/*
 * Copyright 2022 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_DawnResourceProvider_DEFINED
#define skgpu_graphite_DawnResourceProvider_DEFINED

#include "include/gpu/graphite/dawn/DawnGraphiteTypes.h"
#include "src/core/SkLRUCache.h"
#include "src/core/SkTHash.h"
#include "src/gpu/graphite/PipelineData.h"
#include "src/gpu/graphite/ResourceProvider.h"

namespace skgpu::graphite {

class DawnGraphicsPipeline;
class DawnSampler;
class DawnSharedContext;
class DawnTexture;
class DawnBuffer;
class DawnCommandBuffer;

class DawnResourceProvider final : public ResourceProvider {
public:
    template <size_t NumEntries>
    using BindGroupKey = FixedSizeKey<2 * NumEntries>;

    static constexpr size_t kNumUniformEntries = 3;

    class BlitWithDrawEncoder {
    public:
        BlitWithDrawEncoder(wgpu::RenderPipeline pipeline,
                            bool srcIsMSAA);

        operator bool() const { return fPipeline != nullptr; }

        void EncodeBlit(const wgpu::Device& device,
                        const wgpu::RenderPassEncoder& encoder,
                        const wgpu::TextureView& srcTextureView,
                        const SkIPoint& srcOffset,
                        const SkIRect& dstBounds);

    private:
        wgpu::RenderPipeline fPipeline;
        const bool fSrcIsMSAA;
    };

    DawnResourceProvider(SharedContext* sharedContext,
                         SingleOwner*,
                         uint32_t recorderID,
                         size_t resourceBudget);
    ~DawnResourceProvider() override;

    sk_sp<DawnTexture> findOrCreateDiscardableMSAALoadTexture(SkISize dimensions,
                                                              const TextureInfo& msaaInfo);

    BlitWithDrawEncoder findOrCreateBlitWithDrawEncoder(const RenderPassDesc& renderPassDesc,
                                                        SampleCount srcSampleCount);

    sk_sp<DawnBuffer> findOrCreateDawnBuffer(size_t size,
                                             BufferType type,
                                             AccessPattern,
                                             std::string_view label);

    // Find the cached bind group or create a new one based on the bound buffers and their
    // binding sizes (boundBuffersAndSizes) for these uniforms (in order):
    // - Intrinsic constants.
    // - Render step uniforms.
    // - Paint uniforms.
    const wgpu::BindGroup& findOrCreateUniformBuffersBindGroup(
            const std::array<std::pair<const DawnBuffer*, uint32_t>, kNumUniformEntries>&
                    boundBuffersAndSizes);

    // Find or create a bind group containing the given sampler & texture.
    const wgpu::BindGroup& findOrCreateSingleTextureSamplerBindGroup(const DawnSampler* sampler,
                                                                     const DawnTexture* texture);

    // Find the cached bind buffer info, or create a new one for the given intrinsic values.
    BindBufferInfo findOrCreateIntrinsicBindBufferInfo(DawnCommandBuffer* cb,
                                                       UniformDataBlock intrinsicValues);

private:
    sk_sp<ComputePipeline> createComputePipeline(const ComputePipelineDesc&) override;

    sk_sp<Texture> createTexture(SkISize, const TextureInfo&) override;
    sk_sp<Buffer> createBuffer(size_t size, BufferType type, AccessPattern) override;

    sk_sp<Texture> onCreateWrappedTexture(const BackendTexture&) override;

    sk_sp<Sampler> createSampler(const SamplerDesc&) override;

    BackendTexture onCreateBackendTexture(SkISize dimensions, const TextureInfo&) override;
    void onDeleteBackendTexture(const BackendTexture&) override;

    const wgpu::Buffer& getOrCreateNullBuffer();

    DawnSharedContext* dawnSharedContext() const;

    void onFreeGpuResources() override;
    void onPurgeResourcesNotUsedSince(StdSteadyClock::time_point purgeTime) override;

    skia_private::THashMap<uint32_t, wgpu::RenderPipeline> fBlitWithDrawPipelines;

    wgpu::Buffer fNullBuffer;

    template <size_t NumEntries>
    using BindGroupCache = SkLRUCache<BindGroupKey<NumEntries>,
                                      wgpu::BindGroup,
                                      typename BindGroupKey<NumEntries>::Hash>;

    BindGroupCache<kNumUniformEntries> fUniformBufferBindGroupCache;
    BindGroupCache<1> fSingleTextureSamplerBindGroups;

    class IntrinsicBuffer;
    class IntrinsicConstantsManager;
    std::unique_ptr<IntrinsicConstantsManager> fIntrinsicConstantsManager;

    SingleOwner* fSingleOwner = nullptr;
};

}  // namespace skgpu::graphite

#endif  // skgpu_graphite_DawnResourceProvider_DEFINED