/* FCE Ultra - NES/Famicom Emulator
 *
 * Copyright notice for this file:
 *  Copyright (C) 2020 mjbudd77
 *
 * 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
 */
// GameViewer.cpp
//
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>

#ifdef WIN32
#include <windows.h>
#endif

#include <QApplication>
#include <QScreen>
#include <QWindow>
#include <QMouseEvent>

#if defined(QT_OPENGL_ES) || defined(QT_OPENGL_ES_2)
#include <GL/gl.h>
#endif

#include "Qt/nes_shm.h"
#include "Qt/fceuWrapper.h"
#include "Qt/ConsoleViewerGL.h"

extern unsigned int gui_draw_area_width;
extern unsigned int gui_draw_area_height;

ConsoleViewGL_t::ConsoleViewGL_t(QWidget *parent)
	: QOpenGLWidget( parent )
{
	view_width  = 256;
	view_height = 224;
	gltexture   = 0;
	devPixRatio = 1.0f;
	aspectRatio = 1.0f;
	aspectX     = 1.0f;
	aspectY     = 1.0f;
	linearFilter = false;
	forceAspect  = true;
	autoScaleEna = true;
	xscale = 2.0;
	yscale = 2.0;
	sx = 0; sy = 0;
	rw = 256;
	rh = 240;
	txtWidth  = 0;
	txtHeight = 0;
	mouseButtonMask = 0;
	reqPwr2 = true;
	textureType = GL_TEXTURE_2D;
	//textureType = GL_TEXTURE_RECTANGLE;

	setMinimumWidth( 256 );
	setMinimumHeight( 224 );
	setFocusPolicy(Qt::StrongFocus);

	localBufSize = (4 * GL_NES_WIDTH) * (4 * GL_NES_HEIGHT) * sizeof(uint32_t);

	localBuf = (uint32_t*)malloc( localBufSize );

	if ( localBuf )
	{
		memset( localBuf, 0, localBufSize );
	}

	linearFilter = false;

	if ( g_config )
	{
		int opt;
		g_config->getOption("SDL.OpenGLip", &opt );
		
		linearFilter = (opt) ? true : false;

		g_config->getOption ("SDL.AutoScale", &opt);

		autoScaleEna = (opt) ? true : false;

		g_config->getOption("SDL.XScale", &xscale);
		g_config->getOption("SDL.YScale", &yscale);

		g_config->getOption ("SDL.ForceAspect", &forceAspect);
	}
}

ConsoleViewGL_t::~ConsoleViewGL_t(void)
{
	if ( localBuf )
	{
		free( localBuf ); localBuf = NULL;
	}
}

void ConsoleViewGL_t::screenChanged( QScreen *screen )
{
	int w,h;

	devPixRatio = screen->devicePixelRatio();

	w = (int)(devPixRatio * width()  );
	h = (int)(devPixRatio * height() );

	view_width  = w;
	view_height = h;

	gui_draw_area_width = w;
	gui_draw_area_height = h;

	buildTextures();

	//printf("GL Ratio: %f  %ix%i\n", screen->devicePixelRatio(), w, h );
}

int ConsoleViewGL_t::init( void )
{
	QScreen *screen = NULL;

	if ( window() != NULL )
	{
		if ( window()->windowHandle() != NULL )
		{
			screen = window()->windowHandle()->screen();
		}
	}

	if ( screen != NULL )
	{
		devPixRatio = screen->devicePixelRatio();
		printf("GL Ratio: %f \n", screen->devicePixelRatio() );
	}
	return 0;
}

void ConsoleViewGL_t::reset(void)
{
	buildTextures();

	return;
}

int ConsoleViewGL_t::forcePwr2(int in)
{
	int out = 256;

	if ( in > 1024 )
	{
		out = 2048;
	}
	else if ( in > 512 )
	{
		out = 1024;
	}
	else if ( in > 256 )
	{
		out = 512;
	}
	else
	{
		out = 256;
	}
	return out;
}

void ConsoleViewGL_t::buildTextures(void)
{
	int w, h;

	if ( gltexture )
	{
		glDeleteTextures(1, &gltexture);
		gltexture=0;
	}

	if ( textureType == GL_TEXTURE_RECTANGLE )
	{
		//printf("Using GL_TEXTURE_RECTANGLE\n");
		glEnable(GL_TEXTURE_RECTANGLE);
		glGenTextures(1, &gltexture);
		//printf("Linear Interpolation on GL Texture: %s \n", linearFilter ? "Enabled" : "Disabled");

		glBindTexture( GL_TEXTURE_RECTANGLE, gltexture);

		glTexParameteri( GL_TEXTURE_RECTANGLE, GL_TEXTURE_MAG_FILTER, linearFilter ? GL_LINEAR : GL_NEAREST );
		glTexParameteri( GL_TEXTURE_RECTANGLE, GL_TEXTURE_MIN_FILTER, linearFilter ? GL_LINEAR : GL_NEAREST );
		glTexParameteri( GL_TEXTURE_RECTANGLE, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE );
		glTexParameteri( GL_TEXTURE_RECTANGLE, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE );

		txtWidth  = w = nes_shm->video.ncol;
		txtHeight = h = nes_shm->video.nrow;

		glTexImage2D( GL_TEXTURE_RECTANGLE, 0, 
				GL_RGBA8, w, h, 0,
						GL_BGRA, GL_UNSIGNED_BYTE, 0 );
	}
	else
	{
		//printf("Using GL_TEXTURE_2D\n");
		glEnable(GL_TEXTURE_2D);
		glGenTextures(1, &gltexture);
		//printf("Linear Interpolation on GL Texture: %s \n", linearFilter ? "Enabled" : "Disabled");

		glBindTexture( GL_TEXTURE_2D, gltexture);

		glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, linearFilter ? GL_LINEAR : GL_NEAREST );
		glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, linearFilter ? GL_LINEAR : GL_NEAREST );
		glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE );
		glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE );

		if ( reqPwr2 )
		{
			txtWidth  = w = forcePwr2( nes_shm->video.ncol );
			txtHeight = h = forcePwr2( nes_shm->video.nrow );
		}
		else
		{
			txtWidth  = w = nes_shm->video.ncol;
			txtHeight = h = nes_shm->video.nrow;
		}

		glTexImage2D( GL_TEXTURE_2D, 0, 
				GL_RGBA8, w, h, 0,
						GL_BGRA, GL_UNSIGNED_BYTE, 0 );
	}

	//printf("Texture Built: %ix%i\n", w, h);
}

void ConsoleViewGL_t::chkExtnsGL(void)
{

	int i, j, NumberOfExtensions = 0;
	char extName[256];
  	const GLubyte *c;

	glGetIntegerv(GL_NUM_EXTENSIONS, &NumberOfExtensions);

	//printf("Number of GL Externsions: %i \n", NumberOfExtensions );

  	c = glGetString( GL_VERSION );

	if ( c != NULL )
	{
		printf("GL Version: %s \n", c );
	}

  	c = glGetString( GL_EXTENSIONS );

	if ( c != NULL )
	{
		i=0; j=0;

		while ( c[i] != 0 )
		{
			j=0;
			while ( isspace(c[i]) ) i++;

			if ( isalnum(c[i]) || (c[i] == '_') )
			{
				while ( isalnum(c[i]) || (c[i] == '_') )
				{
					extName[j] = c[i]; i++; j++;
				}
				extName[j] = 0;
			}
			else
			{
				// Something is wrong if this is hit
				break;
			}

			if ( j > 0 )
			{
				//printf("%s\n", extName );

				if ( strcmp( extName, "GL_ARB_texture_rectangle" ) == 0 )
				{
					//printf("GL Has: %s\n", extName );
					textureType = GL_TEXTURE_RECTANGLE;
				}
				else if ( strcmp( extName, "GL_ARB_texture_non_power_of_two" ) == 0 )
				{
					//printf("GL Has: %s\n", extName );
					reqPwr2 = false;
				}
			}
			while ( isspace(c[i]) ) i++;

		}
	}

}

void ConsoleViewGL_t::initializeGL(void)
{
	//printf("initializeGL\n");

	initializeOpenGLFunctions();
	// Set up the rendering context, load shaders and other resources, etc.:
	//QOpenGLFunctions *gl = QOpenGLContext::currentContext()->functions();
	glClearColor(0.0f, 0.0f, 0.0f, 0.0f);

	chkExtnsGL();
	 //printf("GL Init!\n");

	 buildTextures();

	 connect(context(), &QOpenGLContext::aboutToBeDestroyed, this, &ConsoleViewGL_t::cleanupGL);
}

void ConsoleViewGL_t::cleanupGL(void)
{
	//printf("cleanupGL\n");
	// Make sure the context is current and then explicitly
	// destroy all underlying OpenGL resources.
	makeCurrent();

	 // Free GL texture
	 if (gltexture) 
	 {
	 	//printf("Destroying GL Texture\n");
	 	glDeleteTextures(1, &gltexture);
	 	gltexture=0;
	 }

	 doneCurrent();
}

void ConsoleViewGL_t::resizeGL(int w, int h)
{
	w = (int)( devPixRatio * w );
	h = (int)( devPixRatio * h );
	//printf("GL Resize: %i x %i \n", w, h );
	glViewport(0, 0, w, h);

	view_width  = w;
	view_height = h;

	gui_draw_area_width = w;
	gui_draw_area_height = h;

	buildTextures();
}

void ConsoleViewGL_t::setLinearFilterEnable( bool ena )
{
   if ( linearFilter != ena )
   {
      linearFilter = ena;

	   buildTextures();
   }
}

void ConsoleViewGL_t::setScaleXY( double xs, double ys )
{
	xscale = xs;
	yscale = ys;

	if ( forceAspect )
	{
		if ( xscale < yscale )
		{
			yscale = xscale;
		}
		else 
		{
			xscale = yscale;
		}
	}
}

void ConsoleViewGL_t::setAspectXY( double x, double y )
{
	aspectX = x;
	aspectY = y;

	aspectRatio = aspectY / aspectX;
}

void ConsoleViewGL_t::getAspectXY( double &x, double &y )
{
	x = aspectX;
	y = aspectY;
}

double ConsoleViewGL_t::getAspectRatio(void)
{
	return aspectRatio;
}

void ConsoleViewGL_t::transfer2LocalBuffer(void)
{
	int i=0, hq = 0;
	int numPixels = nes_shm->video.ncol * nes_shm->video.nrow;
	unsigned int cpSize = numPixels * 4;
 	uint8_t *src, *dest;

	if ( cpSize > localBufSize )
	{
		cpSize = localBufSize;
	}
	src  = (uint8_t*)nes_shm->pixbuf;
	dest = (uint8_t*)localBuf;

	hq = (nes_shm->video.preScaler == 1) || (nes_shm->video.preScaler == 4); // hq2x and hq3x

	if ( hq )
	{
		for (i=0; i<numPixels; i++)
		{
			dest[3] = 0xFF;
			dest[1] = src[1];
			dest[2] = src[2];
			dest[0] = src[0];

			src += 4; dest += 4;
		}
	}
	else
	{
		memcpy( localBuf, nes_shm->pixbuf, cpSize );
	}
}

void ConsoleViewGL_t::mousePressEvent(QMouseEvent * event)
{
	//printf("Mouse Button Press: (%i,%i) %x  %x\n", 
	//		event->pos().x(), event->pos().y(), event->button(), event->buttons() );

	mouseButtonMask = event->buttons();
}

void ConsoleViewGL_t::mouseReleaseEvent(QMouseEvent * event)
{
	//printf("Mouse Button Release: (%i,%i) %x  %x\n", 
	//		event->pos().x(), event->pos().y(), event->button(), event->buttons() );

	mouseButtonMask = event->buttons();
}

bool ConsoleViewGL_t::getMouseButtonState( unsigned int btn )
{
	return (mouseButtonMask & btn) ? true : false;
}

void  ConsoleViewGL_t::getNormalizedCursorPos( double &x, double &y )
{
	QPoint cursor;

	cursor = QCursor::pos();

	//printf("Global Cursor (%i,%i) \n", cursor.x(), cursor.y() );

	cursor = mapFromGlobal( cursor );

	//printf("Window Cursor (%i,%i) \n", cursor.x(), cursor.y() );

	x = (double)(cursor.x() - sx) / (double)rw;
	y = (double)(cursor.y() - sy) / (double)rh;

	if ( x < 0.0 )
	{
		x = 0.0;
	}
	else if ( x > 1.0 )
	{
		x = 1.0;
	}
	if ( y < 0.0 )
	{
		y = 0.0;
	}
	else if ( y > 1.0 )
	{
		y = 1.0;
	}
	//printf("Normalized Cursor (%f,%f) \n", x, y );
}

void ConsoleViewGL_t::paintGL(void)
{
	int texture_width  = nes_shm->video.ncol;
	int texture_height = nes_shm->video.nrow;
	int l=0, r=texture_width;
	int t=0, b=texture_height;

	float ixScale   = (float)nes_shm->video.xscale;
	float iyScale   = (float)nes_shm->video.yscale;
	float xscaleTmp = (float)(view_width)  / (float)(texture_width);
	float yscaleTmp = (float)(view_height) / (float)(texture_height);

	xscaleTmp *= ixScale;
	yscaleTmp *= iyScale;

	if ( forceAspect )
	{
		if ( xscaleTmp < yscaleTmp )
		{
			yscaleTmp = xscaleTmp;
		}
		else 
		{
			xscaleTmp = yscaleTmp;
		}
	}

	if ( autoScaleEna )
	{
		xscale = xscaleTmp;
		yscale = yscaleTmp;
	}
	else
	{
		if ( xscaleTmp > xscale )
		{
			xscaleTmp = xscale;
		}
		if ( yscaleTmp > yscale )
		{
			yscaleTmp = yscale;
		}
	}

	rw=(int)((r-l)*xscaleTmp/ixScale);
	rh=(int)((b-t)*yscaleTmp/iyScale);

	if ( forceAspect )
	{
		int iw, ih, ax, ay;

		ax = (int)(aspectX+0.50);
		ay = (int)(aspectY+0.50);

		iw = rw * ay;
		ih = rh * ax;
		
		if ( iw > ih )
		{
			rh = (rw * ay) / ax;
		}
		else
		{
			rw = (rh * ax) / ay;
		}

		if ( rw > view_width )
		{
			rw = view_width;
			rh = (rw * ay) / ax;
		}

		if ( rh > view_height )
		{
			rh = view_height;
			rw = (rh * ax) / ay;
		}
	}

	if ( rw > view_width ) rw = view_width;
	if ( rh > view_height) rh = view_height;

	sx=(view_width-rw)/2;   
	sy=(view_height-rh)/2;

	glViewport(sx, sy, rw, rh);

	glLoadIdentity();
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	glMatrixMode(GL_MODELVIEW);
	glOrtho( 0.0,  rw,  0.0,  rh,  -1.0,  1.0);

	glDisable(GL_DEPTH_TEST);
	glClearColor( 0.0, 0.0f, 0.0f, 0.0f);	// Background color to black.
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);


	if ( textureType == GL_TEXTURE_RECTANGLE )
	{
		glDisable(GL_TEXTURE_2D);
		glEnable(GL_TEXTURE_RECTANGLE);
		glBindTexture(GL_TEXTURE_RECTANGLE, gltexture);
	
		glTexSubImage2D(GL_TEXTURE_RECTANGLE, 0,
			  	0, 0, texture_width, texture_height,
					GL_BGRA, GL_UNSIGNED_BYTE, localBuf );
	
		glBegin(GL_QUADS);
		glTexCoord2f( l, b); // Bottom left of picture.
		glVertex2f( 0.0, 0.0f);	// Bottom left of target.
	
		glTexCoord2f(r, b);// Bottom right of picture.
		glVertex2f( rw, 0.0f);	// Bottom right of target.
	
		glTexCoord2f(r, t); // Top right of our picture.
		glVertex2f( rw,  rh);	// Top right of target.
	
		glTexCoord2f(l, t);  // Top left of our picture.
		glVertex2f( 0.0f,  rh);	// Top left of target.
		glEnd();
	}
	else
	{
		float x1, y1, x2, y2;

		x1 = 0.0; y1 = 1.0;
		x2 = 1.0; y2 = 0.0;

		x2 = (float)texture_width  / (float)txtWidth;
		y1 = (float)texture_height / (float)txtHeight;

		glDisable(GL_TEXTURE_RECTANGLE);
		glEnable(GL_TEXTURE_2D);
		glBindTexture(GL_TEXTURE_2D, gltexture);
	
		glTexSubImage2D(GL_TEXTURE_2D, 0,
			  	0, 0, texture_width, texture_height,
					GL_BGRA, GL_UNSIGNED_BYTE, localBuf );
	
		glBegin(GL_QUADS);
		glTexCoord2f( x1, y1); // Bottom left of picture.
		glVertex2f( 0.0, 0.0f);	// Bottom left of target.
	
		glTexCoord2f( x2, y1);// Bottom right of picture.
		glVertex2f( rw, 0.0f);	// Bottom right of target.
	
		glTexCoord2f( x2, y2); // Top right of our picture.
		glVertex2f( rw,  rh);	// Top right of target.
	
		glTexCoord2f( x1, y2);  // Top left of our picture.
		glVertex2f( 0.0f,  rh);	// Top left of target.
		glEnd();
	}
	glDisable(GL_TEXTURE_2D);
	glDisable(GL_TEXTURE_RECTANGLE);

	nes_shm->render_count++;
	 //printf("Paint GL!\n");
}
