/**
 *  Java implementation of an Instant Messenger (IM) client
 *  Designed for CS9035, on 2010-10-31
 *
 *  This Java program creates a window with two textboxes, one for storing the
 *  log of messages, and one for a user to type a message into.
 *
 *  @version    1.0, 2010-10-31
 *  @author     Me!
 *  @since      1.6
 *
**/
import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import java.io.PrintWriter;

import java.net.ServerSocket;
import java.net.Socket;

import javax.swing.Box;
import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.ScrollPaneConstants;

import java.util.Scanner;

class InstantMessenger extends JFrame{

    // These variables are set separately, because they are needed for the inner class "buttonSendAction"
    private JTextArea nextMessage;  // The JTextArea where a user types his message
    private JTextArea messageLog;   // The JTextArea where a user can view the message log

    Socket connection;
    Scanner fromClient;
    PrintWriter toClient;

    public InstantMessenger() {
        createWindow();
    }

    public void createWindow(){

        // Properties of outermost window
        // No need to call setSize(), pack() does this automatically.
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setTitle("My Instant Messenger");
        setLocation(200, 200);  // x, y

        // Lets put a JPanel in the JFrame, so we can do a little more.
        JPanel mainPanel = new JPanel();
        // Boxlayout - top to bottom
        mainPanel.setLayout(new BoxLayout(mainPanel, BoxLayout.Y_AXIS));
        add(mainPanel, BorderLayout.CENTER);

        // Create a title for the JTextArea that stores the message log.
        JLabel messageLogTitle = new JLabel(" Message Log");
        messageLogTitle.setAlignmentX(JLabel.CENTER_ALIGNMENT);

        // Create a text box for storing the message log
        messageLog = new JTextArea();
        messageLog.setEditable(false);
        messageLog.setLineWrap(true);

        // Create a title for the next message JTextArea
        JLabel messageTitle = new JLabel(" Message");
        messageTitle.setAlignmentX(JLabel.CENTER_ALIGNMENT);

        // Create a text box for storing the next message
        nextMessage = new JTextArea();
        nextMessage.setLineWrap(true);

        // Create a button
        JButton buttonSend = new JButton("Send");
        buttonSend.setAlignmentX(Component.CENTER_ALIGNMENT);
        buttonSend.addActionListener(new ActionListener(){
            public void actionPerformed(ActionEvent e) {
                // send message to other machine here.
                try{
                    toClient = new PrintWriter(connection.getOutputStream(), true); // autoflush
                    toClient.println(nextMessage.getText());
                    if (nextMessage.getText().equals("QUIT")){
                        messageLog.append("You have disconnected from the chat.\n");
                        toClient.close();
                        //fromClient.close(); // input Scanner - doesn't seem to be any different if it's commented out.
                        connection.close();
                    }
                    else{
                        messageLog.append("me: " + nextMessage.getText() + "\n");
                    }
                    nextMessage.setText("");
                } catch (Exception E){
                    messageLog.append("Error sending previous message. Are you sure a client is connected?" + "\n");
                }
            }
        });

        // Make the two text fields scrollable
        JScrollPane logScroller = new JScrollPane(messageLog);
        logScroller.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_AS_NEEDED);
        logScroller.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);
        logScroller.setPreferredSize(new Dimension(300,200));

        JScrollPane messageScroller = new JScrollPane(nextMessage);
        messageScroller.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_AS_NEEDED);
        messageScroller.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);
        messageScroller.setPreferredSize(new Dimension(300,50));

        // Add the components to the JPanel
        mainPanel.add(messageLogTitle);
        mainPanel.add(Box.createRigidArea(new Dimension(0,5)));    // 5 vertical pixels as a 'filler' space
        mainPanel.add(logScroller);
        mainPanel.add(Box.createRigidArea(new Dimension(0,5)));    // 5 vertical pixels as a 'filler' space
        mainPanel.add(messageTitle);
        mainPanel.add(Box.createRigidArea(new Dimension(0,5)));    // 5 vertical pixels as a 'filler' space
        mainPanel.add(messageScroller);
        mainPanel.add(buttonSend, Component.CENTER_ALIGNMENT);

        // Time to organize a little...
        pack();
    }

    public void startConnection(String mode, String host, int port){
        try{
            if (mode.equals("server")){
                ServerSocket s = new ServerSocket(port);
                messageLog.append("Waiting on port "+ port + " for a connection" + "\n");
                connection = s.accept();
                messageLog.append("Connected on port "+ port + "\n");
            }
            else if (mode.equals("client")){
                messageLog.append("Attempting to connect to "+ host + ":" + port + "\n");
                connection = new Socket(host, port);
                messageLog.append("Connected to "+ host + ":" + port + "\n");
            }

            listen: while (connection.isConnected()) {  // when the client disconnects, this will crash, and go to the catch
                fromClient = new Scanner(connection.getInputStream());
                while(fromClient.hasNextLine()){
                    String incomingMessage = fromClient.nextLine();
                    if (incomingMessage.equals("QUIT")){
                        messageLog.append("This chat has been terminated.\n");
                        fromClient.close();
                        connection.close();
                        break listen;
                    }
                    else{
                        messageLog.append("him: " + incomingMessage + "\n");
                    }
                }
            }
        }
        catch (java.net.UnknownHostException E){
            System.out.println("Error connecting to server"); // typo on the hostname
        }
        catch (java.io.IOException E){
            messageLog.append("Connection error, try again later.\n");
            // You've been disconnected. Normal and expected. Either that, or you tried connecting to a non-existent server
        }

    }
}


class testIM{
    public static void main(String[] args) {

        String mode = "server";
        String host = "127.0.0.1";
        int port = 12345;

        if(args.length > 0)
            mode = args[0];
        if(args.length > 1)
            host = args[1];

        final InstantMessenger IM = new InstantMessenger();
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                IM.setVisible(true);
            }
        } );

        IM.startConnection(mode, host, port);

    }
}