package chatServer;

import java.io.*;
import java.sql.*;
import java.net.*;
import java.text.SimpleDateFormat;
import java.util.*;
import java.util.Date;

import org.mindrot.jbcrypt.BCrypt;

public class Server {
	private static int clientId;
	private ArrayList<ClientThread> clientList;
	private SimpleDateFormat time;
	private int port;
	private boolean running;

	public static void main(String[] args) {
		// start server on port 9007 unless a PortNumber is specified
		int portNumber = 9007;
		switch(args.length) {
			case 1:
				try {
					portNumber = Integer.parseInt(args[0]);
				}
				catch(Exception e) {
					System.out.println("Invalid port number.");
					System.out.println("Java Server [portNumber]");
					return;
				}
			case 0:
				break;
			default:
				System.out.println("Java Server [portNumber]");
				return;

		}
		// create a server object and start it
		Server server = new Server(portNumber);
		server.start();
	}

	public Server(int port){
		this.port = port;
		time = new SimpleDateFormat("HH:mm:ss");
		clientList = new ArrayList<ClientThread>();
		Statement st = null;
		Connection conn = null;
		try{
			Class.forName("org.h2.Driver");
			conn = DriverManager.getConnection("jdbc:h2:~/messageserver", "server", "server");
			st = conn.createStatement();
			st.execute("create table if not exists users(UserName varchar(20) primary key, Password varchar(255));");
		}catch(ClassNotFoundException | SQLException e){
			e.printStackTrace();
		}finally{
			try{
				st.close();
				conn.close();
			}catch(SQLException e){
				e.printStackTrace();
			}
		}
	}
	public void start(){
		running = true;
		try {
			ServerSocket serverSocket = new ServerSocket(port);
			while(running)
			{
				System.out.println("Waiting for connections. Port = " + port);
				Socket socket = serverSocket.accept();
				if(!running)
					break;
				ClientThread t = new ClientThread(socket);
				clientList.add(t); // Needs changing for registered users
				t.start();
			}

			try {
				serverSocket.close();
				for (int i = 0; i < clientList.size(); i++)
				{
					ClientThread tc = clientList.get(i);
					try {
						tc.inStream.close();
						tc.outStream.close();
						tc.socket.close();
					} catch (IOException e) {

					}
				}
			} catch (Exception e) {
				System.out.println("Problem closing connections and server" + e);
			}

		} catch (IOException e){
            String msg = time.format(new Date()) + " Exception on ServerSocket: " + e + "\n";
			System.out.println(msg);
		}
	}

	protected void stop() {
		running = false;
		try {
			new Socket("localhost", port);
		} catch (Exception e) {

		}
	}

	public class ClientThread extends Thread {
		Socket socket;
		ObjectInputStream inStream;
		ObjectOutputStream outStream;
		String date;
		int id;
		public String username;
		ChatMessage cm;

		ClientThread(Socket socket){
			this.socket = socket;
			id = ++clientId;
			try {
				outStream = new ObjectOutputStream(socket.getOutputStream());
				inStream = new ObjectInputStream(socket.getInputStream());

				username = (String) inStream.readObject();
				System.out.print(username + " connected");

			} catch (IOException e) {
				System.out.println("Exception creating streams");
				return;
			}

			catch (ClassNotFoundException e ) {

			}
		}

		public void run() {
			// to loop until LOGOUT
			boolean running = true;
			while(running) {
				// read a String (which is an object)
				try {
					cm = (ChatMessage) inStream.readObject();
				}
				catch (IOException e) {
					System.out.println(username + " Exception reading Streams: " + e);
					break;
				}
				catch(ClassNotFoundException e2) {
					break;
				}
				String message = cm.getMessage();

				// Switch on the type of message receive
				switch(cm.getType()) {

				case ChatMessage.MESSAGE:
					broadcast(username + ": " + message);
					break;
				case ChatMessage.LOGOUT:
					System.out.println(username + " disconnected with a LOGOUT message.");
					running = false;
					break;
				case ChatMessage.WHOISIN:
					writeMsg("List of the users connected at " + time.format(new Date()) + "\n");
					// scan al the users connected
					for(int i = 0; i < clientList.size(); ++i) {
						ClientThread ct = clientList.get(i);
						writeMsg((i+1) + ") " + ct.username + " since " + ct.date);
					}
					break;
				case ChatMessage.LOGIN:
					if(loginAttempt(message)){
						writeMsg("true");
					}else{
						writeMsg("false");
					}
					break;
				case ChatMessage.REGISTER:
					if(register(message)){
						writeMsg("true");
//						loginAttempt(message);		auto login if register is successful?
					}

					break;
				}
			}
			remove(id);
			close();
		}

		private void close() {
			// try to close the connection
			try {
				if(outStream != null) outStream.close();
			}
			catch(Exception e) {}
			try {
				if(inStream != null) inStream.close();
			}
			catch(Exception e) {};
			try {
				if(socket != null) socket.close();
			}
			catch (Exception e) {}
		}

		private boolean writeMsg(String msg) {
			// if Client is still connected send the message to it
			if(!socket.isConnected()) {
				close();
				return false;
			}
			// write the message to the stream
			try {
				outStream.writeObject(msg);
			}
			catch(IOException e) {
				System.out.print("Error sending message to " + username);
				System.out.println(e.toString());
			}
			return true;
		}
	}

	private synchronized void broadcast(String message) {
		String currentTime = time.format(new Date());
		String messageLf = currentTime + " " + message + "\n"; // add HH:mm:ss and \n to the message
		System.out.print(messageLf);

		for(int i = clientList.size(); --i >= 0;) {
			ClientThread ct = clientList.get(i);
			// try to write to the Client if it fails remove it from the list
			if(!ct.writeMsg(messageLf)) {
				clientList.remove(i);
				System.out.print("Disconnected Client " + ct.username + " removed from list.");
			}
		}
	}
	private synchronized boolean loginAttempt(String message){
		String[] messages = message.split("$");
		String Lusername = messages[0];
		String password = messages[1];
		Statement st = null;
		Connection conn = null;
		try{
			String hashed = "";
			Class.forName("org.h2.Driver");
			conn = DriverManager.getConnection("jdbc:h2:~/messageserver", "server", "server");
			st = conn.createStatement();
			ResultSet rs = st.executeQuery("select password from users where username='" + Lusername + "';");
			String storedPassword = rs.getString("password");
			if(BCrypt.checkpw(password, storedPassword)){
			//ClientThread name = new ClientThread(socket)
			//username = Lusername; 		Need to update the username before returning true.
				return true;
			}
			return false;
		}catch(ClassNotFoundException | SQLException e){
			e.printStackTrace();
		}finally{
			try{
				st.close();
				conn.close();
			}catch(SQLException e){
				e.printStackTrace();
			}
		}
		return false;
	}
	private synchronized boolean register(String message){
		String[] messages = message.split("$");
		String username = messages[0];
		String password = messages[1];
		Statement st = null;
		Connection conn = null;
		try{
			String hashed = "";
			Class.forName("org.h2.Driver");
			conn = DriverManager.getConnection("jdbc:h2:~/messageserver", "server", "server");
			st = conn.createStatement();
			ResultSet rs = st.executeQuery("select username from users where username='" + username + "';");
			if(!rs.next()){
				hashed = BCrypt.hashpw(password, BCrypt.gensalt());
				st.executeUpdate("insert into users values('" + username + "', '" + hashed + "');");
				return true;
			}
		}catch(ClassNotFoundException | SQLException e){
			e.printStackTrace();

		}finally{
			try{
				st.close();
				conn.close();
			}catch(SQLException e){
				e.printStackTrace();
			}
		}
		return false;
	}

	synchronized void remove(int id) {
		// scan the array list until we found the Id
		for(int i = 0; i < clientList.size(); ++i) {
			ClientThread ct = clientList.get(i);
			// found it
			if(ct.id == id) {
				clientList.remove(i);
				return;
			}
		}
	}
}