// 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_JINGLE_SESSION_H_
#define REMOTING_PROTOCOL_JINGLE_SESSION_H_

#include <list>
#include <map>
#include <set>
#include <string>

#include "base/memory/ref_counted.h"
#include "base/timer/timer.h"
#include "crypto/rsa_private_key.h"
#include "net/base/completion_callback.h"
#include "remoting/protocol/authenticator.h"
#include "remoting/protocol/datagram_channel_factory.h"
#include "remoting/protocol/jingle_messages.h"
#include "remoting/protocol/session.h"
#include "remoting/protocol/session_config.h"
#include "remoting/protocol/transport.h"
#include "remoting/signaling/iq_sender.h"

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

namespace remoting {
namespace protocol {

class SecureChannelFactory;
class ChannelMultiplexer;
class JingleSessionManager;
class PseudoTcpChannelFactory;

// JingleSessionManager and JingleSession implement the subset of the
// Jingle protocol used in Chromoting. Instances of this class are
// created by the JingleSessionManager.
class JingleSession : public base::NonThreadSafe,
                      public Session,
                      public DatagramChannelFactory,
                      public Transport::EventHandler {
 public:
  ~JingleSession() override;

  // Session interface.
  void SetEventHandler(Session::EventHandler* event_handler) override;
  ErrorCode error() override;
  const std::string& jid() override;
  const CandidateSessionConfig* candidate_config() override;
  const SessionConfig& config() override;
  void set_config(scoped_ptr<SessionConfig> config) override;
  StreamChannelFactory* GetTransportChannelFactory() override;
  StreamChannelFactory* GetMultiplexedChannelFactory() override;
  void Close() override;

  // DatagramChannelFactory interface.
  void CreateChannel(const std::string& name,
                     const ChannelCreatedCallback& callback) override;
  void CancelChannelCreation(const std::string& name) override;

  // Transport::EventHandler interface.
  void OnTransportIceCredentials(Transport* transport,
                                 const std::string& ufrag,
                                 const std::string& password) override;
  void OnTransportCandidate(Transport* transport,
                            const cricket::Candidate& candidate) override;
  void OnTransportRouteChange(Transport* transport,
                              const TransportRoute& route) override;
  void OnTransportFailed(Transport* transport) override;
  void OnTransportDeleted(Transport* transport) override;

 private:
  friend class JingleSessionManager;

  typedef std::map<std::string, Transport*> ChannelsMap;
  typedef base::Callback<void(JingleMessageReply::ErrorType)> ReplyCallback;

  explicit JingleSession(JingleSessionManager* session_manager);

  // Start connection by sending session-initiate message.
  void StartConnection(const std::string& peer_jid,
                       scoped_ptr<Authenticator> authenticator,
                       scoped_ptr<CandidateSessionConfig> config);

  // Passes transport info to a new |channel| in case it was received before the
  // channel was created.
  void AddPendingRemoteTransportInfo(Transport* channel);

  // Called by JingleSessionManager for incoming connections.
  void InitializeIncomingConnection(const JingleMessage& initiate_message,
                                    scoped_ptr<Authenticator> authenticator);
  void AcceptIncomingConnection(const JingleMessage& initiate_message);

  // Sends |message| to the peer. The session is closed if the send fails or no
  // response is received within a reasonable time. All other responses are
  // ignored.
  void SendMessage(const JingleMessage& message);

  // Iq response handler.
  void OnMessageResponse(JingleMessage::ActionType request_type,
                         IqRequest* request,
                         const buzz::XmlElement* response);

  // Creates empty |pending_transport_info_message_| and schedules timer for
  // SentTransportInfo() to sent the message later.
  void EnsurePendingTransportInfoMessage();

  // Sends transport-info message with candidates from |pending_candidates_|.
  void SendTransportInfo();

  // Response handler for transport-info responses. Transport-info timeouts are
  // ignored and don't terminate connection.
  void OnTransportInfoResponse(IqRequest* request,
                               const buzz::XmlElement* response);

  // Called by JingleSessionManager on incoming |message|. Must call
  // |reply_callback| to send reply message before sending any other
  // messages.
  void OnIncomingMessage(const JingleMessage& message,
                         const ReplyCallback& reply_callback);

  // Message handlers for incoming messages.
  void OnAccept(const JingleMessage& message,
                const ReplyCallback& reply_callback);
  void OnSessionInfo(const JingleMessage& message,
                     const ReplyCallback& reply_callback);
  void OnTerminate(const JingleMessage& message,
                   const ReplyCallback& reply_callback);
  void ProcessTransportInfo(const JingleMessage& message);

  // Called from OnAccept() to initialize session config.
  bool InitializeConfigFromDescription(const ContentDescription* description);

  // Called after the initial incoming authenticator message is processed.
  void ContinueAcceptIncomingConnection();

  // Called after subsequent authenticator messages are processed.
  void ProcessAuthenticationStep();

  // Called after the authenticating step is finished.
  void ContinueAuthenticationStep();

  // Called when authentication is finished.
  void OnAuthenticated();

  // Terminates the session and sends session-terminate if it is
  // necessary. |error| specifies the error code in case when the
  // session is being closed due to an error.
  void CloseInternal(ErrorCode error);

  // Sets |state_| to |new_state| and calls state change callback.
  void SetState(State new_state);

  // Returns true if the state of the session is not CLOSED or FAILED
  bool is_session_active();

  JingleSessionManager* session_manager_;
  std::string peer_jid_;
  scoped_ptr<CandidateSessionConfig> candidate_config_;
  Session::EventHandler* event_handler_;

  std::string session_id_;
  State state_;
  ErrorCode error_;

  scoped_ptr<SessionConfig> config_;

  scoped_ptr<Authenticator> authenticator_;

  // Pending Iq requests. Used for all messages except transport-info.
  std::set<IqRequest*> pending_requests_;

  // Pending transport-info requests.
  std::list<IqRequest*> transport_info_requests_;

  ChannelsMap channels_;
  scoped_ptr<PseudoTcpChannelFactory> pseudotcp_channel_factory_;
  scoped_ptr<SecureChannelFactory> secure_channel_factory_;
  scoped_ptr<ChannelMultiplexer> channel_multiplexer_;

  scoped_ptr<JingleMessage> pending_transport_info_message_;
  base::OneShotTimer<JingleSession> transport_info_timer_;

  // Pending remote transport info received before the local channels were
  // created.
  std::list<JingleMessage::IceCredentials> pending_remote_ice_credentials_;
  std::list<JingleMessage::NamedCandidate> pending_remote_candidates_;

  base::WeakPtrFactory<JingleSession> weak_factory_;

  DISALLOW_COPY_AND_ASSIGN(JingleSession);
};

}  // namespace protocol
}  // namespace remoting

#endif  // REMOTING_PROTOCOL_JINGLE_SESSION_H_