/*************************************************************************************
                                 Controller
*************************************************************************************/
<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');

class Signup extends CI_Controller {

    public function user()
    {
        parent::Controller();
        $this->view_data['base_url'] = base_url();
        $this->load->model('User_model');
    }

    public function index()
    {
        $this->register();
    }

    public function register()
    {

        $this->load->library('form_validation');
        $this->load->model('User_model');
        $this->form_validation->set_rules('reg_username', 'Username', 'trim|required|alpha_numeric|min_length[3]|xss_clean|callback_username_not_exists');
        $this->form_validation->set_rules('reg_name', 'Name', 'trim|required|alpha_numeric|min_length[3]|xss_clean');
        $this->form_validation->set_rules('reg_email', 'Email Address', 'trim|required|min_length[3]|xss_clean|valid_email');
        $this->form_validation->set_rules('reg_password', 'Password', 'trim|required|min_length[6]|xss_clean');
        $this->form_validation->set_rules('reg_password_c', 'Password Confirm', 'trim|required|min_length[6]|matches[reg_password_c]|xss_clean');


        if($this->form_validation->run() == FALSE)
        {
            $this->load->view('signup');
        }
        else
        {
            $username = $this->input->post('reg_username');
            $name     = $this->input->post('reg_name');
            $password = $this->input->post('reg_password');
            $email    = $this->input->post('reg_email');

            $this->User_model->register_user($username, $password, $name, $email);
        }
    }

    function username_not_exists($username)
    {
        $this->form_validation->set_message('username_not_exists','That username exists: %s');
        if ($this->User_model->check_exists_username($username))
        {
            return false;
        }
        else
        {
            return true;
        }
    }
    function email_not_exists($email)
    {
        $this->form_validation->set_message('email_not_exists','That email is already in use: %s');
        if ($this->User_model->check_exists_email($email))
        {
            return false;
        }
        else
        {
            return true;
        }
    }
}


/*************************************************************************************
                                 Model
*************************************************************************************/
<?php
class User_model extends CI_Model
{
    function register_user($username, $password, $name, $email)
    {
        $sha1_password = sha1($password);
        $query_str = "INSERT INTO main (username, password, name, email) VALUES (?,?,?,?)";

        $this->db->query($query_str, array($username, $sha1_password, $name, $email));
    }

    function check_exists_username($username)
    {
        $query_str = "SELECT username FROM main WHERE username = ?";
        $result = $this->db->query($query_str, $username);

        if($result->num_rows() > 0)
        {
            return true;
        }
        else
        {
            return false;
        }
    }
    function check_exists_email($email)
    {
        $query_str = "SELECT email FROM main WHERE email = ?";
        $result = $this->db->query($query_str, $email);

        if($result->num_rows() > 0)
        {
            return true;
        }
        else
        {
            return false;
        }
    }
}