<?php
  /**
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements. See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to You under the Apache License, Version 2.0
   * (the "License"); you may not use this file except in compliance with
   * the License. You may obtain a copy of the License at
   *
   *	   http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   *
   * @package log4php
   */
  
  /**
   * This class is specialized in retrieving loggers by name and also maintaining 
   * the logger hierarchy. The logger hierarchy is dealing with the several Log-Levels
   * Logger can have. From log4j website:
   * 
   * "A logger is said to be an ancestor of another logger if its name followed 
   * by a dot is a prefix of the descendant logger name. A logger is said to be
   * a parent of a child logger if there are no ancestors between itself and the 
   * descendant logger."
   * 
   * Child Loggers do inherit their Log-Levels from their Ancestors. They can
   * increase their Log-Level compared to their Ancestors, but they cannot decrease it.
   * 
   * <p>The casual user does not have to deal with this class directly.</p>
   *
   * <p>The structure of the logger hierarchy is maintained by the
   * getLogger method. The hierarchy is such that children link
   * to their parent but parents do not have any pointers to their
   * children. Moreover, loggers can be instantiated in any order, in
   * particular descendant before ancestor.</p>
   *
   * <p>In case a descendant is created before a particular ancestor,
   * then it creates a provision node for the ancestor and adds itself
   * to the provision node. Other descendants of the same ancestor add
   * themselves to the previously created provision node.</p>
   *
   * @version $Revision: 1394956 $
   * @package log4php
   */
  class LoggerHierarchy {
  	
  	/** Array holding all Logger instances. */
  	protected $loggers = array();
  	
  	/** 
  	 * The root logger.
  	 * @var RootLogger 
  	 */
  	protected $root;
  	
  	/** 
  	 * The logger renderer map.
  	 * @var LoggerRendererMap 
  	 */
  	protected $rendererMap;
  
  	/** 
  	 * Main level threshold. Events with lower level will not be logged by any 
  	 * logger, regardless of it's configuration.
  	 * @var LoggerLevel 
  	 */
  	protected $threshold;
  	
  	/**
  	 * Creates a new logger hierarchy.
  	 * @param LoggerRoot $root The root logger.
  	 */
  	public function __construct(LoggerRoot $root) {
  		$this->root = $root;
  		$this->setThreshold(LoggerLevel::getLevelAll());
  		$this->rendererMap = new LoggerRendererMap();
  	}
  	 
  	/**
  	 * Clears all loggers.
  	 */
  	public function clear() {
  		$this->loggers = array();
  	}
  	
  	/**
  	 * Check if the named logger exists in the hierarchy.
  	 * @param string $name
  	 * @return boolean
  	 */
  	public function exists($name) {
  		return isset($this->loggers[$name]);
  	}
  
  	/**
  	 * Returns all the currently defined loggers in this hierarchy as an array.
  	 * @return array
  	 */	 
  	public function getCurrentLoggers() {
  		return array_values($this->loggers);
  	}
  	
  	/**
  	 * Returns a named logger instance logger. If it doesn't exist, one is created.
  	 * 
  	 * @param string $name Logger name
  	 * @return Logger Logger instance.
  	 */
  	public function getLogger($name) {
  		if(!isset($this->loggers[$name])) {
  			$logger = new Logger($name);
  
  			$nodes = explode('.', $name);
  			$firstNode = array_shift($nodes);
  			
  			// if name is not a first node but another first node is their
  			if($firstNode != $name and isset($this->loggers[$firstNode])) {
  				$logger->setParent($this->loggers[$firstNode]);
  			} else {
  				// if there is no father, set root logger as father
  				$logger->setParent($this->root);
  			} 
  		
  			// if there are more nodes than one
  			if(count($nodes) > 0) {
  				// find parent node
  				foreach($nodes as $node) {
  					$parentNode = "$firstNode.$node";
  					if(isset($this->loggers[$parentNode]) and $parentNode != $name) {
  						$logger->setParent($this->loggers[$parentNode]);
  					}
  					$firstNode .= ".$node";
  				}
  			}
  			
  			$this->loggers[$name] = $logger;
  		}		
  		
  		return $this->loggers[$name];
  	} 
  	
  	/**
  	 * Returns the logger renderer map.
  	 * @return LoggerRendererMap 
  	 */
  	public function getRendererMap() {
  		return $this->rendererMap;
  	}
  	
  	/**
  	 * Returns the root logger.
  	 * @return LoggerRoot
  	 */ 
  	public function getRootLogger() {
  		return $this->root;
  	}
  	 
  	/**
  	 * Returns the main threshold level.
  	 * @return LoggerLevel 
  	 */
  	public function getThreshold() {
  		return $this->threshold;
  	} 
  
  	/**
  	 * Returns true if the hierarchy is disabled for given log level and false
  	 * otherwise.
  	 * @return boolean
  	 */
  	public function isDisabled(LoggerLevel $level) {
  		return ($this->threshold->toInt() > $level->toInt());
  	}
  	
  	/**
  	 * Reset all values contained in this hierarchy instance to their
  	 * default. 
  	 *
  	 * This removes all appenders from all loggers, sets
  	 * the level of all non-root loggers to <i>null</i>,
  	 * sets their additivity flag to <i>true</i> and sets the level
  	 * of the root logger to {@link LOGGER_LEVEL_DEBUG}.
  	 * 
  	 * <p>Existing loggers are not removed. They are just reset.
  	 *
  	 * <p>This method should be used sparingly and with care as it will
  	 * block all logging until it is completed.</p>
  	 */
  	public function resetConfiguration() {
  		$root = $this->getRootLogger();
  		
  		$root->setLevel(LoggerLevel::getLevelDebug());
  		$this->setThreshold(LoggerLevel::getLevelAll());
  		$this->shutDown();
  		
  		foreach($this->loggers as $logger) {
  			$logger->setLevel(null);
  			$logger->setAdditivity(true);
  			$logger->removeAllAppenders();
  		}
  		
  		$this->rendererMap->reset();
  		LoggerAppenderPool::clear();
  	}
  	
  	/**
  	 * Sets the main threshold level.
  	 * @param LoggerLevel $l
  	 */
  	public function setThreshold(LoggerLevel $threshold) {
  		$this->threshold = $threshold;
  	}
  	
  	/**
  	 * Shutting down a hierarchy will <i>safely</i> close and remove
  	 * all appenders in all loggers including the root logger.
  	 * 
  	 * The shutdown method is careful to close nested
  	 * appenders before closing regular appenders. This is allows
  	 * configurations where a regular appender is attached to a logger
  	 * and again to a nested appender.
  	 * 
  	 * @todo Check if the last paragraph is correct.
  	 */
  	public function shutdown() {
  		$this->root->removeAllAppenders();
  		
  		foreach($this->loggers as $logger) {
  			$logger->removeAllAppenders();
  		}
  	}
  	
  	/**
  	 * Prints the current Logger hierarchy tree. Useful for debugging.
  	 */
  	public function printHierarchy() {
  		$this->printHierarchyInner($this->getRootLogger(), 0);
  	}
  	
  	private function printHierarchyInner(Logger $current, $level) {
  		for ($i = 0; $i < $level; $i++) {
  			echo ($i == $level - 1) ? "|--" : "|  ";
  		}
  		echo $current->getName() . "
  ";
  		
  		foreach($this->loggers as $logger) {
  			if ($logger->getParent() == $current) {
  				$this->printHierarchyInner($logger, $level + 1);
  			}
  		}
  	}
  }