pagination doesn't work in codeigniter - codeigniter

Question

I made an optional search that makes the user search with username or customer or date from/to the result returning well to the first page but if I click on another page the result return nothing
this my front and all that input optional
i think the problem the pagination path because if i fill all inputs the pagination path become
controllername/userid/customerid/fromdate/todate
and if skip any input I find the pagination path is missing that
this my controller
public function search($page_num = 1){
$this->load->library('pagination');
$this->load->helper("url");
$this->load->model(array('CustomReport_m','user','Customer_m')); // This array to save number of lines only
$username=$this->input->post('select_user');
$username = ($this->uri->segment(3)) ? $this->uri->segment(3) : $username;
$customer=$this->input->post('select_customer');
$customer = ($this->uri->segment(4)) ? $this->uri->segment(4) : $customer;
$datefrom=$this->input->post('from');
$datefrom = ($this->uri->segment(5)) ? $this->uri->segment(5) : $datefrom;
$dateend=$this->input->post('to');
$dateend = ($this->uri->segment(6)) ? $this->uri->segment(6) : $dateend;
$total_row = $this->CustomReport_m->search_count($username,$customer,$datefrom,$dateend);
//$config['use_page_numbers'] = TRUE;
$config['base_url'] = site_url("CustomReport/search/$username/$customer/$datefrom/$dateend");
$config['total_rows'] = $total_row;
$config['per_page'] = 10;
$choice = $config["total_rows"]/$config["per_page"];
$config["num_links"] = floor($choice);
$config['full_tag_open'] = '<ul class="pagination">';
$config['full_tag_close'] = '</ul>';
$config['first_link'] = false;
$config['last_link'] = false;
$config['first_tag_open'] = '<li>';
$config['first_tag_close'] = '</li>';
$config['prev_link'] = '&laquo';
$config['prev_tag_open'] = '<li class="prev">';
$config['prev_tag_close'] = '</li>';
$config['next_link'] = '&raquo';
$config['next_tag_open'] = '<li>';
$config['next_tag_close'] = '</li>';
$config['last_tag_open'] = '<li>';
$config['last_tag_close'] = '</li>';
$config['cur_tag_open'] = '<li class="active"><a href="#">';
$config['cur_tag_close'] = '</a></li>';
$config['num_tag_open'] = '<li>';
$config['num_tag_close'] = '</li>';
$this->pagination->initialize($config);
if ($this->uri->segment(7)) {
$page = ($this->uri->segment(7));
} else {
$page = 1;
}
$str_links = $this->pagination->create_links();
$data["links"]= explode(' ', $str_links);
$data['users']=$this->user->display_users();
$data['userdata'] = $this->user->userdata();
$data['customers']= $this->Customer_m->index();
// if(isset($_POST['submit'])){
$data["rsl"] =$this->CustomReport_m->search($username,$customer,$datefrom,$dateend,$config["per_page"],$page);
$this->load->view('customreport_v',$data);
// }else{
// redirect('CustomReport','refresh');
// }
}
This is my model
public function search_count($username,$customer,$datefrom,$dateend) {
$this->db->select('*');
$this->db->from('transactions');
if (!empty($customer)){
$this->db->where('t_customer_id',$customer);
}
if (!empty($username)){
$this->db->where('t_u_id',$username);
}
if (!empty($dateend)){
$this->db->where('t_date <=',$dateend);
}
if (!empty($datefrom)){
$this->db->where('t_date >=',$datefrom);
}
return $this->db->get()->num_rows();
}
public function search($username,$customer,$datefrom,$dateend,$limit,$start)
{
$start=$start-1;
$this->db->select('*');
$this->db->from('transactions');
if (!empty($customer)){
$this->db->where('t_customer_id',$customer);
}
if (!empty($username)){
$this->db->where('t_u_id',$username);
}
if (!empty($dateend)){
$this->db->where('t_date <=',$dateend);
}
if (!empty($datefrom)){
$this->db->where('t_date >=',$datefrom);
}
$this->db->limit($limit,$start);
$query=$this->db->get();
if($query->num_rows() > 0){
return $query->result();
}else{
return $query->result();
}
}
this my route
$route['CustomReport/(:num)']="CustomReport/index/$1";