<?php
class ChainCollectorNode
{
	private $_isMethod;
	private $_name;
	private $_arguments;
	private $_chain;
	
	public function __construct($chain = array())
	{
		$this->_chain = $chain;
	}

	public function __call($name, $args)
	{
		$this->_isMethod = true;
		$this->_name = $name;
		$this->_arguments = $args;

		$this->_chain[] = $this;
		return new ChainCollectorNode($this->_chain);
	}

	public function __get($name)
	{
		$this->_isMethod = false;
		$this->_name = $name;

		$this->_chain[] = $this;
		return new ChainCollectorNode($this->_chain);
	}

	public function finish()
	{
		return ChainRunner::getInstance()->runChain($this->_chain);
	}
	
	/**
	 * Returns the chain as an array of ChainCollectorNodes
	 *
	 * @return Array
	 */
	public function getChain()
	{
		return $this->_chain;
	}
	
	public function getName()
	{
		return $this->_name;
	}

	public function getArguments()
	{
		return $this->_arguments;
	}
	
	public function isMethodCall()
	{
		return $this->_isMethod;
	}

	public function isPropertyGet()
	{
		return !$this->_isMethod;
	}
}

class ChainCollectorStartNode extends ChainCollectorNode
{
	private $_className;
	
	public function __construct($className)
	{
		parent::__construct();
		$this->_className = $className;
	}

	public function getClassName()
	{
		return $this->_className;
	}
}

class ChainRunner
{
	private $_specialCalls = array();
		
	private static $_instance;

	private function __construct()
	{
	//	$this->_specialCalls['if'] = new IfChainParser();
	}

	/**
	 * Return a ChainRunner instance
	 *
	 * @return ChainRunner
	 */
	public static function getInstance()
	{
		if(!self::$_instance)
			self::$_instance = new ChainRunner();

		return self::$_instance;
	}
	
	/**
	 * Runs a chain
	 * @param Array $chain Array of chaincollectornodes
	 * @return Mixed result
	 */
	public function runChain($chain)
	{
		$firstClass = $chain[0]->getClassName();
		$node = array_shift($chain);
		$obj = new $firstClass();

		$index = 0;
		
		while($node != null)
		{
			if($node->isMethodCall())
			{
				$methodName = $node->getName();
				$arguments = $node->getArguments();
				if($this->_isSpecial($methodName))
				{
					$this->_specialCalls[$methodName]->setChain($chain)
					                                 ->parseIndex($index, $arguments);
				}
				else
				{
					//echo "Mtd ".get_class($obj)." $methodName<br>";
					$obj = call_user_func_array(array($obj,$methodName),$arguments);
				}
			}
			else
			{
				$propertyName = $node->getName();
				//echo "Prop ".get_class($obj)." $propertyName<br>";
				$obj = $obj->$propertyName;
			}

			$node = array_shift($chain);
			$index++;
		}

		//echo "Returning ".get_class($obj)."<br>";
		return $obj;
	}

	private function _isSpecial($name)
	{
		return array_key_exists($name, $this->_specialCalls);
	}
}