/*
 * Copyright 2021 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_MtlCommandBuffer_DEFINED
#define skgpu_graphite_MtlCommandBuffer_DEFINED

#include "include/private/SkLog.h"
#include "src/gpu/graphite/CommandBuffer.h"
#include "src/gpu/graphite/DrawPass.h"
#include "src/gpu/graphite/mtl/MtlResourceProvider.h"

#include <memory>

#include "include/core/SkTypes.h"
#include "include/ports/SkCFObject.h"

#import <Metal/Metal.h>

namespace skgpu::graphite {
class ComputePipeline;
class MtlBlitCommandEncoder;
class MtlComputeCommandEncoder;
class MtlGraphicsPipeline;
class MtlRenderCommandEncoder;
class MtlSharedContext;
struct WorkgroupSize;

class MtlCommandBuffer final : public CommandBuffer {
public:
    static std::unique_ptr<MtlCommandBuffer> Make(id<MTLCommandQueue>,
                                                  const MtlSharedContext*,
                                                  MtlResourceProvider*);
    ~MtlCommandBuffer() override;

    bool setNewCommandBufferResources() override;

    void addWaitSemaphores(size_t numWaitSemaphores,
                           const BackendSemaphore* waitSemaphores) override;
    void addSignalSemaphores(size_t numSignalSemaphores,
                             const BackendSemaphore* signalSemaphores) override;

    bool isFinished() {
        return (*fCommandBuffer).status == MTLCommandBufferStatusCompleted ||
               (*fCommandBuffer).status == MTLCommandBufferStatusError;

    }
    void waitUntilFinished() {
        // TODO: it's not clear what do to if status is Enqueued. Commit and then wait?
        if ((*fCommandBuffer).status == MTLCommandBufferStatusScheduled ||
            (*fCommandBuffer).status == MTLCommandBufferStatusCommitted) {
            [(*fCommandBuffer) waitUntilCompleted];
        }
        if (!this->isFinished()) {
            SKIA_LOG_E("Unfinished command buffer status: %d",
                        (int)(*fCommandBuffer).status);
            SkASSERT(false);
        }
    }
    bool commit();

private:
    MtlCommandBuffer(id<MTLCommandQueue>,
                     const MtlSharedContext* sharedContext,
                     MtlResourceProvider* resourceProvider);

    ResourceProvider* resourceProvider() const override { return fResourceProvider; }

    bool createNewMTLCommandBuffer();

    void onResetCommandBuffer() override;

    bool onAddRenderPass(const RenderPassDesc&,
                         const Texture* colorTexture,
                         const Texture* resolveTexture,
                         const Texture* depthStencilTexture,
                         SkIPoint resolveOffset,
                         SkIRect viewport,
                         const DrawPassList&) override;
    bool onAddComputePass(DispatchGroupSpan) override;

    // Methods for populating a MTLRenderCommandEncoder:
    bool beginRenderPass(const RenderPassDesc&,
                         const Texture* colorTexture,
                         const Texture* resolveTexture,
                         const Texture* depthStencilTexture);
    void endRenderPass();

    [[nodiscard]] bool addDrawPass(DrawPass*);

    void updateIntrinsicUniforms(SkIRect viewport);

    void bindGraphicsPipeline(const GraphicsPipeline*);
    void setBlendConstants(std::array<float, 4> blendConstants);

    void bindUniformBuffer(const BindBufferInfo& info, UniformSlot);
    void bindInputBuffer(const Buffer* buffer, size_t offset, uint32_t bindingIndex);
    void bindIndexBuffer(const Buffer* indexBuffer, size_t offset);
    void bindIndirectBuffer(const Buffer* indirectBuffer, size_t offset);

    void bindTextureAndSampler(const Texture*, const Sampler*, unsigned int bindIndex);

    void setScissor(const Scissor&);
    void setViewport(float x, float y, float width, float height,
                     float minDepth, float maxDepth);

    void draw(PrimitiveType type, unsigned int baseVertex, unsigned int vertexCount);
    void drawIndexed(PrimitiveType type, unsigned int baseIndex, unsigned int indexCount,
                     unsigned int baseVertex);
    void drawInstanced(PrimitiveType type,
                       unsigned int baseVertex, unsigned int vertexCount,
                       unsigned int baseInstance, unsigned int instanceCount);
    void drawIndexedInstanced(PrimitiveType type, unsigned int baseIndex,
                              unsigned int indexCount, unsigned int baseVertex,
                              unsigned int baseInstance, unsigned int instanceCount);
    void drawIndirect(PrimitiveType type);
    void drawIndexedIndirect(PrimitiveType type);

    // Methods for populating a MTLComputeCommandEncoder:
    void beginComputePass();
    void bindComputePipeline(const ComputePipeline*);
    void bindBuffer(const Buffer* buffer, unsigned int offset, unsigned int index);
    void bindTexture(const Texture* texture, unsigned int index);
    void bindSampler(const Sampler* sampler, unsigned int index);
    void dispatchThreadgroups(const WorkgroupSize& globalSize, const WorkgroupSize& localSize);
    void dispatchThreadgroupsIndirect(const WorkgroupSize& localSize,
                                      const Buffer* indirectBuffer,
                                      size_t indirectBufferOffset);
    void endComputePass();

    // Methods for populating a MTLBlitCommandEncoder:
    bool onCopyBufferToBuffer(const Buffer* srcBuffer,
                              size_t srcOffset,
                              const Buffer* dstBuffer,
                              size_t dstOffset,
                              size_t size) override;
    bool onCopyTextureToBuffer(const Texture*,
                               SkIRect srcRect,
                               const Buffer*,
                               size_t bufferOffset,
                               size_t bufferRowBytes) override;
    bool onCopyBufferToTexture(const Buffer*,
                               const Texture*,
                               const BufferTextureCopyData* copyData,
                               int count) override;
    bool onCopyTextureToTexture(const Texture* src,
                                SkIRect srcRect,
                                const Texture* dst,
                                SkIPoint dstPoint,
                                int mipLevel) override;
    bool onSynchronizeBufferToCpu(const Buffer*, bool* outDidResultInWork) override;
    bool onClearBuffer(const Buffer*, size_t offset, size_t size) override;

    MtlBlitCommandEncoder* getBlitCommandEncoder();
    void endBlitCommandEncoder();

    void bindUniformBuffers();

    sk_cfp<id<MTLCommandBuffer>> fCommandBuffer;
    sk_sp<MtlRenderCommandEncoder> fActiveRenderCommandEncoder;
    sk_sp<MtlComputeCommandEncoder> fActiveComputeCommandEncoder;
    sk_sp<MtlBlitCommandEncoder> fActiveBlitCommandEncoder;
    const MtlGraphicsPipeline* fActiveGraphicsPipeline = nullptr;

    std::array<BindBufferInfo, 5> fBoundUniformBuffers;
    bool fBoundUniformBuffersDirty = false;

    id<MTLBuffer> fCurrentIndexBuffer;
    id<MTLBuffer> fCurrentIndirectBuffer;
    size_t fCurrentIndexBufferOffset = 0;
    size_t fCurrentIndirectBufferOffset = 0;

    // The command buffer will outlive the MtlQueueManager which owns the MTLCommandQueue.
    id<MTLCommandQueue> fQueue;
    const MtlSharedContext* fSharedContext;
    MtlResourceProvider* fResourceProvider;

    // If true, the draw commands being added are entirely offscreen and can be skipped.
    // This can happen if a recording is being replayed with a transform that moves the recorded
    // commands outside of the render target bounds.
    bool fDrawIsOffscreen = false;
};

} // namespace skgpu::graphite

#endif // skgpu_graphite_MtlCommandBuffer_DEFINED