<?php

namespace Httpcb\Mvc\Model\Behavior;

use Phalcon\Mvc\Model\Behavior,
    Phalcon\Mvc\Model\BehaviorInterface,
    Phalcon\Mvc\Model\Exception;

/**
 * Generates a unique base64 url-safe id for the field specified.
 *
 * Class RandomId
 * @package Mvc\Model\Behavior
 */
class RandomId extends Behavior implements BehaviorInterface
{
    /**
     * Constructor.
     *
     * @param array|null $options
     * @throws Exception
     */
    public function __construct($options = null)
    {
        if (!isset($options['field']) || strlen($options['field']) < 1) {
            throw new Exception("'field' must be set in the option array.");
        }

        if (isset($options['length'])) {
            if (!is_numeric($options['length'])) {
                throw new Exception("'length' must be a number.");
            }
        } else {
            $options['length'] = 32;
        }

        parent::__construct($options);
    }

    /**
     * @param string $type
     * @param \Phalcon\Mvc\ModelInterface $model
     * @throws \Phalcon\Security\Exception
     */
    public function notify($type, \Phalcon\Mvc\ModelInterface $model)
    {
        switch ($type) {
            case 'beforeValidationOnCreate':
                $this->generateId($model);
                break;
        }
    }

    /**
     * @param \Phalcon\Mvc\ModelInterface $model
     * @throws \Phalcon\Security\Exception
     */
    public function generateId(\Phalcon\Mvc\ModelInterface $model)
    {
        $field = $this->options['field'];
        $len = $this->options['length'];

        if (isset($this->options['expression'])) {
            $expr = 'AND ' . $this->options['expression'];
        } else {
            $expr = '';
        }

        if ($model->$field === null) {

            $random = new \Phalcon\Security\Random();
            for ($i = 0; $i < 3; $i++) {
                $id = substr($random->base64Safe(), 0, $len);

                $count = $model->count(array(
                    "$field = ?0 $expr",
                    'bind' => array($id)
                ));

                if ($count < 1) {
                    $model->$field = $id;
                    break;
                }
            }
        }
    }
}