<?php

/**
 * @package KantPHP
 * @author  Zhenqiang Zhang <zhenqiang.zhang@hotmail.com>
 * @copyright (c) KantPHP Studio, All rights reserved.
 * @license http://www.opensource.org/licenses/BSD-3-Clause  The BSD 3-Clause License
 */
namespace Kant\Captcha;

use Kant\Exception\InvalidConfigException;
use Kant\Helper\Url;
use Kant\Helper\Html;
use Kant\Helper\Json;
use Kant\Widget\InputWidget;

/**
 * Captcha renders a CAPTCHA image and an input field that takes user-entered verification code.
 *
 * Captcha is used together with [[CaptchaAction]] provide [CAPTCHA](http://en.wikipedia.org/wiki/Captcha) - a way
 * of preventing Website spamming.
 *
 * The image element rendered by Captcha will display a CAPTCHA image generated by
 * an action whose route is specified by [[captchaAction]]. This action must be an instance of [[CaptchaAction]].
 *
 * When the user clicks on the CAPTCHA image, it will cause the CAPTCHA image
 * to be refreshed with a new CAPTCHA.
 *
 * You may use [[\Kant\Captcha\CaptchaValidator]] to validate the user input matches
 * the current CAPTCHA verification code.
 *
 * The following example shows how to use this widget with a model attribute:
 *
 * ```php
 * echo Captcha::widget([
 * 'model' => $model,
 * 'attribute' => 'captcha',
 * ]);
 * ```
 *
 * The following example will use the name property instead:
 *
 * ```php
 * echo Captcha::widget([
 * 'name' => 'captcha',
 * ]);
 * ```
 *
 * You can also use this widget in an [[yii\widgets\ActiveForm|ActiveForm]] using the [[yii\widgets\ActiveField::widget()|widget()]]
 * method, for example like this:
 *
 * ```php
 * <?= $form->field($model, 'captcha')->widget(\yii\captcha\Captcha::classname(), [
 * // configure additional widget properties here
 * ]) ?>
 * ```
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @since 2.0
 */
class Captcha extends InputWidget
{

    /**
     *
     * @var string|array the route of the action that generates the CAPTCHA images.
     *      The action represented by this route must be an action of [[CaptchaAction]].
     *      Please refer to [[\Kant\Helper\Url::toRoute()]] for acceptable formats.
     */
    public $captchaAction = 'common/service/captcha';

    /**
     *
     * @var array HTML attributes to be applied to the CAPTCHA image tag.
     * @see \Kant\Helper\Html::renderTagAttributes() for details on how attributes are being rendered.
     */
    public $imageOptions = [];

    /**
     *
     * @var string the template for arranging the CAPTCHA image tag and the text input tag.
     *      In this template, the token `{image}` will be replaced with the actual image tag,
     *      while `{input}` will be replaced with the text input tag.
     */
    public $template = '{image} {input}';

    /**
     *
     * @var array the HTML attributes for the input tag.
     * @see \Kant\Helper\Html::renderTagAttributes() for details on how attributes are being rendered.
     */
    public $options = [
        'class' => 'form-control'
    ];

    /**
     * Initializes the widget.
     */
    public function init()
    {
        parent::init();
        
        static::checkRequirements();
        
        if (!isset($this->imageOptions['id'])) {
            $this->imageOptions['id'] = $this->options['id'] . '-image';
        }
    }

    /**
     * Renders the widget.
     */
    public function run()
    {
        $this->registerClientScript();
        if ($this->hasModel()) {
            $input = Html::activeTextInput($this->model, $this->attribute, $this->options);
        } else {
            $input = Html::textInput($this->name, $this->value, $this->options);
        }
        $route = $this->captchaAction;
		/*
        if (is_array($route)) {
            $route['v'] = uniqid();
        } else {
            $route = [
                $route,
                'v' => uniqid()
            ];
        }
		 */
		$route = Url::to($route, ['v' => uniqid()]);
        $image = Html::img($route, $this->imageOptions);
        echo strtr($this->template, [
            '{input}' => $input,
            '{image}' => $image
        ]);
    }

    /**
     * Registers the needed JavaScript.
     */
    public function registerClientScript()
    {
        $options = $this->getClientOptions();
        $options = empty($options) ? '' : Json::htmlEncode($options);
        $id = $this->imageOptions['id'];
        $view = $this->getView();
        CaptchaAsset::register($view);
        $view->registerJs("jQuery('#$id').kantCaptcha($options);");
    }

    /**
     * Returns the options for the captcha JS widget.
     * 
     * @return array the options
     */
    protected function getClientOptions()
    {
        $route = $this->captchaAction;
        
        $_route = explode("/", $route);
        $options = [
            'refreshUrl' => Url::to($route, [
                CaptchaAction::REFRESH_GET_VAR => 1
            ]),
            'hashKey' => 'kantCaptcha/' . $_route[1] . '/' . $_route[2]
        ];
        return $options;
    }

    /**
     * Checks if there is graphic extension available to generate CAPTCHA images.
     * This method will check the existence of ImageMagick and GD extensions.
     * 
     * @return string the name of the graphic extension, either "imagick" or "gd".
     * @throws InvalidConfigException if neither ImageMagick nor GD is installed.
     */
    public static function checkRequirements()
    {
        if (extension_loaded('imagick')) {
            $imagickFormats = (new \Imagick())->queryFormats('PNG');
            if (in_array('PNG', $imagickFormats, true)) {
                return 'imagick';
            }
        }
        if (extension_loaded('gd')) {
            $gdInfo = gd_info();
            if (!empty($gdInfo['FreeType Support'])) {
                return 'gd';
            }
        }
        throw new InvalidConfigException('Either GD PHP extension with FreeType support or ImageMagick PHP extension with PNG support is required.');
    }
}
