/*
 * eit.c: EIT section filter
 *
 * See the main source file 'vdr.c' for copyright information and
 * how to reach the author.
 *
 * Original version (as used in VDR before 1.3.0) written by
 * Robert Schneider <Robert.Schneider@web.de> and Rolf Hakenes <hakenes@hippomi.de>.
 * Adapted to 'libsi' for VDR 1.3.0 by Marcel Wiesweg <marcel.wiesweg@gmx.de>.
 *
 * $Id: eit.c 5.6 2022/12/23 09:47:23 kls Exp $
 */

// The various ways in which broadcasters handle (or screw up) their EPG:
// - Some use the same version for all tables, and use unique event ids, which are the same in
//   both the 0x5X and the 0x6X tables. And once an event has an id, it keeps it until it is
//   no longer in the tables. Those are the good guys!
// - Some use separate versions for each table (0x50, 0x51, ...).
// - Some broadcast tables 0x5X and 0x6X, but use different event ids for the same event in both
//   sets of tables, and sometimes even use different titles, short texts or descriptions.
// - Some broadcast the full EPG only on one transponder (tables 0x6X), and on the actual transponder
//   they provide only the present/following information.
// - Some have overlapping events, especially when they mess up daylight saving time.
// - Some use all new event ids every time they update their tables.
// So, to bring order to chaos, VDR does as follows:
// - Completely ignore table 0x4F.
// - Once a schedule has seen events from 0x5X, tables 0x6X are ignored for that schedule.
// - When looking up an event in its schedule, the start time is used for tables 0x6X, and the
//   event id for tables 0x4E and 0x5X.

#include "eit.h"
#include <sys/time.h>
#include "epg.h"
#include "i18n.h"
#include "libsi/section.h"
#include "libsi/descriptor.h"

#define VALID_TIME (31536000 * 2) // two years

#define DBGEIT 0

// --- cEitTables ------------------------------------------------------------

cEitTables::cEitTables(void)
{
  complete = false;
  tableStart = 0;
  tableEnd = 0;
}

bool cEitTables::Check(uchar TableId, uchar Version, int SectionNumber)
{
  int ti = Index(TableId);
  return sectionSyncer[ti].Check(Version, SectionNumber);
}

bool cEitTables::Processed(uchar TableId, uchar LastTableId, int SectionNumber, int LastSectionNumber, int SegmentLastSectionNumber)
{
  bool Result = false;
  int ti = Index(TableId);
  int LastIndex = Index(LastTableId);
  complete = false;
  if (sectionSyncer[ti].Processed(SectionNumber, LastSectionNumber, SegmentLastSectionNumber)) {
     Result = true; // the table with TableId is complete
     for (int i = 0; i <= LastIndex; i++) {
         if (!sectionSyncer[i].Complete())
            return Result;
         }
     complete = true; // all tables have been processed
     }
  return Result;
}

// --- cEIT ------------------------------------------------------------------

class cEIT : public SI::EIT {
public:
  cEIT(cEitTablesHash &EitTablesHash, int Source, u_char Tid, const u_char *Data);
  };

cEIT::cEIT(cEitTablesHash &EitTablesHash, int Source, u_char Tid, const u_char *Data)
:SI::EIT(Data, false)
{
  if (!CheckCRCAndParse())
     return;
  int HashId = getServiceId();
  cEitTables *EitTables = EitTablesHash.Get(HashId);
  if (!EitTables) {
     EitTables = new cEitTables;
     EitTablesHash.Add(EitTables, HashId);
     }
  bool Process = EitTables->Check(Tid, getVersionNumber(), getSectionNumber());
  if (Tid != 0x4E && !Process) // we need to set the 'seen' tag to watch the running status of the present/following event
     return;

  time_t Now = time(NULL);
  if (Now < VALID_TIME)
     return; // we need the current time for handling PDC descriptors

  cStateKey ChannelsStateKey;
  cChannels *Channels = cChannels::GetChannelsWrite(ChannelsStateKey, 10);
  if (!Channels)
     return;
  tChannelID channelID(Source, getOriginalNetworkId(), getTransportStreamId(), getServiceId());
  cChannel *Channel = Channels->GetByChannelID(channelID, true);
  if (!Channel || EpgHandlers.IgnoreChannel(Channel)) {
     ChannelsStateKey.Remove(false);
     return;
     }

  cStateKey SchedulesStateKey;
  cSchedules *Schedules = cSchedules::GetSchedulesWrite(SchedulesStateKey, 10);
  if (!Schedules) {
     ChannelsStateKey.Remove(false);
     return;
     }

  cSchedule *pSchedule = (cSchedule *)Schedules->GetSchedule(Channel, true);

  if (pSchedule->OnActualTp(Tid) && (Tid & 0xF0) == 0x60) {
     SchedulesStateKey.Remove(false);
     ChannelsStateKey.Remove(false);
     return;
     }

  if (!EpgHandlers.BeginSegmentTransfer(Channel)) {
     SchedulesStateKey.Remove(false);
     ChannelsStateKey.Remove(false);
     return;
     }

  bool ChannelsModified = false;
  bool handledExternally = EpgHandlers.HandledExternally(Channel);

  bool Empty = true;
  bool Modified = false;
  time_t LingerLimit = Now - EPG_LINGER_TIME;
  time_t SegmentStart = 0; // these are actually "section" start/end times
  time_t SegmentEnd = 0;
  struct tm t = { 0 };
  localtime_r(&Now, &t); // this initializes the time zone in 't'

  SI::EIT::Event SiEitEvent;
  for (SI::Loop::Iterator it; eventLoop.getNext(SiEitEvent, it); ) {
      if (EpgHandlers.HandleEitEvent(pSchedule, &SiEitEvent, Tid, getVersionNumber()))
         continue; // an EPG handler has done all of the processing
      time_t StartTime = SiEitEvent.getStartTime();
      int Duration = SiEitEvent.getDuration();
      // Drop bogus events - but keep NVOD reference events, where all bits of the start time field are set to 1, resulting in a negative number.
      if (StartTime == 0 || StartTime > 0 && Duration == 0)
         continue;
      Empty = false;
      // Ignore events that ended before the "EPG linger time":
      if (StartTime + Duration < LingerLimit)
         continue;
      if (!SegmentStart)
         SegmentStart = StartTime;
      SegmentEnd = StartTime + Duration;
      if (Tid == 0x4E) {
         if (getSectionNumber() == 0)
            EitTables->SetTableStart(SegmentStart);
         else
            EitTables->SetTableEnd(SegmentEnd);
         }
      cEvent *newEvent = NULL;
      cEvent *rEvent = NULL;
      cEvent *pEvent = NULL;
      if (Tid == 0x4E || (Tid & 0xF0) == 0x50)
         pEvent = const_cast<cEvent *>(pSchedule->GetEventById(SiEitEvent.getEventId()));
      else
         pEvent = const_cast<cEvent *>(pSchedule->GetEventByTime(StartTime));
      if (!pEvent || handledExternally) {
         if (handledExternally && !EpgHandlers.IsUpdate(SiEitEvent.getEventId(), StartTime, Tid, getVersionNumber()))
            continue;
         // If we don't have that event yet, we create a new one.
         // Otherwise we copy the information into the existing event anyway, because the data might have changed.
         pEvent = newEvent = new cEvent(SiEitEvent.getEventId());
         newEvent->SetStartTime(StartTime);
         newEvent->SetDuration(Duration);
         if (!handledExternally)
            pSchedule->AddEvent(newEvent);
         }
      else {
         // We have found an existing event, either through its event ID or its start time.
         pEvent->SetSeen();
         uchar TableID = max(pEvent->TableID(), uchar(0x4E)); // for backwards compatibility, table ids less than 0x4E are treated as if they were "present"
         // We never overwrite present/following with events from other tables:
         if (TableID == 0x4E && Tid != 0x4E)
            continue;
         if (pEvent->HasTimer()) {
            if (pEvent->StartTime() != StartTime || pEvent->Duration() != Duration)
               dsyslog("channel %d (%s) event %s times changed to %s-%s", Channel->Number(), Channel->Name(), *pEvent->ToDescr(), *TimeString(StartTime), *TimeString(StartTime + Duration));
            }
         EpgHandlers.SetEventID(pEvent, SiEitEvent.getEventId()); // unfortunately some stations use different event ids for the same event in different tables :-(
         EpgHandlers.SetStartTime(pEvent, StartTime);
         EpgHandlers.SetDuration(pEvent, Duration);
         }
      if (pEvent->TableID() > 0x4E) // for backwards compatibility, table ids less than 0x4E are never overwritten
         pEvent->SetTableID(Tid);
      if (Tid == 0x4E) { // we trust only the present/following info on the actual TS
         int RunningStatus = SiEitEvent.getRunningStatus();
#if DBGEIT
         if (Process)
            dsyslog("channel %d (%s) event %s status %d (raw data from '%s' section)", Channel->Number(), Channel->Name(), *pEvent->ToDescr(), RunningStatus, getSectionNumber() ? "following" : "present");
#endif
         if (RunningStatus >= SI::RunningStatusNotRunning) {
            // Workaround for broadcasters who set an event to status "not running" where
            // this is inappropriate:
            if (RunningStatus != pEvent->RunningStatus()) { // if the running status of the event has changed...
               if (RunningStatus == SI::RunningStatusNotRunning) { // ...and the new status is "not running"...
                  int OverrideStatus = -1;
                  if (getSectionNumber() == 0) { // ...and if this the "present" event...
                     if (pEvent->RunningStatus() == SI::RunningStatusPausing) // ...and if the event has already been set to "pausing"...
                        OverrideStatus = SI::RunningStatusPausing; // ...then we ignore the faulty new status and stay with "pausing"
                     }
                  else // ...and if this is the "following" event...
                     OverrideStatus = SI::RunningStatusUndefined; // ...then we ignore the faulty new status and fall back to "undefined"
                  if (OverrideStatus >= 0) {
#if DBGEIT
                     if (Process)
                        dsyslog("channel %d (%s) event %s status %d (ignored status %d from '%s' section)", Channel->Number(), Channel->Name(), *pEvent->ToDescr(), OverrideStatus, RunningStatus, getSectionNumber() ? "following" : "present");
#endif
                     RunningStatus = OverrideStatus;
                     }
                  }
               }
            pSchedule->SetRunningStatus(pEvent, RunningStatus, Channel);
            }
         if (!Process)
            continue;
         }
      pEvent->SetVersion(getVersionNumber());

      int LanguagePreferenceShort = -1;
      int LanguagePreferenceExt = -1;
      bool UseExtendedEventDescriptor = false;
      SI::Descriptor *d;
      SI::ExtendedEventDescriptors *ExtendedEventDescriptors = NULL;
      SI::ShortEventDescriptor *ShortEventDescriptor = NULL;
      cLinkChannels *LinkChannels = NULL;
      cComponents *Components = NULL;
      for (SI::Loop::Iterator it2; (d = SiEitEvent.eventDescriptors.getNext(it2)); ) {
          switch (d->getDescriptorTag()) {
            case SI::ExtendedEventDescriptorTag: {
                 SI::ExtendedEventDescriptor *eed = (SI::ExtendedEventDescriptor *)d;
                 if (I18nIsPreferredLanguage(Setup.EPGLanguages, eed->languageCode, LanguagePreferenceExt) || !ExtendedEventDescriptors) {
                    delete ExtendedEventDescriptors;
                    ExtendedEventDescriptors = new SI::ExtendedEventDescriptors;
                    UseExtendedEventDescriptor = true;
                    }
                 if (UseExtendedEventDescriptor) {
                    if (ExtendedEventDescriptors->Add(eed))
                       d = NULL; // so that it is not deleted
                    }
                 if (eed->getDescriptorNumber() == eed->getLastDescriptorNumber())
                    UseExtendedEventDescriptor = false;
                 }
                 break;
            case SI::ShortEventDescriptorTag: {
                 SI::ShortEventDescriptor *sed = (SI::ShortEventDescriptor *)d;
                 if (I18nIsPreferredLanguage(Setup.EPGLanguages, sed->languageCode, LanguagePreferenceShort) || !ShortEventDescriptor) {
                    delete ShortEventDescriptor;
                    ShortEventDescriptor = sed;
                    d = NULL; // so that it is not deleted
                    }
                 }
                 break;
            case SI::ContentDescriptorTag: {
                 SI::ContentDescriptor *cd = (SI::ContentDescriptor *)d;
                 SI::ContentDescriptor::Nibble Nibble;
                 int NumContents = 0;
                 uchar Contents[MaxEventContents] = { 0 };
                 for (SI::Loop::Iterator it3; cd->nibbleLoop.getNext(Nibble, it3); ) {
                     if (NumContents < MaxEventContents) {
                        Contents[NumContents] = ((Nibble.getContentNibbleLevel1() & 0xF) << 4) | (Nibble.getContentNibbleLevel2() & 0xF);
                        NumContents++;
                        }
                     }
                 EpgHandlers.SetContents(pEvent, Contents);
                 }
                 break;
            case SI::ParentalRatingDescriptorTag: {
                 int LanguagePreferenceRating = -1;
                 SI::ParentalRatingDescriptor *prd = (SI::ParentalRatingDescriptor *)d;
                 SI::ParentalRatingDescriptor::Rating Rating;
                 for (SI::Loop::Iterator it3; prd->ratingLoop.getNext(Rating, it3); ) {
                     if (I18nIsPreferredLanguage(Setup.EPGLanguages, Rating.languageCode, LanguagePreferenceRating)) {
                        int ParentalRating = (Rating.getRating() & 0xFF);
                        switch (ParentalRating) {
                          // values defined by the DVB standard (minimum age = rating + 3 years):
                          case 0x01 ... 0x0F: ParentalRating += 3; break;
                          // values defined by broadcaster CSAT (now why didn't they just use 0x07, 0x09 and 0x0D?):
                          case 0x11:          ParentalRating = 10; break;
                          case 0x12:          ParentalRating = 12; break;
                          case 0x13:          ParentalRating = 16; break;
                          default:            ParentalRating = 0;
                          }
                        EpgHandlers.SetParentalRating(pEvent, ParentalRating);
                        }
                     }
                 }
                 break;
            case SI::PDCDescriptorTag: {
                 SI::PDCDescriptor *pd = (SI::PDCDescriptor *)d;
                 t.tm_isdst = -1; // makes sure mktime() will determine the correct DST setting
                 int month = t.tm_mon;
                 t.tm_mon = pd->getMonth() - 1;
                 t.tm_mday = pd->getDay();
                 t.tm_hour = pd->getHour();
                 t.tm_min = pd->getMinute();
                 t.tm_sec = 0;
                 if (month == 11 && t.tm_mon == 0) // current month is dec, but event is in jan
                    t.tm_year++;
                 else if (month == 0 && t.tm_mon == 11) // current month is jan, but event is in dec
                    t.tm_year--;
                 time_t vps = mktime(&t);
                 EpgHandlers.SetVps(pEvent, vps);
                 }
                 break;
            case SI::TimeShiftedEventDescriptorTag: {
                 SI::TimeShiftedEventDescriptor *tsed = (SI::TimeShiftedEventDescriptor *)d;
                 cSchedule *rSchedule = (cSchedule *)Schedules->GetSchedule(tChannelID(Source, Channel->Nid(), Channel->Tid(), tsed->getReferenceServiceId()));
                 if (!rSchedule)
                    break;
                 rEvent = (cEvent *)rSchedule->GetEventById(tsed->getReferenceEventId());
                 if (!rEvent)
                    break;
                 EpgHandlers.SetTitle(pEvent, rEvent->Title());
                 EpgHandlers.SetShortText(pEvent, rEvent->ShortText());
                 EpgHandlers.SetDescription(pEvent, rEvent->Description());
                 }
                 break;
            case SI::LinkageDescriptorTag: {
                 SI::LinkageDescriptor *ld = (SI::LinkageDescriptor *)d;
                 tChannelID linkID(Source, ld->getOriginalNetworkId(), ld->getTransportStreamId(), ld->getServiceId());
                 if (ld->getLinkageType() == SI::LinkageTypePremiere) { // Premiere World
                    bool hit = StartTime <= Now && Now < StartTime + Duration;
                    if (hit) {
                       char linkName[ld->privateData.getLength() + 1];
                       strn0cpy(linkName, (const char *)ld->privateData.getData(), sizeof(linkName));
                       // TODO is there a standard way to determine the character set of this string?
                       cChannel *link = Channels->GetByChannelID(linkID);
                       if (link != Channel) { // only link to other channels, not the same one
                          if (link) {
                             if (Setup.UpdateChannels == 1 || Setup.UpdateChannels >= 3)
                                ChannelsModified |= link->SetName(linkName, "", "");
                             }
                          else if (Setup.UpdateChannels >= 4) {
                             cChannel *Transponder = Channel;
                             if (Channel->Tid() != ld->getTransportStreamId())
                                Transponder = Channels->GetByTransponderID(linkID);
                             link = Channels->NewChannel(Transponder, linkName, "", "", ld->getOriginalNetworkId(), ld->getTransportStreamId(), ld->getServiceId());
                             ChannelsModified = true;
                             //XXX patFilter->Trigger();
                             }
                          if (link) {
                             if (!LinkChannels)
                                LinkChannels = new cLinkChannels;
                             LinkChannels->Add(new cLinkChannel(link));
                             }
                          }
                       else
                          ChannelsModified |= Channel->SetPortalName(linkName);
                       }
                    }
                 }
                 break;
            case SI::ComponentDescriptorTag: {
                 SI::ComponentDescriptor *cd = (SI::ComponentDescriptor *)d;
                 uchar Stream = cd->getStreamContent();
                 uchar Ext = cd->getStreamContentExt();
                 uchar Type = cd->getComponentType();
                 if ((1 <= Stream && Stream <= 6 && Type != 0) // 1=MPEG2-video, 2=MPEG1-audio, 3=subtitles, 4=AC3-audio, 5=H.264-video, 6=HEAAC-audio
                    || (Stream == 9 && Ext < 2)) {             // 0x09=HEVC-video, 0x19=AC-4-audio
                    if (!Components)
                       Components = new cComponents;
                    char buffer[Utf8BufSize(256)];
                    if (Stream == 9)
                       Stream |= Ext << 4;
                    Components->SetComponent(Components->NumComponents(), Stream, Type, I18nNormalizeLanguageCode(cd->languageCode), cd->description.getText(buffer, sizeof(buffer)));
                    }
                 }
                 break;
            default: ;
            }
          delete d;
          }

      if (!rEvent) {
         if (ShortEventDescriptor) {
            char buffer[Utf8BufSize(256)];
            EpgHandlers.SetTitle(pEvent, ShortEventDescriptor->name.getText(buffer, sizeof(buffer)));
            EpgHandlers.SetShortText(pEvent, ShortEventDescriptor->text.getText(buffer, sizeof(buffer)));
            }
         else {
            EpgHandlers.SetTitle(pEvent, NULL);
            EpgHandlers.SetShortText(pEvent, NULL);
            }
         if (ExtendedEventDescriptors) {
            char buffer[Utf8BufSize(ExtendedEventDescriptors->getMaximumTextLength(": ")) + 1];
            EpgHandlers.SetDescription(pEvent, ExtendedEventDescriptors->getText(buffer, sizeof(buffer), ": "));
            }
         else
            EpgHandlers.SetDescription(pEvent, NULL);
         }
      delete ExtendedEventDescriptors;
      delete ShortEventDescriptor;

      EpgHandlers.SetComponents(pEvent, Components);

      EpgHandlers.FixEpgBugs(pEvent);
      if (LinkChannels)
         ChannelsModified |= Channel->SetLinkChannels(LinkChannels);
      Modified = true;
      EpgHandlers.HandleEvent(pEvent);
      if (handledExternally)
         delete pEvent;
      }
  if (Tid == 0x4E) {
     if (Empty && getSectionNumber() == 0)
        // ETR 211: an empty entry in section 0 of table 0x4E means there is currently no event running
        pSchedule->ClrRunningStatus(Channel);
     pSchedule->SetPresentSeen();
     }
  if (Process) {
     bool Complete = EitTables->Processed(Tid, getLastTableId(), getSectionNumber(), getLastSectionNumber(), getSegmentLastSectionNumber());
     if (Modified && (Tid >= 0x50 || Complete)) { // we process the 0x5X tables segment by segment, but 0x4E only if we have received ALL its segments (0 and 1, i.e. "present" and "following")
        if (Tid == 0x4E && getLastSectionNumber() == 1) {
           SegmentStart = EitTables->TableStart();
           SegmentEnd = EitTables->TableEnd();
           }
        EpgHandlers.SortSchedule(pSchedule);
        EpgHandlers.DropOutdated(pSchedule, SegmentStart, SegmentEnd, Tid, getVersionNumber());
        }
     }
  EpgHandlers.EndSegmentTransfer(Modified);
  SchedulesStateKey.Remove(Modified);
  ChannelsStateKey.Remove(ChannelsModified);
}

// --- cTDT ------------------------------------------------------------------

#define MAX_TIME_DIFF   1 // number of seconds the local time may differ from dvb time before making any corrections
#define MAX_ADJ_DIFF   10 // number of seconds the local time may differ from dvb time to allow smooth adjustment
#define ADJ_DELTA     300 // number of seconds between calls for smooth time adjustment

class cTDT : public SI::TDT {
private:
  static cMutex mutex;
  static time_t lastAdj;
public:
  cTDT(const u_char *Data);
  };

cMutex cTDT::mutex;
time_t cTDT::lastAdj = 0;

cTDT::cTDT(const u_char *Data)
:SI::TDT(Data, false)
{
  CheckParse();

  time_t dvbtim = getTime();
  time_t loctim = time(NULL);

  int diff = dvbtim - loctim;
  if (abs(diff) > MAX_TIME_DIFF) {
     mutex.Lock();
     if (abs(diff) > MAX_ADJ_DIFF) {
        timespec ts = {};
        ts.tv_sec = dvbtim;
        if (clock_settime(CLOCK_REALTIME, &ts) == 0)
           isyslog("system time changed from %s (%jd) to %s (%jd)", *TimeToString(loctim), intmax_t(loctim), *TimeToString(dvbtim), intmax_t(dvbtim));
        else
           esyslog("ERROR while setting system time: %m");
        }
     else if (time(NULL) - lastAdj > ADJ_DELTA) {
        lastAdj = time(NULL);
        timeval delta;
        delta.tv_sec = diff;
        delta.tv_usec = 0;
        if (adjtime(&delta, NULL) == 0)
           isyslog("system time adjustment initiated from %s (%jd) to %s (%jd)", *TimeToString(loctim), intmax_t(loctim), *TimeToString(dvbtim), intmax_t(dvbtim));
        else
           esyslog("ERROR while adjusting system time: %m");
        }
     mutex.Unlock();
     }
}

// --- cEitFilter ------------------------------------------------------------

time_t cEitFilter::disableUntil = 0;

cEitFilter::cEitFilter(void)
{
  Set(0x12, 0x40, 0xC0);  // event info present&following actual/other TS (0x4E/0x4F), future actual/other TS (0x5X/0x6X)
  Set(0x14, 0x70);        // TDT
}

void cEitFilter::SetStatus(bool On)
{
  cMutexLock MutexLock(&mutex);
  cFilter::SetStatus(On);
  eitTablesHash.Clear();
}

void cEitFilter::SetDisableUntil(time_t Time)
{
  disableUntil = Time;
}

void cEitFilter::Process(u_short Pid, u_char Tid, const u_char *Data, int Length)
{
  cMutexLock MutexLock(&mutex);
  if (disableUntil) {
     if (time(NULL) > disableUntil)
        disableUntil = 0;
     else
        return;
     }
  switch (Pid) {
    case 0x12: {
         if (Tid == 0x4E || Tid >= 0x50 && Tid <= 0x6F) // we ignore 0x4F, which only causes trouble
            cEIT EIT(eitTablesHash, Source(), Tid, Data);
         }
         break;
    case 0x14: {
         if (Setup.SetSystemTime && Setup.TimeSource == Source() && Setup.TimeTransponder && ISTRANSPONDER(Transponder(), Setup.TimeTransponder))
            cTDT TDT(Data);
         }
         break;
    default: ;
    }
}