<?php

/*
 * This file is part of the Symfony package.
 *
 * (c) Fabien Potencier <fabien@symfony.com>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace Symfony\Component\Form\Extension\Core\Type;

use Symfony\Component\Form\AbstractType;
use Symfony\Component\OptionsResolver\OptionsResolverInterface;

class TimezoneType extends AbstractType
{
    /**
     * Stores the available timezone choices
     * @var array
     */
    private static $timezones;

    /**
     * {@inheritdoc}
     */
    public function setDefaultOptions(OptionsResolverInterface $resolver)
    {
        $resolver->setDefaults(array(
            'choices' => self::getTimezones(),
        ));
    }

    /**
     * {@inheritdoc}
     */
    public function getParent()
    {
        return 'choice';
    }

    /**
     * {@inheritdoc}
     */
    public function getName()
    {
        return 'timezone';
    }

    /**
     * Returns the timezone choices.
     *
     * The choices are generated from the ICU function
     * \DateTimeZone::listIdentifiers(). They are cached during a single request,
     * so multiple timezone fields on the same page don't lead to unnecessary
     * overhead.
     *
     * @return array The timezone choices
     */
    public static function getTimezones()
    {
        if (null === static::$timezones) {
            static::$timezones = array();

            foreach (\DateTimeZone::listIdentifiers() as $timezone) {
                $parts = explode('/', $timezone);

                if (count($parts) > 2) {
                    $region = $parts[0];
                    $name = $parts[1].' - '.$parts[2];
                } elseif (count($parts) > 1) {
                    $region = $parts[0];
                    $name = $parts[1];
                } else {
                    $region = 'Other';
                    $name = $parts[0];
                }

                static::$timezones[$region][$timezone] = str_replace('_', ' ', $name);
            }
        }

        return static::$timezones;
    }
}