=head1 DESCRIPTION

Check distances of waypoints ...

=cut

$usage = "Usage:\n\tperl -w $0 waypoint-file name_col col1 col2 [ --dskip pattern ] [ data-file ]";

=head1 COMMAND LINE PARAMETERS

 perl -w ... waypoint-file name_col col1 col2 [ --dskip pattern ] [ data-file ]

 waypoint-file has one waypoint per line,
 in the format:
 	name[tab]coord1[tab]coord2
 lines beginning with "#" are ignored.

 data-file contains the tab-separated data;
 if not given, standard input is used.
 This file should have waypoint names in column name_col.
 The coordinates to be checked are at columns col1 and col2, respectively.
 Lines in the input which contain the pattern,
 given on the command line by "--dskip pattern", are ignored.

=cut

sub errx {
	print STDERR $_[0], "\n";
	exit 1;
}

sub errp {
	print STDERR $_[0], "\n";
}

##
## get the command-line parameters
##
$wfile = shift or &errx($usage);
$name_col = shift or &errx($usage);
$col1 = shift or &errx($usage);
$col2 = shift or &errx($usage);
$debug = 0;
$dskip_pattern = qr/^Region|^\s*$/i;
while (@ARGV+0 && $ARGV[0] =~ /^-/) {
	my $aa = $ARGV[0];
	last if $aa eq '--';
	if ($aa eq '--dskip') {
		$dskip_pattern = $ARGV[1];
		shift @ARGV;
		shift @ARGV;
	}
	elsif ($aa eq '-d') {
		$debug = 1;
		shift @ARGV;
	} else {
		print STDERR "bad arg: $aa\n";
		&errx($usage);
	}
}
# $dfile = shift or &errx($usage);

##
## read in the waypoints
##
open(WFILE, "< $wfile") or &errx("cannot open $wfile: $!");

$format = "simple";

%wp = ();
WPLINE: while (<WFILE>) {
	#print STDERR "WPLINE: $_";
	chomp;
       	if ($format eq 'simple')
       	{
		next WPLINE if /^#/;
		@f = split /\t/;
		($name,$aaa,$bbb) = ($f[0],$f[1],$f[2]);
		print STDERR ":$name:", "\n" if $debug;
	}
	$wp{$name} = [ $aaa, $bbb ];
}
close(WFILE);

sub distance {
	$a = shift;
	$b = shift;
	$d = shift;
	$e = shift;
	return sqrt(($a-$d)**2 + ($b-$e)**2);
}

##
## filter the tab-separated data
##
$do_chomp = 1;
DLINE: while (<>) {
	chomp if $do_chomp;
	@f = split "\t";
	if ( defined($dskip_pattern) && $_ =~ $dskip_pattern ) {
		#print $_;
		next DLINE;
	}
	$wpname = $f[$name_col];

	# project-specific <<<
	#
	$wpname =~ s/^#//;
	$wpname =~ s/\s+//g;
	$wpname =~ s/-/_/g;

	$wp = $wp{$wpname};
	if (! ref $wp) {
		errp "unknown waypoint '$wpname' at row $.   ****" ;
		next DLINE;
	};
	$aaa = $$wp[0];
	$bbb = $$wp[1];

	printf STDERR "line $.: wp=$wpname, distance is %s ", $dist = distance($f[$col1], $f[$col2], $aaa, $bbb);
	printf STDERR " *****" if $dist > 100;
	print STDERR "\n";

	#print join("\t", @f);
	#print "\n" if $do_chomp;
}