<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
class Login extends CI_Controller {
    function __construct() {
        parent::__construct();
          $this->load->model('login_model','',TRUE);
    }

    public function index() {
        $this->load->helper('form');
        $this->load->library('form_validation');
        $this->form_validation->set_rules('username', 'Username', 'required');
        $this->form_validation->set_rules('password', 'Password', 'required');
        if ($this->form_validation->run() == FALSE) {
            if (isset($this->session->userdata['id'])) {
                redirect('home/profile');
            } else {
                //else it will redirect you to login page.
                $this->load->view('templates/header');
                $this->load->view('login');
                $this->load->view('templates/footer');
            }
        } else {
            //if it's a post request with valid data it will validate data in database.
            $username = $this->input->post('username');
            $password = md5($this->input->post('password'));
            $result = $this->login_model->login($username, $password);
            //This condition redirect you to homepage if you entered valid credentials
            if (count($result) !== 0) {
                $this->session->set_userdata('id', $username);
                redirect('home/profile');
            } else {
                //This will redirect you to login page with error.
                $this->session->set_flashdata('message', 'Login Fail!!<br>Invalid username or password!!');
                redirect('login');
            }
        }
    }
}
?>

<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
class Login_model extends CI_Model{
    function login($username, $password)
        $this->db->select('id','username','password');
        $this->db->from('users');
        $this->db->where('username', $username);
        $this->db->where('password', md5($password));
        $this->db->limit(1);
        $query = $this->db->get();

        if($query->num_rows()>1){
            return $query->result();
        }else{
            return false;
        }
    }
}

if( $query->num_rows() == 1 ){
  return $query->result();
}

$this->db->where('password', md5($password));

$this->db->where('password', $password);