package channel;

import util.Logger;

import java.net.InetSocketAddress;
import java.net.ServerSocket;
import java.nio.ByteBuffer;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;

/**
 * Created by huangyinhuang on 1/31/2018.
 */
public class ChannelServer {

    public static void main(String[] args) throws Exception {
        // please note: configure channel blocking state as false
        Logger.info("start the server.");
        ServerSocketChannel server = ServerSocketChannel.open();
        server.configureBlocking(false);

        ServerSocket serverSocket = server.socket();
        serverSocket.bind(new InetSocketAddress(9000));

        int count = 0;
        while (true) {
            // please note: server.accept() will not block current thread
            Logger.info("try to connect new client...");
            SocketChannel channel = server.accept();

            if (channel == null) {
                Logger.info("waiting for new client, count = " + count++);
                Thread.sleep(5000);
            } else {
                Logger.info("connected with client...");
                Logger.printClientInfo(channel);

                ByteBuffer clientMsg = ByteBuffer.allocate(1024);
                channel.read(clientMsg);
                clientMsg.flip();
                if (clientMsg.hasRemaining()) {
                    // print messages from client
                    byte[] msgBytes = new byte[clientMsg.remaining()];
                    clientMsg.get(msgBytes);
                    Logger.printNewMessage(new String(msgBytes).trim());
                }
                clientMsg.clear();

                // prepare the message
                ByteBuffer replyMsg = ByteBuffer.wrap("Hello client, this is channel server.".getBytes());
                channel.write(replyMsg);

                // close the client, wait for next client connection
                channel.close();
            }
        }
    }

}