/* Asteroid element program   */
/* Based upon Earl Spillar's  planet.c */
/* 95/11/24  Robert R. Howell          */

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

double	cal_jd();				/* Convert date to JD   */
int		gtline();				/* Get line from input  */
void	trimstr();				/* Trim trailing spaces */

main()		/* Asteroid entry program */
{
	FILE *output_file;
	double epoch_jul_date, Omega, i, w, n;
	double a,e,equinox_jul_date,mag,semdia,M;
	char number[16], pnumber[18];	/* Short name or number, then same with quotes */
	char name[40],   pname[42];     /* Full name, then same with quotes. */
	char outfile[80],c='N';
	void convert();
		struct date{
		int year;
		int month;
		double day;
	}epoch,equinox;

	printf("Enter all angles in degrees\n");
	
	printf("\nEnter the equinox for the elements (yyyy mm dd.dd)");
	printf("\nThis will probably by 1950 1 1 or 2000  1  1 : ");
	scanf("%d %d %lf",&equinox.year,&equinox.month,&equinox.day);

	printf("Enter the epoch of the elements yyyy mm dd.dd: ");
	scanf("%d %d %lf",&epoch.year,&epoch.month,&epoch.day);

	/* Discard rest of line, in case limit caused end of input */
	while (c != EOF && c != '\n') c=getchar();

	printf("Enter the name of the asteroid: ");
	gtline(name, 40);
	name[39] = 0;			/* Make sure it is null terminated */
	
	printf("Enter the alternate name (such as 5a): ");
	gtline(number, 16);
	number[15] = 0;			/* Make sure it is null terminated */

	printf("Enter the magnitude (m) or 0.0: ");
	scanf("%lf",&mag);

	printf("Enter the diameter (km) or 0.0: ");
	scanf("%lf",&semdia);
	semdia = semdia / 2.;	/* Center diameter -- use semidiam. */

	printf("Enter the inclination (i): ");
	scanf("%lf",&i);

	printf("Enter the ascending node (Omega): ");
	scanf("%lf",&Omega);

	printf("Enter the argument of the perihelion (omega): ");
	scanf("%lf",&w);

	printf("Enter the mean distance (a): ");
	scanf("%lf",&a);

	printf("Enter the daily motion (n) or 0.0 to calculate: ");
	scanf("%lf",&n);

	printf("Enter the eccentricity (e): ");
	scanf("%lf",&e);

	printf("Enter the mean anomaly (M): ");
	scanf("%lf", &M);

	printf("Orbit catalog file where elements will be appended: ");
	scanf("%s",outfile);
	output_file=fopen(outfile,"a");
	
	equinox_jul_date = (double) cal_jd(equinox.year, equinox.month, equinox.day);
	epoch_jul_date   = (double) cal_jd(epoch.year,   epoch.month,   epoch.day  );

	/* Add quotes around short and full name */
	trimstr(number);
	strcpy(pnumber, "\'");
	strcat(pnumber, number);
	strcat(pnumber, "\'");
	
	trimstr(name);
	strcpy(pname, "\'");
	strcat(pname, name);
	strcat(pname, "\'");
	
	fprintf(output_file,"%-6s %-20s %9.4f %10.5f %9.5f %9.5f %11.7f\n",
		pnumber, pname, epoch_jul_date,i,Omega,w,a);
	fprintf(output_file,"%10.5f %10.7f %10.7f %9.4f %7.3f %7.3f\n",
		n,e, M, equinox_jul_date,mag,semdia); 

	fclose(output_file);
}


double cal_jd(yyyy, m, d)   /* Conversion routine */
int yyyy;
int m;
double d;
{
	double B,jul_date;

	if (m <= 2){
		m = m + 12;
		yyyy = yyyy - 1;
	}
	
	B = -15.0;	/* approximation only good between 1 March 1900 and */
				/* 28 February 2100                                  */
	
	jul_date = ((floor(365.25 * yyyy))+(floor(30.6001*(m+1)))+(B)+
	(1720996.5)+(d));
    
	return((double)jul_date);    
}


int gtline(s, lim)
char s[];
int	lim;
{
/* Get line & return length, or EOF if FIRST character IS EOF        */
/* The limit is the FULL LENGTH, including the final '\n'.           */
/* This is very similar to K&R 1st ed. getline, except I also return */
/* EOF, and I don't return the final '\n'.                           */
/* Because I return EOF, I'm implicitly assuming that EOF is not the */
/* same as any valid integer.  Usually it is -1.                     */

        int c, i;
		int	found_eol = 0;
        
		/* Input characters till limit or EOL */
		for (i=0; i<lim-1; i++) {
			c = getchar();
			if (c==EOF || c == '\n') break;
			s[i] = (char) c;
		}
        s[i] = '\0';
        
		/* Discard rest of line, in case limit caused end of input */
		while (c != EOF && c != '\n') c=getchar();
		
		if (i==0 && c==EOF)
                return (EOF);
        else
                return(i);
}

/* Eliminate trailing spaces on a string */
void	trimstr(str)
char str[];
{
		int slen;
		int	i;
		slen = strlen(str);
		for (i=slen-1; i>=0; i--)
			if (str[i] == ' ') str[i] = '\0';
}