import javax.swing.*;
import java.awt.event.*;
import java.awt.*;
import java.util.*;


/**
 * JMSChat implements the JMS chat client. It is a multi-threaded
 * program that uses a pub/sub topic for broadcasting messages to all
 * subscribers to the topic.
 * It creates the user interface and several threads; one to send
 * messages, one to receive messages, and one to update the user
 * interface.
 * The threads for sending and receiving messages are implemented by
 * the JMSChatThread class.
 */

public class JMSChat extends JFrame {

    JFrame              frame;
    CardPanel           cardStackPanel;
    ChatPanel           chatCard;
    LoginPanel          loginCard;
    static String       chatUser = null;
    static String       chatTopic = null;
    JMSChatThread       receiverThread = null;
    JMSChatThread       senderThread = null;
    Thread              updateThread = null;
    UpdateTextArea      doUpdate;
    private ChatData    controlData;

    final static String newline           = "\n";
    final static String loginButtonLabel  = "Login";
    final static String resetButtonLabel  = "Reset";
    final static String exitButtonLabel   = "Exit";
    final static String defaultTopic      = "ChatTopic";
    final static String defaultUserLabel  =
        "Please enter a user name :";
    final static String defaultTopicLabel =
        "Please enter a topic name (" + defaultTopic +
        " is default) :";
    final static String errorUserLabel    =
        "PLEASE ENTER A VALID USER NAME :";
    final static String errorTopicLabel   =
        "PLEASE ENTER A VALID TOPIC NAME :";

    /**
     * Class constructor.
     *
     * @param     controlData          control flags and data
     */
    public JMSChat(ChatData controlData) {
        this.controlData = controlData;
        frame = new JFrame("JMS Chat Client");
        frame.setDefaultCloseOperation(
            JFrame.DISPOSE_ON_CLOSE);
        frame.setBackground(Color.lightGray);
        frame.setForeground(Color.white);
        frame.setSize(580,300);
        frame.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {
                exitJMSChat();
            }
        });
        cardStackPanel = new CardPanel();
        loginCard = new LoginPanel(frame);
        cardStackPanel.add(loginCard,"loginCard");
        cardStackPanel.showCard("loginCard");
        frame.getContentPane().add(cardStackPanel);
        frame.setVisible(true);
        /*
         * Start the thread to update the user interface. 
         * This thread only uses the thread-safe append
         * method, so no "SwingWorker" thread is required.
         */
        doUpdate = new UpdateTextArea();
        updateThread = new Thread(doUpdate);
        updateThread.start();
    }

    /**
     * Thread to update the user interface with messages
     * received from the JMS chat topic.
     */
    class UpdateTextArea implements Runnable {
        public void run() {
            String message = null;
            while (true) {
                try {
                    message = controlData.retrieveInbound();
                    if (message != null) {
                        chatCard.receivedTextArea.append(message + newline);
                    }
                } catch (Exception e) {
                    System.out.println("Exception occurred: " +
                        e.toString());
                }
            }
        }
    }

    /**
     * The main entry point.
     */
    public static void main(String[] args) {
        if (args.length != 0) {
            System.out.println(
                "Usage: java -Djms.properties=<properties> JMSChat");
            System.exit(1);
        }
        ChatData controlData = new ChatData();
        JMSChat myChat = new JMSChat(controlData);
    }

    /**
     * Exit routine.
     */
    private void exitJMSChat() {
	// Set the exit flag
	controlData.setExitFlag();
        // Interrupting sender thread triggers tidy up
        if (senderThread != null) {
            senderThread.interrupt();
        }
        // Have to be more brutal with receiver thread
        if (receiverThread != null) {
            receiverThread.tidyUp();
        }
        frame.setVisible(false);
        frame.dispose();
        System.exit(0);
    }

    /**
     * User interface login panel.
     * Used to obtain user login name and chat topic name.
     */
    private class LoginPanel extends JPanel {

        JButton    loginButton;
        JButton    resetButton;
        JLabel     userLabel;
        JLabel     topicLabel;
        JTextField userName;
        JTextField topicName;

        public LoginPanel(JFrame parent) {

            GridBagLayout gridbag = new GridBagLayout();
            GridBagConstraints c = new GridBagConstraints();
            setLayout(gridbag);
            setBorder(BorderFactory.createCompoundBorder(
                BorderFactory.createMatteBorder(
                    1,1,2,2,Color.black),
                    BorderFactory.createEmptyBorder(5,5,5,5)));

            c.fill = GridBagConstraints.HORIZONTAL;
            c.anchor = GridBagConstraints.NORTH;
            c.gridwidth = GridBagConstraints.REMAINDER;
	    c.gridheight = 1;
            userLabel = new JLabel(defaultUserLabel);
            gridbag.setConstraints(userLabel, c);
            add(userLabel);

            c.weighty = 1.0;
            userName = new JTextField();
            userName.setEditable(true);
	    userName.setText("");
            gridbag.setConstraints(userName, c);
            add(userName);

            c.weightx = 0.0;
            c.weighty = 0.0;
            topicLabel = new JLabel(defaultTopicLabel);
            gridbag.setConstraints(topicLabel, c);
            add(topicLabel);

            c.weighty = 1.0;
            topicName = new JTextField();
            topicName.setEditable(true);
	    topicName.setText(defaultTopic);
            gridbag.setConstraints(topicName, c);
            add(topicName);

            c.weightx = 1.0;
            c.weighty = 0.0;
            c.gridwidth = 1;
            c.insets = new Insets(10, 10, 0, 10);

            c.gridwidth = GridBagConstraints.RELATIVE;
            loginButton = new JButton(loginButtonLabel);
            gridbag.setConstraints(loginButton, c);
            add(loginButton);
            c.gridwidth = GridBagConstraints.REMAINDER;
            resetButton = new JButton(resetButtonLabel);
            gridbag.setConstraints(resetButton, c);
            add(resetButton);

            loginButton.addActionListener((new ActionListener () {
                public void actionPerformed(ActionEvent ae) {
		    chatUser = userName.getText();
		    chatTopic = topicName.getText();
		    if ((chatUser.length() == 0) ||
			(chatTopic.length() == 0)) {
			// Invalid input, try again
			userName.setText("");
			topicName.setText(defaultTopic);
			if (chatUser.length() == 0) {
			    userLabel.setText(errorUserLabel);
			} else {
			    userLabel.setText(defaultUserLabel);
			}
			if (chatTopic.length() == 0) {
			    topicLabel.setText(errorTopicLabel);
			} else {
			    topicLabel.setText(defaultTopicLabel);
			}
			cardStackPanel.showCard("loginCard");
		    }
		    else
		    {
                        // Create the message sender and receiver
                        // threads
			senderThread =
			    new JMSChatThread(JMSChatThread.SENDER,
					      controlData,
					      chatUser,
					      chatTopic);
			receiverThread =
			    new JMSChatThread(JMSChatThread.RECEIVER,
					      controlData,
					      chatUser,
					      chatTopic);
			senderThread.start();
			receiverThread.start();
			// Do not proceed until both threads connected
			controlData.waitUntilConnected();
			chatCard = new ChatPanel();
			cardStackPanel.add(chatCard,"chatCard");
			cardStackPanel.showCard("chatCard");
		    }
                }
            }));

            resetButton.addActionListener((new ActionListener () {
                public void actionPerformed(ActionEvent ae) {
		    userLabel.setText(defaultUserLabel);
		    userName.setText("");
		    topicLabel.setText(defaultTopicLabel);
		    topicName.setText(defaultTopic);
		    cardStackPanel.showCard("loginCard");
                }
            }));

        }
    }

    /**
     * User interface chat panel.
     * Used to input messages to send to the chat topic, and to
     * display messages received from the chat topic.
     */
    private class ChatPanel extends JPanel {

        JTextArea  receivedTextArea;
        JTextField sendTextField;
        JButton    exitButton;

        // Constructor
        public ChatPanel() {

            JLabel l = null;
            GridBagLayout gridbag = new GridBagLayout();
            GridBagConstraints c = new GridBagConstraints();
            setLayout(gridbag);
            setBorder(BorderFactory.createCompoundBorder(
                BorderFactory.createMatteBorder(
                    1,1,2,2,Color.black),
                    BorderFactory.createEmptyBorder(5,5,5,5)));

            c.fill = GridBagConstraints.HORIZONTAL;
            c.anchor = GridBagConstraints.NORTH;
            c.gridwidth = GridBagConstraints.REMAINDER;
	    c.gridheight = 1;
            c.gridx = GridBagConstraints.REMAINDER;
            c.gridy = GridBagConstraints.RELATIVE;
            c.weightx = 10;
            c.weighty = 10;
            l = new JLabel("What " + chatUser +
                " receives from " + chatTopic + " :");
            gridbag.setConstraints(l, c);
            add(l);

            c.fill = GridBagConstraints.BOTH;
            c.weighty = 100;
            c.gridheight = 6;
            receivedTextArea = new JTextArea();
            receivedTextArea.setEditable(false);
            JScrollPane topScrollPane = new JScrollPane(receivedTextArea);
            topScrollPane.setVerticalScrollBarPolicy(
                JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
            gridbag.setConstraints(topScrollPane, c);
            add(topScrollPane);

            c.fill = GridBagConstraints.HORIZONTAL;
            c.anchor = GridBagConstraints.SOUTH;
            c.weighty = 10;
            c.gridheight = 1;
            l = new JLabel("Enter text to send to "
                + chatTopic + " :");
            gridbag.setConstraints(l, c);
            add(l);

            sendTextField = new JTextField();
            sendTextField.setEditable(true);
            gridbag.setConstraints(sendTextField, c);
            add(sendTextField);

            c.weightx = 1.0;
            c.weighty = 0.0;
            c.insets = new Insets(10, 10, 0, 10);

            c.gridheight = GridBagConstraints.REMAINDER;
            c.gridwidth = GridBagConstraints.REMAINDER;
            exitButton = new JButton(exitButtonLabel);
            gridbag.setConstraints(exitButton, c);
            add(exitButton);

            sendTextField.addActionListener((new ActionListener () {
                public void actionPerformed(ActionEvent ae) {
                    String textIn = sendTextField.getText();
                    if (textIn.length() != 0) {
                        controlData.storeOutbound(textIn);
                    }
                    chatCard.sendTextField.setText("");
                }
            }));

            exitButton.addActionListener((new ActionListener () {
                public void actionPerformed(ActionEvent ae) {
                    exitJMSChat();
                }
            }));
        }
    }
}