<?php

/**
 * Klasa dodająca obsługę "okruszków chleba"
 * 
 * @package stNavigationPlugin
 */
class stNavigationBreadcrumbs implements \Iterator, \Countable
{
    /**
     * Instancja kontekstu aplikacji
     *
     * @var sfContext
     */
    protected $content;

    /**
     * "Okruszki chleba"
     *
     * @var stNavigationBreadcrumbItem[]
     */
    protected $breadcrumbs = array();

    /**
     * Singleton
     *
     * @var static
     */
    protected static $instance = null;

    public function __construct(sfContext $context)
    {
        $this->context = $context;
    }

    /**
     * Zwraca singleton
     * 
     * @return static 
     */
    public static function getInstance()
    {
        if (null === self::$instance)
        {
            self::$instance = new static(sfContext::getInstance());
        }

        return self::$instance;
    }

    /**
     * Dodaje nowy "okruszek chleba"
     *
     * @param string $title Tytuł
     * @param string $url Adres url
     * @return $this
     */
    public function add($title, $url = null)
    {
        if (null !== $url)
        {
            $url = $this->context->getController()->genUrl($url);
        }

        $this->breadcrumbs[] = new stNavigationBreadcrumbItem($title, $url);
        return $this;
    }

    /**
     * Zwraca "okruszki chleba"
     *
     * @return stNavigationBreadcrumbItem[]
     */
    public function getBreadcrumbs()
    {
        return $this->breadcrumbs;
    }

    public function current()
    {
        return current($this->breadcrumbs);
    }

    public function next()
    {
        return next($this->breadcrumbs);
    }

    public function key()
    {
        return key($this->breadcrumbs);
    }

    public function valid()
    {
        return null !== $this->key();
    }

    public function rewind()
    {
        return reset($this->breadcrumbs);
    }

    public function count()
    {
        return count($this->breadcrumbs);
    }
}