/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.beam.runners.extensions.metrics;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.ServerSocket;
import java.net.Socket;
import java.nio.charset.Charset;
import java.util.Collection;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.concurrent.atomic.AtomicBoolean;

/** Mock of a network server. */
class NetworkMockServer {
  private final int port;

  private ServerSocket server;
  private GraphiteThread thread;

  private Collection<String> messages = new CopyOnWriteArrayList<String>();

  public NetworkMockServer(final int port) {
    this.port = port;
  }

  public int getPort() {
    return port;
  }

  public NetworkMockServer start() throws IOException {
    server = new ServerSocket(port);
    thread = new GraphiteThread(server, messages);
    thread.start();
    return this;
  }

  public void stop() throws IOException {
    thread.shutdown();
    server.close();
  }

  public Collection<String> getMessages() {
    return messages;
  }

  public void clear() {
    messages.clear();
  }

  private static class GraphiteThread extends Thread {
    private final Collection<String> messages;

    private final AtomicBoolean done = new AtomicBoolean(false);
    private final ServerSocket server;

    public GraphiteThread(final ServerSocket server, final Collection<String> messages) {
      this.messages = messages;
      this.server = server;
      setName("network-mock-server");
    }

    @Override
    public void run() {
      while (!done.get()) {
        try {
          final Socket s = server.accept();
          synchronized (this) {
            final InputStream is = s.getInputStream();
            final BufferedReader reader =
                new BufferedReader(new InputStreamReader(is, Charset.forName("UTF-8")));
            String line;

            try {
              while ((line = reader.readLine()) != null) {
                messages.add(line);
              }
            } finally {
              s.close();
            }
          }
        } catch (final IOException e) {
          if (!done.get()) {
            throw new RuntimeException(e);
          }
        }
      }
    }

    public void shutdown() {
      done.set(true);
    }
  }
}

Introduce NetworkMockServer to be used for all metrics sinks tests