#!/usr/bin/perl

use strict;
use warnings;

my $cvs_header_line = '\$' . 'CVSHeader';

foreach my $arg (@ARGV) {
	my ($conf_file, $dist_file);
	
	if ($arg =~ /^(.*)\.dist$/) {
		$conf_file = $1;
		$dist_file = $arg;
	} else {
		$conf_file = $arg;
		$dist_file = "$arg.dist";
	}
	
	my $conf_version = cvs_version($conf_file)
		or die "couldn't find CVS version in $conf_file\n";
	my $dist_version = cvs_version($dist_file)
		or die "couldn't find CVS version in $dist_file\n";
	
	if ($conf_version eq $dist_version) {
		print "$conf_file is up-to-date at version $conf_version.\n";
		next;
	}
	
	#print "conf_version=$conf_version dist_version=$dist_version\n";
	system "cvs diff -r '$conf_version' -r '$dist_version' '$dist_file'"
		. "| patch '$conf_file'";
}

sub cvs_version {
	my ($file) = @_;
	open my $fh, "<", $file or die "couldn't open $file for reading: $!\n";
	my $line;
	while (my $line = <$fh>) {
		if ($line =~ /$cvs_header_line.*?(1(?:\.\d+)+)/) {
			return $1;
		}
	}
}