package com.github.celldynamics.quimp.registration;
   
   import java.awt.BorderLayout;
   import java.awt.Desktop;
   import java.awt.Dimension;
   import java.awt.FlowLayout;
   import java.awt.GridLayout;
   import java.awt.Window;
   import java.awt.event.ActionEvent;
  import java.awt.event.ActionListener;
  import java.awt.event.MouseAdapter;
  import java.awt.event.MouseEvent;
  import java.io.IOException;
  import java.net.URISyntaxException;
  import java.nio.charset.StandardCharsets;
  import java.security.MessageDigest;
  import java.security.NoSuchAlgorithmException;
  import java.util.List;
  
  import javax.swing.JButton;
  import javax.swing.JDialog;
  import javax.swing.JEditorPane;
  import javax.swing.JFrame;
  import javax.swing.JLabel;
  import javax.swing.JMenuItem;
  import javax.swing.JOptionPane;
  import javax.swing.JPanel;
  import javax.swing.JPopupMenu;
  import javax.swing.JScrollPane;
  import javax.swing.JTextField;
  import javax.swing.SwingWorker;
  import javax.swing.event.HyperlinkEvent;
  import javax.swing.event.HyperlinkListener;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import com.github.celldynamics.quimp.PropertyReader;
  import com.github.celldynamics.quimp.QuimP;
  
  import ij.Prefs;
  
  /*
   * !>
   * @startuml doc-files/Registration_1_UML.png
   * actor User
   * activate Module
   * Module-->Registration : <<create>>
   * activate Registration
   * Registration->Registration : check if registered
   * Registration->UI : not registered, show UI
   * activate UI
   * == Cancelled ==
   * User -> UI : Cancel
   * UI->UI : wait
   * ... Wait ...
   * UI-->Registration
   * deactivate UI
   * Registration-->Module
   * destroy Registration
   * ... Continue with module...
   * Module->Module : Run()
   * deactivate Module
   * @enduml
   * 
   * @startuml doc-files/Registration_2_UML.png
   * actor User
   * activate Module
   * Module-->Registration : <<create>>
   * activate Registration
   * Registration->Registration : check if registered
   * Registration->UI : not registered, show UI
   * activate UI
   * == Apply ==
   * User -> UI : Apply
   * UI->UI : compare hashes
   * UI-->Registration
   * deactivate UI
   * Registration-->Module
   * destroy Registration
   * ... Continue with module...
   * Module->Module : Run()
   * deactivate Module
   * @enduml
   * 
   * @startuml doc-files/Registration_3_UML.png
   * start
   * :read reg details;
   * note right
   * From IJ_Prefs.txt file
   * end note
   * :compute hash from email;
   * note left
   * Validate whether hash and email
   * from prefs matches
   * end note
   * if(hash the same as in IJ_Prefs?) then (no)
   * 
   * :show registration UI;
  * if(Button) then (cancel)
  * :wait;
  * else (apply)
  * :Check registration;
  * if(registration correct) then (yes)
  * :Store in IJ_Prefs.txt;
  * else (no)
  * start
  * endif
  * endif
  * endif
  * stop
  * @enduml
  * 
  * @startuml doc-files/Registration_4_UML.png
  * [*] --> DisplayUI
  * DisplayUI : Cancel
  * DisplayUI : Apply
  * 
  * DisplayUI->Wait : Cancel
  * Wait -> [*]
  * 
  * DisplayUI->Register : Apply
  * Register : compute hashes\nand compare
  * Register-> DisplayUI : hash not valid
  * Register ->[*] : hash valid
  * @enduml
  * 
  * !<
  */
 /**
  * Support registration checking.
  * 
  * <p>Registration component is self running. It should be located at very beginning of Module code.
  * It
  * blocks Module from execution until driving from Registration is returned to it.
  * 
  * <p>Registration process follows the scheme for cancel action: <br>
  * <img src="doc-files/Registration_1_UML.png"/><br>
  * And for register action: <br>
  * <img src="doc-files/Registration_2_UML.png"/><br>
  * Tests on first run: <br>
  * <img src="doc-files/Registration_3_UML.png"/><br>
  * UI transactions: <br>
  * <img src="doc-files/Registration_4_UML.png"/><br>
  * 
  * @author p.baniukiewicz
  *
  */
 public class Registration extends JDialog implements ActionListener {
 
   /**
    * The Constant LOGGER.
    */
   static final Logger LOGGER = LoggerFactory.getLogger(Registration.class.getName());
 
   private JButton bnOk;
   private JButton bnCancel;
   /**
    * Flag that indicates that user has waited already.
    */
   public boolean waited = false;
   /**
    * How long to wait in sec.
    */
   private final int secondsToWait = 5;
   private JTextField tfEmail;
   private JTextField tfKey;
   private Window owner;
 
   private JPopupMenu popup;
   private JEditorPane helpArea;
 
   private static final long serialVersionUID = -3889439366816085913L;
 
   /**
    * Create and display registration window if necessary.
    * 
    * @param owner owner
    * @param title title
    */
   public Registration(Window owner, String title) {
     super(owner, title, ModalityType.APPLICATION_MODAL);
     this.owner = owner;
     // skip if debug mode
     String skipReg = new PropertyReader().readProperty("quimpconfig.properties", "noRegWindow");
     if (Boolean.parseBoolean(skipReg) == true) {
       LOGGER.info("Skipping reg window. Hope ony for tests... ");
       return;
     }
     // display reg window if not registered
     if (checkRegistration() == false) {
       build(title, true);
     }
   }
 
   /**
    * Construct object but does not display window.
    * 
    * <p>Allow to set some parameters before window construction.
    * 
    * @param owner owner
    */
   public Registration(Window owner) {
     this.owner = owner;
   }
 
   /**
    * Construct and display window.
    * 
    * @param title title
    * @param show indicate whether show window on screen
    */
   public void build(String title, boolean show) {
     buildMenu();
     buildWindow();
     setVisible(show);
   }
 
   /**
    * Build popup menu.
    */
   private void buildMenu() {
     popup = new JPopupMenu();
     // changing the name must follow with actionPerformed
     JMenuItem selectall = new JMenuItem("Select All");
     // changing the name must follow with actionPerformed
     JMenuItem copy = new JMenuItem("Copy");
     selectall.addActionListener(this);
     copy.addActionListener(this);
     popup.add(selectall);
     popup.add(copy);
 
   }
 
   /**
    * Build main window.
    */
   private void buildWindow() {
     JPanel wndpanel = new JPanel();
     wndpanel.setLayout(new BorderLayout());
 
     // ok, cancel row
     JPanel caButtons = new JPanel();
     caButtons.setLayout(new FlowLayout(FlowLayout.CENTER));
     bnOk = new JButton("Apply");
     bnOk.addActionListener(this);
     bnCancel = new JButton("Cancel");
     bnCancel.addActionListener(this);
     caButtons.add(bnOk);
     caButtons.add(bnCancel);
     wndpanel.add(caButtons, BorderLayout.SOUTH);
     // registration area and key and email
     JPanel centerarea = new JPanel();
     centerarea.setLayout(new BorderLayout());
     wndpanel.add(centerarea, BorderLayout.CENTER);
     // html info
     try {
       helpArea = new JEditorPane(getClass().getResource("reg.html").toURI().toURL());
 
       helpArea.setContentType("text/html");
       helpArea.setEditable(false);
       JScrollPane helpPanel = new JScrollPane(helpArea);
       helpPanel.setPreferredSize(new Dimension(500, 600));
       centerarea.add(helpPanel, BorderLayout.CENTER);
       // add mouse listeners
       helpArea.addMouseListener(new MouseAdapter() {
         @Override
         public void mousePressed(MouseEvent e) {
           maybeShowPopup(e);
         }
 
         @Override
         public void mouseReleased(MouseEvent e) {
           maybeShowPopup(e);
         }
 
         private void maybeShowPopup(MouseEvent e) {
           if (e.isPopupTrigger()) {
             popup.show(e.getComponent(), e.getX(), e.getY());
           }
         }
       });
       // add link listener
       helpArea.addHyperlinkListener(new HyperlinkListener() {
         public void hyperlinkUpdate(HyperlinkEvent e) {
           if (e.getEventType() == HyperlinkEvent.EventType.ACTIVATED) {
             try {
               Desktop.getDesktop().browse(e.getURL().toURI());
             } catch (Exception e1) {
               LOGGER.error("Can not start browser: " + e1.getMessage());
               LOGGER.debug(e1.getMessage(), e1);
             }
           }
         }
       });
     } catch (IOException | URISyntaxException e2) {
       LOGGER.error("Can not read resource registration page: " + e2.getMessage());
       LOGGER.debug(e2.getMessage(), e2);
     }
     // email and key fields
     JPanel regarea = new JPanel();
     // regarea.setBackground(Color.YELLOW);
     regarea.setLayout(new GridLayout(3, 2));
     ((GridLayout) regarea.getLayout()).setHgap(10);
     ((GridLayout) regarea.getLayout()).setVgap(2);
     centerarea.add(regarea, BorderLayout.SOUTH);
     tfEmail = new JTextField(16);
     tfKey = new JTextField(16);
     regarea.add(new JLabel(""));
     regarea.add(new JLabel(""));
 
     regarea.add(tfEmail);
     regarea.add(new JLabel("Registration email"));
 
     regarea.add(tfKey);
     regarea.add(new JLabel("Your key"));
 
     add(wndpanel);
     if (owner != null) {
       setLocation(owner.getLocation());
     }
     setAlwaysOnTop(true);
     pack();
     setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
   }
 
   /*
    * (non-Javadoc)
    * 
    * @see java.awt.event.ActionListener#actionPerformed(java.awt.event.ActionEvent)
    */
   @Override
   public void actionPerformed(ActionEvent e) {
     // clicked Cancel and user has not not waited yet
     if (e.getSource() == bnCancel && waited == false) {
       bnOk.setEnabled(false);
       bnCancel.setEnabled(false);
       Worker w = new Worker(secondsToWait); // will change button text
       w.execute();
       return;
     }
     // Cancel and waited already - quit
     if (e.getSource() == bnCancel && waited == true) {
       dispose();
       return;
     }
     // apply - get code, say thank you and exit
     if (e.getSource() == bnOk) {
       boolean ret = validateRegInfo(tfEmail.getText(), tfKey.getText());
       if (ret) {
         waited = true;
         registerUser(tfEmail.getText(), tfKey.getText());
         JOptionPane.showMessageDialog(this, "Thank you for registering our product.", "OK!",
                 JOptionPane.INFORMATION_MESSAGE);
         dispose();
       } else {
         JOptionPane.showMessageDialog(this, "The key you provided does not match to the email.",
                 "Error", JOptionPane.WARNING_MESSAGE);
       }
       return;
     }
     // support for action events
     switch (e.getActionCommand()) {
       case "Copy":
         helpArea.copy();
         break;
       case "Select All":
         helpArea.selectAll();
         break;
       default:
         throw new IllegalArgumentException("Unknown action.");
     }
   }
 
   /**
    * Add registration info to the IJ configuration.
    * 
    * @param email email
    * @param key key
    */
   private void registerUser(final String email, final String key) {
     Prefs.set("registration" + QuimP.QUIMP_PREFS_SUFFIX + ".mail", email);
     Prefs.set("registration" + QuimP.QUIMP_PREFS_SUFFIX + ".key", key);
 
   }
 
   /**
    * Read info from IJ container.
    * 
    * @return Array of [0] reg email, [1] key
    */
   public String[] readRegInfo() {
     String[] ret = new String[2];
     ret[0] = Prefs.get("registration" + QuimP.QUIMP_PREFS_SUFFIX + ".mail", "");
     ret[1] = Prefs.get("registration" + QuimP.QUIMP_PREFS_SUFFIX + ".key", "");
     return ret;
   }
 
   /**
    * Read registration details from IJ and fills the registration window.
    */
   public void fillRegForm() {
     String[] reg = readRegInfo();
     tfEmail.setText(reg[0]);
     tfKey.setText(reg[1]);
   }
 
   /**
    * Check if user is registered.
    * 
    * @return True if user registration info is available in IJ_Prefs.txt and data are valid.
    */
   private boolean checkRegistration() {
     String[] reginfo = readRegInfo();
     boolean ret = validateRegInfo(reginfo[0], reginfo[1]);
     return ret;
   }
 
   /**
    * Validate whether key matches to email.
    * 
    * @param email email
    * @param key key
    * @return <tt>true</tt> is key matches to email.
    */
   private boolean validateRegInfo(final String email, final String key) {
     if (email == null || key == null) {
       return false;
     }
     String emails = email.toLowerCase();
     String keys = key.toLowerCase();
     // remove all white chars
     emails = emails.replaceAll("\\s+", "");
     keys = keys.replaceAll("\\s+", "");
     if (email.isEmpty() || key.isEmpty()) {
       return false;
     }
 
     String salt = "secret"; // :)
     // add secret word
     emails = emails + salt;
     // compute hash
     try {
       MessageDigest md = MessageDigest.getInstance("MD5");
       md.update(emails.getBytes(StandardCharsets.UTF_8));
       StringBuilder sb = new StringBuilder();
       for (byte b : md.digest()) { // convert to char
         // dealing with conversion to int from byte and leading 0 for values smaller than 16
         String ss = Integer.toHexString(0x100 | (b & 0xff)).substring(1);
         sb.append(ss);
       }
       String digest = sb.toString().toLowerCase();
       LOGGER.trace("email: " + email + " Digest: " + digest);
       if (digest.equals(keys)) {
         return true;
       }
     } catch (NoSuchAlgorithmException e) {
       e.printStackTrace();
     }
     return false;
   }
 
   /**
    * Do counting and waiting in background updating UI in the same time.
    * 
    * @author p.baniukiewicz
    * @see <a href=
    *      "link">http://stackoverflow.com/questions/11817688/how-to-update-swing-gui-from-inside-a-long-method</a>
    */
   class Worker extends SwingWorker<String, String> {
     private int wait;
     private Dimension dc;
 
     /**
      * Instantiates a new worker.
      *
      * @param wait the wait
      */
     public Worker(int wait) {
       this.wait = wait;
     }
 
     /*
      * (non-Javadoc)
      * 
      * @see javax.swing.SwingWorker#doInBackground()
      */
     @Override
     protected String doInBackground() throws Exception {
       dc = bnCancel.getSize(); // remember size of button
       // This is what's called in the .execute method
       for (int i = 0; i < wait; i++) {
         // This sends the results to the .process method
         publish(String.valueOf(wait - i));
         Thread.sleep(1000);
       }
       // at the end of job reenable everything
       waited = true; // set flag on the end of wait
       bnOk.setEnabled(true);
       bnCancel.setEnabled(true);
       bnCancel.setText("Cancel");
       return null;
     }
 
     /*
      * (non-Javadoc)
      * 
      * @see javax.swing.SwingWorker#process(java.util.List)
      */
     @Override
     protected void process(List<String> item) {
       // This updates the UI
       bnCancel.setText(item.get(0));
       bnCancel.setPreferredSize(dc); // keep size as original
     }
   }
 
   /**
    * Support for popupmenu.
    * 
    * @author p.baniukiewicz
    *
    */
   class PopupListener extends MouseAdapter {
 
     /*
      * (non-Javadoc)
      * 
      * @see java.awt.event.MouseAdapter#mousePressed(java.awt.event.MouseEvent)
      */
     @Override
     public void mousePressed(MouseEvent e) {
       maybeShowPopup(e);
     }
 
     /*
      * (non-Javadoc)
      * 
      * @see java.awt.event.MouseAdapter#mouseReleased(java.awt.event.MouseEvent)
      */
     @Override
     public void mouseReleased(MouseEvent e) {
       maybeShowPopup(e);
     }
 
     private void maybeShowPopup(MouseEvent e) {
       if (e.isPopupTrigger()) {
         popup.show(e.getComponent(), e.getX(), e.getY());
       }
     }
   }
 
 }