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

namespace yii\web;

use Yii;
use yii\base\InlineAction;
use yii\helpers\Url;

/**
 * Controller is the base class of web controllers.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @since 2.0
 */
class Controller extends \yii\base\Controller
{
    /**
     * @var boolean whether to enable CSRF validation for the actions in this controller.
     * CSRF validation is enabled only when both this property and [[Request::enableCsrfValidation]] are true.
     */
    public $enableCsrfValidation = true;
    /**
     * @var array the parameters bound to the current action.
     */
    public $actionParams = [];


    /**
     * Renders a view in response to an AJAX request.
     *
     * This method is similar to [[renderPartial()]] except that it will inject into
     * the rendering result with JS/CSS scripts and files which are registered with the view.
     * For this reason, you should use this method instead of [[renderPartial()]] to render
     * a view to respond to an AJAX request.
     *
     * @param string $view the view name. Please refer to [[render()]] on how to specify a view name.
     * @param array $params the parameters (name-value pairs) that should be made available in the view.
     * @return string the rendering result.
     */
    public function renderAjax($view, $params = [])
    {
        return $this->getView()->renderAjax($view, $params, $this);
    }

    /**
     * Binds the parameters to the action.
     * This method is invoked by [[\yii\base\Action]] when it begins to run with the given parameters.
     * This method will check the parameter names that the action requires and return
     * the provided parameters according to the requirement. If there is any missing parameter,
     * an exception will be thrown.
     * @param \yii\base\Action $action the action to be bound with parameters
     * @param array $params the parameters to be bound to the action
     * @return array the valid parameters that the action can run with.
     * @throws BadRequestHttpException if there are missing or invalid parameters.
     */
    public function bindActionParams($action, $params)
    {
        if ($action instanceof InlineAction) {
            // 如果action是InlineAction的实例，就new一个controller上actionMethod的ReflectionMethod实例
            $method = new \ReflectionMethod($this, $action->actionMethod);
        } else {
            // 否则，就new一个action上run方法的ReflectionMethod实例
            $method = new \ReflectionMethod($action, 'run');
        }

        $args = [];
        $missing = [];
        $actionParams = [];
        // ReflectionFunctionAbstract::getParameters — 获取参数
        foreach ($method->getParameters() as $param) {
            // ReflectionParameter::getName — Gets parameter name
            $name = $param->getName();
            if (array_key_exists($name, $params)) {
                // ReflectionParameter::isArray — Checks if parameter expects an array
                if ($param->isArray()) {
                    $args[] = $actionParams[$name] = (array)$params[$name];
                } elseif (!is_array($params[$name])) {
                    $args[] = $actionParams[$name] = $params[$name];
                } else {
                    throw new BadRequestHttpException(Yii::t('yii', 'Invalid data received for parameter "{param}".', [
                        'param' => $name,
                    ]));
                }
                unset($params[$name]);
            } elseif ($param->isDefaultValueAvailable()) {
                // ReflectionParameter::isDefaultValueAvailable — Checks if a default value is available
                // ReflectionParameter::getDefaultValue — Gets default parameter value
                $args[] = $actionParams[$name] = $param->getDefaultValue();
            } else {
                $missing[] = $name;
            }
        }

        if (!empty($missing)) {
            throw new BadRequestHttpException(Yii::t('yii', 'Missing required parameters: {params}', [
                'params' => implode(', ', $missing),
            ]));
        }

        $this->actionParams = $actionParams;

        return $args;
    }

    /**
     * @inheritdoc
     */
    public function beforeAction($action)
    {
        if (parent::beforeAction($action)) {
            if ($this->enableCsrfValidation && Yii::$app->getErrorHandler()->exception === null && !Yii::$app->getRequest()->validateCsrfToken()) {
                throw new BadRequestHttpException(Yii::t('yii', 'Unable to verify your data submission.'));
            }
            return true;
        } else {
            return false;
        }
    }

    /**
     * Redirects the browser to the specified URL.
     * This method is a shortcut to [[Response::redirect()]].
     *
     * You can use it in an action by returning the [[Response]] directly:
     *
     * ```php
     * // stop executing this action and redirect to login page
     * return $this->redirect(['login']);
     * ```
     *
     * @param string|array $url the URL to be redirected to. This can be in one of the following formats:
     *
     * - a string representing a URL (e.g. "http://example.com")
     * - a string representing a URL alias (e.g. "@example.com")
     * - an array in the format of `[$route, ...name-value pairs...]` (e.g. `['site/index', 'ref' => 1]`)
     *   [[Url::to()]] will be used to convert the array into a URL.
     *
     * Any relative URL will be converted into an absolute one by prepending it with the host info
     * of the current request.
     *
     * @param integer $statusCode the HTTP status code. Defaults to 302.
     * See <http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html>
     * for details about HTTP status code
     * @return Response the current response object
     */
    public function redirect($url, $statusCode = 302)
    {
        return Yii::$app->getResponse()->redirect(Url::to($url), $statusCode);
    }

    /**
     * Redirects the browser to the home page.
     *
     * You can use this method in an action by returning the [[Response]] directly:
     *
     * ```php
     * // stop executing this action and redirect to home page
     * return $this->goHome();
     * ```
     *
     * @return Response the current response object
     */
    public function goHome()
    {
        return Yii::$app->getResponse()->redirect(Yii::$app->getHomeUrl());
    }

    /**
     * Redirects the browser to the last visited page.
     *
     * You can use this method in an action by returning the [[Response]] directly:
     *
     * ```php
     * // stop executing this action and redirect to last visited page
     * return $this->goBack();
     * ```
     *
     * For this function to work you have to [[User::setReturnUrl()|set the return URL]] in appropriate places before.
     *
     * @param string|array $defaultUrl the default return URL in case it was not set previously.
     * If this is null and the return URL was not set previously, [[Application::homeUrl]] will be redirected to.
     * Please refer to [[User::setReturnUrl()]] on accepted format of the URL.
     * @return Response the current response object
     * @see User::getReturnUrl()
     */
    public function goBack($defaultUrl = null)
    {
        return Yii::$app->getResponse()->redirect(Yii::$app->getUser()->getReturnUrl($defaultUrl));
    }

    /**
     * Refreshes the current page.
     * This method is a shortcut to [[Response::refresh()]].
     *
     * You can use it in an action by returning the [[Response]] directly:
     *
     * ```php
     * // stop executing this action and refresh the current page
     * return $this->refresh();
     * ```
     *
     * @param string $anchor the anchor that should be appended to the redirection URL.
     * Defaults to empty. Make sure the anchor starts with '#' if you want to specify it.
     * @return Response the response object itself
     */
    public function refresh($anchor = '')
    {
        return Yii::$app->getResponse()->redirect(Yii::$app->getRequest()->getUrl() . $anchor);
    }
}
