/*
Program to generate a regular grid of points.
*/


#include <stdio.h>
#include <string.h>
#include <time.h>
#include "../lib/logger.h"
#include "../lib/version.h"
#include "../lib/parsers.h"


/* Print the help message for tessgrd program */
void print_tessgrd_help()
{
    printf("Usage: tessgrd [PARAMS] [OPTIONS]\n\n");
    printf("Make a regular grid of points.\n\n");
    printf("All units either SI or degrees!\n\n");
    printf("Output:\n");
    printf("  Printed to standard output (stdout) in the format:\n");
    printf("    lon1    lat1    height\n");
    printf("    lon2    lat1    height\n");
    printf("    ...     ...     ...\n");
    printf("    lonNLON lat1    height\n");
    printf("    lon1    lat2    height\n");
    printf("    ...     ...     ...\n");
    printf("    ...     ...     ...\n");
    printf("    lonNLON latNLAT height\n\n");
    printf("  * Comments about the provenance of the data are inserted into\n");
    printf("    the top of the output\n\n");
    printf("Parameters:\n");
    printf("  -r           W/E/S/N: Bounding region of the grid.\n");
    printf("  -b           NLON/NLAT: Number of grid points in the\n");
    printf("               longitudinal and latitudinal directions.\n");
    printf("  -z           HEIGHT: Height of the grid with respect to the\n");
    printf("               mean Earth radius.\n");
    printf("  -h           Print instructions.\n");
    printf("  --version    Print version and license information.\n");
    printf("\nOptions:\n");
    printf("  -v           Enable verbose printing to stderr.\n");
    printf("  -lFILENAME   Print log messages to file FILENAME.\n");
    print_copyright();
}


/** Main */
int main(int argc, char **argv)
{
    TESSGRD_ARGS args;
    char progname[] = "tessgrd";
    int rc;
    FILE *logfile = NULL;
    time_t rawtime;
    struct tm * timeinfo;
    double dlon, dlat;
    double lon, lat;
    /* Keep track of how many printed. Used to check if produced right amount */
    int lons = 0, lats = 0, total = 0;

    log_init(LOG_INFO);

    rc = parse_tessgrd_args(argc, argv, &args, &print_tessgrd_help);
    if(rc == 2)
    {
        return 0;
    }
    if(rc == 1)
    {
        log_warning("Terminating due to bad input");
        log_warning("Try '%s -h' for instructions", progname);
        return 1;
    }
    /* Set the appropriate logging level and log to file if necessary */
    if(!args.verbose)
    {
        log_init(LOG_WARNING);
    }
    if(args.logtofile)
    {
        logfile = fopen(args.logfname, "w");
        if(!logfile)
        {
            log_error("unable to create log file %s", args.logfname);
            log_warning("Terminating due to bad input");
            log_warning("Try '%s -h' for instructions", progname);
            return 1;
        }
        log_tofile(logfile, LOG_INFO);
    }

    /* Print standard verbose */
    log_info("%s (Tesseroids project) %s", progname, tesseroids_version);
    time(&rawtime);
    timeinfo = localtime(&rawtime);
    log_info("(local time) %s", asctime(timeinfo));

    /* CREATE THE GRID AND PRINT IT TO STDOUT */
    log_info("Generating regular grid in region: %g W / %g E / %g S / %g N",
             args.w, args.e, args.s, args.n);
    log_info("Grid size: %d lon X %d lat = %d points in total", args.nlon,
             args.nlat, args.nlon*args.nlat);

    /* Define the grid spacing. used nlon or nlat -1 because the borders should
       be in the grid */
    dlon = (args.e - args.w)/(args.nlon - 1);
    dlat = (args.n - args.s)/(args.nlat - 1);
    log_info("Grid spacing: %.10f lon / %.10f lat", dlon, dlat);

    /* Print a header on the output with provenance information */
    printf("# Grid generated with %s %s:\n", progname, tesseroids_version);
    printf("#   local time: %s", asctime(timeinfo));
    printf("#   args: -r%g/%g/%g/%g -b%d/%d -z%g\n", args.w, args.e, args.s,
           args.n, args.nlon, args.nlat, args.height);
    printf("#   grid spacing: %.10f lon / %.10f lat\n", dlon, dlat);
    printf("#   total %d points\n", args.nlon*args.nlat);

    /* Make the grid points. Print lon first as x */
    for(lat = args.s; lat <= args.n; lat += dlat)
    {
        lons = 0;
        for(lon = args.w; lon <= args.e; lon += dlon)
        {
            printf("%.15g %.15g %.15g\n", lon, lat, args.height);
            lons++;
            total++;
        }
        /* Sometimes prints one less because of rounding errors */
        if(lons != args.nlon)
        {
            printf("%.15g %.15g %.15g\n", lon, lat, args.height);
            lons++;
            total++;
        }
        lats++;
        printf("\n"); /* To ease plotting in Gnuplot */
    }
    /* Sometimes prints one less because of rounding errors */
    if(lats != args.nlat)
    {
        lons = 0;
        for(lon = args.w; lon <= args.e; lon += dlon)
        {
            printf("%.15g %.15g %.15g\n", lon, lat, args.height);
            lons++;
            total++;
        }
        if(lons != args.nlon)
        {
            printf("%.15g %.15g %.15g\n", lon, lat, args.height);
            lons++;
            total++;
        }
    }
    if(total != args.nlat*args.nlon)
    {
        log_warning("%d total points made instead of required %d", total,
                    args.nlat*args.nlon);
    }
    log_info("Total points generated: %d", total);
    /* Clean up */
    if(args.logtofile)
        fclose(logfile);
    return 0;
}