package logscan;
BEGIN {}

use Tie::File;

sub scan {
	_scan(@_, sub {lognum($b) <=> lognum($a)}, sub {
		local ($fname, $apply) = @_;
		open(LOG, $fname) or die "Can't open $fname: $!";;
		while (<LOG>) {
			if (not &$apply($_)) {
				close(LOG);
				return 0;
			}
		}
		close(LOG);
		return 1;
	});
}

sub scan_backwards {
	_scan(@_, sub {lognum($a) <=> lognum($b)}, sub {
		local ($fname, $apply) = @_;
		
		# This approach is slower but requires a fixed amount of memory
		# indepening of the size of the log file.
		# 2:02, up to 16Mb (logfiles size: 64Mb )
		tie(@lines, "Tie::File", $fname, mode => 0) or die "Can't tie $fname: $!";
		$max_lines = $#lines;
		for ($i = $max_lines; $i; $i--) {
			if (not &$apply($lines[$i])) {
				return 0;
			}
		}

		# This approach is faster but requires at least as much available
		# memory as the size of the log file.
		# 1:02, up to 150Mb (logfiles size: 64Mb )
#		open(LOG, $fname) or die "Can't open $fname: $!";;
#		@lines = reverse <LOG>;
#		foreach $line (@lines) {
#			chomp $line;
#			if (not &$apply($line)) {
#				close(LOG);
#				return 0;
#			}
#		}
#		close(LOG);

		return 1;
	});
}

sub _scan {
	local ($logname, $apply, $sort, $scan_file) = @_;

	opendir(DIRHANDLE, ".") || die "Cannot opendir: $!";

	OUTER: foreach $fname (sort $sort readdir(DIRHANDLE))
	{
		if ($fname =~ /^$logname\.log(.[0-9]+)?$/) 
		{
			print "> $fname\n";
			last OUTER if (not &$scan_file($fname, $apply));
		}
	}
	closedir(DIRHANDLE);
}

sub lognum {
	local $fname = shift;
	if ($fname =~ /\.([0-9]+)$/) {
		return $1;
	}
	return 0;
}

return 1;
END {}