<?php
/**
 * The middlware debug output system. A *real* or concrete output class shall
 * become registered with this middleware because the back-fall class will
 * become deprecated soon.
 *
 * @author		Roland Haeder <webmaster@ship-simu.org>
 * @version		0.0.0
 * @copyright	Copyright(c) 2007, 2008 Roland Haeder, this is free software
 * @license		GNU GPL 3.0 or any newer version
 * @link 		http://www.ship-simu.org
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
class DebugMiddleware extends BaseMiddleware {
	/**
	 * The concrete output instance
	 */
	private $outputHandler = null;

	/**
	 * An instance of this class
	 */
	private static $thisInstance = null;

	/**
	 * Private constructor
	 *
	 * @return	void
	 */
	protected function __construct () {
		// Call parent constructor
		parent::__construct(__CLASS__);

		// Set description
		$this->setObjectDescription("Debug-Ausgabe-Handler");

		// Create an unique ID
		$this->createUniqueID();

		// Set own instance
		self::$thisInstance = $this;
	}

	/**
	 * Create a new debug output system.
	 * If no output is given this class is currently being used for back-fall.
	 * This fall-back mechanism will become deprecated very soon.
	 *
	 * @param		$debuggerClass	     The class name which we shall use for
	 *							registering the *real* debug output
	 * @return	$debugInstance		An instance of this middleware class
	 */
	public final static function createDebugMiddleware ($debuggerClass) {
		// Create an instance if this middleware
		$debugInstance = new DebugMiddleware();

		// Is there a valid output handler provided?
		if ((!is_null($debuggerClass)) && (is_object($debuggerClass)) && (method_exists($debuggerClass, 'outputStream'))) {
			// Use the given output system
			$debugInstance->setOutputHandler($debuggerClass);
		} elseif ((!is_null($debuggerClass)) && (is_string($debuggerClass)) && (class_exists($debuggerClass))) {
			// A name for a debug output class has been provided so we try to get it
			$eval = sprintf("\$debuggerClass = %s::create%s();",
				$debuggerClass,
				$debuggerClass
			);

			// Run the constructed name
			@eval($eval);

			// Was this successfull?
			if ((is_object($debuggerClass)) && (method_exists($debuggerClass, "outputStream"))) {
				// Set this as output class
				$debugInstance->setOutputHandler($debuggerClass);
			} else {
				// No object or method is missing use fall-back
				throw new MissingMethodException(array($debuggerClass, 'outputStream'), self::EXCEPTION_MISSING_METHOD);
			}
		}

		// Return instance
		return $debugInstance;
	}

	/**
	 * Getter for an instance of this class
	 *
	 * @return	$thisInstance		An instance of this class
	 */
	public final static function getInstance() {
		return self::$thisInstance;
	}

	/**
	 * Setter for output handler
	 *
	 * @return	void
	 */
	public final function setOutputHandler ($outputHandler) {
		$this->outputHandler = $outputHandler;
	}

	/**
	 * This method shall send debug output which can be HTML code for the
	 * browser or debug lines for a log file, etc. to the registered debug
	 * output handler.
	 *
	 * @return	void
	 */
	public final function output ($outStream) {
		// Check if the output handler is valid
		if (is_null($this->outputHandler)) {
			// Debug output handler was not set
			throw new NullPointerException($this, self::EXCEPTION_IS_NULL_POINTER);
		} elseif (!is_object($this->outputHandler)) {
			// The debug output handler is not an object
			throw new NoObjectException($this->ouputHandler, self::EXCEPTION_IS_NO_OBJECT);
		} elseif (!method_exists($this->outputHandler, 'outputStream')) {
			// The required method outputStream() is missing
			throw new MissingMethodException(array($this->outputHandler, 'outputStream'), self::EXCEPTION_MISSING_METHOD);
		}

		// Is the output stream set
		if (empty($outStream)) {
			// Initialization phase
			return;
		}

		// Use the output handler
		$this->outputHandler->outputStream($outStream);
	}
}

// [EOF]
?>