#!/usr/bin/perl -w

#    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 3 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, see <http://www.gnu.org/licenses/>.

# This program, predict-format, is written by Jeffrey Hundstad <jeffrey@hundstad.net> Copyright (c) 2010


use warnings;
use strict;
use Time::Local;

if (!defined($ARGV[0])) {
	die "Usage: $0 <satellite name>\n";
}

my $tsat = $ARGV[0];

my $begtime = time();

my ($mon,$year,$isdst) = (localtime($begtime))[4,5,8];
$begtime = timelocal(0, 0, 0, 1, $mon, $year);
my $endmon = $mon+1;
my $endyear = $year;
if ($endmon > 12) {
	$endmon = 1;
	$endyear++;
}
my $endtime = timelocal(0, 0, 0, 1, $endmon, $endyear);

($mon,$year,$isdst) = (localtime($begtime))[4,5,8];
my $tz = ($isdst) ? 'CST' : 'DST';

print "Date ($tz)          Time ($tz) of        Duration   Azimuth at  Peak Vis Orbit\n";
print "                AOS      MEL      LOS     of Pass  AOS MEL LOS  Elev\n";

my @days=('Sun','Mon','Tue','Wed','Thu','Fri','Sat');
my @months=('Jan','Feb','Mar','Apr','May','Jun','Jul','Aug','Sep','Oct','Nov','Dec');

my $lastdate = '';
while ($begtime <= $endtime) {
	open (PREDICT, "predict -p $tsat $begtime |") or die "\nPlease install Predict, http://www.qsl.net/kd2bd/predict.html\n\n";
	last if (eof(PREDICT));
	($begtime,$lastdate) = nextpass($lastdate);
	$begtime += 60;
}
exit;

sub nextpass {
	my $lastdate = shift;
	my ($taos,$tmel,$tlos);
	my ($aaos,$amel,$alos);
	my ($vaos,$vmel,$vlos);
	my ($oaos,$omel,$olos);
	my $pe;
	my $first = 1;
	my ($sepoc,$sday,$sdate,$stime,$selev,$sazim,$sphas,$slat,$slon,$srange,$sorbit,$sv);
	while (<PREDICT>) {
		chomp;
		($sepoc,$sday,$sdate,$stime,$selev,$sazim,$sphas,$slat,$slon,$srange,$sorbit,$sv) = split(/ +/,$_);
		if ($first) {
			$taos = $sepoc;
			$aaos = $sazim;
			$vaos = $sv;
			$oaos = $sorbit;
			$tmel = 0;
			$amel = 0;
			$vmel = 0;
			$pe = $selev;
			$first = 0;
		} elsif ($selev > $pe) {
			$tmel = $sepoc;
			$amel = $sazim;
			$vmel = $sv;
			$omel = $sorbit;
			$pe = $selev
		}
	}
	$tlos = $sepoc;
	$alos = $sazim;
	$olos = $sorbit;
	$vlos = $sv;

	my $newdate = ftime($taos,'d');
	if ($newdate ne $lastdate) {
		$lastdate = $newdate;
		print "\n" . $newdate . ' ';
	} else {
		print '             ';
	}
	print ftime($taos) . ' ' . ftime($tmel) . ' ' . ftime($tlos) . '  ';
	print timeform($tlos - $taos) . '  ';
	printf "%3d %3d %3d  ", $aaos,$amel,$alos;
	printf "%2d", $pe;
	print (($pe < 40) ? '   ' : '*  ');

	print dn($vaos) . dn($vmel) . dn($vlos) . ' ';
	print "$oaos\n";

	return ($tlos,$lastdate);
}

sub timeform {
	my $insec = shift;
	my $hours = int($insec / 3600);
	$insec -= $hours * 3600;
	my $min = int($insec / 60);
	$insec -= $min * 60;
	return sprintf "%02d:%02d:%02d", $hours,$min,$insec;
}

sub dn {
	my $sv = shift;
	my $daynight;
	if ($sv eq '*') {
		$daynight = 'D';
	} elsif ($sv eq '+') {
		$daynight = 'V';
	} else {
		$daynight = 'N';
	}
	return $daynight;
}


sub ftime {
	my $sepoc = shift;
	my $type = shift;
        my ($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst) = localtime($sepoc);
	$year -= 100;
	my $localtime = sprintf("%02d:%02d:%02d",$hour,$min,$sec);
	my $localdate = sprintf("%3s  %02d%3s%02d",$days[$wday],$mday,$months[$mon],$year);
	if (!defined($type)) {
		return $localtime;
	} elsif ($type eq 'b') {
		return ($localdate,$localtime);
	} else {
		return $localdate;
	}
}