/**
 * 客户端
 */
public class ChatClient {
    private SocketChannel socketChannel;
    private String host = "127.0.0.1";
    private Integer port = 8083;
    private String userName;
    public ChatClient(){
        try {
            //得到传输通道
            socketChannel = SocketChannel.open();
            //设置非阻塞
            socketChannel.configureBlocking(false);
            //设置网络连接
            InetSocketAddress address = new InetSocketAddress(host,port);
            //连接服务器
            if (!socketChannel.connect(address)){
                while (!socketChannel.finishConnect()){
                    System.out.println("client:没有服务端进行连接");
                }
            }
            //得到客户端 IP 地址和端口信息，作为聊天用户名使用
            userName = socketChannel.getLocalAddress().toString().substring(1);
            System.out.println("---------------Client(" + userName + ") is ready---------------");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    /**
     * 往服务端发送数据
     */
    public void sendMsg(String msg){
        try {
            //如果控制台输入 bye 就关闭通道，结束聊天
            if (msg.equalsIgnoreCase("bye")) {
                socketChannel.close();
                socketChannel = null;
                return;
            }
            msg = userName + "说: " + msg;
            ByteBuffer byteBuffer = ByteBuffer.wrap(msg.getBytes());
            socketChannel.write(byteBuffer);

        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    /**
     * 接收服务端消息
     */
    public void receiveMsg(){
        ByteBuffer byteBuffer = ByteBuffer.allocate(1024);
        try {
            int count = socketChannel.read(byteBuffer);
            if(count>=1){
                String msg = new String(byteBuffer.array());
                System.out.println(msg.trim());
            }
        } catch (IOException e) {
            e.printStackTrace();
        }

    }
}

//启动聊天程序客户端
public class TestClient {
    public static void main(String[] args) {
        ChatClient chatClient = new ChatClient();

        new Thread(()->{
            while (true){
                chatClient.receiveMsg();
                try {
                    Thread.sleep(2000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }).start();
        Scanner sc = new Scanner(System.in);
        while (sc.hasNextLine()){
            chatClient.sendMsg(sc.nextLine());
        }
    }
}

/**
 * 聊天服务端
 */
public class ChatServer {

    private ServerSocketChannel serverSocketChannel;
    private Selector selector;
    private int port = 8083;
    public ChatServer(){
        try {
            //获取监听通道
            serverSocketChannel = ServerSocketChannel.open();
            //获取选择器
            selector = Selector.open();
            //设置非阻塞
            serverSocketChannel.configureBlocking(false);
            //绑定端口
            serverSocketChannel.bind(new InetSocketAddress(port));
            //将选择器绑定到监听通道并监听accept通道
            serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT);
            printInfo("Chat Server is ready.......");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    /**
     * 开始聊天
     */
    public void startChat(){
        while (true){
            try {
                if(selector.select(200)==0){
                    System.out.println("没有人上线:");
                }
                //获取被监听的accept
                Iterator<SelectionKey> iterator = selector.selectedKeys().iterator();
                while(iterator.hasNext()){
                    SelectionKey selectionKey = iterator.next();
                    //监听accept
                    if(selectionKey.isAcceptable()){
                        //获取通道
                        SocketChannel socketChannel = serverSocketChannel.accept();
                        //设置为非阻塞
                        socketChannel.configureBlocking(false);
                        //注册
                        socketChannel.register(selector,SelectionKey.OP_READ);
                        System.out.println(socketChannel.getRemoteAddress().toString().substring(1)+"上线了...");
                    }
                    //读取数据
                    if(selectionKey.isReadable()){
                        //获取通道
                        SocketChannel socketChannel = (SocketChannel) selectionKey.channel();
                        //读取数据
                        readMsg(socketChannel);
                    }
                    //防止重复
                    iterator.remove();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    /**
     * 读取数据
     * @param socketChannel
     */
    private void readMsg(SocketChannel socketChannel) {
        ByteBuffer buffer = ByteBuffer.allocate(1024);
        try {
            int count = socketChannel.read(buffer);
            if (count>=1){
                //打印数据
                String msg = new String(buffer.array());
                printInfo(new String(buffer.array()));
                //广播消息
                broadCast(socketChannel,msg);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    /**
     * 广播消息
     * @param socketChannel
     */
   private void broadCast(SocketChannel socketChannel,String msg){
       System.out.println("发送广播");
       try {
           //广播数据到所有的 SocketChannel 中
           for (SelectionKey key : selector.keys()) {
               Channel targetChannel = key.channel();
               //排除自身
               if(targetChannel instanceof SocketChannel &&targetChannel!=socketChannel){
                   SocketChannel destChannel = (SocketChannel) targetChannel;
                   //把数据存入到缓冲区
                   ByteBuffer buffer = ByteBuffer.wrap(msg.getBytes());
                   //往通道里面写数据
                   destChannel.write(buffer);
               }
           }
           ;
       } catch (IOException e) {
           e.printStackTrace();
       }
   }
    /**
     * 打印内容
     * @param content
     */
    private void printInfo(String content) {
        SimpleDateFormat format = new SimpleDateFormat("yyyy-HH-dd HH:mm:ss");
        System.out.println("["+format.format(new Date())+"]->"+content);
    }

    public static void main(String[] args) {
        ChatServer server = new ChatServer();
        server.startChat();
    }
}