/*
 *
 * (C) 2013-20 - ntop.org
 *
 *
 * 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 3 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 */

#include "ntop_includes.h"

/* **************************************************** */

static void* startActivity(void* ptr)  {
  Utils::setThreadName(((ThreadedActivity*)ptr)->activityPath());

  ((ThreadedActivity*)ptr)->activityBody();
  return(NULL);
}

/* ******************************************* */

ThreadedActivity::ThreadedActivity(const char* _path,
				   u_int32_t _periodicity_seconds,
				   u_int32_t _max_duration_seconds,
				   bool _align_to_localtime,
				   bool _exclude_viewed_interfaces,
				   bool _exclude_pcap_dump_interfaces,
				   bool _reuse_vm,
				   ThreadPool *_pool) {
  terminating = false;
  periodicity = _periodicity_seconds;
  max_duration_secs = _max_duration_seconds;
  align_to_localtime = _align_to_localtime;
  exclude_viewed_interfaces = _exclude_viewed_interfaces;
  exclude_pcap_dump_interfaces = _exclude_pcap_dump_interfaces;
#ifndef WIN32
  reuse_vm = _reuse_vm;
#else
  /* Don't reuse the VM in Windows as it seems like some file/error state
   * is cached causing ntopng script failures on demo expiration. */
  reuse_vm = false;
#endif
  thread_started = false;
  path = strdup(_path); /* ntop->get_callbacks_dir() */;
  interfaceTasksRunning = (ThreadedActivityState*) calloc(MAX_NUM_INTERFACE_IDS + 1 /* For the system interface */, sizeof(ThreadedActivityState));
  for(int i = 0; i < MAX_NUM_INTERFACE_IDS + 1; i++) {
    interfaceTasksRunning[i] = threaded_activity_state_sleeping;
  }
  threaded_activity_stats = new (std::nothrow) ThreadedActivityStats*[MAX_NUM_INTERFACE_IDS + 1 /* For the system interface */]();
  pool = _pool;
  setDeadlineApproachingSecs();

#ifdef THREADED_DEBUG
  ntop->getTrace()->traceEvent(TRACE_WARNING, "[%p] Creating ThreadedActivity '%s'", this, path);
#endif
}

/* ******************************************* */

ThreadedActivity::~ThreadedActivity() {
  std::map<int, LuaReusableEngine*>::iterator it;

  /* NOTE: terminateEnqueueLoop should have already been called by the PeriodicActivities
   * destructor. */
  terminateEnqueueLoop();

  if(threaded_activity_stats) {
    for(u_int i = 0; i < MAX_NUM_INTERFACE_IDS; i++) {
      if(threaded_activity_stats[i])
	delete threaded_activity_stats[i];
    }

    delete[] threaded_activity_stats;
  }

  if(interfaceTasksRunning)
    free(interfaceTasksRunning);

  if(path) free(path);

  for(it = vms.begin(); it != vms.end(); ++it)
    delete(it->second);
}

/* ******************************************* */

void ThreadedActivity::setDeadlineApproachingSecs() {
  if(periodicity <= 1)
    deadline_approaching_secs =  0;
  else if(periodicity <= 5)
    deadline_approaching_secs =  1;
  else if(periodicity <= 60)
    deadline_approaching_secs =  5;
  else /* > 60 secs */
    deadline_approaching_secs = 10;
}

/* ******************************************* */

/* Stop the possibly running pthreadLoop, so that new activities
 * won't be enqueued. */
void ThreadedActivity::terminateEnqueueLoop() {
  void *res;

  shutdown();

  if(thread_started) {
    pthread_join(pthreadLoop, &res);

#ifdef THREAD_DEBUG
    ntop->getTrace()->traceEvent(TRACE_NORMAL, "Joined thread %s", path);
#endif

    thread_started = false;
  }
}

/* ******************************************* */

bool ThreadedActivity::isTerminating() {
  return(terminating
	 || ntop->getGlobals()->isShutdownRequested()
	 || ntop->getGlobals()->isShutdown());
};

/* ******************************************* */

ThreadedActivityState *ThreadedActivity::getThreadedActivityState(NetworkInterface *iface) const {
  if(iface) {
    /* As the system interface has id -1, we add 1 to the offset to access the array.
       The array is allocated in the constructor with MAX_NUM_INTERFACE_IDS + 1 to also
       accomodate the system interface */
    int stats_idx = iface->get_id() + 1;

    if(stats_idx >= 0 && stats_idx < MAX_NUM_INTERFACE_IDS + 1)
      return &interfaceTasksRunning[stats_idx];
    else {
      ntop->getTrace()->traceEvent(TRACE_ERROR, "Internal error. Interface id too large. [path: %s][iface: %s]",
				   path, iface->get_name());
      return NULL;
    }
  } else
    ntop->getTrace()->traceEvent(TRACE_ERROR, "Internal error. NULL interface.");

  return NULL;
}

/* ******************************************* */

const char* ThreadedActivity::get_state_label(ThreadedActivityState ta_state) {
  switch(ta_state) {
  case threaded_activity_state_sleeping:
    return("sleeping");
    break;
  case threaded_activity_state_queued:
    return("queued");
    break;
  case threaded_activity_state_running:
    return("running");
    break;
  case threaded_activity_state_unknown:
  default:
    return("unknown");
    break;
  }
}

/* ******************************************* */

static bool skipExecution(const char *path) {
#if 0
  if((ntop->getPrefs()->getTimeseriesDriver() != ts_driver_influxdb) &&
      (strcmp(path, TIMESERIES_SCRIPT_PATH) == 0))
    return(true);
#endif

  // Always execute periodic activities, thread timeseries.lua
  // is now also used by rrds to dequeue writes
  return(false);
}

/* ******************************************* */

void ThreadedActivity::set_state(NetworkInterface *iface, ThreadedActivityState ta_state) {
  ThreadedActivityState *cur_state = getThreadedActivityState(iface);

  if(cur_state) {
    if((*cur_state == threaded_activity_state_queued
	  && ta_state != threaded_activity_state_running)
	 || (*cur_state == threaded_activity_state_running
	     && ta_state != threaded_activity_state_sleeping))
	ntop->getTrace()->traceEvent(TRACE_ERROR, "Internal error. Invalid state transition. [path: %s][iface: %s]",
				     path, iface->get_name());
      /* Everything is OK, let's set the state. */
      *cur_state = ta_state;
  }
}

/* ******************************************* */

ThreadedActivityState ThreadedActivity::get_state(NetworkInterface *iface) const {
  ThreadedActivityState *cur_state = getThreadedActivityState(iface);

  if(cur_state)
    return *cur_state;

  return threaded_activity_state_unknown;

}

/* ******************************************* */

void ThreadedActivity::set_state_sleeping(NetworkInterface *iface) {
  set_state(iface, threaded_activity_state_sleeping);
}

/* ******************************************* */

void ThreadedActivity::set_state_queued(NetworkInterface *iface) {
  ThreadedActivityStats *ta_stats = getThreadedActivityStats(iface, true /* Allocate if missing */);

  set_state(iface, threaded_activity_state_queued);

  if(ta_stats)
    ta_stats->updateStatsQueuedTime(time(NULL));
}

/* ******************************************* */

void ThreadedActivity::set_state_running(NetworkInterface *iface) {
  set_state(iface, threaded_activity_state_running);
}

/* ******************************************* */

bool ThreadedActivity::isQueueable(NetworkInterface *iface) const {
  ThreadedActivityState *cur_state = getThreadedActivityState(iface);

  if(cur_state && *cur_state == threaded_activity_state_sleeping)
    return true;

  return false;
}

/* ******************************************* */

bool ThreadedActivity::isDeadlineApproaching(time_t deadline) const {
  /*
    The deadline is approaching if the current time is closer than deadline_approaching_secs
    with reference to the deadline passed as parameter
   */
  bool res = deadline - time(NULL) <= deadline_approaching_secs;

  return res;
}

/* ******************************************* */

/* NOTE: this runs into a separate thread, launched by PeriodicActivities
 * after creation. */
void ThreadedActivity::activityBody() {
  if(periodicity == 0)       /* The script is not periodic */
    aperiodicActivityBody();
  else if(periodicity == 1) /* Accurate time computation with micro-second-accurate sleep */
    uSecDiffPeriodicActivityBody();
  else
    periodicActivityBody();
}

/* ******************************************* */

void ThreadedActivity::run() {
  bool pcap_dump_only = true;

  for(int i = 0; i < ntop->get_num_interfaces(); i++) {
    NetworkInterface *iface = ntop->getInterface(i);
    if(iface && iface->getIfType() != interface_type_PCAP_DUMP)
      pcap_dump_only = false;
  }
  /* Don't schedule periodic activities it we are processing pcap files only. */
  if (exclude_pcap_dump_interfaces && pcap_dump_only)
    return;

  if(pthread_create(&pthreadLoop, NULL, startActivity, (void*)this) == 0) {
    thread_started = true;
#ifdef HAVE_LIBCAP
    Utils::setThreadAffinityWithMask(pthreadLoop, ntop->getPrefs()->get_other_cpu_affinity_mask());
#endif
  }
}

/* ******************************************* */

ThreadedActivityStats *ThreadedActivity::getThreadedActivityStats(NetworkInterface *iface, bool allocate_if_missing) {
  ThreadedActivityStats *ta = NULL;

  if(!isTerminating() && iface) {
    /* As the system interface has id -1, we add 1 to the offset to access the array of stats.
       The array of stats is allocated in the constructor with MAX_NUM_INTERFACE_IDS + 1 to also
       accomodate the system interface */
    int stats_idx = iface->get_id() + 1;

    if(stats_idx >= 0 && stats_idx < MAX_NUM_INTERFACE_IDS + 1) {
	if(!threaded_activity_stats[stats_idx]) {
	  if(allocate_if_missing) {
	    try {
	      ta = new ThreadedActivityStats(this);
	    } catch(std::bad_alloc& ba) {
	      return NULL;
	    }
	    threaded_activity_stats[stats_idx] = ta;
	  }
	} else
	  ta = threaded_activity_stats[stats_idx];
      }
  }

  return ta;
}

/* ******************************************* */

void ThreadedActivity::updateThreadedActivityStatsBegin(NetworkInterface *iface, struct timeval *begin) {
  ThreadedActivityStats *ta = getThreadedActivityStats(iface, true /* Allocate if missing */);

  if(ta)
    ta->updateStatsBegin(begin);
}

/* ******************************************* */

void ThreadedActivity::updateThreadedActivityStatsEnd(NetworkInterface *iface, u_long latest_duration) {
  ThreadedActivityStats *ta = getThreadedActivityStats(iface, true /* Allocate if missing */);

  if(ta)
    ta->updateStatsEnd(latest_duration);
}

/* ******************************************* */

/* Run a one-shot script / accurate (e.g. second) periodic script */
void ThreadedActivity::runSystemScript(time_t now) {
  struct stat buf;
  char script_path[MAX_PATH];
  
  snprintf(script_path, sizeof(script_path), "%s/system/%s",
	   ntop->get_callbacks_dir(), path);

  if(stat(script_path, &buf) == 0) {
    set_state_running(ntop->getSystemInterface());
    runScript(now, script_path, ntop->getSystemInterface(), now + max_duration_secs /* this is the deadline */);
    set_state_sleeping(ntop->getSystemInterface());
  } else
    ntop->getTrace()->traceEvent(TRACE_WARNING, "Unable to find script %s", path);
}

/* ******************************************* */

/* Run a script - both periodic and one-shot scripts are called here */
void ThreadedActivity::runScript(time_t now, char *script_path, NetworkInterface *iface, time_t deadline) {
  LuaEngine *l = NULL;
  u_long msec_diff;
  struct timeval begin, end;
  ThreadedActivityStats *thstats = getThreadedActivityStats(iface, true);

  if(!iface)
    return;

  if(strcmp(path, SHUTDOWN_SCRIPT_PATH) && isTerminating())
    return;

  if(iface->isViewed() && exclude_viewed_interfaces)
    return;

#ifdef THREADED_DEBUG
  ntop->getTrace()->traceEvent(TRACE_WARNING, "[%p] Running %s", this, path);
#endif

  ntop->getTrace()->traceEvent(TRACE_INFO, "Running %s (iface=%p)", script_path, iface);

  l = loadVm(script_path, iface, now);
  if(!l) {
    ntop->getTrace()->traceEvent(TRACE_ERROR, "Unable to load the Lua vm [%s][vm: %s]", iface->get_name(), path);
    return;
  }

  /* Set the deadline and the threaded activity in the vm so they can be accessed */
  l->setThreadedActivityData(this, thstats, deadline);

  if(thstats) {
    thstats->setDeadline(deadline);
    thstats->setCurrentProgress(0);

    /* Reset the internal state for the current execution */
    thstats->setNotExecutedAttivity(false);
    thstats->setSlowPeriodicActivity(false);
  }

  gettimeofday(&begin, NULL);
  updateThreadedActivityStatsBegin(iface, &begin);

  /* Set the current time globally  */
  lua_pushinteger(l->getState(), now);
  lua_setglobal(l->getState(), "_now");
  l->run_loaded_script();

  gettimeofday(&end, NULL);
  msec_diff = (end.tv_sec - begin.tv_sec) * 1000 + (end.tv_usec - begin.tv_usec) / 1000;
  updateThreadedActivityStatsEnd(iface, msec_diff);

  if(thstats && isDeadlineApproaching(deadline))
    thstats->setSlowPeriodicActivity(true);

  if(l && !reuse_vm)
    delete l;
}

/* ******************************************* */

LuaEngine* ThreadedActivity::loadVm(char *script_path, NetworkInterface *iface, time_t when) {
  LuaEngine *l = NULL;

  try {
    if(reuse_vm) {
      /* Reuse an existing engine or allocate a new one */
      LuaReusableEngine *engine;
      std::map<int, LuaReusableEngine*>::iterator it;

      vms_mutex.lock(__FILE__, __LINE__);

      if((it = vms.find(iface->get_id())) != vms.end())
	engine = it->second;
      else {
	engine = new LuaReusableEngine(script_path, iface, 300 /* reload interval */);

	/* Save the VM for later use */
	vms[iface->get_id()] = engine;
      }

      vms_mutex.unlock(__FILE__, __LINE__);

      l = engine->getVm(when);
    } else {
      /* NOTE: this needs to be deallocated by the caller */
      l = new LuaEngine(NULL);

      if(l->load_script(script_path, iface) != 0) {
	delete l;
	l = NULL;
      }
    }
  } catch(std::bad_alloc& ba) {
    l = NULL;
  }

  return(l);
}

/* ******************************************* */

void ThreadedActivity::aperiodicActivityBody() {
  if(!isTerminating())
    runSystemScript(time(NULL));
}

/* ******************************************* */

void ThreadedActivity::uSecDiffPeriodicActivityBody() {
  struct timeval begin, end;

  while(!isTerminating()) {
    gettimeofday(&begin, NULL);
    runSystemScript(begin.tv_sec);
    gettimeofday(&end, NULL);

    /* We must guarantee that the "now" time, passed to the script,
     * it's monotonically increasing. */
    while(end.tv_sec < (begin.tv_sec + periodicity)) {
      /* Align to the start of the second to avoid crossing second bounds.
       * Alignment only happens if the script hasn't already crossed
       * its periodicity bound, otherwise the while is just skipped. */
      u_long to_sleep = 1e6 - end.tv_usec;

      //ntop->getTrace()->traceEvent(TRACE_NORMAL, "[%s] Sleeping %lu us [%lu/%lu]\n", path, to_sleep, end.tv_sec, (begin.tv_sec + periodicity));
      _usleep(to_sleep);

      gettimeofday(&end, NULL);
    }
  }
}

/* ******************************************* */

void ThreadedActivity::periodicActivityBody() {
  u_int now;
  u_int32_t next_deadline, next_schedule = (u_int32_t)time(NULL);

  next_schedule = Utils::roundTime(next_schedule, periodicity, align_to_localtime ? ntop->get_time_offset() : 0);

  while(!isTerminating()) {
    now = (u_int)time(NULL);

    if(now >= next_schedule) {
      next_deadline = now + max_duration_secs; /* deadline is max_duration_secs from now */
      next_schedule = Utils::roundTime(now, periodicity, align_to_localtime ? ntop->get_time_offset() : 0);

      if(!skipExecution(path))
	schedulePeriodicActivity(pool, now, next_deadline);
    }

    sleep(1);
  }

  /* ntop->getTrace()->traceEvent(TRACE_NORMAL, "Terminating %s(%s) exit", __FUNCTION__, path); */
}

/* ******************************************* */

/* This function enqueues the periodic activity job into the ThreadPool.
 * The ThreadPool, running into another thread, will dequeue the job and call
 * ThreadedActivity::runScript. The variables interfaceTasksRunning
 * are used to ensure that only a single instance of the job is running for a given
 * NetworkInterface. */
void ThreadedActivity::schedulePeriodicActivity(ThreadPool *pool, time_t scheduled_time, time_t deadline) {
  /* Schedule per system / interface */
  char script_path[MAX_PATH];
  struct stat buf;

#ifdef THREAD_DEBUG
  char deadline_buf[32], scheduled_time_buf[32];
  struct tm deadline_tm, scheduled_time_tm;

  strftime(deadline_buf, sizeof(deadline_buf), "%H:%M:%S", localtime_r(&deadline, &deadline_tm));
  strftime(scheduled_time_buf, sizeof(scheduled_time_buf), "%H:%M:%S", localtime_r(&scheduled_time, &scheduled_time_tm));
  ntop->getTrace()->traceEvent(TRACE_NORMAL, "Scheduling [%s][schedule: %s][deadline: %s]",
			       path, scheduled_time_buf, deadline_buf);
#endif

  /* Schedule system script */
  snprintf(script_path, sizeof(script_path), "%s/system/%s",
	   ntop->get_callbacks_dir(), path);

  if(stat(script_path, &buf) == 0) {
    if(pool->queueJob(this, script_path, ntop->getSystemInterface(), scheduled_time, deadline)) {
#ifdef THREAD_DEBUG
      ntop->getTrace()->traceEvent(TRACE_NORMAL, "Queued system job %s", script_path);
#endif
    }
  }

  /* Schedule interface script, one for each interface */
  snprintf(script_path, sizeof(script_path), "%s/interface/%s",
	   ntop->get_callbacks_dir(), path);

  if(stat(script_path, &buf) == 0) {
    for(int i = 0; i < ntop->get_num_interfaces(); i++) {
      NetworkInterface *iface = ntop->getInterface(i);

      if(iface
	 && (iface->getIfType() != interface_type_PCAP_DUMP || !exclude_pcap_dump_interfaces)) {
	if(pool->queueJob(this, script_path, iface, scheduled_time, deadline)) {
#ifdef THREAD_DEBUG
	  ntop->getTrace()->traceEvent(TRACE_NORMAL, "Queued interface job %s [%s]", script_path, iface->get_name());
#endif
	}	
      }
    }
  }
}

/* ******************************************* */

void ThreadedActivity::lua(NetworkInterface *iface, lua_State *vm) {
  ThreadedActivityStats *ta = getThreadedActivityStats(iface, false /* Do not allocate if missing */);

  if(ta) {
    lua_newtable(vm);

    ta->lua(vm);

    lua_push_str_table_entry(vm, "state", get_state_label(get_state(iface)));
    lua_push_uint64_table_entry(vm, "periodicity", getPeriodicity());
    lua_push_uint64_table_entry(vm, "max_duration_secs", max_duration_secs);
    lua_push_uint64_table_entry(vm, "deadline_secs", deadline_approaching_secs);

    lua_pushstring(vm, path ? path : "");
    lua_insert(vm, -2);
    lua_settable(vm, -3);
  }
}

/* ******************************************* */

void ThreadedActivity::setNextVmReload(time_t t) {
  std::map<int, LuaReusableEngine*>::iterator it;

  vms_mutex.lock(__FILE__, __LINE__);

  for(it = vms.begin(); it != vms.end(); ++it)
    it->second->setNextVmReload(t);

  vms_mutex.unlock(__FILE__, __LINE__);
}