CodeIgniter-bcrypt:登录过程

我使用CodeIgniter-bcrypt作为我的登录表单，遇到了一堵墙，我希望有人能给我一些启示。

在我的控制器中，根据指令，我有以下命令将密码存储为散列:

$parent_password = $this->bcrypt->hash_password('parent_password');

在登录表单中，我有以下代码(现在，出于测试目的，我只是使用父登录进行测试，然后再传递给其他用户):

public function login_process(){
    if($this->input->post('action_type') == 'login'){
        $username = $this->input->post('username');
        $normal_password = $this->input->post('password');
        $password = md5($normal_password);
        $remember_me = $this->input->post('remember_me');
        $user_type = $this->input->post('t');
        if($user_type == 'admin'){
            $user_info_array = $this->admins_m->get_admin_detail("admin_username = " . $this->db->escape($username) . " AND MD5(admin_password) = " . $this->db->escape($password) . "");
        }else if($user_type == 'teacher'){
            $user_info_array = $this->teachers_m->get_teacher_detail("teacher_email = " . $this->db->escape($username) . " AND teacher_password = " . $this->db->escape($password, $stored_hash) . "");
        }else{
            $user_info_array = $this->parents_m->get_parents_detail("parent_email = " . $this->db->escape($username) . " AND parent_password = " . $this->bcrypt->check_password($password, $stored_hash) . "");
        }

当我尝试登录使用父测试，我得到一个PHP错误的stored_hash不是一个定义的变量。

这里的任何帮助将是非常感激的。提前感谢大家。

$user = $this->db->where('username', $this->input->post('username')
                 ->get('users')->row();

$valid = $this->bcrypt->verify($this->input->post('password'), $user->password);