<?php

class Zend_Controller_Plugin_Acl extends Zend_Controller_Plugin_Abstract
{
    /**
     * @var Zend_Acl
     **/
    protected $_acl;

    /**
     * @var string
     **/
    protected $_roleName;

    /**
     * @var array
     **/
    protected $_errorPage;

    /**
     * Constructor
     *
     * @param mixed $aclData
     * @param $roleName
     * @return void
     **/
    public function __construct(Zend_Acl $aclData, $roleName = 'G')
    {
        $this->_errorPage = array('module' => 'default',
                                  'controller' => 'error',
                                  'action' => 'error');

        $this->_roleName = $roleName;

        if (null !== $aclData) {
            $this->setAcl($aclData);
        }
    }

    /**
     * Sets the ACL object
     *
     * @param  mixed $aclData
     * @return void
     **/
    public function setAcl(Zend_Acl $aclData)
    {
        $this->_acl = $aclData;
    }

    /**
     * Returns the ACL object
     *
     * @return Zend_Acl
     **/
    public function getAcl()
    {
        return $this->_acl;
    }

    /**
     * Returns the ACL role used
     *
     * @return string
     * @author
     **/
    public function getRoleName()
    {
        return $this->_roleName;
    }

    public function setRoleName($type)
    {
        $this->_roleName = $type;
    }

    /**
     * Sets the error page
     *
     * @param  string $action
     * @param  string $controller
     * @param  string $module
     * @return void
     **/
    public function setErrorPage($action, $controller = 'error', $module = 'default')
    {
        $this->_errorPage = array('module' => $module,
                                  'controller' => $controller,
                                  'action' => $action);
    }

    /**
     * Returns the error page
     *
     * @return array
     **/
    public function getErrorPage()
    {
        return $this->_errorPage;
    }

    /**
     * Predispatch
     * Checks if the current user identified by roleName has rights to the requested url (module/controller/action)
     * If not, it will call denyAccess to be redirected to errorPage
     *
     * @return void
     **/
    public function preDispatch(Zend_Controller_Request_Abstract $request)
    {
        $controller = strtolower($request->getControllerName());

        if (in_array($controller, array(
                "index",
                "login",
                "api",
                "auth",
                "error",
                "locale",
                "upgrade",
                "embed",
                "feeds"
            )))
        {
            $this->setRoleName("G");
        }
        elseif (Zend_Session::isStarted() && !Zend_Auth::getInstance()->hasIdentity()) {

            //The controller uses sessions but we don't have an identity yet.

            // If we don't have an identity and we're making a RESTful request,
            // we need to do API key verification
            if ($request->getModuleName() == "rest") {
                if (!$this->verifyAuth()) {
                    //$this->denyAccess();
                    //$this->getResponse()->sendResponse();
                    //$r->gotoSimpleAndExit('index', 'login', $request->getModuleName());

                    //die();
                    throw new Zend_Controller_Exception("Incorrect API key", 401);
                }
            }
            else  //Non-REST, regular Airtime web app requests
            {
                // Redirect user to the landing page if they are trying to
                // access a resource that requires a valid session.
                // Skip the redirection if they are already on the landing page
                // or the login page.
                if ($controller !== 'index' && $controller !== 'login') {

                    if ($request->isXmlHttpRequest()) {

                        $url = 'http://'.$request->getHttpHost().'/';
                        $json = Zend_Json::encode(array('auth' => false, 'url' => $url));

                        // Prepare response
                        $this->getResponse()
                             ->setHttpResponseCode(401)
                             ->setBody($json)
                             ->sendResponse();

                        //redirectAndExit() cleans up, sends the headers and stops the script
                        Zend_Controller_Action_HelperBroker::getStaticHelper('redirector')->redirectAndExit();
                    } else {
                        $r = Zend_Controller_Action_HelperBroker::getStaticHelper('redirector');
                        $r->gotoSimpleAndExit('index', 'index', $request->getModuleName());
                   }
                }
            }
        } else { //We have a session/identity.

            // If we have an identity and we're making a RESTful request,
            // we need to check the CSRF token
            if ($_SERVER['REQUEST_METHOD'] != "GET" && $request->getModuleName() == "rest") {
                $token = $request->getParam("csrf_token");
                // PUT requests don't parameterize the data in the body, so we can't
                // fetch it with getParam or getPost; instead we have to parse the body and
                // check for the token in the JSON. (Hopefully we can find a better way to do this) -- Duncan
                if (empty($token)) {
                    $token = json_decode($this->getRequest()->getRawBody(), true)["csrf_token"];
                }
                $tokenValid = $this->verifyCSRFToken($token);

                if (!$tokenValid) {
                    $csrf_namespace = new Zend_Session_Namespace('csrf_namespace');
                    $csrf_namespace->authtoken = sha1(openssl_random_pseudo_bytes(128));

                    Logging::warn("Invalid CSRF token: $token");
                    $this->getResponse()
                         ->setHttpResponseCode(401)
                         ->appendBody("ERROR: CSRF token mismatch.")
                         ->sendResponse();
                    die();
                }
            }
            
            $userInfo = Zend_Auth::getInstance()->getStorage()->read();
            $this->setRoleName($userInfo->type);

            Zend_View_Helper_Navigation_HelperAbstract::setDefaultAcl($this->_acl);
            Zend_View_Helper_Navigation_HelperAbstract::setDefaultRole($this->_roleName);

            $resourceName = '';

            if ($request->getModuleName() != 'default') {
                $resourceName .= strtolower($request->getModuleName()) . ':';
            }

            $resourceName .= $controller;

            /** Check if the controller/action can be accessed by the current user */
            if (!$this->getAcl()->has($resourceName)) {
                $this->setErrorPage('error404');
                $this->denyAccess();
            } else if (!$this->getAcl()->isAllowed($this->_roleName,
                        $resourceName, 
                        $request->getActionName())) {
                /** Redirect to access denied page */
                $this->setErrorPage('error403');
                $this->denyAccess();
            }
        }
    }

    private function verifyAuth() {
        if ($this->verifyAPIKey() || $this->isVerifiedDownload()) {
            return true;
        }

        $this->getResponse()
            ->setHttpResponseCode(401)
            ->appendBody("ERROR: Incorrect API key.");

        return false;
    }

    /**
     * Check if the requested file can be downloaded.
     * It should satisfy the following requirements:
     *  * request path is /rest/media/:id/download
     *  * download key is correct
     *  * requested file belongs to the station podcast
     *
     * @return bool
     */
    private function isVerifiedDownload() {
        $request = $this->getRequest();
        $fileId = $request->getParam("id");
        $key = $request->getParam("download_key");
        $module = $request->getModuleName();
        $controller = $request->getControllerName();
        $action = $request->getActionName();
        $stationPodcast = StationPodcastQuery::create()
            ->findOneByDbPodcastId(Application_Model_Preference::getStationPodcastId());
        return $module == "rest" && $controller == "media" && $action == "download"
            && $key === Application_Model_Preference::getStationPodcastDownloadKey()
            && $stationPodcast->hasEpisodeForFile($fileId);
    }

    private function verifyCSRFToken($token) {
        return SecurityHelper::verifyCSRFToken($token);
    }
    
    private function verifyAPIKey() {
        // The API key is passed in via HTTP "basic authentication":
        // http://en.wikipedia.org/wiki/Basic_access_authentication
        $CC_CONFIG = Config::getConfig();
    
        // Decode the API key that was passed to us in the HTTP request.
        $authHeader = $this->getRequest()->getHeader("Authorization");
        $encodedRequestApiKey = substr($authHeader, strlen("Basic "));
        $encodedStoredApiKey = base64_encode($CC_CONFIG["apiKey"][0] . ":");
    
        return ($encodedRequestApiKey === $encodedStoredApiKey);
    }

    /**
     * Deny Access Function
     * Redirects to errorPage, this can be called from an action using the action helper
     *
     * @return void
     **/
    public function denyAccess()
    {
        $this->_request->setModuleName($this->_errorPage['module']);
        $this->_request->setControllerName($this->_errorPage['controller']);
        $this->_request->setActionName($this->_errorPage['action']);
    }
}