function generate_html() {

$invoice_id = uri_assoc('invoice_id');

$this->load->library('invoices/lib_output');

$this->load->model('invoices/mdl_invoice_history');

$this->mdl_invoice_history->save($invoice_id, $this->session->userdata('user_id'), $this->lang->line('generated_invoice_html'));

$this->lib_output->html($invoice_id, uri_assoc('invoice_template'));

 /*  ------------------ GENERATE MD5-HTML ---------------------------  */
     $file = md5('my_output_path'.$invoice_id).'.html';

     echo "<a href='my_output_path".$file."'>Link to client invoice</a>";
     $f = fopen('my_invoice_path'.$file, 'w');
     $template = $this->load->view('invoice_templates/default_template');
 fwrite($f, $template);true;
     /*  ------------------ End generate md5 ---------------------------  */
     }