<?php
/**
 * @link http://www.yiiframework.com/
 * @copyright Copyright (c) 2008 Yii Software LLC
 * @license http://www.yiiframework.com/license/
 */

namespace yii\validators;

use Yii;
use yii\base\InvalidConfigException;
use yii\helpers\Html;
use yii\web\JsExpression;
use yii\helpers\Json;

/**
 * UrlValidator validates that the attribute value is a valid http or https URL.
 *
 * Note that this validator only checks if the URL scheme and host part are correct.
 * It does not check the rest part of a URL.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @since 2.0
 */
class UrlValidator extends Validator
{
	/**
	 * @var string the regular expression used to validate the attribute value.
	 * The pattern may contain a `{schemes}` token that will be replaced
	 * by a regular expression which represents the [[validSchemes]].
	 */
	public $pattern = '/^{schemes}:\/\/(([A-Z0-9][A-Z0-9_-]*)(\.[A-Z0-9][A-Z0-9_-]*)+)/i';
	/**
	 * @var array list of URI schemes which should be considered valid. By default, http and https
	 * are considered to be valid schemes.
	 **/
	public $validSchemes = ['http', 'https'];
	/**
	 * @var string the default URI scheme. If the input doesn't contain the scheme part, the default
	 * scheme will be prepended to it (thus changing the input). Defaults to null, meaning a URL must
	 * contain the scheme part.
	 **/
	public $defaultScheme;
	/**
	 * @var boolean whether validation process should take into account IDN (internationalized
	 * domain names). Defaults to false meaning that validation of URLs containing IDN will always
	 * fail. Note that in order to use IDN validation you have to install and enable `intl` PHP
	 * extension, otherwise an exception would be thrown.
	 */
	public $enableIDN = false;


	/**
	 * @inheritdoc
	 */
	public function init()
	{
		parent::init();
		if ($this->enableIDN && !function_exists('idn_to_ascii')) {
			throw new InvalidConfigException('In order to use IDN validation intl extension must be installed and enabled.');
		}
		if ($this->message === null) {
			$this->message = Yii::t('yii', '{attribute} is not a valid URL.');
		}
	}

	/**
	 * @inheritdoc
	 */
	public function validateAttribute($object, $attribute)
	{
		$value = $object->$attribute;
		$result = $this->validateValue($value);
		if (!empty($result)) {
			$this->addError($object, $attribute, $result[0], $result[1]);
		} elseif ($this->defaultScheme !== null && strpos($value, '://') === false) {
			$object->$attribute = $this->defaultScheme . '://' . $value;
		}
	}

	/**
	 * @inheritdoc
	 */
	protected function validateValue($value)
	{
		// make sure the length is limited to avoid DOS attacks
		if (is_string($value) && strlen($value) < 2000) {
			if ($this->defaultScheme !== null && strpos($value, '://') === false) {
				$value = $this->defaultScheme . '://' . $value;
			}

			if (strpos($this->pattern, '{schemes}') !== false) {
				$pattern = str_replace('{schemes}', '(' . implode('|', $this->validSchemes) . ')', $this->pattern);
			} else {
				$pattern = $this->pattern;
			}

			if ($this->enableIDN) {
				$value = preg_replace_callback('/:\/\/([^\/]+)/', function ($matches) {
					return '://' . idn_to_ascii($matches[1]);
				}, $value);
			}

			if (preg_match($pattern, $value)) {
				return null;
			}
		}
		return [$this->message, []];
	}

	/**
	 * @inheritdoc
	 */
	public function clientValidateAttribute($object, $attribute, $view)
	{
		if (strpos($this->pattern, '{schemes}') !== false) {
			$pattern = str_replace('{schemes}', '(' . implode('|', $this->validSchemes) . ')', $this->pattern);
		} else {
			$pattern = $this->pattern;
		}

		$options = [
			'pattern' => new JsExpression($pattern),
			'message' => strtr($this->message, [
				'{attribute}' => $object->getAttributeLabel($attribute),
			]),
			'enableIDN' => (boolean)$this->enableIDN,
		];
		if ($this->skipOnEmpty) {
			$options['skipOnEmpty'] = 1;
		}
		if ($this->defaultScheme !== null) {
			$options['defaultScheme'] = $this->defaultScheme;
		}

		ValidationAsset::register($view);
		if ($this->enableIDN) {
			PunycodeAsset::register($view);
		}
		return 'yii.validation.url(value, messages, ' . Json::encode($options) . ');';
	}
}
