#include "elastro.h"


/*
/////////////////////////////////////////////////////
///// calculations used for guiding /////////////////
/////////////////////////////////////////////////////



// calculates sector of current position of arcsecons
// returns:

// north
//  0  = az   0 -  90  alt >=  pole
//  1  = az   0 -  90  alt <   pole

//  2  = az 270 - 360  alt >=  pole
//  3  = az 270 - 360  alt <   pole

// south
// 10  = az  90 - 180
// 12  = az 180 - 270

// az,alt, and altnorth must be given in arcseconds
// altnorth must be the altitude position of the sky-northpole
// normally this should be the latitude
*/
int gcalcSector( double az, double alt, double altnorth )
{
	int 	south;
	int 	upper;
	int     sector;
	
	
	upper = 1;
	if( ( az >= ARC90 ) && ( az < ARC270 ) ){
		south = 1;
	}
	else {
		south = 0;
		if( alt < altnorth ) {
			upper = 0;
		}
	}

	if( south ) {
		sector = 10;
		if( ( az >= ARC180 ) && ( az < ARC270 ) ){
			sector = 12;
		}
		return( sector );
	}

	sector = 0;
	if( ( az >= ARC270 ) && ( az <= ARC360 ) ){
		sector = 2;
	}

	if( ! upper ){
		sector++;
	}

	return( sector );
}





/*
// dependend of previous calculated sector
// the direction of the az-motor will be calculated
// returns 1 if az should be turn left,
// otherwise 0
*/
int gcalcAzDirLeft( int sector )
{
	switch( sector ) {
		case 0:  return(1);
		case 2:  return(1);
		default: break;
	}
	
	return(0);
}




/*
// dependend of previous calculated sector
// the direction of the alt-motor will be calculated
// returns 1 if tubus should be turn down,
// otherwise 0
*/
int gcalcAltDirDown( int sector )
{
	switch( sector ) {
		case 2:  return(1);
		case 3:  return(1);
		case 12: return(1);
		default: break;
	}	
	return(0);
}
	

/*
// dependend of previous calculated sector
// the direction of the fr-motor will be calculated
// returns 1 if fr should be turn left,
// otherwise 0
*/
int gcalcFrDirLeft( int sector )
{
	switch( sector ) {
		case 0:  return(1);
		case 1:  return(1);
		case 2:  return(1);
		case 3:  return(1);
		default: break;
	}	
	return(0);
}


/*
// calculates radius of current koordinates ( to north, or southpole ) and
// returnes it as number of arcseconds
// az,alt,altnorth must be given as arcseconds
// altnorth must be the altitude of current sky-northpole
// ( must be latitude )
// if koordinates looks to south, the radius to the southpole will be returned.
*/
double gcalcR( double az, double alt,double altnorth, int sector )
{
	double x,y,altsouth;
	
	altsouth = altnorth + ARC180;
	
	x  = 0;
	y  = 0;
	
	switch( sector ) {
	
		case 0:
			x = az;
			y = alt - altnorth;		
			break;
		case 1:
			x = az;
			y = altnorth - alt;		
			break;
		case 2:
			x = ARC360 - az;
			y = alt - altnorth;
			break;

		case 3:
			x = ARC360 - az;
			y = altnorth - alt;
			break;
			
		case 10:
			x = ARC180 - az;
			y = altnorth + alt;
			break;

		case 12:
			x = ARC270 - az;
			y = altnorth + alt;
			break;
	
		default:
			return( -1 );
			break;
	}

	return( sqrt( ( x * x ) + ( y * y  ) ) );
}







/*

			
	sector	= gcalcSector( az, alt );
	
	if( gcalcAzDirLeft( sector ) ) {
		//go left, otherwise right
	}
	if( gcalcAltDirDown( sector ) ) {
		//go down, otherwise up
	}
	if( gcalcFrDirLeft( sector ) ) {
		//rotate left, otherwise right
	}
	
*/