/**
    * Copyright 2011, Aiki IT, FotoRenamer
    * <p/>
    * 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
    * <p/>
    * http://www.apache.org/licenses/LICENSE-2.0
    * <p/>
   * 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 de.aikiit.fotorenamer.gui;
  
  import de.aikiit.fotorenamer.util.ComponentGaugeUtil;
  import org.apache.logging.log4j.LogManager;
  import org.apache.logging.log4j.Logger;
  
  import javax.swing.*;
  import java.awt.*;
  import java.awt.event.ActionEvent;
  import java.awt.event.ActionListener;
  import java.io.File;
  
  import static de.aikiit.fotorenamer.util.LocalizationHelper.getBundleString;
  import static de.aikiit.fotorenamer.util.LocalizationHelper.getLanguage;
  import static de.aikiit.fotorenamer.util.LocalizationHelper.getParameterizedBundleString;
  
  /**
   * This class represents a help window component. It loads a HTML-page to show
   * as application help.
   *
   * @author hirsch, 20.10.2003
   * @version 2004-01-08
   */
  class HelpWindow extends JFrame implements ActionListener {
      /**
       * Logger for this class.
       */
      private static final Logger LOG = LogManager.getLogger(HelpWindow.class);
      /**
       * End button needs to be visible inside the class to perform application
       * exit.
       */
      private JButton endButton = null;
  
      /**
       * Relative location of the UI's help page.
       */
      private static final String HTML_HELP_LOCATION = File.separator + "html"
              + File.separator;
  
      /**
       * Creates a HelpWindow, initializes its components but does
       * <strong>not</strong> show the window.
       */
      HelpWindow() {
          SwingUtilities.invokeLater(this::init);
      }
  
      /**
       * Initialize UI-compontens and make them visible.
       */
      private void init() {
          this.setTitle(getBundleString(
                  "fotorenamer.ui.help.title"));
          this.setResizable(false);
          JPanel top = new JPanel(new FlowLayout());
          JPanel bottom = new JPanel(new FlowLayout());
  
          JEditorPane textfield = new JEditorPane();
          textfield.setContentType("text/html");
          textfield.setEditable(false);
          loadHelpContents(top, textfield);
  
          JScrollPane rollpanel = new JScrollPane(top);
          rollpanel.setPreferredSize(new Dimension(350, 300));
          rollpanel.setVerticalScrollBarPolicy(
                  JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
  
          this.endButton = new JButton(getBundleString(
                  "fotorenamer.ui.help.close"));
          this.endButton.addActionListener(this);
          this.endButton.setMnemonic(getBundleString("fotorenamer.ui.help.close.mnemonic").charAt(0));
          bottom.add(this.endButton);
  
          this.getContentPane().setLayout(new BorderLayout());
          this.getContentPane().add(rollpanel, BorderLayout.NORTH);
          this.getContentPane().add(bottom, BorderLayout.CENTER);
  
          this.pack();
          ComponentGaugeUtil.makeCentered(this);
  
          // let button get the focus, needs to be run in the and and async
          SwingUtilities.invokeLater(() -> {
              getRootPane().setDefaultButton(endButton);
             endButton.requestFocusInWindow();
         });
 
         LOG.debug("HelpWindow init done.");
     }
 
     /**
      * Load page contents depending on available languages (fallback is English).
      *
      * @param base      base panel.
      * @param textfield where to put the contents to.
      */
     private void loadHelpContents(final JPanel base, final JEditorPane textfield) {
         try {
             String helpPageLocation = HTML_HELP_LOCATION;
 
             if (getLanguage().startsWith("de")) {
                 helpPageLocation += "hilfe.html";
             } else {
                 helpPageLocation += "help.html";
             }
 
             textfield.setPage(HelpWindow.class.getResource(helpPageLocation));
             base.add(textfield);
         } catch (Exception e) {
             base.setLayout(new GridLayout(1, 1));
             base.add(new JLabel(getParameterizedBundleString("fotorenamer.ui.help.error", e.getMessage(), e.getClass().getSimpleName())));
         }
     }
 
     /**
      * Make this component react to close button.
      *
      * @param event Event to react on in this UI-component.
      */
     public final void actionPerformed(final ActionEvent event) {
         if (event.getSource() == this.endButton) {
             LOG.debug("Disabling visibility of helpWindow.");
             setVisible(false);
         }
     }
 }