayout != VK_NULL_HANDLE;
    }

private:
    VulkanProgramInfo(const VulkanProgramInfo&) = delete;
    explicit VulkanProgramInfo(const VulkanSharedContext* sharedContext)
            : fSharedContext(sharedContext) {}

    const VulkanSharedContext* fSharedContext; // For cleanup

    VkShaderModule fVS = VK_NULL_HANDLE;
    VkShaderModule fFS = VK_NULL_HANDLE;
    VkPipelineLayout fLayout = VK_NULL_HANDLE;
};

class VulkanGraphicsPipeline final : public GraphicsPipeline {
public:
    inline static constexpr unsigned int kCombinedUniformIndex = 0; // Paint AND renderstep!
    inline static constexpr unsigned int kGradientBufferIndex = 1;
    inline static constexpr unsigned int kMaxNumUniformBuffers = 2;

    // For now, rigidly assign all descriptor types to be at statically-defined set indices.
    // TODO(b/274762935): Make the bindings and descriptor set organization more flexible.
    inline static constexpr unsigned int kDstAsInputDescSetIndex = 0;
    inline static constexpr unsigned int kUniformBufferDescSetIndex = 1;
    inline static constexpr unsigned int kTextureBindDescSetIndex = 2;
    inline static constexpr unsigned int kLoadMsaaFromResolveInputDescSetIndex = 3;
    inline static constexpr unsigned int kMaxNumDescSets = 4;

    inline static constexpr unsigned int kStaticDataBufferIndex = 0;
    inline static constexpr unsigned int kAppendDataBufferIndex = 1;
    inline static constexpr unsigned int kNumInputBuffers = 2;

    // Define a static DescriptorData to represent input attachments which have the same values
    // across all pipelines (we currently only ever use one input attachment within a set).
    inline static const DescriptorData kInputAttachmentDescriptor = {
            DescriptorType::kInputAttachment, /*count=*/1,
            /*bindingIdx=*/0, // We only expect to encounter one input attachment
            PipelineStageFlags::kFragmentShader};

    static sk_sp<VulkanGraphicsPipeline> Make(VulkanSharedContext*,
                                              const RuntimeEffectDictionary*,
                                              const UniqueKey&,
                                              const GraphicsPipelineDesc&,
                                              const RenderPassDesc&,
                                              SkEnumBitMask<PipelineCreationFlags>,
                                              uint32_t compilationID);

    // The created program info can be provided to MakeLoadMSAAPipeline for reuse with different
    // render pass descriptions. Returns null on failure.
    static std::unique_ptr<VulkanProgramInfo> CreateLoadMSAAProgram(const VulkanSharedContext*);

    static sk_sp<VulkanGraphicsPipeline> MakeLoadMSAAPipeline(
            VulkanSharedContext*,
            const VulkanProgramInfo& loadMSAAProgram,
            const RenderPassDesc&);

    ~VulkanGraphicsPipeline() override {}

    VkPipelineLayout layout() const {
        SkASSERT(fPipelineLayout != VK_NULL_HANDLE);
        return fPipelineLayout;
    }

    VkPipeline pipeline() const {
        SkASSERT(fPipeline != VK_NULL_HANDLE);
        return fPipeline;
    }

    // Returns null if the ith sampler is not an immutable sampler.
    const VulkanSampler* immutableSampler(int i) const {
        return fImmutableSamplers[i].get();
    }

    // Update any dynamic state (including none, if dynamic state is not available) that has changed
    // since the previously bound Graphite pipeline.
    void updateDynamicState(const VulkanSharedContext*,
                            VkCommandBuffer commandBuffer,
                            const VulkanGraphicsPipeline* previous) const;

private:
    using VertexInputBindingDescriptions =
            skia_private::STArray<2, VkVertexInputBindingDescription2EXT>;
    using VertexInputAttributeDescriptions =
            skia_private::STArray<16, VkVertexInputAttributeDescription2EXT>;

    VulkanGraphicsPipeline(const VulkanSharedContext* sharedContext,
                           const PipelineInfo& pipelineInfo,
                           std::string_view pipelineLabel,
                           VkPipelineLayout,
                           VkPipeline,
                           VkPipeline,
                           bool ownsPipelineLayout,
                           skia_private::TArray<sk_sp<VulkanSampler>>&& immutableSamplers,
                           RenderStep::RenderStepID renderStepID,
                           PrimitiveType primitiveType,
                           const DepthStencilSettings& depthStencilSettings,
                           VertexInputBindingDescriptions&& vertexBindingDescriptions,
                           VertexInputAttributeDescriptions&& vertexAttributeDescriptions);

    void freeGpuData() override;

    // The fragment shader can be null if no shading is performed by the pipeline.
    // This function does not cleanup any of the VulkanProgramInfo's objects on success or failure.
    static VkPipeline MakePipeline(VulkanSharedContext*,
                                   const VulkanProgramInfo&,
                                   int subpassIndex,
                                   PrimitiveType,
                                   VkVertexInputRate appendInputRate,
                                   SkSpan<const Attribute> staticAttrs,
                                   SkSpan<const Attribute> appendAttrs,
                                   VertexInputBindingDescriptions& vertexBindingDescriptions,
                                   VertexInputAttributeDescriptions& vertexAttributeDescriptions,
                                   const DepthStencilSettings&,
                                   const BlendInfo&,
                                   const RenderPassDesc&,
                                   VkPipeline*);

    VkPipelineLayout fPipelineLayout = VK_NULL_HANDLE;
    VkPipeline fPipeline = VK_NULL_HANDLE;
    VkPipeline fShadersPipeline = VK_NULL_HANDLE;
    bool fOwnsPipelineLayout = true;

    // Hold a ref to immutable samplers used such that their lifetime is properly managed.
    const skia_private::TArray<sk_sp<VulkanSampler>> fImmutableSamplers;

    // State that needs to be set dynamically.  When a new pipeline is bound, only the diff with the
    // previous pipeline is set.  This is not optimal, and eventually the front-end should calculate
    // this diff and set the state directly instead of the graphics pipeline tracking it, at which
    // point these members can be removed (b/414645289).
    //
    // Render step ID is used to quickly determine if the vertex attribute description needs an
    // update.  A few render steps have identical vertex attribute structures, so updating the
    // vertex attribute descriptions on render step ID change can be slightly suboptimal.  This can
    // be further optimized by having a "render step ID -> unique vertex attribute structure" table
    // in the future.
    PrimitiveType fPrimitiveType;
    DepthStencilSettings fDepthStencilSettings;
    RenderStep::RenderStepID fRenderStepID;
    // The Vulkan vertex attribute descriptions are cached to avoid recomputing them every time.
    VertexInputBindingDescriptions fVertexBindingDescriptions;
    VertexInputAttributeDescriptions fVertexAttributeDescriptions;
};

} // namespace skgpu::graphite

#endif // skgpu_graphite_MtlGraphicsPipeline_DEFINED