/*
 * Copyright 2011, Blender Foundation.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * Contributor: 
 *		Jeroen Bakker 
 *		Monique Dewanchand
 */

class MemoryBuffer;

#ifndef _COM_MemoryBuffer_h_
#define _COM_MemoryBuffer_h_

#include "COM_ExecutionGroup.h"
#include "COM_MemoryProxy.h"

extern "C" {
#  include "BLI_math.h"
#  include "BLI_rect.h"
}

/**
 * @brief state of a memory buffer
 * @ingroup Memory
 */
typedef enum MemoryBufferState {
	/** @brief memory has been allocated on creator device and CPU machine, but kernel has not been executed */
	COM_MB_ALLOCATED = 1,
	/** @brief memory is available for use, content has been created */
	COM_MB_AVAILABLE = 2,
	/** @brief chunk is consolidated from other chunks. special state.*/
	COM_MB_TEMPORARILY = 6
} MemoryBufferState;

typedef enum MemoryBufferExtend {
	COM_MB_CLIP,
	COM_MB_EXTEND,
	COM_MB_REPEAT
} MemoryBufferExtend;

class MemoryProxy;

/**
 * @brief a MemoryBuffer contains access to the data of a chunk
 */
class MemoryBuffer {
private:
	/**
	 * @brief proxy of the memory (same for all chunks in the same buffer)
	 */
	MemoryProxy *m_memoryProxy;
	
	/**
	 * @brief the type of buffer COM_DT_VALUE, COM_DT_VECTOR, COM_DT_COLOR
	 */
	DataType m_datatype;
	
	
	/**
	 * @brief region of this buffer inside relative to the MemoryProxy
	 */
	rcti m_rect;
	
	/**
	 * brief refers to the chunknumber within the executiongroup where related to the MemoryProxy
	 * @see memoryProxy
	 */
	unsigned int m_chunkNumber;
	
	/**
	 * @brief width of the chunk
	 */
	unsigned int m_chunkWidth;
	
	/**
	 * @brief state of the buffer
	 */
	MemoryBufferState m_state;
	
	/**
	 * @brief the actual float buffer/data
	 */
	float *m_buffer;

public:
	/**
	 * @brief construct new MemoryBuffer for a chunk
	 */
	MemoryBuffer(MemoryProxy *memoryProxy, unsigned int chunkNumber, rcti *rect);
	
	/**
	 * @brief construct new temporarily MemoryBuffer for an area
	 */
	MemoryBuffer(MemoryProxy *memoryProxy, rcti *rect);
	
	/**
	 * @brief destructor
	 */
	~MemoryBuffer();
	
	/**
	 * @brief read the ChunkNumber of this MemoryBuffer
	 */
	unsigned int getChunkNumber() { return this->m_chunkNumber; }
	
	/**
	 * @brief get the data of this MemoryBuffer
	 * @note buffer should already be available in memory
	 */
	float *getBuffer() { return this->m_buffer; }
	
	/**
	 * @brief after execution the state will be set to available by calling this method
	 */
	void setCreatedState()
	{
		this->m_state = COM_MB_AVAILABLE;
	}
	
	inline void wrap_pixel(int &x, int &y, MemoryBufferExtend extend_x, MemoryBufferExtend extend_y)
	{
		int w = m_rect.xmax - m_rect.xmin;
		int h = m_rect.ymax - m_rect.ymin;
		x = x - m_rect.xmin;
		y = y - m_rect.ymin;
		
		switch (extend_x) {
			case COM_MB_CLIP:
				break;
			case COM_MB_EXTEND:
				if (x < 0) x = 0;
				if (x >= w) x = w;
				break;
			case COM_MB_REPEAT:
				x = (x >= 0.0f ? (x % w) : (x % w) + w);
				break;
		}
		
		switch (extend_y) {
			case COM_MB_CLIP:
				break;
			case COM_MB_EXTEND:
				if (y < 0) y = 0;
				if (y >= h) y = h;
				break;
			case COM_MB_REPEAT:
				y = (y >= 0.0f ? (y % h) : (y % h) + h);
				break;
		}
	}
	
	inline void read(float result[4], int x, int y,
	                 MemoryBufferExtend extend_x = COM_MB_CLIP,
	                 MemoryBufferExtend extend_y = COM_MB_CLIP)
	{
		bool clip_x = (extend_x == COM_MB_CLIP && (x < m_rect.xmin || x >= m_rect.xmax));
		bool clip_y = (extend_y == COM_MB_CLIP && (y < m_rect.ymin || y >= m_rect.ymax));
		if (clip_x || clip_y) {
			/* clip result outside rect is zero */
			zero_v4(result);
		}
		else {
			wrap_pixel(x, y, extend_x, extend_y);
			const int offset = (this->m_chunkWidth * y + x) * COM_NUMBER_OF_CHANNELS;
			copy_v4_v4(result, &this->m_buffer[offset]);
		}
	}

	inline void readNoCheck(float result[4], int x, int y,
	                        MemoryBufferExtend extend_x = COM_MB_CLIP,
	                        MemoryBufferExtend extend_y = COM_MB_CLIP)
	{
		wrap_pixel(x, y, extend_x, extend_y);
		const int offset = (this->m_chunkWidth * y + x) * COM_NUMBER_OF_CHANNELS;

		BLI_assert(offset >= 0);
		BLI_assert(offset < this->determineBufferSize() * COM_NUMBER_OF_CHANNELS);
		BLI_assert(!(extend_x == COM_MB_CLIP && (x < m_rect.xmin || x >= m_rect.xmax)) &&
		           !(extend_y == COM_MB_CLIP && (y < m_rect.ymin || y >= m_rect.ymax)));

#if 0
		/* always true */
		BLI_assert((int)(MEM_allocN_len(this->m_buffer) / sizeof(*this->m_buffer)) ==
		           (int)(this->determineBufferSize() * COM_NUMBER_OF_CHANNELS));
#endif

		copy_v4_v4(result, &this->m_buffer[offset]);
	}
	
	void writePixel(int x, int y, const float color[4]);
	void addPixel(int x, int y, const float color[4]);
	inline void readBilinear(float result[4], float x, float y,
	                         MemoryBufferExtend extend_x = COM_MB_CLIP,
	                         MemoryBufferExtend extend_y = COM_MB_CLIP)
	{
		int x1 = floor(x);
		int y1 = floor(y);
		int x2 = x1 + 1;
		int y2 = y1 + 1;
		wrap_pixel(x1, y1, extend_x, extend_y);
		wrap_pixel(x2, y2, extend_x, extend_y);

		float valuex = x - x1;
		float valuey = y - y1;
		float mvaluex = 1.0f - valuex;
		float mvaluey = 1.0f - valuey;

		float color1[4];
		float color2[4];
		float color3[4];
		float color4[4];

		read(color1, x1, y1);
		read(color2, x1, y2);
		read(color3, x2, y1);
		read(color4, x2, y2);

		color1[0] = color1[0] * mvaluey + color2[0] * valuey;
		color1[1] = color1[1] * mvaluey + color2[1] * valuey;
		color1[2] = color1[2] * mvaluey + color2[2] * valuey;
		color1[3] = color1[3] * mvaluey + color2[3] * valuey;

		color3[0] = color3[0] * mvaluey + color4[0] * valuey;
		color3[1] = color3[1] * mvaluey + color4[1] * valuey;
		color3[2] = color3[2] * mvaluey + color4[2] * valuey;
		color3[3] = color3[3] * mvaluey + color4[3] * valuey;

		result[0] = color1[0] * mvaluex + color3[0] * valuex;
		result[1] = color1[1] * mvaluex + color3[1] * valuex;
		result[2] = color1[2] * mvaluex + color3[2] * valuex;
		result[3] = color1[3] * mvaluex + color3[3] * valuex;
	}

	void readEWA(float result[4], const float uv[2], const float derivatives[2][2], PixelSampler sampler);
	
	/**
	 * @brief is this MemoryBuffer a temporarily buffer (based on an area, not on a chunk)
	 */
	inline const bool isTemporarily() const { return this->m_state == COM_MB_TEMPORARILY; }
	
	/**
	 * @brief add the content from otherBuffer to this MemoryBuffer
	 * @param otherBuffer source buffer
	 *
	 * @note take care when running this on a new buffer since it wont fill in
	 *       uninitialized values in areas where the buffers don't overlap.
	 */
	void copyContentFrom(MemoryBuffer *otherBuffer);
	
	/**
	 * @brief get the rect of this MemoryBuffer
	 */
	rcti *getRect() { return &this->m_rect; }
	
	/**
	 * @brief get the width of this MemoryBuffer
	 */
	int getWidth() const;
	
	/**
	 * @brief get the height of this MemoryBuffer
	 */
	int getHeight() const;
	
	/**
	 * @brief clear the buffer. Make all pixels black transparent.
	 */
	void clear();
	
	MemoryBuffer *duplicate();
	
	float *convertToValueBuffer();
	float getMaximumValue();
	float getMaximumValue(rcti *rect);
private:
	unsigned int determineBufferSize();

#ifdef WITH_CXX_GUARDEDALLOC
	MEM_CXX_CLASS_ALLOC_FUNCS("COM:MemoryBuffer")
#endif
};

#endif