sub new {
	my $class_name = shift;
	my $self = {};	
	$output_file = shift;	
	$append = shift;
	$file_handle = undef ;
	
	
        bless ($self,$class_name);
        bless ($self);
        return $self;     
}

# opens log file for writing
# (no argument) will be called from first call to &message if not called from outside
sub start{

	my $now = &get_timestamp;
	print "opening $output_file\n"; 
	if (uc($append)eq'APPEND') {
		open ($file_handle,">>$output_file")  || open ($file_handle,">$output_file") || die "Can't open $output_file $!";
	}else{
		open ($file_handle,">$output_file") || die "Can't open $output_file $!";
	}

	print $file_handle "Started logging at $now\n";
	print $file_handle "Logging to $output_file\n";	
	print $file_handle "\n";
}

#log a message 
# argument <a status>, <a text message>
sub message{

	#run start subprocedure if file not already open
	&start if (!$file_handle);
	
	my $status = $_[1];	
	my $text = $_[2];
	print $file_handle "$status : $text\n" ;
	#$message_number++;
}

#close log
# (no argument)
sub finish{

	#run start subprocedure if file not already open
	if (!$file_handle){
		&start;	
	}else{
		my $now = &get_timestamp;
		print $file_handle "\n";
		print $file_handle "Finished logging at $now\n";
		print $file_handle "-------------------------------------\n";
		#close ($file_handle);
	}

}