/*
    * Licensed to the Apache Software Foundation (ASF) under one or more
    * contributor license agreements.  See the NOTICE file distributed with
    * this work for additional information regarding copyright ownership.
    * The ASF licenses this file to You 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.apache.log4j.chainsaw;
  
  import org.apache.log4j.Logger;
  import org.apache.log4j.chainsaw.help.HelpManager;
  
  import javax.swing.*;
  import javax.swing.event.HyperlinkEvent;
  import java.awt.*;
  
  /**
   * A simple About box telling people stuff about this project
   *
   * @author Paul Smith <psmith@apache.org>
   */
  class ChainsawAbout extends JDialog {
      private static final Logger LOG = Logger.getLogger(ChainsawAbout.class);
  
      private final JEditorPane editPane = new JEditorPane("text/html", "");
  
      private final JScrollPane scrollPane = new JScrollPane(editPane,
          ScrollPaneConstants.VERTICAL_SCROLLBAR_NEVER,
          ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);
  
      private final String url = ChainsawAbout.class.getName().replace('.', '/')
          + ".html";
  
      private boolean sleep = false;
  
      private final Object guard = new Object();
  
      ChainsawAbout(JFrame parent) {
          super(parent, "About Chainsaw v2", true);
          // setResizable(false);
          setBackground(Color.white);
          getContentPane().setLayout(new BorderLayout());
  
          JButton closeButton = new JButton(" Close ");
          closeButton.addActionListener(e -> setVisible(false));
          closeButton.setDefaultCapable(true);
  
          try {
              editPane.setPage(this.getClass().getClassLoader().getResource(url));
          } catch (Exception e) {
              throw new RuntimeException("Failed to find the About panel HTML", e);
          }
          getContentPane().add(scrollPane, BorderLayout.CENTER);
          getContentPane().add(closeButton, BorderLayout.SOUTH);
          JTextComponentFormatter.applySystemFontAndSize(editPane);
  
          editPane.setEditable(false);
          editPane.addHyperlinkListener(
              e -> {
                  if (e.getEventType() == HyperlinkEvent.EventType.ACTIVATED) {
                      HelpManager.getInstance().setHelpURL(e.getURL());
                  }
              });
  
          setSize(320, 240);
          new Thread(new Scroller()).start();
          scrollPane.getViewport().setViewPosition(new Point(0, 0));
  
          setLocationRelativeTo(parent);
      }
  
      private class Scroller implements Runnable {
  
          public void run() {
              while (true) {
                  try {
                      if (sleep) {
                          synchronized (guard) {
                              guard.wait();
                          }
                          SwingUtilities.invokeLater(() -> scrollPane.getViewport().setViewPosition(
                              new Point(0, 0)));
                          continue;
                      }
                      SwingUtilities.invokeLater(() -> scrollPane.getViewport().setViewPosition(
                          new Point(0, scrollPane.getViewport()
                              .getViewPosition().y + 1)));
                      Thread.sleep(100);
                  } catch (Exception e) {
                      LOG.error("Error during scrolling", e);
                 }
 
             }
         }
     }
 
     public void setVisible(boolean visible) {
         super.setVisible(visible);
         sleep = !visible;
         synchronized (guard) {
             guard.notifyAll();
         }
     }
 }