<?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\Form\ChoiceList\ArrayChoiceList;
use Symfony\Component\Form\ChoiceList\Loader\ChoiceLoaderInterface;
use Symfony\Component\OptionsResolver\OptionsResolver;

class TimezoneType extends AbstractType implements ChoiceLoaderInterface
{
    /**
     * Timezone loaded choice list.
     *
     * The choices are generated from the ICU function \DateTimeZone::listIdentifiers().
     *
     * @var ArrayChoiceList
     */
    private $choiceList;

    /**
     * {@inheritdoc}
     */
    public function configureOptions(OptionsResolver $resolver)
    {
        $resolver->setDefaults(array(
            'choice_loader' => $this,
            'choice_translation_domain' => false,
        ));
    }

    /**
     * {@inheritdoc}
     */
    public function getParent()
    {
        return __NAMESPACE__.'\ChoiceType';
    }

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

    /**
     * {@inheritdoc}
     */
    public function loadChoiceList($value = null)
    {
        if (null !== $this->choiceList) {
            return $this->choiceList;
        }

        return $this->choiceList = new ArrayChoiceList($this->getTimezones(), $value);
    }

    /**
     * {@inheritdoc}
     */
    public function loadChoicesForValues(array $values, $value = null)
    {
        // Optimize
        if (empty($values)) {
            return array();
        }

        // If no callable is set, values are the same as choices
        if (null === $value) {
            return $values;
        }

        return $this->loadChoiceList($value)->getChoicesForValues($values);
    }

    /**
     * {@inheritdoc}
     */
    public function loadValuesForChoices(array $choices, $value = null)
    {
        // Optimize
        if (empty($choices)) {
            return array();
        }

        // If no callable is set, choices are the same as values
        if (null === $value) {
            return $choices;
        }

        return $this->loadChoiceList($value)->getValuesForChoices($choices);
    }

    /**
     * Returns a normalized array of timezone choices.
     *
     * @return array The timezone choices
     */
    private static function getTimezones()
    {
        $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];
            }

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

        return $timezones;
    }
}
