// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef REMOTING_PROTOCOL_SESSION_H_
#define REMOTING_PROTOCOL_SESSION_H_

#include <string>

#include "base/callback.h"
#include "base/threading/non_thread_safe.h"
#include "remoting/protocol/buffered_socket_writer.h"
#include "remoting/protocol/errors.h"
#include "remoting/protocol/session_config.h"

namespace net {
class IPEndPoint;
class Socket;
class StreamSocket;
}  // namespace net

namespace remoting {
namespace protocol {

struct TransportRoute;

// Generic interface for Chromotocol connection used by both client and host.
// Provides access to the connection channels, but doesn't depend on the
// protocol used for each channel.
//
// Because libjingle's sigslot class doesn't handle deletion properly
// while it is being invoked all Session instances must be deleted
// with a clean stack, i.e. not from event handlers, when sigslot may
// be present in the stack.
class Session : public base::NonThreadSafe {
 public:
  enum State {
    // Created, but not connecting yet.
    INITIALIZING,

    // Sent or received session-initiate, but haven't sent or received
    // session-accept.
    // TODO(sergeyu): Do we really need this state?
    CONNECTING,

    // Session has been accepted and is pending authentication.
    CONNECTED,

    // Session has been connected and authenticated.
    AUTHENTICATED,

    // Session has been closed.
    CLOSED,

    // Connection has failed.
    FAILED,
  };

  // State change callbacks are called after session state has
  // changed. It is not safe to destroy the session from within the
  // handler unless |state| is CLOSED or FAILED.
  typedef base::Callback<void(State state)> StateChangeCallback;

  // TODO(lambroslambrou): Merge this together with StateChangeCallback into a
  // single interface.
  typedef base::Callback<void(
      const std::string& channel_name,
      const TransportRoute& route)> RouteChangeCallback;

  // TODO(sergeyu): Specify connection error code when channel
  // connection fails.
  typedef base::Callback<void(scoped_ptr<net::StreamSocket>)>
      StreamChannelCallback;
  typedef base::Callback<void(scoped_ptr<net::Socket>)>
      DatagramChannelCallback;

  Session() { }
  virtual ~Session() { }

  // Set callback that is called when state of the connection is changed.
  virtual void SetStateChangeCallback(const StateChangeCallback& callback) = 0;

  // Set callback that is called when the route for a channel is changed.
  // The callback must be registered immediately after
  // JingleSessionManager::Connect() or from OnIncomingSession() callback.
  virtual void SetRouteChangeCallback(const RouteChangeCallback& callback) = 0;

  // Returns error code for a failed session.
  virtual ErrorCode error() = 0;

  // Creates new channels for this connection. The specified callback
  // is called when then new channel is created and connected. The
  // callback is called with NULL if connection failed for any reason.
  // All channels must be destroyed before the session is
  // destroyed. Can be called only when in CONNECTING, CONNECTED or
  // AUTHENTICATED states.
  virtual void CreateStreamChannel(
      const std::string& name, const StreamChannelCallback& callback) = 0;
  virtual void CreateDatagramChannel(
      const std::string& name, const DatagramChannelCallback& callback) = 0;

  // Cancels a pending CreateStreamChannel() or CreateDatagramChannel()
  // operation for the named channel. If the channel creation already
  // completed then cancelling it has no effect. When shutting down
  // this method must be called for each channel pending creation.
  virtual void CancelChannelCreation(const std::string& name) = 0;

  // JID of the other side.
  virtual const std::string& jid() = 0;

  // Configuration of the protocol that was sent or received in the
  // session-initiate jingle message. Returned pointer is valid until
  // connection is closed.
  virtual const CandidateSessionConfig* candidate_config() = 0;

  // Protocol configuration. Can be called only after session has been accepted.
  // Returned pointer is valid until connection is closed.
  virtual const SessionConfig& config() = 0;

  // Set protocol configuration for an incoming session. Must be
  // called on the host before the connection is accepted, from
  // ChromotocolServer::IncomingConnectionCallback.
  virtual void set_config(const SessionConfig& config) = 0;

  // Closes connection. Callbacks are guaranteed not to be called
  // after this method returns. Must be called before the object is
  // destroyed, unless the state is set to FAILED or CLOSED.
  virtual void Close() = 0;

 private:
  DISALLOW_COPY_AND_ASSIGN(Session);
};

}  // namespace protocol
}  // namespace remoting

#endif  // REMOTING_PROTOCOL_SESSION_H_