import java.awt.*;
import java.awt.event.*;
import java.net.*;
import java.io.*;
import java.util.Enumeration;
import java.util.Hashtable;
import java.util.Calendar;

public class Server extends Frame implements ActionListener{
	
	private boolean serving = false;
	private Color bg = new Color(176, 196, 227);
	private String rightNow;	
	private InetAddress svrAddress;
	private ServerSocket server;
	private ServerThread st;
	private Hashtable ht;		// 記錄 String userName -> DataOutPutStream out
	private Hashtable ht_s;		// 記錄 String userName -> Socket connection

	private Label svrIP = new Label("Server IP:");
	private TextField showSvrIP = new TextField();
	private Label svrPort = new Label("Server port:");
	private TextField getSvrPort = new TextField("8888");
	private Button enter = new Button("Start");
	private TextArea output = new TextArea();
	private Label user = new Label("User (0)");
	private List list = new List();
	 
	// 響應關閉按鈕的內部類
	private class WindowCloser extends WindowAdapter
	{
		public void windowClosing(WindowEvent we)
		{
			System.exit(0);
		}
	}
	// 布局設置方法，在構造方法里面調用
	private void setup()
	{		
		Panel top = new Panel();
		top.setLayout(new FlowLayout());
		top.add(svrIP);
		svrIP.setBackground(bg);
		top.add(showSvrIP);
		showSvrIP.setBackground(bg);
		top.add(svrPort);
		svrPort.setBackground(bg);
		top.add(getSvrPort);
		getSvrPort.setBackground(bg);
		top.add(enter);
		enter.setBackground(bg);
		
		Panel east = new Panel();
		east.setLayout(new BorderLayout());
		east.add("North", user);
		user.setBackground(bg);
		east.add("Center", list);
		list.setBackground(bg);
		
		setLayout(new BorderLayout());
		add("North", top);
		top.setBackground(bg);
		add("East", east);
		east.setBackground(bg);
		add("Center", output);
		output.setBackground(bg);		
		
		setBackground(bg);
	}
	// 構造方法
	public Server()throws UnknownHostException, IOException
	{
		super("Chat Room Server");
		
		serving = false;
		svrAddress = InetAddress.getLocalHost();
		byte[] ip = svrAddress.getAddress();
		showSvrIP.setText((ip[0]&0xFF)+"."+(ip[1]&0xFF)+"."
				+(ip[2]&0xFF)+"."+(ip[3]&0xFF));

		showSvrIP.setEditable(false);
		output.setEditable(false);
		
		enter.addActionListener(this);
		addWindowListener(new WindowCloser());
		
		setup();
		pack();
		setSize(500, 400);
		show();
	}
	// 用于接收客戶消息的線程類
	private class ServerThreadSingle extends Thread{
		public Socket connection;
		private DataInputStream in;
		private DataOutputStream out;
		private boolean login;
		private String userName;
		public ServerThreadSingle(Socket _connection){
			try{
				connection = _connection;
				in = new DataInputStream(connection.getInputStream());
				out = new DataOutputStream(connection.getOutputStream());
				login = false;
				userName = new String("");
				start();				
			}catch(IOException ioe){
				output.append("Error: "+ioe);
			}			
		}
		public void run(){
			try{
				String line = new String("Q");
				while(!login){
					if(!serving) break;
					line = in.readUTF();
					if(line.charAt(0) == 'L'){						
						userName = line.substring(2);
						if(userName.length() == 0){
							out.writeUTF("R");	//refused
							break;
						}
						// 判斷是否已存在該用戶名
						for(Enumeration e = ht.keys(); e.hasMoreElements();){
							String str = (String)(e.nextElement());
							if(str.equalsIgnoreCase(userName)){
								out.writeUTF("R");		//refused
								return;
							}
						}
						// 向登陸的用戶發送當前在線用戶列表
						login = true;
						list.add(userName);
						user.setText("User ("+list.getItemCount()+")");
						String[] str = list.getItems();
						line = "A ";				//accepted
						for (int i = 0; i < str.length; i ++){
							line += (str [i] + " ");
						}
						out.writeUTF(line);
						
						line = "L "+userName;
						rightNow = Calendar.getInstance().getTime().toLocaleString();
						output.append(rightNow+"\n"+userName+" log in.\n\n");
						// 向在線用戶（不包括當前客戶）發送消息
						for(Enumeration e = ht.elements(); e.hasMoreElements();){
							DataOutputStream out = (DataOutputStream)(e.nextElement());
							out.writeUTF(line);
						}
						ht.put(userName, out);	// 將登錄的客戶加入名單
						ht_s.put(userName, connection);
					}
				}
				while(login){
					line = in.readUTF();
					if(!serving) break;
					if(line.charAt(0) == 'Q'){
						out.writeUTF("Q");
						login = false;
						ht.remove(userName);	// 將退出登錄的客戶從名單中剔除
						ht_s.remove(userName);
						list.remove(userName);
						user.setText("User ("+list.getItemCount()+")");

						line = "Q "+userName;
					}
					else{
						line = userName+" said:\n"+line.substring(2);
					}
					rightNow = Calendar.getInstance().getTime().toLocaleString();
					output.append(rightNow+"\n"+(line.charAt(0)=='Q'?userName+" log out.":line)+"\n\n");
					// 向所有客戶發送消息
					for(Enumeration e = ht.elements(); e.hasMoreElements();){
						DataOutputStream out = (DataOutputStream)(e.nextElement());
						out.writeUTF(line);
					}		
				}
				in.close();
				out.close();
				connection.close();
			}catch(SocketException se){
				ht.remove(userName);
				ht_s.remove(connection);
				list.remove(userName);
				output.append("Connection to "+userName+" closed\n");
			}catch(IOException ioe){
				if(!(ioe instanceof EOFException)){
					output.append("Error: "+ioe+"\n\n");
				}				
			}
		}		
	}
	// 用于接受客戶連接請求的線程類
	private class ServerThread extends Thread{
		private boolean running;
		public ServerThread()
		{
			start();
		}
		public void run()
		{
			try{
				while(serving){
					Socket connection = server.accept();
					ServerThreadSingle handler
						= new ServerThreadSingle(connection);
				}
			}catch(SocketException se){
				rightNow = Calendar.getInstance().getTime().toLocaleString();
				output.append(rightNow+"\nServing stoped.\n\n");
			}catch(IOException ioe){
				output.append("Error: "+ioe+"\n\n");
			}		
		}
	}
	// 消息處理方法
	public void actionPerformed(ActionEvent event)
	{
		if(event.getSource() == enter) 
		{
			if(serving){				
				try{
					for(Enumeration e = ht.elements(); e.hasMoreElements();){
						DataOutputStream out = (DataOutputStream)(e.nextElement());
						out.writeUTF("Q");					
					}
					serving = false;
					ht.clear();
					ht_s.clear();
					list.clear();
					user.setText("User (0)");
					server.close();
					enter.setLabel("Start");				
				}catch(SocketException se){
					rightNow = Calendar.getInstance().getTime().toLocaleString();
					output.append(rightNow+"\nServing stoped.\n\n");
				}catch(IOException ioe){
					output.append("Error: "+ioe+"\n\n");
				}
			}
			else{				
				try{
					server = new ServerSocket(Integer.parseInt(getSvrPort.getText()));
					rightNow = Calendar.getInstance().getTime().toLocaleString();
					output.append(rightNow+"\nServing started.\n\n");
					enter.setLabel("Stop");
					ht = new Hashtable();
					ht_s = new Hashtable();
					st = new ServerThread();
					serving = true;
				}catch(IOException ioe){
					output.append("Error: "+ioe+"\n\n");
				}				
			}
		}
	}
	
	// 主方法
	public static void main(String args [])throws UnknownHostException, IOException
	{
		Server s = new Server();
	}

}