/*
 *  Copyright 2012 The WebRTC project authors. All Rights Reserved.
 *
 *  Use of this source code is governed by a BSD-style license
 *  that can be found in the LICENSE file in the root of the source
 *  tree. An additional intellectual property rights grant can be found
 *  in the file PATENTS.  All contributing project authors may
 *  be found in the AUTHORS file in the root of the source tree.
 */

// This file contains a class used for gathering statistics from an ongoing
// libjingle PeerConnection.

#ifndef PC_STATSCOLLECTOR_H_
#define PC_STATSCOLLECTOR_H_

#include <map>
#include <memory>
#include <string>
#include <utility>
#include <vector>

#include "api/mediastreaminterface.h"
#include "api/peerconnectioninterface.h"
#include "api/statstypes.h"
#include "pc/peerconnectioninternal.h"

namespace webrtc {

// Conversion function to convert candidate type string to the corresponding one
// from  enum RTCStatsIceCandidateType.
const char* IceCandidateTypeToStatsType(const std::string& candidate_type);

// Conversion function to convert adapter type to report string which are more
// fitting to the general style of http://w3c.github.io/webrtc-stats. This is
// only used by stats collector.
const char* AdapterTypeToStatsType(rtc::AdapterType type);

// A mapping between track ids and their StatsReport.
typedef std::map<std::string, StatsReport*> TrackIdMap;

class StatsCollector {
 public:
  // The caller is responsible for ensuring that the pc outlives the
  // StatsCollector instance.
  explicit StatsCollector(PeerConnectionInternal* pc);
  virtual ~StatsCollector();

  // Adds a MediaStream with tracks that can be used as a |selector| in a call
  // to GetStats.
  void AddStream(MediaStreamInterface* stream);
  void AddTrack(MediaStreamTrackInterface* track);

  // Adds a local audio track that is used for getting some voice statistics.
  void AddLocalAudioTrack(AudioTrackInterface* audio_track, uint32_t ssrc);

  // Removes a local audio tracks that is used for getting some voice
  // statistics.
  void RemoveLocalAudioTrack(AudioTrackInterface* audio_track, uint32_t ssrc);

  // Gather statistics from the session and store them for future use.
  void UpdateStats(PeerConnectionInterface::StatsOutputLevel level);

  // Gets a StatsReports of the last collected stats. Note that UpdateStats must
  // be called before this function to get the most recent stats. |selector| is
  // a track label or empty string. The most recent reports are stored in
  // |reports|.
  // TODO(tommi): Change this contract to accept a callback object instead
  // of filling in |reports|.  As is, there's a requirement that the caller
  // uses |reports| immediately without allowing any async activity on
  // the thread (message handling etc) and then discard the results.
  void GetStats(MediaStreamTrackInterface* track,
                StatsReports* reports);

  // Prepare a local or remote SSRC report for the given ssrc. Used internally
  // in the ExtractStatsFromList template.
  StatsReport* PrepareReport(bool local,
                             uint32_t ssrc,
                             const StatsReport::Id& transport_id,
                             StatsReport::Direction direction);

  // A track is invalid if there is no report data for it.
  bool IsValidTrack(const std::string& track_id);

  // Method used by the unittest to force a update of stats since UpdateStats()
  // that occur less than kMinGatherStatsPeriod number of ms apart will be
  // ignored.
  void ClearUpdateStatsCacheForTest();

 private:
  friend class StatsCollectorTest;

  // Overridden in unit tests to fake timing.
  virtual double GetTimeNow();

  bool CopySelectedReports(const std::string& selector, StatsReports* reports);

  // Helper method for creating IceCandidate report. |is_local| indicates
  // whether this candidate is local or remote.
  StatsReport* AddCandidateReport(
      const cricket::CandidateStats& candidate_stats,
      bool local);

  // Adds a report for this certificate and every certificate in its chain, and
  // returns the leaf certificate's report (|cert_stats|'s report).
  StatsReport* AddCertificateReports(
      std::unique_ptr<rtc::SSLCertificateStats> cert_stats);

  StatsReport* AddConnectionInfoReport(const std::string& content_name,
      int component, int connection_id,
      const StatsReport::Id& channel_report_id,
      const cricket::ConnectionInfo& info);

  void ExtractDataInfo();
  void ExtractSessionInfo();
  void ExtractBweInfo();
  void ExtractMediaInfo();
  void ExtractSenderInfo();
  webrtc::StatsReport* GetReport(const StatsReport::StatsType& type,
                                 const std::string& id,
                                 StatsReport::Direction direction);

  // Helper method to get stats from the local audio tracks.
  void UpdateStatsFromExistingLocalAudioTracks(bool has_remote_tracks);
  void UpdateReportFromAudioTrack(AudioTrackInterface* track,
                                  StatsReport* report,
                                  bool has_remote_tracks);

  // Helper method to get the id for the track identified by ssrc.
  // |direction| tells if the track is for sending or receiving.
  bool GetTrackIdBySsrc(uint32_t ssrc,
                        std::string* track_id,
                        StatsReport::Direction direction);

  // Helper method to update the timestamp of track records.
  void UpdateTrackReports();

  // A collection for all of our stats reports.
  StatsCollection reports_;
  TrackIdMap track_ids_;
  // Raw pointer to the peer connection the statistics are gathered from.
  PeerConnectionInternal* const pc_;
  double stats_gathering_started_;

  // TODO(tommi): We appear to be holding on to raw pointers to reference
  // counted objects?  We should be using scoped_refptr here.
  typedef std::vector<std::pair<AudioTrackInterface*, uint32_t> >
      LocalAudioTrackVector;
  LocalAudioTrackVector local_audio_tracks_;
};

}  // namespace webrtc

#endif  // PC_STATSCOLLECTOR_H_