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

namespace yii\rest;

use Yii;
use yii\base\InvalidConfigException;
use yii\web\Response;
use yii\web\UnauthorizedHttpException;
use yii\web\UnsupportedMediaTypeHttpException;
use yii\web\TooManyRequestsHttpException;
use yii\filters\VerbFilter;
use yii\web\ForbiddenHttpException;

/**
 * Controller is the base class for RESTful API controller classes.
 *
 * Controller implements the following steps in a RESTful API request handling cycle:
 *
 * 1. Resolving response format and API version number (see [[supportedFormats]], [[supportedVersions]] and [[version]]);
 * 2. Validating request method (see [[verbs()]]).
 * 3. Authenticating user (see [[authenticate()]]);
 * 4. Formatting response data (see [[serializeData()]]).
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @since 2.0
 */
class Controller extends \yii\web\Controller
{
    /**
     * @var string the name of the header parameter representing the API version number.
     */
    public $versionHeaderParam = 'version';
    /**
     * @var string|array the configuration for creating the serializer that formats the response data.
     */
    public $serializer = 'yii\rest\Serializer';
    /**
     * @inheritdoc
     */
    public $enableCsrfValidation = false;
    /**
     * @var array the supported authentication methods. This property should take a list of supported
     * authentication methods, each represented by an authentication class or configuration.
     * If this is not set or empty, it means authentication is disabled.
     */
    public $authMethods;
    /**
     * @var string|array the rate limiter class or configuration. If this is not set or empty,
     * the rate limiting will be disabled. Note that if the user is not authenticated, the rate limiting
     * will also NOT be performed.
     * @see checkRateLimit()
     * @see authMethods
     */
    public $rateLimiter = 'yii\rest\RateLimiter';
    /**
     * @var string the chosen API version number, or null if [[supportedVersions]] is empty.
     * @see supportedVersions
     */
    public $version;
    /**
     * @var array list of supported API version numbers. If the current request does not specify a version
     * number, the first element will be used as the [[version|chosen version number]]. For this reason, you should
     * put the latest version number at the first. If this property is empty, [[version]] will not be set.
     */
    public $supportedVersions = [];
    /**
     * @var array list of supported response formats. The array keys are the requested content MIME types,
     * and the array values are the corresponding response formats. The first element will be used
     * as the response format if the current request does not specify a content type.
     */
    public $supportedFormats = [
        'application/json' => Response::FORMAT_JSON,
        'application/xml' => Response::FORMAT_XML,
    ];

    /**
     * @inheritdoc
     */
    public function behaviors()
    {
        return [
            'verbFilter' => [
                'class' => VerbFilter::className(),
                'actions' => $this->verbs(),
            ],
        ];
    }

    /**
     * @inheritdoc
     */
    public function init()
    {
        parent::init();
        $this->resolveFormatAndVersion();
    }

    /**
     * @inheritdoc
     */
    public function beforeAction($action)
    {
        $this->authenticate($action);
        $this->checkRateLimit($action);
        return parent::beforeAction($action);
    }

    /**
     * @inheritdoc
     */
    public function afterAction($action, $result)
    {
        $result = parent::afterAction($action, $result);
        return $this->serializeData($result);
    }

    /**
     * Resolves the response format and the API version number.
     * @throws UnsupportedMediaTypeHttpException
     */
    protected function resolveFormatAndVersion()
    {
        $this->version = empty($this->supportedVersions) ? null : reset($this->supportedVersions);
        Yii::$app->getResponse()->format = reset($this->supportedFormats);
        $types = Yii::$app->getRequest()->getAcceptableContentTypes();
        if (empty($types)) {
            $types['*/*'] = [];
        }

        foreach ($types as $type => $params) {
            if (isset($this->supportedFormats[$type])) {
                Yii::$app->getResponse()->format = $this->supportedFormats[$type];
                if (isset($params[$this->versionHeaderParam])) {
                    if (in_array($params[$this->versionHeaderParam], $this->supportedVersions, true)) {
                        $this->version = $params[$this->versionHeaderParam];
                    } else {
                        throw new UnsupportedMediaTypeHttpException('You are requesting an invalid version number.');
                    }
                }

                return;
            }
        }

        if (!isset($types['*/*'])) {
            throw new UnsupportedMediaTypeHttpException('None of your requested content types is supported.');
        }
    }

    /**
     * Declares the allowed HTTP verbs.
     * Please refer to [[VerbFilter::actions]] on how to declare the allowed verbs.
     * @return array the allowed HTTP verbs.
     */
    protected function verbs()
    {
        return [];
    }

    /**
     * Authenticates the user.
     * This method implements the user authentication based on an access token sent through the `Authorization` HTTP header.
     * @param \yii\base\Action $action the action to be executed
     * @throws UnauthorizedHttpException if the user is not authenticated successfully
     * @throws InvalidConfigException if an auth method declared in [[authMethods]] is invalid.
     */
    protected function authenticate($action)
    {
        if (empty($this->authMethods)) {
            return;
        }

        $user = Yii::$app->getUser();
        $request = Yii::$app->getRequest();
        $response = Yii::$app->getResponse();
        foreach ($this->authMethods as $i => $auth) {
            $this->authMethods[$i] = $auth = Yii::createObject($auth);
            if (!$auth instanceof AuthInterface) {
                throw new InvalidConfigException(get_class($auth) . ' must implement yii\rest\AuthInterface');
            } elseif ($auth->authenticate($user, $request, $response) !== null) {
                return;
            }
        }

        /** @var AuthInterface $auth */
        $auth = reset($this->authMethods);
        $auth->handleFailure($response);
    }

    /**
     * Ensures the rate limit is not exceeded.
     *
     * This method will use [[rateLimiter]] to check rate limit. In order to perform rate limiting check,
     * the user must be authenticated and the user identity object (`Yii::$app->user->identity`) must
     * implement [[RateLimitInterface]].
     *
     * @param \yii\base\Action $action the action to be executed
     * @throws TooManyRequestsHttpException if the rate limit is exceeded.
     */
    protected function checkRateLimit($action)
    {
        if (empty($this->rateLimiter)) {
            return;
        }

        $identity = Yii::$app->getUser()->getIdentity(false);
        if ($identity instanceof RateLimitInterface) {
            /** @var RateLimiter $rateLimiter */
            $rateLimiter = Yii::createObject($this->rateLimiter);
            $rateLimiter->check($identity, Yii::$app->getRequest(), Yii::$app->getResponse(), $action);
        }
    }

    /**
     * Serializes the specified data.
     * The default implementation will create a serializer based on the configuration given by [[serializer]].
     * It then uses the serializer to serialize the given data.
     * @param mixed $data the data to be serialized
     * @return mixed the serialized data.
     */
    protected function serializeData($data)
    {
        return Yii::createObject($this->serializer)->serialize($data);
    }

    /**
     * Checks the privilege of the current user.
     *
     * This method should be overridden to check whether the current user has the privilege
     * to run the specified action against the specified data model.
     * If the user does not have access, a [[ForbiddenHttpException]] should be thrown.
     *
     * @param string $action the ID of the action to be executed
     * @param object $model the model to be accessed. If null, it means no specific model is being accessed.
     * @param array $params additional parameters
     * @throws ForbiddenHttpException if the user does not have access
     */
    public function checkAccess($action, $model = null, $params = [])
    {
    }
}
