#include "BsD3D11GpuBufferView.h"
#include "BsD3D11GpuBuffer.h"
#include "BsD3D11RenderAPI.h"
#include "BsD3D11Device.h"
#include "BsRenderStats.h"
#include "BsException.h"

namespace BansheeEngine
{
	D3D11GpuBufferView::D3D11GpuBufferView()
		:GpuBufferView(), mSRV(nullptr), mUAV(nullptr)
	{

	}

	D3D11GpuBufferView::~D3D11GpuBufferView()
	{
		SAFE_RELEASE(mSRV);
		SAFE_RELEASE(mUAV);

		BS_INC_RENDER_STAT_CAT(ResDestroyed, RenderStatObject_ResourceView);
	}

	void D3D11GpuBufferView::initialize(const SPtr<GpuBufferCore>& buffer, GPU_BUFFER_DESC& desc)
	{
		GpuBufferView::initialize(buffer, desc);

		D3D11GpuBufferCore* d3d11GpuBuffer = static_cast<D3D11GpuBufferCore*>(buffer.get());

		if((desc.usage & GVU_RANDOMWRITE) != 0)
			mUAV = createUAV(d3d11GpuBuffer, desc.firstElement, desc.numElements, desc.useCounter);
		else if((desc.usage & GVU_RENDERTARGET) != 0)
		{
			BS_EXCEPT(NotImplementedException, "Cannot create a render target view for buffers yet.");
		}
		else
			mSRV = createSRV(d3d11GpuBuffer, desc.firstElement, desc.elementWidth, desc.numElements);

		BS_INC_RENDER_STAT_CAT(ResCreated, RenderStatObject_ResourceView);
	}

	ID3D11ShaderResourceView* D3D11GpuBufferView::createSRV(D3D11GpuBufferCore* buffer, UINT32 firstElement, UINT32 elementWidth, UINT32 numElements)
	{
		const GpuBufferProperties& props = buffer->getProperties();

		if (props.getType() == GBT_APPENDCONSUME)
			BS_EXCEPT(InvalidParametersException, "Cannot create ShaderResourceView for an append/consume buffer.");

		D3D11_SHADER_RESOURCE_VIEW_DESC desc;
		ZeroMemory(&desc, sizeof(desc));

		if (props.getType() == GBT_STRUCTURED)
		{
			desc.Format = DXGI_FORMAT_UNKNOWN;
			desc.ViewDimension = D3D11_SRV_DIMENSION_BUFFER;
			desc.Buffer.ElementOffset = firstElement * elementWidth;
			desc.Buffer.ElementWidth = elementWidth;
		}
		else if (props.getType() == GBT_RAW)
		{
			desc.Format = DXGI_FORMAT_R32_TYPELESS;
			desc.ViewDimension = D3D11_SRV_DIMENSION_BUFFEREX;
			desc.BufferEx.Flags = D3D11_BUFFEREX_SRV_FLAG_RAW;
			desc.BufferEx.FirstElement = firstElement;
			desc.BufferEx.NumElements = numElements;
		}
		else if (props.getType() == GBT_INDIRECTARGUMENT)
		{
			desc.Format = DXGI_FORMAT_R32_UINT;
			desc.ViewDimension = D3D11_SRV_DIMENSION_BUFFER;
			desc.Buffer.ElementOffset = firstElement * elementWidth;
			desc.Buffer.ElementWidth = elementWidth;
		}

		ID3D11ShaderResourceView* srv = nullptr;

		D3D11RenderAPI* d3d11rs = static_cast<D3D11RenderAPI*>(D3D11RenderAPI::instancePtr());
		HRESULT hr = d3d11rs->getPrimaryDevice().getD3D11Device()->CreateShaderResourceView(buffer->getDX11Buffer(), &desc, &srv);

		if (FAILED(hr) || d3d11rs->getPrimaryDevice().hasError())
		{
			String msg = d3d11rs->getPrimaryDevice().getErrorDescription();
			BS_EXCEPT(RenderingAPIException, "Cannot create ShaderResourceView: " + msg);
		}

		return srv;
	}

	ID3D11UnorderedAccessView* D3D11GpuBufferView::createUAV(D3D11GpuBufferCore* buffer, UINT32 firstElement, UINT32 numElements, bool useCounter)
	{
		const GpuBufferProperties& props = buffer->getProperties();

		D3D11_UNORDERED_ACCESS_VIEW_DESC desc;
		ZeroMemory(&desc, sizeof(desc));

		desc.ViewDimension = D3D11_UAV_DIMENSION_BUFFER;

		if (props.getType() == GBT_STRUCTURED)
		{
			desc.Format = DXGI_FORMAT_UNKNOWN;
			desc.Buffer.FirstElement = firstElement;
			desc.Buffer.NumElements = numElements;

			if(useCounter)
				desc.Buffer.Flags = D3D11_BUFFER_UAV_FLAG_COUNTER;
			else
				desc.Buffer.Flags = 0;
		}
		else if (props.getType() == GBT_RAW)
		{
			desc.Format = DXGI_FORMAT_R32_TYPELESS;
			desc.Buffer.Flags = D3D11_BUFFER_UAV_FLAG_RAW;
			desc.Buffer.FirstElement = firstElement;
			desc.Buffer.NumElements = numElements;
		}
		else if (props.getType() == GBT_INDIRECTARGUMENT)
		{
			desc.Format = DXGI_FORMAT_R32_UINT;
			desc.Buffer.Flags = 0;
			desc.Buffer.FirstElement = firstElement;
			desc.Buffer.NumElements = numElements;
		}
		else if (props.getType() == GBT_APPENDCONSUME)
		{
			desc.Format = DXGI_FORMAT_UNKNOWN;
			desc.Buffer.Flags = D3D11_BUFFER_UAV_FLAG_APPEND;
			desc.Buffer.FirstElement = firstElement;
			desc.Buffer.NumElements = numElements;
		}

		ID3D11UnorderedAccessView* uav = nullptr;

		D3D11RenderAPI* d3d11rs = static_cast<D3D11RenderAPI*>(D3D11RenderAPI::instancePtr());
		HRESULT hr = d3d11rs->getPrimaryDevice().getD3D11Device()->CreateUnorderedAccessView(buffer->getDX11Buffer(), &desc, &uav);

		if (FAILED(hr) || d3d11rs->getPrimaryDevice().hasError())
		{
			String msg = d3d11rs->getPrimaryDevice().getErrorDescription();
			BS_EXCEPT(RenderingAPIException, "Cannot create UnorderedAccessView: " + msg);
		}

		return uav;
	}
}