#include <memory>

#include "ext/meshtexturizer.h"

// TnzCore includes
#include "tgl.h" // OpenGL includes

// Qt includes
#include <QReadWriteLock>
#include <QReadLocker>
#include <QWriteLocker>

// tcg includes
#include "tcg/tcg_macros.h"
#include "tcg/tcg_list.h"
#include "tcg/tcg_misc.h"

#define COPIED_BORDER 1								 // Amount of tile border from the original image
#define TRANSP_BORDER 1								 // Amount of transparent tile border
#define NONPREM_BORDER 1							 // Amount of nonpremultiplied copied transparent border
#define TOTAL_BORDER (COPIED_BORDER + TRANSP_BORDER) // Overall border to texture tiles above
#define TOTAL_BORDER_2 (2 * TOTAL_BORDER)			 // Twice the above

TCG_STATIC_ASSERT(COPIED_BORDER > 0);				// Due to GL_LINEAR alpha blending on tile seams
TCG_STATIC_ASSERT(TRANSP_BORDER > 0);				// Due to GL_CLAMP beyond tile limits
TCG_STATIC_ASSERT(NONPREM_BORDER <= TRANSP_BORDER); // The nonpremultiplied border is transparent

//******************************************************************************************
//    MeshTexturizer::Imp  definition
//******************************************************************************************

class MeshTexturizer::Imp
{
	typedef MeshTexturizer::TextureData TextureData;

public:
	QReadWriteLock m_lock;									  //!< Lock for synchronized access
	tcg::list<std::shared_ptr<TextureData>> m_textureDatas; //!< Pool of texture datas

public:
	Imp() : m_lock(QReadWriteLock::Recursive) {}

	bool testTextureAlloc(int lx, int ly);
	GLuint textureAlloc(const TRaster32P &ras, const TRaster32P &aux,
						int x, int y, int textureLx, int textureLy,
						bool premultiplied);

	void allocateTextures(int groupIdx, const TRaster32P &ras, const TRaster32P &aux,
						  int x, int y, int textureLx, int textureLy,
						  bool premultiplied);

	TextureData *getTextureData(int groupIdx);
};

//---------------------------------------------------------------------------------

bool MeshTexturizer::Imp::testTextureAlloc(int lx, int ly)
{
	lx += TOTAL_BORDER_2, ly += TOTAL_BORDER_2; // Add border

	glTexImage2D(GL_PROXY_TEXTURE_2D,
				 0,				   // one level only
				 GL_RGBA,		   // number of pixel channels
				 lx,			   // width
				 ly,			   // height
				 0,				   // border size
				 TGL_FMT,		   // pixel format
				 GL_UNSIGNED_BYTE, // pixel data type
				 0);

	int outLx;
	glGetTexLevelParameteriv(GL_PROXY_TEXTURE_2D, 0, GL_TEXTURE_WIDTH, &outLx);

	return (lx == outLx);
}

//---------------------------------------------------------------------------------

GLuint MeshTexturizer::Imp::textureAlloc(const TRaster32P &ras, const TRaster32P &aux,
										 int x, int y, int textureLx, int textureLy,
										 bool premultiplied)
{
	struct locals {
		static void clearMatte(const TRaster32P &ras, int xBegin, int yBegin, int xEnd, int yEnd)
		{
			for (int y = yBegin; y != yEnd; ++y) {
				TPixel32 *line = ras->pixels(y), *pixEnd = line + xEnd;

				for (TPixel32 *pix = line + xBegin; pix != pixEnd; ++pix)
					pix->m = 0;
			}
		}

		static void clearMatte_border(const TRaster32P &ras, int border0, int border1)
		{
			assert(border0 < border1);

			// Horizontal
			clearMatte(ras, border0, border0, ras->getLx() - border0, border1);
			clearMatte(ras, border0, ras->getLy() - border1, ras->getLx() - border0, ras->getLy() - border0);

			// Vertical
			clearMatte(ras, border0, border1, border1, ras->getLy() - border1);
			clearMatte(ras, ras->getLx() - border1, border1, ras->getLx() - border0, ras->getLy() - border1);
		}
	}; // locals

	// Prepare the texture tile
	assert(aux->getLx() >= textureLx + TOTAL_BORDER_2 && aux->getLy() >= textureLy + TOTAL_BORDER_2);

	TRect rasRect(x, y, x + textureLx - 1, y + textureLy - 1);
	rasRect = rasRect.enlarge(premultiplied ? COPIED_BORDER : COPIED_BORDER + NONPREM_BORDER);
	rasRect = rasRect * ras->getBounds();

	TRect auxRect(rasRect - TPoint(x - TOTAL_BORDER, y - TOTAL_BORDER));

	// An auxiliary raster must be used to supply the transparent border
	TRaster32P tex(aux->extract(0, 0, textureLx + TOTAL_BORDER_2 - 1, textureLy + TOTAL_BORDER_2 - 1));
	tex->clear();
	aux->extract(auxRect)->copy(ras->extract(rasRect));

	if (!premultiplied && NONPREM_BORDER > 0)
		locals::clearMatte_border(aux, TRANSP_BORDER - NONPREM_BORDER, TRANSP_BORDER);

	// Pass the raster into VRAM
	GLuint texId;
	glGenTextures(1, &texId);
	glBindTexture(GL_TEXTURE_2D, texId);

	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);	  // These must be used on a bound texture,
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);	  // and are remembered in the OpenGL context.
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); // They can be set here, no need for
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); // the user to do it.

	glPixelStorei(GL_UNPACK_ROW_LENGTH, tex->getWrap());
	glPixelStorei(GL_UNPACK_ALIGNMENT, 1);

	glTexImage2D(GL_TEXTURE_2D,
				 0,				   // one level only
				 GL_RGBA,		   // pixel channels count
				 tex->getLx(),	 // width
				 tex->getLy(),	 // height
				 0,				   // border size
				 TGL_FMT,		   // pixel format
				 GL_UNSIGNED_BYTE, // pixel data type
				 (GLvoid *)tex->getRawData());

	return texId;
}

//---------------------------------------------------------------------------------

void MeshTexturizer::Imp::allocateTextures(int groupIdx, const TRaster32P &ras, const TRaster32P &aux,
										   int x, int y, int textureLx, int textureLy,
										   bool premultiplied)
{
	TextureData *data = m_textureDatas[groupIdx].get();

	// Test the specified texture allocation
	if (testTextureAlloc(textureLx, textureLy)) {
		TPointD scale(data->m_geom.getLx() / (double)ras->getLx(),
					  data->m_geom.getLy() / (double)ras->getLy());
		TRectD tileGeom(
			TRectD(
				scale.x * (x - TOTAL_BORDER), scale.y * (y - TOTAL_BORDER),
				scale.x * (x + textureLx + TOTAL_BORDER), scale.y * (y + textureLy + TOTAL_BORDER)) +
			data->m_geom.getP00());

		GLuint texId = textureAlloc(ras, aux, x, y, textureLx, textureLy, premultiplied);

		TextureData::TileData td = {texId, tileGeom};
		data->m_tileDatas.push_back(td);

		return;
	}

	if (textureLx <= 1 && textureLy <= 1)
		return; // No texture can be allocated

	// The texture could not be allocated. Then, bisecate and branch.
	if (textureLx > textureLy) {
		int textureLx_2 = textureLx >> 1;
		allocateTextures(groupIdx, ras, aux, x, y, textureLx_2, textureLy, premultiplied);
		allocateTextures(groupIdx, ras, aux, x + textureLx_2, y, textureLx_2, textureLy, premultiplied);
	} else {
		int textureLy_2 = textureLy >> 1;
		allocateTextures(groupIdx, ras, aux, x, y, textureLx, textureLy_2, premultiplied);
		allocateTextures(groupIdx, ras, aux, x, y + textureLy_2, textureLx, textureLy_2, premultiplied);
	}
}

//---------------------------------------------------------------------------------

MeshTexturizer::TextureData *MeshTexturizer::Imp::getTextureData(int groupIdx)
{
	typedef MeshTexturizer::TextureData TextureData;

	// Copy tile datas container
	return m_textureDatas[groupIdx].get();
}

//******************************************************************************************
//    MeshTexturizer  implementation
//******************************************************************************************

MeshTexturizer::MeshTexturizer()
	: m_imp(new Imp)
{
}

//---------------------------------------------------------------------------------

MeshTexturizer::~MeshTexturizer()
{
}

//---------------------------------------------------------------------------------

int MeshTexturizer::bindTexture(const TRaster32P &ras, const TRectD &geom,
								PremultMode premultiplyMode)
{
	QWriteLocker locker(&m_imp->m_lock);

	// Backup the state of some specific OpenGL variables that will be changed throughout the code
	int row_length, alignment;
	glGetIntegerv(GL_UNPACK_ROW_LENGTH, &row_length);
	glGetIntegerv(GL_UNPACK_ALIGNMENT, &alignment);

	// Initialize a new texture data
	int dataIdx = m_imp->m_textureDatas.push_back(std::make_shared<TextureData>(geom));

	// Textures must have 2-power sizes. So, let's start with the smallest 2 power
	// >= ras's sizes.
	int textureLx = tcg::numeric_ops::GE_2Power((unsigned int)ras->getLx() + TOTAL_BORDER_2);
	int textureLy = tcg::numeric_ops::GE_2Power((unsigned int)ras->getLy() + TOTAL_BORDER_2);

	// We'll assume a strict granularity max of 512 x 512 textures
	textureLx = std::min(textureLx, 1 << 9);
	textureLy = std::min(textureLy, 1 << 9);

	// Allocate a suitable texture raster. The texture will include a transparent 1-pix border
	// that is needed to perform texture mapping with GL_CLAMP transparent wrapping
	TRaster32P tex(textureLx, textureLy);

	// Now, let's tile the specified raster. We'll start from the lower-left corner in case
	// the raster can be completely included in just one tile

	int lx = ras->getLx(), ly = ras->getLy();
	int tileLx = textureLx - TOTAL_BORDER_2, tileLy = textureLy - TOTAL_BORDER_2; // Texture size without border

	int xEntireCells = (lx - 1) / tileLx, yEntireCells = (ly - 1) / tileLy; // +1 so in case l == tileL, we get the remainder case

	int lastTexLx = tcg::numeric_ops::GE_2Power((unsigned int)(lx - xEntireCells * tileLx + TOTAL_BORDER_2));
	int lastTexLy = tcg::numeric_ops::GE_2Power((unsigned int)(ly - yEntireCells * tileLy + TOTAL_BORDER_2));

	int lastTileLx = lastTexLx - TOTAL_BORDER_2, lastTileLy = lastTexLy - TOTAL_BORDER_2;

	bool premultiplied = (premultiplyMode == PREMULTIPLIED);

	int i, j;
	for (i = 0; i < yEntireCells; ++i) {
		for (j = 0; j < xEntireCells; ++j)
			// Perform a (possibly subdividing) allocation of the specified tile
			m_imp->allocateTextures(dataIdx, ras, tex, j * tileLx, i * tileLy, tileLx, tileLy, premultiplied);

		m_imp->allocateTextures(dataIdx, ras, tex, j * tileLx, i * tileLy, lastTileLx, tileLy, premultiplied);
	}

	for (j = 0; j < xEntireCells; ++j)
		m_imp->allocateTextures(dataIdx, ras, tex, j * tileLx, i * tileLy, tileLx, lastTileLy, premultiplied);

	m_imp->allocateTextures(dataIdx, ras, tex, j * tileLx, i * tileLy, lastTileLx, lastTileLy, premultiplied);

	// Restore OpenGL variables
	glPixelStorei(GL_UNPACK_ROW_LENGTH, row_length);
	glPixelStorei(GL_UNPACK_ALIGNMENT, alignment);

	return dataIdx;
}

//---------------------------------------------------------------------------------

void MeshTexturizer::rebindTexture(int texId, const TRaster32P &ras, const TRectD &geom,
								   PremultMode premultiplyMode)
{
	QWriteLocker locker(&m_imp->m_lock);

	unbindTexture(texId);
	int newTexId = bindTexture(ras, geom, premultiplyMode);

	assert(texId == newTexId);
}

//---------------------------------------------------------------------------------

void MeshTexturizer::unbindTexture(int texId)
{
	QWriteLocker locker(&m_imp->m_lock);
	m_imp->m_textureDatas.erase(texId);
}

//---------------------------------------------------------------------------------

MeshTexturizer::TextureData *MeshTexturizer::getTextureData(int textureId)
{
	QReadLocker locker(&m_imp->m_lock);
	return m_imp->getTextureData(textureId);
}