/*
 * 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.thrift.transport;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.SocketException;

/**
 * Wrapper around ServerSocket for Thrift.
 *
 */
public class TServerSocket extends TServerTransport {

  private static final Logger LOGGER = LoggerFactory.getLogger(TServerSocket.class.getName());

  /**
   * Underlying ServerSocket object
   */
  private ServerSocket serverSocket_ = null;

  /**
   * Timeout for client sockets from accept
   */
  private int clientTimeout_ = 0;

  public static class ServerSocketTransportArgs extends AbstractServerTransportArgs<ServerSocketTransportArgs> {
    ServerSocket serverSocket;

    public ServerSocketTransportArgs serverSocket(ServerSocket serverSocket) {
      this.serverSocket = serverSocket;
      return this;
    }
  }

  /**
   * Creates a server socket from underlying socket object
   */
  public TServerSocket(ServerSocket serverSocket) throws TTransportException {
    this(serverSocket, 0);
  }

  /**
   * Creates a server socket from underlying socket object
   */
  public TServerSocket(ServerSocket serverSocket, int clientTimeout) throws TTransportException {
    this(new ServerSocketTransportArgs().serverSocket(serverSocket).clientTimeout(clientTimeout));
  }

  /**
   * Creates just a port listening server socket
   */
  public TServerSocket(int port) throws TTransportException {
    this(port, 0);
  }

  /**
   * Creates just a port listening server socket
   */
  public TServerSocket(int port, int clientTimeout) throws TTransportException {
    this(new InetSocketAddress(port), clientTimeout);
  }

  public TServerSocket(InetSocketAddress bindAddr) throws TTransportException {
    this(bindAddr, 0);
  }

  public TServerSocket(InetSocketAddress bindAddr, int clientTimeout) throws TTransportException {
    this(new ServerSocketTransportArgs().bindAddr(bindAddr).clientTimeout(clientTimeout));
  }

  public TServerSocket(ServerSocketTransportArgs args) throws TTransportException {
    clientTimeout_ = args.clientTimeout;
    if (args.serverSocket != null) {
      this.serverSocket_ = args.serverSocket;
      return;
    }
    try {
      // Make server socket
      serverSocket_ = new ServerSocket();
      // Prevent 2MSL delay problem on server restarts
      serverSocket_.setReuseAddress(true);
      // Bind to listening port
      serverSocket_.bind(args.bindAddr, args.backlog);
    } catch (IOException ioe) {
      close();
      throw new TTransportException("Could not create ServerSocket on address " + args.bindAddr.toString() + ".", ioe);
    }
  }

  public void listen() throws TTransportException {
    // Make sure to block on accept
    if (serverSocket_ != null) {
      try {
        serverSocket_.setSoTimeout(0);
      } catch (SocketException sx) {
        LOGGER.error("Could not set socket timeout.", sx);
      }
    }
  }

  @Override
  public TSocket accept() throws TTransportException {
    if (serverSocket_ == null) {
      throw new TTransportException(TTransportException.NOT_OPEN, "No underlying server socket.");
    }
    Socket result;
    try {
      result = serverSocket_.accept();
    } catch (Exception e) {
      throw new TTransportException(e);
    }
    if (result == null) {
      throw new TTransportException("Blocking server's accept() may not return NULL");
    }
    TSocket socket = new TSocket(result);
    socket.setTimeout(clientTimeout_);
    return socket;
  }

  public void close() {
    if (serverSocket_ != null) {
      try {
        serverSocket_.close();
      } catch (IOException iox) {
        LOGGER.warn("Could not close server socket.", iox);
      }
      serverSocket_ = null;
    }
  }

  public void interrupt() {
    // The thread-safeness of this is dubious, but Java documentation suggests
    // that it is safe to do this from a different thread context
    close();
  }

  public ServerSocket getServerSocket() {
    return serverSocket_;
  }
}