/*
 * Copyright (c) 2010-2020 Nathan Rajlich
 *
 *  Permission is hereby granted, free of charge, to any person
 *  obtaining a copy of this software and associated documentation
 *  files (the "Software"), to deal in the Software without
 *  restriction, including without limitation the rights to use,
 *  copy, modify, merge, publish, distribute, sublicense, and/or sell
 *  copies of the Software, and to permit persons to whom the
 *  Software is furnished to do so, subject to the following
 *  conditions:
 *
 *  The above copyright notice and this permission notice shall be
 *  included in all copies or substantial portions of the Software.
 *
 *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 *  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
 *  OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 *  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 *  HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 *  WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 *  FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 *  OTHER DEALINGS IN THE SOFTWARE.
 */

package org.java_websocket;

import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import org.java_websocket.drafts.Draft;
import org.java_websocket.exceptions.InvalidDataException;
import org.java_websocket.framing.CloseFrame;
import org.java_websocket.framing.Framedata;
import org.java_websocket.framing.PingFrame;
import org.java_websocket.handshake.ClientHandshake;
import org.java_websocket.handshake.Handshakedata;
import org.java_websocket.handshake.ServerHandshake;
import org.java_websocket.handshake.ServerHandshakeBuilder;

/**
 * Implemented by <tt>WebSocketClient</tt> and <tt>WebSocketServer</tt>. The methods within are
 * called by <tt>WebSocket</tt>. Almost every method takes a first parameter conn which represents
 * the source of the respective event.
 */
public interface WebSocketListener {

  /**
   * Called on the server side when the socket connection is first established, and the WebSocket
   * handshake has been received. This method allows to deny connections based on the received
   * handshake.<br> By default this method only requires protocol compliance.
   *
   * @param conn    The WebSocket related to this event
   * @param draft   The protocol draft the client uses to connect
   * @param request The opening http message send by the client. Can be used to access additional
   *                fields like cookies.
   * @return Returns an incomplete handshake containing all optional fields
   * @throws InvalidDataException Throwing this exception will cause this handshake to be rejected
   */
  ServerHandshakeBuilder onWebsocketHandshakeReceivedAsServer(WebSocket conn, Draft draft,
      ClientHandshake request) throws InvalidDataException;

  /**
   * Called on the client side when the socket connection is first established, and the
   * WebSocketImpl handshake response has been received.
   *
   * @param conn     The WebSocket related to this event
   * @param request  The handshake initially send out to the server by this websocket.
   * @param response The handshake the server sent in response to the request.
   * @throws InvalidDataException Allows the client to reject the connection with the server in
   *                              respect of its handshake response.
   */
  void onWebsocketHandshakeReceivedAsClient(WebSocket conn, ClientHandshake request,
      ServerHandshake response) throws InvalidDataException;

  /**
   * Called on the client side when the socket connection is first established, and the
   * WebSocketImpl handshake has just been sent.
   *
   * @param conn    The WebSocket related to this event
   * @param request The handshake sent to the server by this websocket
   * @throws InvalidDataException Allows the client to stop the connection from progressing
   */
  void onWebsocketHandshakeSentAsClient(WebSocket conn, ClientHandshake request)
      throws InvalidDataException;

  /**
   * Called when an entire text frame has been received. Do whatever you want here...
   *
   * @param conn    The <tt>WebSocket</tt> instance this event is occurring on.
   * @param message The UTF-8 decoded message that was received.
   */
  void onWebsocketMessage(WebSocket conn, String message);

  /**
   * Called when an entire binary frame has been received. Do whatever you want here...
   *
   * @param conn The <tt>WebSocket</tt> instance this event is occurring on.
   * @param blob The binary message that was received.
   */
  void onWebsocketMessage(WebSocket conn, ByteBuffer blob);

  /**
   * Called after <var>onHandshakeReceived</var> returns <var>true</var>. Indicates that a complete
   * WebSocket connection has been established, and we are ready to send/receive data.
   *
   * @param conn The <tt>WebSocket</tt> instance this event is occurring on.
   * @param d    The handshake of the websocket instance
   */
  void onWebsocketOpen(WebSocket conn, Handshakedata d);

  /**
   * Called after <tt>WebSocket#close</tt> is explicity called, or when the other end of the
   * WebSocket connection is closed.
   *
   * @param ws     The <tt>WebSocket</tt> instance this event is occurring on.
   * @param code   The codes can be looked up here: {@link CloseFrame}
   * @param reason Additional information string
   * @param remote Returns whether or not the closing of the connection was initiated by the remote
   *               host.
   */
  void onWebsocketClose(WebSocket ws, int code, String reason, boolean remote);

  /**
   * Called as soon as no further frames are accepted
   *
   * @param ws     The <tt>WebSocket</tt> instance this event is occurring on.
   * @param code   The codes can be looked up here: {@link CloseFrame}
   * @param reason Additional information string
   * @param remote Returns whether or not the closing of the connection was initiated by the remote
   *               host.
   */
  void onWebsocketClosing(WebSocket ws, int code, String reason, boolean remote);

  /**
   * send when this peer sends a close handshake
   *
   * @param ws     The <tt>WebSocket</tt> instance this event is occurring on.
   * @param code   The codes can be looked up here: {@link CloseFrame}
   * @param reason Additional information string
   */
  void onWebsocketCloseInitiated(WebSocket ws, int code, String reason);

  /**
   * Called if an exception worth noting occurred. If an error causes the connection to fail onClose
   * will be called additionally afterwards.
   *
   * @param conn The <tt>WebSocket</tt> instance this event is occurring on.
   * @param ex   The exception that occurred. <br> Might be null if the exception is not related to
   *             any specific connection. For example if the server port could not be bound.
   */
  void onWebsocketError(WebSocket conn, Exception ex);

  /**
   * Called a ping frame has been received. This method must send a corresponding pong by itself.
   *
   * @param conn The <tt>WebSocket</tt> instance this event is occurring on.
   * @param f    The ping frame. Control frames may contain payload.
   */
  void onWebsocketPing(WebSocket conn, Framedata f);

  /**
   * Called just before a ping frame is sent, in order to allow users to customize their ping frame
   * data.
   *
   * @param conn The <tt>WebSocket</tt> connection from which the ping frame will be sent.
   * @return PingFrame to be sent.
   */
  PingFrame onPreparePing(WebSocket conn);

  /**
   * Called when a pong frame is received.
   *
   * @param conn The <tt>WebSocket</tt> instance this event is occurring on.
   * @param f    The pong frame. Control frames may contain payload.
   **/
  void onWebsocketPong(WebSocket conn, Framedata f);

  /**
   * This method is used to inform the selector thread that there is data queued to be written to
   * the socket.
   *
   * @param conn The <tt>WebSocket</tt> instance this event is occurring on.
   */
  void onWriteDemand(WebSocket conn);

  /**
   * @param conn The <tt>WebSocket</tt> instance this event is occurring on.
   * @return Returns the address of the endpoint this socket is bound to.
   * @see WebSocket#getLocalSocketAddress()
   */
  InetSocketAddress getLocalSocketAddress(WebSocket conn);

  /**
   * @param conn The <tt>WebSocket</tt> instance this event is occurring on.
   * @return Returns the address of the endpoint this socket is connected to, or{@code null} if it
   * is unconnected.
   * @see WebSocket#getRemoteSocketAddress()
   */
  InetSocketAddress getRemoteSocketAddress(WebSocket conn);
}
