<?php

namespace Artmark\BreadCrumbs;

/**
 * Description of BreadCrumbSequence
 *
 * @author Andrey Pokidov <pokidov@e-traffic.ru>
 */
class BreadCrumbSequence
{
    /**
     *
     * @var BreadCrumbSequence
     */
    private static $instance = null;
    
    /**
     *
     * @var CrumbInterface[]
     */
    private $crumbs = [];

    private function __construct()
    {
    }
    
    /**
     * 
     * @return BreadCrumbSequence
     */
    public static function instance()
    {
        if (is_null(self::$instance)) {
            self::$instance = new BreadCrumbSequence();
        }
        
        return self::$instance;
    }
    
    /**
     * 
     * @return CrumbInterface[]
     */
    public function crumbs()
    {
        return $this->crumbs;
    }
    
    /**
     * 
     * @return $this
     */
    public function reset()
    {
        if (count($this->crumbs) > 0) {
            $this->crumbs = [];
        }
        
        return $this;
    }
    
    /**
     * 
     * @param string $url
     * @param string $label
     * @param string $icon
     * @return $this
     */
    public function append(string $url, string $label, string $icon = '')
    {
        $this->push(new Crumb($url, $label, $icon));
        
        return $this;
    }
    
    /**
     * 
     * @param CrumbInterface $crumb
     * @return $this
     */
    public function push(CrumbInterface $crumb)
    {
        if (!in_array($crumb, $this->crumbs)) {
            $this->crumbs[] = $crumb;
        }
        
        return $this;
    }
}