class RulesElementMap

class RulesElementMap {
    
    /**
     * @var RulesPlugin
     */
    protected $configuration;
    protected $index = array();
    protected $counter = 0;
    
    /**
     * Constructor.
     */
    public function __construct(RulesPlugin $config) {
        $this->configuration = $config->root();
    }
    
    /**
     * Makes sure each element has an assigned id.
     */
    public function index() {
        foreach ($this->getUnIndexedElements($this->configuration) as $element) {
            $id =& $element->property('elementId');
            $id = ++$this->counter;
            $this->index[$id] = $element;
        }
    }
    protected function getUnIndexedElements($element, &$unindexed = array()) {
        // Remember unindexed elements.
        $id = $element->property('elementId');
        if (!isset($id)) {
            $unindexed[] = $element;
        }
        else {
            // Make sure $this->counter refers to the highest id.
            if ($id > $this->counter) {
                $this->counter = $id;
            }
            $this->index[$id] = $element;
        }
        // Recurse down the tree.
        if ($element instanceof RulesContainerPlugin) {
            foreach ($element as $child) {
                $this->getUnIndexedElements($child, $unindexed);
            }
        }
        return $unindexed;
    }
    
    /**
     * Looks up the element with the given id.
     */
    public function lookup($id) {
        if (!$this->index) {
            $this->index();
        }
        return isset($this->index[$id]) ? $this->index[$id] : FALSE;
    }

}