#include "RenderAPI.h"
#include "PlatformBase.h"


// Metal implementation of RenderAPI.


#if SUPPORT_METAL

#include "Unity/IUnityGraphicsMetal.h"
#import <Metal/Metal.h>

#import <Foundation/Foundation.h>
#import <MetalFX/MTLFXSpatialScaler.h>


class RenderAPI_Metal : public RenderAPI
{
public:
	RenderAPI_Metal();
	virtual ~RenderAPI_Metal() { }

	virtual void processDeviceEvent(UnityGfxDeviceEventType type, IUnityInterfaces* interfaces);

	virtual bool getUsesReverseZ() { return true; }

	virtual void initSupportFeature();

	virtual void spatialUpScale(void* src, void*data, void* dst);
private:
	id <MTLFXSpatialScaler> mfx_spatial_scaler; 
	IUnityGraphicsMetal* metal_graphics;
};


RenderAPI* CreateRenderAPI_Metal()
{
	return new RenderAPI_Metal();
}


RenderAPI_Metal::RenderAPI_Metal()
{
}

void RenderAPI_Metal::processDeviceEvent(UnityGfxDeviceEventType type, IUnityInterfaces* interfaces)
{
	if (type == kUnityGfxDeviceEventInitialize)
	{
		metal_graphics = interfaces->Get<IUnityGraphicsMetal>();
	}
	else if (type == kUnityGfxDeviceEventShutdown)
	{
		//@TODO: release resources
	}
}
void RenderAPI_Metal::initSupportFeature()
{
	if (@available(iOS 16.0, macOS 13.0, *)) 
	{
		support_features[GraphicsFeature::METAL_FX_SPATIAL_SR] = true;
		support_features[GraphicsFeature::METAL_FX_TEMPORAL_SR] = true;
	}
}

void RenderAPI_Metal::spatialUpScale(void* src, void* data, void* dst)
{
	if (@available(iOS 16.0, macOS 13.0, *)) 
	{
		id<MTLTexture> srctex = (__bridge id<MTLTexture>)src;
		id<MTLTexture> dsttex = (__bridge id<MTLTexture>)dst;
		
		id<MTLDevice> _device = metal_graphics->MetalDevice();
		id<MTLCommandBuffer> cmd = (id<MTLCommandBuffer>)metal_graphics->CurrentCommandBuffer();

        cmd.label = @"Upscale Command Buffer";
		
        if (mfx_spatial_scaler == nil) 
		{
			MTLFXSpatialScalerDescriptor* desc = [[MTLFXSpatialScalerDescriptor alloc]init]; 
			desc.inputWidth = [srctex width]; 
			desc.inputHeight = [srctex height]; 
			desc.outputWidth = [dsttex width]; 
			desc.outputHeight = [dsttex height]; 

			desc.colorTextureFormat = [srctex pixelFormat]; 
			desc.outputTextureFormat = [dsttex pixelFormat]; 
			desc.colorProcessingMode  = MTLFXSpatialScalerColorProcessingModeLinear;

			mfx_spatial_scaler = [desc newSpatialScalerWithDevice:_device];
			if (mfx_spatial_scaler == nil) 
			{
				return;
			}
		}

		mfx_spatial_scaler.colorTexture = srctex; 
		mfx_spatial_scaler.outputTexture = dsttex; 
		[mfx_spatial_scaler encodeToCommandBuffer:cmd];
		[cmd commit];
	}
}

#endif // #if SUPPORT_METAL