/**
    * Copyright 2011-2019 PrimeFaces Extensions
    *
    * Licensed under the Apache License, Version 2.0 (the "License");
    * you may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    *
    * http://www.apache.org/licenses/LICENSE-2.0
    *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package org.primefaces.extensions.renderer;
  
  import java.io.IOException;
  import javax.el.ValueExpression;
  import javax.faces.context.FacesContext;
  import org.primefaces.component.commandbutton.CommandButton;
  import org.primefaces.component.commandbutton.CommandButtonRenderer;
  
  /**
   * {@link CommandButton} renderer disabling the button while action is processed for buttons that are using Ajax.
   *
   * @author Jasper de Vries <jepsar@gmail.com>
   * @since 8.0
   */
  public class CommandButtonSingleClickRenderer extends CommandButtonRenderer {
  
      @Override
      protected void encodeMarkup(FacesContext context, CommandButton button) throws IOException {
          if (isEligible(button)) {
              String widgetVar = button.resolveWidgetVar(context);
              String onClick = getAttributeValue(context, button, "onclick");
              String onComplete = getAttributeValue(context, button, "oncomplete");
              button.setOnclick(prefix(onClick, getToggleJS(widgetVar, false)));
              button.setOncomplete(prefix(onComplete, getToggleJS(widgetVar, true)));
          }
          super.encodeMarkup(context, button);
      }
  
      protected boolean isEligible(final CommandButton button) {
          return button.isAjax()
                 && button.isRendered()
                 && button.getActionExpression() != null
                 && !button.isDisabled()
                 && !isConfirmation(button);
      }
  
      protected boolean isConfirmation(final CommandButton button) {
          String styleClass = button.getStyleClass();
          return styleClass != null && styleClass.contains("ui-confirmdialog");
      }
  
      protected String getToggleJS(final String widgetVar, final boolean enabled) {
          return String.format("var w=PF('%s');if(w){w.%sable();};", widgetVar, enabled ? "en" : "dis");
      }
  
      protected String getAttributeValue(final FacesContext context, final CommandButton button, final String attribute) {
          ValueExpression ve = button.getValueExpression(attribute);
          return ve == null ? null : (String) ve.getValue(context.getELContext());
      }
  
      protected String prefix(final String base, final String prefix) {
          return base == null ? prefix : prefix + base;
      }
  
  }