// 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_VULKAN_VULKANBACKEND_H_
#define BACKEND_VULKAN_VULKANBACKEND_H_

#include "nxt/nxtcpp.h"

#include "backend/ComputePipeline.h"
#include "backend/DepthStencilState.h"
#include "backend/Device.h"
#include "backend/Queue.h"
#include "backend/Sampler.h"
#include "backend/ToBackend.h"
#include "backend/vulkan/VulkanFunctions.h"
#include "backend/vulkan/VulkanInfo.h"
#include "common/DynamicLib.h"
#include "common/Serial.h"
#include "common/SerialQueue.h"

#include <queue>

namespace backend { namespace vulkan {

    class BindGroup;
    class BindGroupLayout;
    class BlendState;
    class Buffer;
    using BufferView = BufferViewBase;
    class CommandBuffer;
    using ComputePipeline = ComputePipelineBase;
    using DepthStencilState = DepthStencilStateBase;
    class Device;
    class Framebuffer;
    class InputState;
    class PipelineLayout;
    class Queue;
    class RenderPass;
    class RenderPipeline;
    using Sampler = SamplerBase;
    class ShaderModule;
    class SwapChain;
    class Texture;
    class TextureView;

    class BufferUploader;
    class FencedDeleter;
    class MapReadRequestTracker;
    class MemoryAllocator;

    struct VulkanBackendTraits {
        using BindGroupType = BindGroup;
        using BindGroupLayoutType = BindGroupLayout;
        using BlendStateType = BlendState;
        using BufferType = Buffer;
        using BufferViewType = BufferView;
        using CommandBufferType = CommandBuffer;
        using ComputePipelineType = ComputePipeline;
        using DepthStencilStateType = DepthStencilState;
        using DeviceType = Device;
        using FramebufferType = Framebuffer;
        using InputStateType = InputState;
        using PipelineLayoutType = PipelineLayout;
        using QueueType = Queue;
        using RenderPassType = RenderPass;
        using RenderPipelineType = RenderPipeline;
        using SamplerType = Sampler;
        using ShaderModuleType = ShaderModule;
        using SwapChainType = SwapChain;
        using TextureType = Texture;
        using TextureViewType = TextureView;
    };

    template <typename T>
    auto ToBackend(T&& common) -> decltype(ToBackendBase<VulkanBackendTraits>(common)) {
        return ToBackendBase<VulkanBackendTraits>(common);
    }

    class Device : public DeviceBase {
      public:
        Device(const std::vector<const char*>& requiredInstanceExtensions);
        ~Device();

        // Contains all the Vulkan entry points, vkDoFoo is called via device->fn.DoFoo.
        const VulkanFunctions fn;

        const VulkanDeviceInfo& GetDeviceInfo() const;
        VkInstance GetInstance() const;
        VkPhysicalDevice GetPhysicalDevice() const;
        VkDevice GetVkDevice() const;
        uint32_t GetGraphicsQueueFamily() const;
        VkQueue GetQueue() const;

        BufferUploader* GetBufferUploader() const;
        FencedDeleter* GetFencedDeleter() const;
        MapReadRequestTracker* GetMapReadRequestTracker() const;
        MemoryAllocator* GetMemoryAllocator() const;

        Serial GetSerial() const;

        VkCommandBuffer GetPendingCommandBuffer();
        void SubmitPendingCommands();
        void AddWaitSemaphore(VkSemaphore semaphore);

        // NXT API
        BindGroupBase* CreateBindGroup(BindGroupBuilder* builder) override;
        BindGroupLayoutBase* CreateBindGroupLayout(BindGroupLayoutBuilder* builder) override;
        BlendStateBase* CreateBlendState(BlendStateBuilder* builder) override;
        BufferBase* CreateBuffer(BufferBuilder* builder) override;
        BufferViewBase* CreateBufferView(BufferViewBuilder* builder) override;
        CommandBufferBase* CreateCommandBuffer(CommandBufferBuilder* builder) override;
        ComputePipelineBase* CreateComputePipeline(ComputePipelineBuilder* builder) override;
        DepthStencilStateBase* CreateDepthStencilState(DepthStencilStateBuilder* builder) override;
        FramebufferBase* CreateFramebuffer(FramebufferBuilder* builder) override;
        InputStateBase* CreateInputState(InputStateBuilder* builder) override;
        PipelineLayoutBase* CreatePipelineLayout(PipelineLayoutBuilder* builder) override;
        QueueBase* CreateQueue(QueueBuilder* builder) override;
        RenderPassBase* CreateRenderPass(RenderPassBuilder* builder) override;
        RenderPipelineBase* CreateRenderPipeline(RenderPipelineBuilder* builder) override;
        SamplerBase* CreateSampler(SamplerBuilder* builder) override;
        ShaderModuleBase* CreateShaderModule(ShaderModuleBuilder* builder) override;
        SwapChainBase* CreateSwapChain(SwapChainBuilder* builder) override;
        TextureBase* CreateTexture(TextureBuilder* builder) override;
        TextureViewBase* CreateTextureView(TextureViewBuilder* builder) override;

        void TickImpl() override;

      private:
        bool CreateInstance(VulkanGlobalKnobs* usedKnobs,
                            const std::vector<const char*>& requiredExtensions);
        bool CreateDevice(VulkanDeviceKnobs* usedKnobs);
        void GatherQueueFromDevice();

        bool RegisterDebugReport();
        static VKAPI_ATTR VkBool32 VKAPI_CALL
        OnDebugReportCallback(VkDebugReportFlagsEXT flags,
                              VkDebugReportObjectTypeEXT objectType,
                              uint64_t object,
                              size_t location,
                              int32_t messageCode,
                              const char* pLayerPrefix,
                              const char* pMessage,
                              void* pUserdata);

        // To make it easier to use fn it is a public const member. However
        // the Device is allowed to mutate them through these private methods.
        VulkanFunctions* GetMutableFunctions();

        VulkanGlobalInfo mGlobalInfo;
        VulkanDeviceInfo mDeviceInfo;

        DynamicLib mVulkanLib;

        VkInstance mInstance = VK_NULL_HANDLE;
        VkPhysicalDevice mPhysicalDevice = VK_NULL_HANDLE;
        VkDevice mVkDevice = VK_NULL_HANDLE;
        uint32_t mQueueFamily = 0;
        VkQueue mQueue = VK_NULL_HANDLE;
        VkDebugReportCallbackEXT mDebugReportCallback = VK_NULL_HANDLE;

        BufferUploader* mBufferUploader = nullptr;
        FencedDeleter* mDeleter = nullptr;
        MapReadRequestTracker* mMapReadRequestTracker = nullptr;
        MemoryAllocator* mMemoryAllocator = nullptr;

        VkFence GetUnusedFence();
        void CheckPassedFences();

        // We track which operations are in flight on the GPU with an increasing serial.
        // This works only because we have a single queue. Each submit to a queue is associated
        // to a serial and a fence, such that when the fence is "ready" we know the operations
        // have finished.
        std::queue<std::pair<VkFence, Serial>> mFencesInFlight;
        std::vector<VkFence> mUnusedFences;
        Serial mNextSerial = 1;
        Serial mCompletedSerial = 0;

        struct CommandPoolAndBuffer {
            VkCommandPool pool = VK_NULL_HANDLE;
            VkCommandBuffer commandBuffer = VK_NULL_HANDLE;
        };

        CommandPoolAndBuffer GetUnusedCommands();
        void RecycleCompletedCommands();
        void FreeCommands(CommandPoolAndBuffer* commands);

        SerialQueue<CommandPoolAndBuffer> mCommandsInFlight;
        std::vector<CommandPoolAndBuffer> mUnusedCommands;
        CommandPoolAndBuffer mPendingCommands;
        std::vector<VkSemaphore> mWaitSemaphores;
    };

    class Queue : public QueueBase {
      public:
        Queue(QueueBuilder* builder);
        ~Queue();

        // NXT API
        void Submit(uint32_t numCommands, CommandBuffer* const* commands);
    };

}}  // namespace backend::vulkan

#endif  // BACKEND_VULKAN_VULKANBACKEND_H_