Codeigniter Twitter Login

<?php defined('BASEPATH') OR exit('No direct script access allowed');
class User_Authentication extends CI_Controller
{
    function __construct() {
        parent::__construct();

		// Load twitter config
        $this->load->config('twitter');

		//Load user model
        $this->load->model('user');
    }

    public function index(){
        $userData = array();

        //Include the twitter oauth php libraries
        include_once APPPATH."libraries/twitter-oauth-client/twitteroauth.php";

        //Twitter API Configuration
        $consumerKey = $this->config->item('twitter_api_key');
		$consumerSecret = $this->config->item('twitter_api_secret');
		//$consumerKey = 'Insert_Twitter_API_Key';
        //$consumerSecret = 'Insert_Twitter_API_Secret';
        $oauthCallback = base_url().'user_authentication/';

        //Get existing token and token secret from session
        $sessToken = $this->session->userdata('token');
        $sessTokenSecret = $this->session->userdata('token_secret');

        //Get status and user info from session
        $sessStatus = $this->session->userdata('status');
        $sessUserData = $this->session->userdata('userData');

        if(isset($sessStatus) && $sessStatus == 'verified'){
            //Connect and get latest tweets
            $connection = new TwitterOAuth($consumerKey, $consumerSecret, $sessUserData['accessToken']['oauth_token'], $sessUserData['accessToken']['oauth_token_secret']);
            $data['tweets'] = $connection->get('statuses/user_timeline', array('screen_name' => $sessUserData['username'], 'count' => 5));

            //User info from session
            $userData = $sessUserData;
        }elseif(isset($_REQUEST['oauth_token']) && $sessToken == $_REQUEST['oauth_token']){
            //Successful response returns oauth_token, oauth_token_secret, user_id, and screen_name
            $connection = new TwitterOAuth($consumerKey, $consumerSecret, $sessToken, $sessTokenSecret);
            $accessToken = $connection->getAccessToken($_REQUEST['oauth_verifier']);
            if($connection->http_code == '200'){
                //Get user profile info
                $userInfo = $connection->get('account/verify_credentials');

                //Preparing data for database insertion
                $name = explode(" ",$userInfo->name);
                $first_name = isset($name[0])?$name[0]:'';
                $last_name = isset($name[1])?$name[1]:'';
                $userData = array(
                    'oauth_provider' => 'twitter',
                    'oauth_uid' => $userInfo->id,
                    'username' => $userInfo->screen_name,
                    'first_name' => $first_name,
                    'last_name' => $last_name,
                    'locale' => $userInfo->lang,
                    'profile_url' => 'https://twitter.com/'.$userInfo->screen_name,
                    'picture_url' => $userInfo->profile_image_url
                );

                //Insert or update user data
                $userID = $this->user->checkUser($userData);

                //Store status and user profile info into session
                $userData['accessToken'] = $accessToken;
                $this->session->set_userdata('status','verified');
                $this->session->set_userdata('userData',$userData);

                //Get latest tweets
                $data['tweets'] = $connection->get('statuses/user_timeline', array('screen_name' => $userInfo->screen_name, 'count' => 5));
            }else{
                $data['error_msg'] = 'Some problem occurred, please try again later!';
            }
        }else{
            //unset token and token secret from session
            $this->session->unset_userdata('token');
            $this->session->unset_userdata('token_secret');

            //Fresh authentication
            $connection = new TwitterOAuth($consumerKey, $consumerSecret);
            $requestToken = $connection->getRequestToken($oauthCallback);

            //Received token info from twitter
            $this->session->set_userdata('token',$requestToken['oauth_token']);
            $this->session->set_userdata('token_secret',$requestToken['oauth_token_secret']);

            //Any value other than 200 is failure, so continue only if http code is 200
            if($connection->http_code == '200'){
                //Get twitter oauth url
                $twitterUrl = $connection->getAuthorizeURL($requestToken['oauth_token']);
                $data['oauthURL'] = $twitterUrl;
            }else{
                $data['oauthURL'] = base_url().'user_authentication';
                $data['error_msg'] = 'Error connecting to twitter! try again later!';
            }
        }

        $data['userData'] = $userData;
        $this->load->view('user_authentication/index',$data);
    }

    public function logout() {
        $this->session->unset_userdata('token');
        $this->session->unset_userdata('token_secret');
        $this->session->unset_userdata('status');
        $this->session->unset_userdata('userData');
        $this->session->sess_destroy();
        redirect('/user_authentication');
    }
}