// Copyright 2017 The NXT 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 BACKEND_DEVICEBASE_H_
#define BACKEND_DEVICEBASE_H_

#include "backend/Error.h"
#include "backend/Forward.h"
#include "backend/RefCounted.h"

#include "nxt/nxtcpp.h"

namespace backend {

    using ErrorCallback = void (*)(const char* errorMessage, void* userData);

    class DeviceBase {
      public:
        DeviceBase();
        virtual ~DeviceBase();

        void HandleError(const char* message);

        // Used by autogenerated code, returns itself
        DeviceBase* GetDevice();

        virtual BindGroupBase* CreateBindGroup(BindGroupBuilder* builder) = 0;
        virtual BindGroupLayoutBase* CreateBindGroupLayout(BindGroupLayoutBuilder* builder) = 0;
        virtual BlendStateBase* CreateBlendState(BlendStateBuilder* builder) = 0;
        virtual BufferBase* CreateBuffer(BufferBuilder* builder) = 0;
        virtual BufferViewBase* CreateBufferView(BufferViewBuilder* builder) = 0;
        virtual CommandBufferBase* CreateCommandBuffer(CommandBufferBuilder* builder) = 0;
        virtual ComputePipelineBase* CreateComputePipeline(ComputePipelineBuilder* builder) = 0;
        virtual DepthStencilStateBase* CreateDepthStencilState(
            DepthStencilStateBuilder* builder) = 0;
        virtual InputStateBase* CreateInputState(InputStateBuilder* builder) = 0;
        virtual PipelineLayoutBase* CreatePipelineLayout(PipelineLayoutBuilder* builder) = 0;
        virtual QueueBase* CreateQueue(QueueBuilder* builder) = 0;
        virtual RenderPassDescriptorBase* CreateRenderPassDescriptor(
            RenderPassDescriptorBuilder* builder) = 0;
        virtual RenderPipelineBase* CreateRenderPipeline(RenderPipelineBuilder* builder) = 0;
        virtual ShaderModuleBase* CreateShaderModule(ShaderModuleBuilder* builder) = 0;
        virtual SwapChainBase* CreateSwapChain(SwapChainBuilder* builder) = 0;
        virtual TextureBase* CreateTexture(TextureBuilder* builder) = 0;
        virtual TextureViewBase* CreateTextureView(TextureViewBuilder* builder) = 0;

        virtual void TickImpl() = 0;

        // Many NXT objects are completely immutable once created which means that if two
        // builders are given the same arguments, they can return the same object. Reusing
        // objects will help make comparisons between objects by a single pointer comparison.
        //
        // Technically no object is immutable as they have a reference count, and an
        // application with reference-counting issues could "see" that objects are reused.
        // This is solved by automatic-reference counting, and also the fact that when using
        // the client-server wire every creation will get a different proxy object, with a
        // different reference count.
        //
        // When trying to create an object, we give both the builder and an example of what
        // the built object will be, the "blueprint". The blueprint is just a FooBase object
        // instead of a backend Foo object. If the blueprint doesn't match an object in the
        // cache, then the builder is used to make a new object.
        BindGroupLayoutBase* GetOrCreateBindGroupLayout(const BindGroupLayoutBase* blueprint,
                                                        BindGroupLayoutBuilder* builder);
        void UncacheBindGroupLayout(BindGroupLayoutBase* obj);

        // NXT API
        BindGroupBuilder* CreateBindGroupBuilder();
        BindGroupLayoutBuilder* CreateBindGroupLayoutBuilder();
        BlendStateBuilder* CreateBlendStateBuilder();
        BufferBuilder* CreateBufferBuilder();
        CommandBufferBuilder* CreateCommandBufferBuilder();
        ComputePipelineBuilder* CreateComputePipelineBuilder();
        DepthStencilStateBuilder* CreateDepthStencilStateBuilder();
        InputStateBuilder* CreateInputStateBuilder();
        PipelineLayoutBuilder* CreatePipelineLayoutBuilder();
        QueueBuilder* CreateQueueBuilder();
        RenderPassDescriptorBuilder* CreateRenderPassDescriptorBuilder();
        RenderPipelineBuilder* CreateRenderPipelineBuilder();
        SamplerBase* CreateSampler(const nxt::SamplerDescriptor* descriptor);
        ShaderModuleBuilder* CreateShaderModuleBuilder();
        SwapChainBuilder* CreateSwapChainBuilder();
        TextureBuilder* CreateTextureBuilder();

        void Tick();
        void SetErrorCallback(nxt::DeviceErrorCallback callback, nxt::CallbackUserdata userdata);
        void Reference();
        void Release();

      private:
        virtual ResultOrError<SamplerBase*> CreateSamplerImpl(
            const nxt::SamplerDescriptor* descriptor) = 0;

        // The object caches aren't exposed in the header as they would require a lot of
        // additional includes.
        struct Caches;
        Caches* mCaches = nullptr;

        nxt::DeviceErrorCallback mErrorCallback = nullptr;
        nxt::CallbackUserdata mErrorUserdata = 0;
        uint32_t mRefCount = 1;
    };

}  // namespace backend

#endif  // BACKEND_DEVICEBASE_H_