#include <stdint.h>

#include <vector>
#include <queue>
#include <mutex>

#include "UnityPluginAPI/IUnityInterface.h"
#include "UnityPluginAPI/IUnityLog.h"
#include "UnityPluginAPI/IUnityGraphics.h"
#include "UnityPluginAPI/IUnityRenderingExtensions.h"

#include <d3d12.h>
#include <dxgi.h>
#include "UnityPluginAPI/IUnityGraphicsD3D12.h"

#include "FSR3UnityTypes.h"

static const int32_t BaseEventId = 0;

static IUnityInterfaces* s_UnityInterfaces = nullptr;
static IUnityLog* s_Log = nullptr;
static IUnityGraphics* s_Graphics = nullptr;
static IUnityGraphicsD3D12v7* s_GraphicsD3D12 = nullptr;
static UnityGfxRenderer s_RendererType = kUnityGfxRendererNull;

static void UNITY_INTERFACE_API OnGraphicsDeviceEvent(UnityGfxDeviceEventType eventType);
static void UNITY_INTERFACE_API OnRenderEventAndData(int eventID, void* data);
static void UNITY_INTERFACE_API OnSetTextureEvent(int eventID, void* data);

struct FSR3Context
{
    // TODO: contains FSR3 context object + related metadata (texture table etc)
};

static std::vector<FSR3Context> s_Contexts;
static std::queue<uint32_t> s_FeatureSlots;
static std::mutex s_FeatureMutex;

// Unity plugin load event
extern "C" void UNITY_INTERFACE_EXPORT UNITY_INTERFACE_API UnityPluginLoad(IUnityInterfaces* unityInterfaces)
{
    s_UnityInterfaces = unityInterfaces;
    s_Log = unityInterfaces->Get<IUnityLog>();
    s_Graphics = unityInterfaces->Get<IUnityGraphics>();

    s_Graphics->RegisterDeviceEventCallback(OnGraphicsDeviceEvent);

    // Run OnGraphicsDeviceEvent(initialize) manually on plugin load
    // to not miss the event in case the graphics device is already initialized
    OnGraphicsDeviceEvent(kUnityGfxDeviceEventInitialize);
}

// Unity plugin unload event
extern "C" void UNITY_INTERFACE_EXPORT UNITY_INTERFACE_API UnityPluginUnload()
{
    s_Graphics->UnregisterDeviceEventCallback(OnGraphicsDeviceEvent);
}

static void UNITY_INTERFACE_API OnGraphicsDeviceEvent(UnityGfxDeviceEventType eventType)
{
    switch (eventType)
    {
    case kUnityGfxDeviceEventInitialize:
    {
        s_RendererType = s_Graphics->GetRenderer();
        if (s_RendererType != kUnityGfxRendererD3D12)
            return;

        s_GraphicsD3D12 = s_UnityInterfaces->Get<IUnityGraphicsD3D12v7>();
        if (s_GraphicsD3D12 == nullptr)
        {
            UNITY_LOG_ERROR(s_Log, "Could not obtain D3D12 Graphics interface!");
            return;
        }

        break;
    }
    case kUnityGfxDeviceEventShutdown:
    {
        s_GraphicsD3D12 = nullptr;
        s_RendererType = kUnityGfxRendererNull;
        break;
    }
    case kUnityGfxDeviceEventBeforeReset:
    {
        break;
    }
    case kUnityGfxDeviceEventAfterReset:
    {
        break;
    }
    };
}

// Thread-safe allocation of FSR3 Context feature slot
static uint32_t AllocateFeatureSlot()
{
    std::lock_guard<std::mutex> lock(s_FeatureMutex);

    if (s_FeatureSlots.empty())
    {
        uint32_t featureSlot = (uint32_t)s_Contexts.size();
        s_Contexts.push_back(std::move(FSR3Context()));
        return featureSlot;
    }

    uint32_t featureSlot = s_FeatureSlots.front();
    s_FeatureSlots.pop();
    return featureSlot;
}

// Thread-safe freeing and clearing of FSR3 Context feature slot
static void FreeFeatureSlot(uint32_t featureSlot)
{
    std::lock_guard<std::mutex> lock(s_FeatureMutex);

    s_FeatureSlots.push(featureSlot);
    memset(&s_Contexts[featureSlot], 0, sizeof(FSR3Context));
}

extern "C" bool UNITY_INTERFACE_EXPORT UNITY_INTERFACE_API AMDUP_InitApi()
{
    // TODO: implement
    return false;
}

extern "C" void UNITY_INTERFACE_EXPORT UNITY_INTERFACE_API AMDUP_ShutdownApi()
{
    // TODO: implement
}

extern "C" uint32_t UNITY_INTERFACE_EXPORT UNITY_INTERFACE_API AMDUP_GetDeviceVersion()
{
    return 0x0u;
}

extern "C" UnityRenderingEventAndData UNITY_INTERFACE_EXPORT UNITY_INTERFACE_API AMDUP_GetRenderEventCallback()
{
    return OnRenderEventAndData;
}

extern "C" UnityRenderingEventAndData UNITY_INTERFACE_EXPORT UNITY_INTERFACE_API AMDUP_GetSetTextureEventCallback()
{
    return OnSetTextureEvent;
}

extern "C" uint32_t UNITY_INTERFACE_EXPORT UNITY_INTERFACE_API AMDUP_CreateFeatureSlot()
{
    return AllocateFeatureSlot();
}

extern "C" bool UNITY_INTERFACE_EXPORT UNITY_INTERFACE_API AMDUP_GetRenderResolutionFromQualityMode(FSR3Quality qualityMode, uint32_t displayWidth, uint32_t displayHeight, uint32_t* renderWidth, uint32_t* renderHeight)
{
    // TODO: implement
    return false;
}

extern "C" float UNITY_INTERFACE_EXPORT UNITY_INTERFACE_API AMDUP_GetUpscaleRatioFromQualityMode(FSR3Quality qualityMode)
{
    // TODO: implement
    return 1.0f;
}

extern "C" int32_t UNITY_INTERFACE_EXPORT UNITY_INTERFACE_API AMDUP_GetBaseEventId()
{
    return BaseEventId;
}

// Plugin function to handle a specific rendering event
static void UNITY_INTERFACE_API OnRenderEventAndData(int eventID, void* data)
{
    // User rendering code
    switch (eventID)
    {
    case BaseEventId + FSR3PluginEvent::eDestroyFeature:
    {
        uint32_t featureSlot = (uint32_t)(int64_t)data;
        // TODO: destroy FSR3Context at feature slot index
        FreeFeatureSlot(featureSlot);
        break;
    }
    case BaseEventId + FSR3PluginEvent::eExecute:
    {
        auto* params = (FSR3CommandExecutionData*)data;
        break;
    }
    case BaseEventId + FSR3PluginEvent::ePostExecute:
    {
        auto* params = (FSR3CommandExecutionData*)data;
        break;
    }
    case BaseEventId + FSR3PluginEvent::eInit:
    {
        auto* params = (FSR3CommandInitializationData*)data;
        break;
    }
    }
}

static void UNITY_INTERFACE_API OnSetTextureEvent(int eventID, void* data)
{
    auto* params = (UnityRenderingExtTextureUpdateParamsV2*)data;

    uint32_t featureSlot = (params->userData >> 16) & 0xFFFF;
    uint32_t textureSlot = (params->userData >> 1) & 0x7FFF;    // TODO: could just use as numeric index to calculate a pointer offset
    uint32_t clearTextureTable = params->userData & 0x1;

    // User rendering code
    switch (eventID)
    {
    case kUnityRenderingExtEventUpdateTextureBeginV2:
    {
        break;
    }
    case kUnityRenderingExtEventUpdateTextureEndV2:
    {
        break;
    }
    }
}