//
// ZoneMinder Core Interfaces, $Date$, $Revision$
// Copyright (C) 2001-2008 Philip Coombes
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation; either version 2
// of the License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
//

#ifndef ZM_EVENT_H
#define ZM_EVENT_H

#include "zm_config.h"
#include "zm_define.h"
#include "zm_packet.h"
#include "zm_packetqueue.h"
#include "zm_storage.h"
#include "zm_time.h"
#include "zm_utils.h"
#include "zm_zone.h"

#include <atomic>
#include <condition_variable>
#include <map>
#include <memory>
#include <mutex>
#include <queue>
#include <set>
#include <thread>


class EventStream;
class Frame;
class Image;
class Monitor;
class Tag;
class VideoStore;
class ZMPacket;
class Zone;

// True when a failed link(2) means renaming instead is worth trying, rather
// than something being wrong that a rename would hit too. EXDEV is deliberately
// excluded: a cross-device link is one rename(2) cannot do either.
//
// EOPNOTSUPP (and its alias ENOTSUP) and ENOSYS mean the filesystem has no hard
// links at all, on both platforms.
//
// EPERM only means that on Linux, where the VFS returns it for a filesystem
// with no link operation, which is the exFAT and FAT case. Linux overloads it
// with fs.protected_hardlinks, immutable sources and idmapped mounts, so this
// is a broader "try the rename" than the errno alone proves; rename is the
// right attempt in all of those, and where it genuinely cannot proceed it fails
// and gets reported. FreeBSD is excluded because there EPERM only ever means a
// directory source, an immutable source or an immutable target directory, all
// real errors, and absent link support arrives as EOPNOTSUPP above.
// See https://github.com/ZoneMinder/zoneminder/issues/5048
inline bool ErrnoMeansNoHardLinkSupport(int err) {
  if ((err == EOPNOTSUPP) || (err == ENOTSUP) || (err == ENOSYS)) return true;
#ifndef __FreeBSD__
  if (err == EPERM) return true;
#endif
  return false;
}

// Event::max_score starts at -1 so that the first frame, even with score 0,
// becomes the max-score frame. Events.MaxScore is unsigned: an event closed
// before its first frame has to store 0, or strict SQL mode rejects the
// whole closing UPDATE and the event stays open in the database.
inline int EventMaxScoreForDb(int max_score) {
  return max_score < 0 ? 0 : max_score;
}

// Maximum number of prealarm frames that can be stored
#define MAX_PRE_ALARM_FRAMES  16

typedef uint64_t event_id_t;

//
// Class describing events, i.e. captured periods of activity.
//
class Event {
  friend class EventStream;

 public:
  typedef std::set<std::string> StringSet;
  typedef std::map<std::string, StringSet> StringSetMap;

 protected:
  static const char * frame_type_names[3];

  struct PreAlarmData {
    Image *image;
    struct timeval timestamp;
    unsigned int score;
    Image *alarm_frame;
  };
  std::queue<Frame*> frame_data;

  static int pre_alarm_count;
  static PreAlarmData pre_alarm_data[MAX_PRE_ALARM_FRAMES];

  uint64_t  id;
  Monitor      *monitor;
  Storage *storage;
  PacketQueue * packetqueue;
  packetqueue_iterator * packetqueue_it;
  SystemTimePoint start_time;
  // Written by the event thread (AddPacket_), read by Analyse through
  // Duration()/Frames()/AlarmFrames(): atomic.
  std::atomic<SystemTimePoint> end_time;
  std::string     cause;
  StringSetMap    noteSetMap;
  std::atomic<int> frames;
  std::atomic<int> alarm_frames;
  bool alarm_frame_written;
  int  tot_score;
  int  max_score;
  int max_score_frame_id;
  std::string path;
  std::string snapshot_file;
  bool snapshot_file_written;
  std::string alarm_file;
  VideoStore *videoStore;

  std::string container;
  std::string codec;
  std::string video_file;
  std::string video_path;
  std::string video_incomplete_file;
  std::string video_incomplete_path;

  int        last_db_frame;
  bool have_video_keyframe; // a flag to tell us if we have had a video keyframe when writing an mp4.  The first frame SHOULD be a video keyframe.
  Storage::Schemes  scheme;
  int save_jpegs;

  void createNotes(std::string &notes);

  void Run();

  std::atomic<bool> terminate_;
  std::thread thread_;

  std::map<const std::string,Tag> tags;
 public:
  static bool OpenFrameSocket(int);
  static bool ValidateFrameSocket(int);

  Event(Monitor *p_monitor,
      packetqueue_iterator * p_packetqueue_it,
      SystemTimePoint p_start_time,
      const std::string &p_cause,
      const StringSetMap &p_noteSetMap);
  ~Event();

  uint64_t Id() const { return id; }
  const std::string &Cause() const { return cause; }
  void addNote(const char *cause, const std::string &note);
  int Frames() const { return frames; }
  int AlarmFrames() const { return alarm_frames; }

  SystemTimePoint StartTime() const { return start_time; }
  SystemTimePoint EndTime() const { return end_time.load(); }
  TimePoint::duration Duration() const { return end_time.load() - start_time; };

  void AddPacket_(const std::shared_ptr<ZMPacket> p);
  bool WritePacket(const std::shared_ptr<ZMPacket> p);
  bool SendFrameImage(const Image *image, bool alarm_frame=false);
  bool WriteFrameImage(Image *image, SystemTimePoint timestamp, const char *event_file, bool alarm_frame = false) const;

  void updateNotes(const StringSetMap &stringSetMap);

  void AddFrame(const std::shared_ptr<ZMPacket>&packet);

  void Stop() {
    terminate_ = true;
    packetqueue->notify_all();
  }
  bool Stopped() const { return terminate_; }

 private:
  void WriteDbFrames();
  bool SetPath(Storage *storage);

 public:
  static std::string getSubPath(tm time) {
    std::string subpath = stringtf("%02d/%02d/%02d/%02d/%02d/%02d",
                                   time.tm_year - 100, time.tm_mon + 1, time.tm_mday,
                                   time.tm_hour, time.tm_min, time.tm_sec);
    return subpath;
  }
  static std::string getSubPath(time_t *time) {
    tm time_tm = {};
    localtime_r(time, &time_tm);
    return Event::getSubPath(time_tm);
  }

  const char* getEventFile() const {
    return video_file.c_str();
  }

  static int PreAlarmCount() {
    return pre_alarm_count;
  }
  static void EmptyPreAlarmFrames() {
    pre_alarm_count = 0;
  }
  static void AddPreAlarmFrame(
    Image *image,
    SystemTimePoint timestamp,
    int score=0,
    Image *alarm_frame=nullptr
  ) {
    pre_alarm_count++;
  }
  void SavePreAlarmFrames() {
    EmptyPreAlarmFrames();
  }
  int MonitorId() const;
};
#endif // ZM_EVENT_H