package otherTests.multicast;
   
   import java.io.BufferedReader;
   import java.io.IOException;
   import java.io.InputStream;
   import java.io.InputStreamReader;
   import java.io.OutputStream;
   import java.io.PrintWriter;
   import java.net.Socket;
  
  public final class Message {
      private static final int CLIENT_PORT = 8000;
  
      private final Client[] to;
      private final String contents;
      private final StatusListener listener;
  
      public Message(Client[] to, String contents, StatusListener listener) {
          this.to = to;
          this.contents = contents;
          this.listener = listener;
      }
  
      /**
       * Sends the message contents to all clients, notifying the status listener about the corresponding events as they
       * occur.
       * <p>
       * Network communication with clients occurs asynchronously, without ever blocking the caller. Status notifications
       * are executed on the Swing EDT (Event Dispatching Thread), so that the UI can be safely updated.
       */
      public void dispatch() {
          for (Client client : to) {
              MessageDispatcher dispatcher = new MessageDispatcher(client);
              new Thread(dispatcher).start();
          }
      }
  
      private final class MessageDispatcher implements Runnable {
          private final Client client;
  
          MessageDispatcher(Client client) {
              this.client = client;
          }
  
          @Override
          public void run() {
              try {
                  communicateWithClient();
              } catch (IOException e) {
                  throw new RuntimeException(e);
              }
          }
  
          private void communicateWithClient() throws IOException {
              try (Socket connection = new Socket(client.getAddress(), CLIENT_PORT)) {
                  sendMessage(connection.getOutputStream());
                  readRequiredReceipts(connection.getInputStream());
              }
          }
  
          private void sendMessage(OutputStream output) {
              new PrintWriter(output, true).println(contents);
              listener.messageSent(client);
          }
  
          private void readRequiredReceipts(InputStream input) throws IOException {
              BufferedReader in = new BufferedReader(new InputStreamReader(input));
  
              // Wait for display receipt:
              in.readLine();
              listener.messageDisplayedByClient(client);
  
              // Wait for read receipt:
              in.readLine();
              listener.messageReadByClient(client);
          }
      }
  }