/* -*- c++ -*-
 * Copyright ©2008 Hugo Mills <hugo@carfax.org.uk>
 *
 * This software is distributed under the terms of the GNU GPL v3
 * For more information on the GPL, see the file COPYING or 
 * visit http://www.gnu.org/
 *
 * This software is distributed without warranty
 */

#include "xforbit_sunpos.h"
#include "magellan/xfsphere.h"

extern "C" PluginInfo* getmodules(int i)
{
	if(i==0)
	{
		PluginInfo_Orbit* pi = new PluginInfo_Orbit();

		pi->name = "Sun Position Orbit";
		pi->author = "Hugo Mills";
		pi->copyright = "©2008 Hugo Mills";
		pi->version = 0x00001;
		pi->parser = XfOrbit_Sunpos::parser;
		return pi;
	}
	else
		return NULL;
}

XfOrbit* XfOrbit_Sunpos::parser(
	ConfigLexer* lex,
	const std::string& type,
	const std::string& subtype
	)
{
	if(type != "sunpos")
		return NULL;
		
	long timeorigin = 0;

	while(!lex->eos()) {
		if(lex->type() == TOKEN && lex->value() == "time-origin")
		{
			lex->next();
			if(lex->type() == TOKEN && lex->value() == "now")
			{
				timeorigin = time(NULL);
				lex->next();
				if(lex->type() != CHAR || lex->value() != ";")
					// Syntax error -- missing semicolon?
					throw(MissingSemicolon(lex));
			}
			/* else if(lex->type() == STRING)
			   {
			   // Parse date and set timeorigin
			   lex->next();
			   } */
			else if(lex->type() == INTEGER)
			{
				// Parse date and set timeorigin
				timeorigin = time(NULL);
				int offset = atoi(lex->value().c_str());
				timeorigin += offset;
				lex->next();
				if(lex->type() != CHAR || lex->value() != ";")
					// Syntax error -- missing semicolon?
					throw(MissingSemicolon(lex));
			}
			else
				throw(UnknownConfigToken(lex));
		}
		else
			throw(UnknownConfigToken(lex));
	}
	
	return new XfOrbit_Sunpos(timeorigin);
}

XfOrbit_Sunpos::XfOrbit_Sunpos(long t)
	: XfOrbit(),
	  timeorigin(t)
{
	reset();
}

void XfOrbit_Sunpos::reset(void)
{
	time_t tm = time(NULL);
	struct tm now;
	gmtime_r(&tm, &now);

	// One day is 86400 seconds
	double theta = -(now.tm_hour * 3600.0
					 + now.tm_min * 60.0
					 + now.tm_sec)
		/ 43200.0 * M_PI;
	theta += M_PI;
	
	// Really awful approximation.
	// Offset by 80 days, as that's March 21st
	// Assume 365.25 days in the year
	double phi = sin( (now.tm_yday - 80) / 365.25) * (degrad(23.5));

	setmatrices(theta, phi);
}