controller login

<?php
//defined('BASEPATH') OR exit('No direct script access allowed');
/**
*
*/
class Login extends CI_Controller
{

    function __construct()
    {
        parent::__construct();

        $this->load->model('model_login');
    }

    function index()
    {
        $this->load->view('login');
    }

    function ceklogin()
    {
        $username = $this->input->post('username');
        $password = $this->input->post('password');

        $where = array(
            'username' => $username,
            'password' => $password
        );

        $cek = $this->model_login->ceklogin("login",$where)->num_rows();
        if ($cek > 0) {
            $data_session = array(
                'nama' => $username,
                'status' => "login");

            $this->session->set_userdata($data_session);

            //$this->load->view('admin');
            //redirect(base_url("admin"));
            redirect(site_url('admin/admin'));
        }else if($cek <= 0){
            echo "<script type='text/javascript'>
                    alert ('Maaf Username dan Password Anda salah!');
                    </script>";
            redirect('login','refresh');
            //echo "string";

            /*echo "<div id="failModal" class="modal fade" role="dialog">";
            echo "<div class="modal-dialog">";
            echo "<div class="modal-content">";
            echo "<div class="modal-header">";
            echo "<h4 class="modal-title">Peringatan</h4>";
            echo "</div>";
            echo "<div class="modal-body">";
            echo "<p style="font-size: 16px">Username dan Password Salah!</p>";
            echo "</div>";
            echo "<div class="modal-footer">";
            echo "<button type="button" class="btn-primary" data-dismiss="modal">OK</button>";
            echo "</div>";
            echo "</div>";
            echo "</div>";
            echo "</div>";*/
            /*$this->session->set_flashdata('result_login',"Username atau Password salah!");
                redirect(base_url('login'));*/

            //$this->load->view('login');

        }
    }

    public function logout()
    {
        //$this->load->library('session');
        //$array_items = array('username');
        //$this->session->unset_userdata('username');

        $this->session->sess_destroy();

        //$this->session->userdata = array();

        //sebelum=============================
        //redirect(site_url('login/logout'));
        redirect(site_url('login'));

    }
}

?>