//
// Chat.java
//

import java.io.*;
import java.awt.*;
import java.applet.*;
import java.net.*;

/**
 * The TextArea thread that listens to the socket.
 */

class ServerChat extends TextArea implements Runnable
{
        Chat chat;                      // the applet
        public Thread thread;           // the thread that this class runs in
        public int curpos = 0;          // current position in the TextArea
        final static int MAXLENGTH = 5000;   // largest message we can handle
        final static int TEXTAREA_WIDTH = 50;  // no. columns in the TextArea
        final static int TEXTAREA_HEIGHT = 4;  // no. rows in the TextArea
        /**
         * The constructor.
         */

        public ServerChat(Chat c)
        {
                super(TEXTAREA_WIDTH, TEXTAREA_HEIGHT);
                chat = c;
                setEditable(false);

                thread = new Thread(this);
        }

        /**
         * Called when the component is exposed, or when repaint() is called.
         */
        public void update(Graphics g)
        {
                paint(g);
        }

        /**
         * Read data from the socket. Blocks.
         */

        public String readln(DataInputStream dis)
        throws
                IOException
        {
                byte b[] = new byte[MAXLENGTH];

                String s;
                int nchars = dis.read(b, 0, MAXLENGTH);
                if (nchars > 0)
                {
                        s = new String(b, 0, 0, nchars);
                }
                else
                {
                        s = "";
                }

                return s;
        }

        /**
         * The thread's main routine, in effect. Called by Thread.start().
         */

        public void run()
        {
        // Read from socket; when there is data, post event to the applet

                String inData = null;
                for (;;)
                {
                        // Wait on a socket read...
                        try {inData = readln(chat.dis);}
                        catch (IOException ex)
                        {
                        System.out.println("IO Exception reading from server");
                                System.exit(1);
                        }

                        // Write the data to the text area...
                        if (inData.equals("\b"))   //Backspace
                        {
                            curpos--; 
                            replaceText("", curpos - 1, curpos + 1);
                        }
                        else
                        {
                            insertText(inData, curpos);
                            curpos += inData.length();
                        }
                }
        }
}

	/**
 * The TextArea that handles user input.
 */

class UserChat extends TextArea
{
        public int curpos = 0;      // the current position in the TextArea
        final static int TEXTAREA_WIDTH = 50;  // no. columns in the TextArea
        final static int TEXTAREA_HEIGHT = 4;   // no. rows in the TextArea

        /**
         * The constructor.
         */

        public UserChat()
        {
                super(TEXTAREA_WIDTH, TEXTAREA_HEIGHT);
                curpos = 1;
        }

        /**
         * Write data to the socket.
         */

        public void write(DataOutputStream dos, String s)
        throws
                IOException
        {
                // Write buffer to the socket
                dos.writeBytes(s);
        }

        /**
         * Called when the component is exposed, or when repaint() is called.
         */

        public void update(Graphics g)
        {
                paint(g);
        }
}

/**
 * The applet.
 */

public class Chat extends Applet
{
        final static int DEFAULT_FRAME_WIDTH = 600;
        final static int DEFAULT_FRAME_HEIGHT = 400;
        //applet dimensions; browser overrides

        final static String HOSTNAME = "minitorn.tpu.ee";
        // the server name

        final static int PORTNUMBER = 6001; // must match port in server code
	final static String newline = new String("\n");

        String hostname;          // the name of the host we connected to
        int port;                 // the port we connected to
        Socket socket;            // the socket
        DataInputStream dis;      // a DataInputStream on the socket
        DataOutputStream dos;     // a DataOutputStream on the socket

        ServerChat serverChat;    // the ServerChat object
        UserChat userChat;        // the UserChat object

        boolean connected = false; // flag indicating if we are connected

        /**
         * The constructor.
         */

        public Chat()
        {
                setLayout(new GridLayout(2, 1, 10, 10));
                Panel panel1 = new Panel();
                Panel panel2 = new Panel();
                add(panel1);
                add(panel2); 
                panel1.setLayout(new GridLayout(2, 1, 10, 10));
                panel2.setLayout(new GridLayout(2, 1, 10, 10));

                // Create input window
                userChat = new UserChat();

                // Create output window
                serverChat = new ServerChat(this);

                panel1.add(new Label("Type into Input Window below:"));
                panel1.add(userChat);
                panel2.add(new Label("List of messages received and sent:"));
                panel2.add(serverChat);

                resize(DEFAULT_FRAME_WIDTH-20, DEFAULT_FRAME_HEIGHT-50);
        }

        /**
         * Establish connection with server and start the monitor thread.
         */

        public void init()
        {
                try {makeConnection(HOSTNAME, PORTNUMBER);}
                catch (Exception ex)
                {
                     System.out.println("Unable to make connection to host");
                        connected = false;
                }
                connected = true;
                resize(DEFAULT_FRAME_WIDTH, DEFAULT_FRAME_HEIGHT);
        }

        /**
         * Start
         */

        public void start()
        {
                if (! connected) return;
                serverChat.thread.start(); // calls run()
        }

        /**
         * Called when browser leaves this page.
         */

        public void stop()
        {
            serverChat.thread.stop();
            try {socket.close();} catch (IOException ex) {System.out.println(ex);}
            connected = false;
        }

        /**
         * Establish a connection with the chat server program.
         */

        void makeConnection(String h, int p)
        throws
                java.net.UnknownHostException,
                IOException
        {
                hostname = h;
                port = p;

                socket = new Socket(hostname, port);

                // Issue confirmation to user
                InetAddress rina = socket.getInetAddress();
                System.out.println("Connected to " + rina.toString());
                InetAddress lina = rina.getLocalHost();
            System.out.println("Local host designation: " + lina.toString());

                // Determine the socket's input and output stream handles
                dis = new DataInputStream(socket.getInputStream());
                dos = new DataOutputStream(socket.getOutputStream());
        }

        /**
         * Handle all applet events, incl. component events.
         */
        public boolean handleEvent(Event evt)
        {
                switch(evt.id)
                {
                case Event.KEY_RELEASE:
                // Handle special case of bug related to the period character
                    if ((char)(evt.key) != '.') return super.handleEvent(evt);
                case Event.KEY_PRESS:
                      // Append the new char to the TextArea
                      String s = new String();
                      if ((char)(evt.key) != '\b')
               		t.append((char)(evt.key));
                      s += (char)(evt.key);
                      if ((t.length() > 70) || (t.length() > 60 &&
                 		(char)evt.key == ' '))
                          {
                  	  t.append("\n");
                  	  sendToServer();
                 	  userChat.insertText(newline, userChat.curpos);
                 	  }
                      if ((char)(evt.key) == '\b')  //Backspace
                          {
                          userChat.curpos--;
        userChat.replaceText("", userChat.curpos - 1, userChat.curpos + 1);
                 	  t.setLength( t.length() - 1);
                          }
                      else if ((char)(evt.key) != '.') // (skip special case)
                          // For all characters except period:
                          {
                          userChat.insertText(s, userChat.curpos);
                          userChat.curpos++;
                          }
                      else
                          userChat.curpos++;

                        // Send the input to the server
                	if ((char)(evt.key) == '\n') 
                  		sendToServer();
                        return true;
                }

                return super.handleEvent(evt);
        }

  	private void sendToServer()
	{
	String tmp = new String(t);
        try {userChat.write(dos, tmp);}
	catch (IOException ex)
	{
	System.out.println("IO Exception writint to server");
		System.exit(1);
	}
	t.setLength(0);
	}

        /**
         * We only need this if we run standalone (not in a browser).
         */

        public static void main(String args[])
        {
                ChatFrame f = new ChatFrame("Chat");
                f.chat = new Chat();

                f.add("Center", f.chat);

                f.resize(DEFAULT_FRAME_WIDTH, DEFAULT_FRAME_HEIGHT);
                f.show();

                f.chat.init();
                f.chat.start();
        }
             StringBuffer t = new StringBuffer(90);
}

/**
 * A closeable frame. Used only by Chat.main().
 */

class ChatFrame extends Frame
{
        Chat chat;

        public ChatFrame(String s)
        {
                super(s);
        }

        public boolean handleEvent(Event evt)
        {

                if (evt.id == Event.WINDOW_DESTROY)
                {
                        System.exit(0);
                }
                return super.handleEvent(evt);
        }
}