/**
Logger class - add messages to log.
Usage
	logger::error('some error message');
	logger::notice('some notice message');
**/
class logger {

	const OUTPUT_DISABLED 	= 0; // 00
	const OUTPUT_TO_FILE 	= 1; // 01
	const OUTPUT_TO_SCREEN 	= 2; // 10

	//
	// define dynamic functions call (like 'fatal', 'error', 'info', etc).
	// 		logger::error('some error messages'); // the message will be added to 'error's array
	//
	// to get all the messages (array), just call the function without parameters:
	// 		$fatal_messages_array = logger::error();
	//
	public static function __callStatic($func, $args) {
		if (empty($args)) {
			return array_key_exists($func, self::$messages) ? self::$messages[$func] : array();
		} else {
			self::add_message($func, implode($args));
		}
	}

	// possibility to set the output to a file
	public static function set_output($output_type, $filename = null) {
		self::$output_destination = $output_type;
		self::$filename = $filename;
	}

	//**--------- PROTECTED -----------**//

	// logger output properties
	protected static $filename = null;
	protected static $output_destination = self::OUTPUT_TO_SCREEN;

	// logger messages
	protected static $messages = array();
	protected static function add_message($type, $msg) {
		$type = strtolower($type);

		// check the messages array for the type
		if (!array_key_exists($type, self::$messages)) {
			self::$messages[$type] = array();
		}

		// add the message to it's type
		self::$messages[$type][] = $msg;
		// output the message to a file / screen / both
		self::_output_message($type, $msg);
	}

	// write message to file in the next format:
	// [date] ([type]): [message]
	protected static function _output_message($type, $msg) {
		// generate the log message
		$log_message = self::_get_log_message($type, $msg);

		// check that the file name was defined, and there is a permission to write to file
		if (!is_null(self::$filename) && (self::$output_destination & self::OUTPUT_TO_FILE)) {
			@file_put_contents(self::$filename, $log_message, FILE_APPEND);
		}

		// check the permission to output to the screen (stdout)
		if (self::$output_destination & self::OUTPUT_TO_SCREEN) {
			echo $log_message, '<br/>';
		}
	}

	protected static function _get_log_message($type, $msg) {
		return date('d.m.Y H:i:s').' ('.$type.'): '.$msg."\r\n";
	}
}