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

Audacity: A Digital Audio Editor

MixAndRender.cpp

Paul Licameli split from Mix.cpp

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

#include "MixAndRender.h"

#include "BasicUI.h"
#include "Mix.h"
#include "RealtimeEffectList.h"
#include "StretchingSequence.h"
#include "WaveTrack.h"

using WaveTrackConstArray = std::vector < std::shared_ptr < const WaveTrack > >;

//TODO-MB: wouldn't it make more sense to DELETE the time track after 'mix and render'?
TrackListHolder MixAndRender(const TrackIterRange<const WaveTrack> &trackRange,
   const Mixer::WarpOptions &warpOptions,
   const wxString &newTrackName,
   WaveTrackFactory *trackFactory,
   double rate, sampleFormat format,
   double startTime, double endTime)
{
   if (trackRange.empty())
      return {};

   // This function was formerly known as "Quick Mix".
   bool mono = false;   /* flag if output can be mono without losing anything*/
   bool oneinput = false;  /* flag set to true if there is only one input track
                              (mono or stereo) */

   auto first = *trackRange.begin();
   assert(first); // because the range is known to be nonempty
   assert(first->IsLeader()); // precondition on trackRange

   // this only iterates tracks which are relevant to this function, i.e.
   // selected WaveTracks. The tracklist is (confusingly) the list of all
   // tracks in the project

   int numWaves = 0; /* number of wave tracks in the selection */
   int numMono = 0;  /* number of mono, centre-panned wave tracks in selection*/
   for (auto wt : trackRange) {
      numWaves += wt->NChannels();
      if (IsMono(*wt) && wt->GetPan() == 0)
         numMono++;
   }

   if (numMono == numWaves)
      mono = true;

   /* the next loop will do two things at once:
    * 1. build an array of all the wave tracks were are trying to process
    * 2. determine when the set of WaveTracks starts and ends, in case we
    *    need to work out for ourselves when to start and stop rendering.
    */

   double mixStartTime = 0.0;    /* start time of first track to start */
   bool gotstart = false;  // flag indicates we have found a start time
   double mixEndTime = 0.0;   /* end time of last track to end */
   double tstart, tend;    // start and end times for one track.

   Mixer::Inputs waveArray;

   for (auto wt : trackRange) {
      const auto stretchingSequence =
         StretchingSequence::Create(*wt, wt->GetClipInterfaces());
      waveArray.emplace_back(stretchingSequence, GetEffectStages(*wt));
      tstart = wt->GetStartTime();
      tend = wt->GetEndTime();
      if (tend > mixEndTime)
         mixEndTime = tend;
      // try and get the start time. If the track is empty we will get 0,
      // which is ambiguous because it could just mean the track starts at
      // the beginning of the project, as well as empty track. The give-away
      // is that an empty track also ends at zero.

      if (tstart != tend) {
         // we don't get empty tracks here
         if (!gotstart) {
            // no previous start, use this one unconditionally
            mixStartTime = tstart;
            gotstart = true;
         } else if (tstart < mixStartTime)
            mixStartTime = tstart;  // have a start, only make it smaller
      }  // end if start and end are different
   }

   /* create the destination track (NEW track) */
   if (numWaves == (int)TrackList::NChannels(*first))
      oneinput = true;
   // only one input track (either 1 mono or one linked stereo pair)

   auto result = trackFactory->Create(mono ? 1 : 2, *first);
   auto mix = static_cast<WaveTrack*>(*result->begin());
   mix->SetPan(0);
   mix->SetGain(1.0f);
   mix->SetRate(rate);
   mix->ConvertToSampleFormat(format);
   if(!oneinput)
      mix->SetName(newTrackName);
   mix->MoveTo(mixStartTime);

   auto maxBlockLen = mix->GetIdealBlockSize();

   // If the caller didn't specify a time range, use the whole range in which
   // any input track had clips in it.
   if (startTime == endTime) {
      startTime = mixStartTime;
      endTime = mixEndTime;
   }

   Mixer mixer(move(waveArray),
      // Throw to abort mix-and-render if read fails:
      true, warpOptions,
      startTime, endTime, mono ? 1 : 2, maxBlockLen, false,
      rate, format);

   using namespace BasicUI;
   auto updateResult = ProgressResult::Success;
   {
      auto effectiveFormat = mixer.EffectiveFormat();
      auto pProgress = MakeProgress(XO("Mix and Render"),
         XO("Mixing and rendering tracks"));

      while (updateResult == ProgressResult::Success) {
         auto blockLen = mixer.Process();

         if (blockLen == 0)
            break;

         for(auto channel : mix->Channels())
         {
            auto buffer = mixer.GetBuffer(channel->ReallyGetChannelIndex());
            channel->AppendBuffer(buffer, format, blockLen, 1, effectiveFormat);
         }

         updateResult = pProgress->Poll(
            mixer.MixGetCurrentTime() - startTime, endTime - startTime);
      }
   }
   mix->Flush();
   if (updateResult == ProgressResult::Cancelled ||
       updateResult == ProgressResult::Failed)
      return {};
   else {
#if 0
   int elapsedMS = wxGetElapsedTime();
   double elapsedTime = elapsedMS * 0.001;
   double maxTracks = totalTime / (elapsedTime / numWaves);

   // Note: these shouldn't be translated - they're for debugging
   // and profiling only.
   wxPrintf("      Tracks: %d\n", numWaves);
   wxPrintf("  Mix length: %f sec\n", totalTime);
   wxPrintf("Elapsed time: %f sec\n", elapsedTime);
   wxPrintf("Max number of tracks to mix in real time: %f\n", maxTracks);
#endif
      RealtimeEffectList::Get(*mix).Clear();
   }

   return result;
}

#include "RealtimeEffectList.h"
#include "RealtimeEffectState.h"

std::vector<MixerOptions::StageSpecification>
GetEffectStages(const WaveTrack &track)
{
   auto &effects = RealtimeEffectList::Get(track);
   if (!effects.IsActive())
      return {};
   std::vector<MixerOptions::StageSpecification> result;
   for (size_t i = 0, count = effects.GetStatesCount(); i < count; ++i) {
      const auto pState = effects.GetStateAt(i);
      if (!pState->IsEnabled())
         continue;
      const auto pEffect = pState->GetEffect();
      if (!pEffect)
         continue;
      const auto &settings = pState->GetSettings();
      if (!settings.has_value())
         continue;
      auto &stage = result.emplace_back(MixerOptions::StageSpecification{
         [pEffect]{ return pEffect->MakeInstance(); },
         settings });
   }
   return result;
}

/* The following registration objects need a home at a higher level to avoid
 dependency either way between WaveTrack or RealtimeEffectList, which need to
 be in different libraries that do not depend either on the other.

 WaveTrack, like AudacityProject, has a registry for attachment of serializable
 data.  RealtimeEffectList exposes an interface for serialization.  This is
 where we connect them.
 
 There is also registration for serialization of the project-wide master effect
 stack (whether or not UI makes it available).
 */
#include "Project.h"
static ProjectFileIORegistry::ObjectReaderEntry projectAccessor {
   RealtimeEffectList::XMLTag(),
   [](AudacityProject &project) { return &RealtimeEffectList::Get(project); }
};

static ProjectFileIORegistry::ObjectWriterEntry projectWriter {
[](const AudacityProject &project, XMLWriter &xmlFile){
   RealtimeEffectList::Get(project).WriteXML(xmlFile);
} };

static WaveTrackIORegistry::ObjectReaderEntry waveTrackAccessor {
   RealtimeEffectList::XMLTag(),
   [](WaveTrack &track) { return &RealtimeEffectList::Get(track); }
};

static WaveTrackIORegistry::ObjectWriterEntry waveTrackWriter {
[](const WaveTrack &track, auto &xmlFile) {
   if (track.IsLeader())
      RealtimeEffectList::Get(track).WriteXML(xmlFile);
} };
