// 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.

#ifndef DAWNNATIVE_BUFFER_H_
#define DAWNNATIVE_BUFFER_H_

#include "dawn_native/Error.h"
#include "dawn_native/Forward.h"
#include "dawn_native/IntegerTypes.h"
#include "dawn_native/ObjectBase.h"

#include "dawn_native/dawn_platform.h"

#include <memory>

namespace dawn_native {

    struct CopyTextureToBufferCmd;

    enum class MapType : uint32_t;

    MaybeError ValidateBufferDescriptor(DeviceBase* device, const BufferDescriptor* descriptor);

    static constexpr wgpu::BufferUsage kReadOnlyBufferUsages =
        wgpu::BufferUsage::MapRead | wgpu::BufferUsage::CopySrc | wgpu::BufferUsage::Index |
        wgpu::BufferUsage::Vertex | wgpu::BufferUsage::Uniform | kReadOnlyStorageBuffer |
        wgpu::BufferUsage::Indirect;

    static constexpr wgpu::BufferUsage kMappableBufferUsages =
        wgpu::BufferUsage::MapRead | wgpu::BufferUsage::MapWrite;

    class BufferBase : public ApiObjectBase {
      public:
        enum class BufferState {
            Unmapped,
            Mapped,
            MappedAtCreation,
            Destroyed,
        };
        BufferBase(DeviceBase* device, const BufferDescriptor* descriptor);

        static BufferBase* MakeError(DeviceBase* device, const BufferDescriptor* descriptor);

        bool Destroy() override;
        ObjectType GetType() const override;

        uint64_t GetSize() const;
        uint64_t GetAllocatedSize() const;
        wgpu::BufferUsage GetUsage() const;

        MaybeError MapAtCreation();
        void OnMapRequestCompleted(MapRequestID mapID, WGPUBufferMapAsyncStatus status);

        MaybeError ValidateCanUseOnQueueNow() const;

        bool IsFullBufferRange(uint64_t offset, uint64_t size) const;
        bool IsDataInitialized() const;
        void SetIsDataInitialized();

        void* GetMappedRange(size_t offset, size_t size, bool writable = true);
        void Unmap();

        // Dawn API
        void APIMapAsync(wgpu::MapMode mode,
                         size_t offset,
                         size_t size,
                         WGPUBufferMapCallback callback,
                         void* userdata);
        void* APIGetMappedRange(size_t offset, size_t size);
        const void* APIGetConstMappedRange(size_t offset, size_t size);
        void APIUnmap();
        void APIDestroy();

      protected:
        BufferBase(DeviceBase* device,
                   const BufferDescriptor* descriptor,
                   ObjectBase::ErrorTag tag);

        // Constructor used only for mocking and testing.
        BufferBase(DeviceBase* device, BufferState state);

        ~BufferBase() override;

        MaybeError MapAtCreationInternal();

        uint64_t mAllocatedSize = 0;

      private:
        virtual MaybeError MapAtCreationImpl() = 0;
        virtual MaybeError MapAsyncImpl(wgpu::MapMode mode, size_t offset, size_t size) = 0;
        virtual void UnmapImpl() = 0;
        virtual void* GetMappedPointerImpl() = 0;

        virtual bool IsCPUWritableAtCreation() const = 0;
        MaybeError CopyFromStagingBuffer();
        void CallMapCallback(MapRequestID mapID, WGPUBufferMapAsyncStatus status);

        MaybeError ValidateMapAsync(wgpu::MapMode mode,
                                    size_t offset,
                                    size_t size,
                                    WGPUBufferMapAsyncStatus* status) const;
        MaybeError ValidateUnmap() const;
        bool CanGetMappedRange(bool writable, size_t offset, size_t size) const;
        void UnmapInternal(WGPUBufferMapAsyncStatus callbackStatus);

        uint64_t mSize = 0;
        wgpu::BufferUsage mUsage = wgpu::BufferUsage::None;
        BufferState mState;
        bool mIsDataInitialized = false;

        std::unique_ptr<StagingBufferBase> mStagingBuffer;

        WGPUBufferMapCallback mMapCallback = nullptr;
        void* mMapUserdata = 0;
        MapRequestID mLastMapID = MapRequestID(0);
        wgpu::MapMode mMapMode = wgpu::MapMode::None;
        size_t mMapOffset = 0;
        size_t mMapSize = 0;
    };

}  // namespace dawn_native

#endif  // DAWNNATIVE_BUFFER_H_