#pragma once

#include "BsD3D11Prerequisites.h"
#include "BsHardwareBuffer.h"

namespace BansheeEngine
{
	/**
	 * @brief	Class containing common functionality for all DirectX 11 hardware buffers.
	 */
	class BS_D3D11_EXPORT D3D11HardwareBuffer : public HardwareBuffer
	{
	public:
		/**
		 * @brief	Available types of DX11 buffers
		 */
		enum BufferType
		{
			BT_VERTEX = 0x1, /**< Contains geometry vertices and their properties. */
			BT_INDEX = 0x2, /**< Contains triangle to vertex mapping. */
			BT_CONSTANT = 0x4, /**< Contains GPU program parameters. */
			BT_GROUP_GENERIC = 0x8, /**< Special value signifying a buffer is of generic type. Not an actual buffer. */
			BT_STRUCTURED = BT_GROUP_GENERIC | 0x10, /**< Generic buffer that holds one or more user-defined structures laid out sequentially. */
			BT_RAW = BT_GROUP_GENERIC | 0x20, /**< Generic buffer that holds raw block of bytes with no defined structure. */
			BT_INDIRECTARGUMENT = BT_GROUP_GENERIC | 0x40, /**< Generic buffer that is used for holding parameters used for indirect rendering. */
			BT_APPENDCONSUME = BT_GROUP_GENERIC | 0x80 /**< Generic buffer that allows the GPU program to use append/consume functionality. */
		};

		/**
		 * @copydoc	HardwareBuffer::HardwareBuffer
		 */
		D3D11HardwareBuffer(BufferType btype, GpuBufferUsage usage, UINT32 elementCount, UINT32 elementSize, 
			D3D11Device& device, bool useSystemMem = false, bool streamOut = false, bool randomGpuWrite = false, bool useCounter = false);
		~D3D11HardwareBuffer();

		/**
		 * @copydoc	HardwareBuffer::readData
		 */
		void readData(UINT32 offset, UINT32 length, void* pDest) override;

		/**
		 * @copydoc	HardwareBuffer::writeData
		 */
		void writeData(UINT32 offset, UINT32 length, const void* pSource, 
			BufferWriteType writeFlags = BufferWriteType::Normal) override;

		/**
		 * @copydoc	HardwareBuffer::copyData
		 */
		void copyData(HardwareBuffer& srcBuffer, UINT32 srcOffset, UINT32 dstOffset, 
			UINT32 length, bool discardWholeBuffer = false) override;

		/**
		 * @brief	Returns the internal DX11 buffer object.
		 */
		ID3D11Buffer* getD3DBuffer() { return mD3DBuffer; }

	protected:
		/**
		 * @copydoc	HardwareBuffer::lockImpl
		 */
		void* lockImpl(UINT32 offset, UINT32 length, GpuLockOptions options) override;

		/**
		 * @copydoc	HardwareBuffer::unlockImpl
		 */
		void unlockImpl() override;

		BufferType mBufferType;
		bool mRandomGpuWrite;
		bool mUseCounter;
		UINT32 mElementCount;
		UINT32 mElementSize;

		ID3D11Buffer* mD3DBuffer;

		bool mUseTempStagingBuffer;
		D3D11HardwareBuffer* mpTempStagingBuffer;
		bool mStagingUploadNeeded;
		
		D3D11Device& mDevice;
		D3D11_BUFFER_DESC mDesc;
	};
}