public static function sender_submission_fields(SI_Invoice $invoice)
 {
     $fields = array();
     $from_name = SI_Notifications_Control::from_name(array('invoice_id' => $invoice->get_id()));
     $from_email = SI_Notifications_Control::from_email(array('invoice_id' => $invoice->get_id()));
     $fields['send_as'] = array('weight' => 1, 'label' => self::__('Sender'), 'type' => 'text', 'placeholder' => '', 'attributes' => array('readonly' => 'readonly'), 'default' => $from_name . ' <' . $from_email . '>');
     // options for recipients
     $client = $invoice->get_client();
     $recipient_options = '<div class="form-group"><div class="input_wrap">';
     // client users
     if (is_a($client, 'SI_Client')) {
         $client_users = $client->get_associated_users();
         foreach ($client_users as $user_id) {
             if (!is_wp_error($user_id)) {
                 $recipient_options .= sprintf('<label class="clearfix"><input type="checkbox" name="sa_metabox_recipients[]" value="%1$s"> %2$s</label>', $user_id, esc_attr(SI_Notifications::get_user_email($user_id)));
             }
         }
     }
     $recipient_options .= sprintf('<label class="clearfix"><input type="checkbox" name="sa_metabox_custom_recipient_check" disabled="disabled"><input type="text" name="sa_metabox_custom_recipient" placeholder="%1$s"><span class="helptip" title="%2$s"></span></label>', self::__('*****@*****.**'), self::__('Entering an email will prevent some notification shortcodes from working since there is no client.'));
     // Send to me.
     $recipient_options .= sprintf('<label class="clearfix"><input type="checkbox" name="sa_metabox_recipients[]" value="%1$s"> %2$s</label>', get_current_user_id(), si__('Send me a copy'));
     $recipient_options .= '</div></div>';
     $fields['recipients'] = array('weight' => 5, 'label' => sprintf('%s <span class="helptip" title="%s"></span>', si__('Recipients'), si__('A notification will be sent if recipients are selected and this invoice is saved.')), 'type' => 'bypass', 'output' => $recipient_options);
     $fields['sender_note'] = array('weight' => 10, 'label' => self::__('Note'), 'type' => 'textarea', 'default' => $invoice->get_sender_note(), 'description' => si__('This note will be added to the Invoice Notification via the [admin_note] shortcode.'));
     $fields['doc_id'] = array('type' => 'hidden', 'value' => $invoice->get_id(), 'weight' => 10000);
     $fields['notification_nonce'] = array('type' => 'hidden', 'value' => wp_create_nonce(SI_Controller::NONCE), 'weight' => 10001);
     $fields = apply_filters('si_sender_submission_fields', $fields);
     uasort($fields, array(__CLASS__, 'sort_by_weight'));
     return $fields;
 }