// 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_COMMON_DEVICEBASE_H_
#define BACKEND_COMMON_DEVICEBASE_H_

#include "common/Forward.h"
#include "common/RefCounted.h"

#include "nxt/nxtcpp.h"

namespace backend {

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

    class DeviceBase {
        public:
            DeviceBase();
            ~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 BufferBase* CreateBuffer(BufferBuilder* builder) = 0;
            virtual BufferViewBase* CreateBufferView(BufferViewBuilder* builder) = 0;
            virtual CommandBufferBase* CreateCommandBuffer(CommandBufferBuilder* builder) = 0;
            virtual DepthStencilStateBase* CreateDepthStencilState(DepthStencilStateBuilder* builder) = 0;
            virtual FramebufferBase* CreateFramebuffer(FramebufferBuilder* builder) = 0;
            virtual InputStateBase* CreateInputState(InputStateBuilder* builder) = 0;
            virtual PipelineBase* CreatePipeline(PipelineBuilder* builder) = 0;
            virtual PipelineLayoutBase* CreatePipelineLayout(PipelineLayoutBuilder* builder) = 0;
            virtual QueueBase* CreateQueue(QueueBuilder* builder) = 0;
            virtual RenderPassBase* CreateRenderPass(RenderPassBuilder* builder) = 0;
            virtual SamplerBase* CreateSampler(SamplerBuilder* builder) = 0;
            virtual ShaderModuleBase* CreateShaderModule(ShaderModuleBuilder* 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();
            BufferBuilder* CreateBufferBuilder();
            BufferViewBuilder* CreateBufferViewBuilder();
            CommandBufferBuilder* CreateCommandBufferBuilder();
            DepthStencilStateBuilder* CreateDepthStencilStateBuilder();
            FramebufferBuilder* CreateFramebufferBuilder();
            InputStateBuilder* CreateInputStateBuilder();
            PipelineBuilder* CreatePipelineBuilder();
            PipelineLayoutBuilder* CreatePipelineLayoutBuilder();
            QueueBuilder* CreateQueueBuilder();
            RenderPassBuilder* CreateRenderPassBuilder();
            SamplerBuilder* CreateSamplerBuilder();
            ShaderModuleBuilder* CreateShaderModuleBuilder();
            TextureBuilder* CreateTextureBuilder();

            void Tick();
            void CopyBindGroups(uint32_t start, uint32_t count, BindGroupBase* source, BindGroupBase* target);
            void SetErrorCallback(nxt::DeviceErrorCallback callback, nxt::CallbackUserdata userdata);

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

            nxt::DeviceErrorCallback errorCallback = nullptr;
            nxt::CallbackUserdata errorUserdata = 0;
    };

}

#endif // BACKEND_COMMON_DEVICEBASE_H_