/*
 * Stellarium
 * Copyright (C) 2004 Robert Spearman
 * Copyright (C) 2014 Marcos Cardinot
 *
 * 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, Suite 500, Boston, MA  02110-1335, USA.
 */

#include "LandscapeMgr.hpp"
#include "Meteor.hpp"
#include "MeteorMgr.hpp"
#include "SolarSystem.hpp"
#include "StelApp.hpp"
#include "StelCore.hpp"
#include "StelFileMgr.hpp"
#include "StelModuleMgr.hpp"
#include "StelPainter.hpp"
#include "StelTextureMgr.hpp"

#include <QSettings>

const double MeteorMgr::zhrToWsr = 1.6667f / 3600.f;

MeteorMgr::MeteorMgr(int zhr, int maxv )
	: ZHR(zhr)
	, maxVelocity(maxv)
	, flagShow(true)
{
	setObjectName("MeteorMgr");
}

MeteorMgr::~MeteorMgr()
{
	std::vector<Meteor*>::iterator iter;
	for(iter = active.begin(); iter != active.end(); ++iter)
	{
		delete *iter;
	}
	active.clear();
	Meteor::bolideTexture.clear();
}

void MeteorMgr::init()
{
	Meteor::bolideTexture = StelApp::getInstance().getTextureManager().createTextureThread(StelFileMgr::getInstallationDir()+"/textures/cometComa.png", StelTexture::StelTextureParams(true, GL_LINEAR, GL_CLAMP_TO_EDGE));

	setZHR(StelApp::getInstance().getSettings()->value("astro/meteor_rate", 10).toInt());
}

/*************************************************************************
 Reimplementation of the getCallOrder method
*************************************************************************/
double MeteorMgr::getCallOrder(StelModuleActionName actionName) const
{
	if (actionName==StelModule::ActionDraw)
	{
		return GETSTELMODULE(SolarSystem)->getCallOrder(actionName)+10.;
	}
	return 0;
}

void MeteorMgr::setZHR(int zhr)
{
	ZHR = zhr;
	emit zhrChanged(zhr);
}

int MeteorMgr::getZHR()
{
	return ZHR;
}

void MeteorMgr::setMaxVelocity(int maxv)
{
	maxVelocity = maxv;
}

void MeteorMgr::update(double deltaTime)
{
#ifdef _MSC_BUILD
	return;
#endif
	if (!flagShow)
	{
		return;
	}

	StelCore* core = StelApp::getInstance().getCore();

	double tspeed = core->getTimeRate()*86400;  // sky seconds per actual second
	if (!tspeed) { // is paused?
		return; // freeze meteors at the current position
	}

	deltaTime*=1000;
	// if stellarium has been suspended, don't create
	// huge number of meteors to make up for lost time!
	if (deltaTime > 500)
	{
		deltaTime = 500;
	}

	// step through and update all active meteors
	std::vector<Meteor*>::iterator iter;
	for (iter = active.begin(); iter != active.end(); ++iter)
	{
		if (!(*iter)->update(deltaTime))
		{
			delete *iter;
			iter = active.erase(iter);
			iter--;  // important!
		}
	}

	// only makes sense given lifetimes of meteors to draw when timeSpeed is realtime
	// otherwise high overhead of large numbers of meteors
	if (tspeed<0 || fabs(tspeed)>1.)
	{
		// don't start any more meteors
		return;
	}

	// determine average meteors per frame needing to be created
	int mpf = (int)((double)ZHR*zhrToWsr*deltaTime/1000.0 + 0.5);
	if (mpf<1)
	{
		mpf = 1;
	}

	for (int i=0; i<mpf; ++i)
	{
		// start new meteor based on ZHR time probability
		double prob = ((double)rand())/RAND_MAX;
		if (ZHR>0 && prob<((double)ZHR*zhrToWsr*deltaTime/1000.0/(double)mpf))
		{
			Meteor *m = new Meteor(core, maxVelocity);
			active.push_back(m);
		}
	}
}


void MeteorMgr::draw(StelCore* core)
{
	if (!flagShow)
	{
		return;
	}

	LandscapeMgr* landmgr = GETSTELMODULE(LandscapeMgr);
	if (landmgr->getFlagAtmosphere() && landmgr->getLuminance()>5)
	{
		return;
	}

	// step through and draw all active meteors
	StelPainter sPainter(core->getProjection(StelCore::FrameAltAz));
	std::vector<Meteor*>::iterator iter;
	for (iter = active.begin(); iter != active.end(); ++iter)
	{
		(*iter)->draw(core, sPainter);
	}
}