/**
* This file is a part of the Cairo-Dock project
*
* Copyright : (C) see the 'copyright' file.
* E-mail    : see the 'copyright' file.
*
* 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 3
* 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, see <http://www.gnu.org/licenses/>.
*/

#include <stdlib.h>
#include <string.h>
#include <math.h>

#include "applet-struct.h"
#include "applet-star.h"

#define cd_icon_effect_load_star_texture(...) CD_APPLET_LOAD_LOCAL_TEXTURE ("star.png")


static gboolean init (Icon *pIcon, CairoDock *pDock, double dt, CDIconEffectData *pData)
{
	if (pData->pStarSystem != NULL)
		return TRUE;
	
	if (myData.iStarTexture == 0)
		myData.iStarTexture = cd_icon_effect_load_star_texture ();
	
	double fMaxScale = 1. + g_fAmplitude * pDock->fMagnitudeMax;
	CairoParticleSystem *pParticleSystem = cairo_dock_create_particle_system (myConfig.iNbStarParticles, myData.iStarTexture, pIcon->fWidth * pIcon->fScale, pIcon->fHeight * fMaxScale);
	g_return_val_if_fail (pParticleSystem != NULL, FALSE);
	pParticleSystem->dt = dt;
	pParticleSystem->bAddLuminance = TRUE;
	
	static double a = .4;
	static double epsilon = 0.1;
	double r = myConfig.iStarParticleSize;
	double fBlend;
	CairoParticle *p;
	int i;
	for (i = 0; i < myConfig.iNbStarParticles; i ++)
	{
		p = &pParticleSystem->pParticles[i];
		
		p->x = 2 * g_random_double () - 1;
		p->y = g_random_double ();
		p->z = 2 * g_random_double () - 1;
		p->fWidth = r*(p->z + 1)/2 * g_random_double ();
		p->fHeight = p->fWidth;
		
		p->vx = 0.;
		p->vy = 0.;
		
		p->iInitialLife = myConfig.iStarDuration / dt;
		p->iLife = p->iInitialLife * (g_random_double () + a) / (1 + a);
		
		if (myConfig.bMysticalStars)
		{
			p->color[0] = g_random_double ();
			p->color[1] = g_random_double ();
			p->color[2] = g_random_double ();
		}
		else
		{
			fBlend = g_random_double ();
			p->color[0] = fBlend * myConfig.pStarColor1[0] + (1 - fBlend) * myConfig.pStarColor2[0];
			p->color[1] = fBlend * myConfig.pStarColor1[1] + (1 - fBlend) * myConfig.pStarColor2[1];
			p->color[2] = fBlend * myConfig.pStarColor1[2] + (1 - fBlend) * myConfig.pStarColor2[2];
		}
		p->color[3] = 0.;  // on va gerer nous-mêmes la transparence.
		
		p->fOscillation = 0.;
		p->fOmega = 0.;
		
		p->fSizeFactor = 1.;
		p->fResizeSpeed = - 1. / myConfig.iStarDuration * dt;  // zoom 0 a la fin.
	}
	
	pData->pStarSystem = pParticleSystem;
	return TRUE;
}

static gboolean _update_star_system (CairoParticleSystem *pParticleSystem, CairoDockRewindParticleFunc pRewindParticle)
{
	static double a = .4;
	gboolean bAllParticlesEnded = TRUE;
	double x;
	CairoParticle *p;
	int i;
	for (i = 0; i < pParticleSystem->iNbParticles; i ++)
	{
		p = &(pParticleSystem->pParticles[i]);
		
		if (p->iLife > a * p->iInitialLife)
			p->color[3] = 0.;
		else
		{
			x = 1. * p->iLife / p->iInitialLife;
			p->color[3] = 1 - fabs (x - a/2) / (a/2);
		}
		
		p->fSizeFactor += p->fResizeSpeed;
		if (p->iLife > 0)
		{
			p->iLife --;
			if (pRewindParticle && p->iLife == 0)
			{
				pRewindParticle (p, pParticleSystem->dt);
			}
			if (bAllParticlesEnded && p->iLife != 0)
				bAllParticlesEnded = FALSE;
		}
	}
	return ! bAllParticlesEnded;
}

static void _rewind_star_particle (CairoParticle *p, double dt)
{
	double a = .2;
	p->x = 2 * g_random_double () - 1;
	p->y = g_random_double ();
	p->fSizeFactor = 1.;
	p->iInitialLife = myConfig.iStarDuration / dt;
	p->iLife = p->iInitialLife * (g_random_double () + a) / (1 + a);
}

static gboolean update (Icon *pIcon, CairoDock *pDock, gboolean bRepeat, CDIconEffectData *pData)
{
	if (pData->pStarSystem == NULL)
		return FALSE;
		
	gboolean bContinue = _update_star_system (pData->pStarSystem,
		(bRepeat ? _rewind_star_particle : NULL));
	pData->pStarSystem->fWidth = pIcon->fWidth * pIcon->fScale;
	
	double fMaxScale = 1. + g_fAmplitude * pDock->fMagnitudeMax;
	pData->fAreaWidth = pData->pStarSystem->fWidth + myConfig.iStarParticleSize * pDock->container.fRatio;  // demi-largeur des particules a droite et a gauche.
	pData->fAreaHeight = pIcon->fHeight * fMaxScale + myConfig.iStarParticleSize * pDock->container.fRatio;
	pData->fBottomGap = myConfig.iStarParticleSize * pDock->container.fRatio / 2;
	
	return bContinue;
}


static void render (CDIconEffectData *pData)
{
	if (pData->pStarSystem == NULL)
		return ;
	
	cairo_dock_render_particles (pData->pStarSystem);
}


static void free_effect (CDIconEffectData *pData)
{
	if (pData->pStarSystem != NULL)
	{
		cairo_dock_free_particle_system (pData->pStarSystem);
		pData->pStarSystem = NULL;
	}
}


void cd_icon_effect_register_stars (CDIconEffect *pEffect)
{
	pEffect->init = init;
	pEffect->update = update;
	pEffect->render = render;
	pEffect->free = free_effect;
}
