// online2bin/online2-wav-nnet3-latgen-grammar.cc
  
  // Copyright 2014-2018  Johns Hopkins University (author: Daniel Povey)
  //           2016  Api.ai (Author: Ilya Platonov)
  
  // See ../../COPYING for clarification regarding multiple authors
  //
  // Licensed under the Apache License, Version 2.0 (the "License");
  // you may not use this file except in compliance with the License.
  // You may obtain a copy of the License at
  //
  //  http://www.apache.org/licenses/LICENSE-2.0
  //
  // THIS CODE IS PROVIDED *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  // KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
  // WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE,
  // MERCHANTABLITY OR NON-INFRINGEMENT.
  // See the Apache 2 License for the specific language governing permissions and
  // limitations under the License.
  
  #include "feat/wave-reader.h"
  #include "online2/online-nnet3-decoding.h"
  #include "online2/online-nnet2-feature-pipeline.h"
  #include "online2/onlinebin-util.h"
  #include "online2/online-timing.h"
  #include "online2/online-endpoint.h"
  #include "fstext/fstext-lib.h"
  #include "lat/lattice-functions.h"
  #include "util/kaldi-thread.h"
  #include "nnet3/nnet-utils.h"
  #include "decoder/grammar-fst.h"
  
  namespace kaldi {
  
  void GetDiagnosticsAndPrintOutput(const std::string &utt,
                                    const fst::SymbolTable *word_syms,
                                    const CompactLattice &clat,
                                    int64 *tot_num_frames,
                                    double *tot_like) {
    if (clat.NumStates() == 0) {
      KALDI_WARN << "Empty lattice.";
      return;
    }
    CompactLattice best_path_clat;
    CompactLatticeShortestPath(clat, &best_path_clat);
  
    Lattice best_path_lat;
    ConvertLattice(best_path_clat, &best_path_lat);
  
    double likelihood;
    LatticeWeight weight;
    int32 num_frames;
    std::vector<int32> alignment;
    std::vector<int32> words;
    GetLinearSymbolSequence(best_path_lat, &alignment, &words, &weight);
    num_frames = alignment.size();
    likelihood = -(weight.Value1() + weight.Value2());
    *tot_num_frames += num_frames;
    *tot_like += likelihood;
    KALDI_VLOG(2) << "Likelihood per frame for utterance " << utt << " is "
                  << (likelihood / num_frames) << " over " << num_frames
                  << " frames.";
  
    if (word_syms != NULL) {
      std::cerr << utt << ' ';
      for (size_t i = 0; i < words.size(); i++) {
        std::string s = word_syms->Find(words[i]);
        if (s == "")
          KALDI_ERR << "Word-id " << words[i] << " not in symbol table.";
        std::cerr << s << ' ';
      }
      std::cerr << std::endl;
    }
  }
  
  }
  
  int main(int argc, char *argv[]) {
    try {
      using namespace kaldi;
      using namespace fst;
  
      typedef kaldi::int32 int32;
      typedef kaldi::int64 int64;
  
      const char *usage =
          "Reads in wav file(s) and simulates online decoding with neural nets
  "
          "(nnet3 setup), with optional iVector-based speaker adaptation and
  "
          "optional endpointing.  Note: some configuration values and inputs are
  "
          "set via config files whose filenames are passed as options.
  "
          "This program like online2-wav-nnet3-latgen-faster but when the FST to
  "
          "be decoded is of type GrammarFst.
  "
          "
  "
          "Usage: online2-wav-nnet3-latgen-grammar [options] <nnet3-in> <fst-in> "
          "<spk2utt-rspecifier> <wav-rspecifier> <lattice-wspecifier>
  "
          "The spk2utt-rspecifier can just be <utterance-id> <utterance-id> if
  "
          "you want to decode utterance by utterance.
  ";
  
      ParseOptions po(usage);
  
      std::string word_syms_rxfilename;
  
      // feature_opts includes configuration for the iVector adaptation,
      // as well as the basic features.
      OnlineNnet2FeaturePipelineConfig feature_opts;
      nnet3::NnetSimpleLoopedComputationOptions decodable_opts;
      LatticeFasterDecoderConfig decoder_opts;
      OnlineEndpointConfig endpoint_opts;
  
      BaseFloat chunk_length_secs = 0.18;
      bool do_endpointing = false;
      bool online = true;
  
      po.Register("chunk-length", &chunk_length_secs,
                  "Length of chunk size in seconds, that we process.  Set to <= 0 "
                  "to use all input in one chunk.");
      po.Register("word-symbol-table", &word_syms_rxfilename,
                  "Symbol table for words [for debug output]");
      po.Register("do-endpointing", &do_endpointing,
                  "If true, apply endpoint detection");
      po.Register("online", &online,
                  "You can set this to false to disable online iVector estimation "
                  "and have all the data for each utterance used, even at "
                  "utterance start.  This is useful where you just want the best "
                  "results and don't care about online operation.  Setting this to "
                  "false has the same effect as setting "
                  "--use-most-recent-ivector=true and --greedy-ivector-extractor=true "
                  "in the file given to --ivector-extraction-config, and "
                  "--chunk-length=-1.");
      po.Register("num-threads-startup", &g_num_threads,
                  "Number of threads used when initializing iVector extractor.");
  
      feature_opts.Register(&po);
      decodable_opts.Register(&po);
      decoder_opts.Register(&po);
      endpoint_opts.Register(&po);
  
  
      po.Read(argc, argv);
  
      if (po.NumArgs() != 5) {
        po.PrintUsage();
        return 1;
      }
  
      std::string nnet3_rxfilename = po.GetArg(1),
          fst_rxfilename = po.GetArg(2),
          spk2utt_rspecifier = po.GetArg(3),
          wav_rspecifier = po.GetArg(4),
          clat_wspecifier = po.GetArg(5);
  
      OnlineNnet2FeaturePipelineInfo feature_info(feature_opts);
  
      if (!online) {
        feature_info.ivector_extractor_info.use_most_recent_ivector = true;
        feature_info.ivector_extractor_info.greedy_ivector_extractor = true;
        chunk_length_secs = -1.0;
      }
  
      TransitionModel trans_model;
      nnet3::AmNnetSimple am_nnet;
      {
        bool binary;
        Input ki(nnet3_rxfilename, &binary);
        trans_model.Read(ki.Stream(), binary);
        am_nnet.Read(ki.Stream(), binary);
        SetBatchnormTestMode(true, &(am_nnet.GetNnet()));
        SetDropoutTestMode(true, &(am_nnet.GetNnet()));
        nnet3::CollapseModel(nnet3::CollapseModelConfig(), &(am_nnet.GetNnet()));
      }
  
      // this object contains precomputed stuff that is used by all decodable
      // objects.  It takes a pointer to am_nnet because if it has iVectors it has
      // to modify the nnet to accept iVectors at intervals.
      nnet3::DecodableNnetSimpleLoopedInfo decodable_info(decodable_opts,
                                                          &am_nnet);
  
  
      fst::GrammarFst fst;
      ReadKaldiObject(fst_rxfilename, &fst);
  
      fst::SymbolTable *word_syms = NULL;
      if (word_syms_rxfilename != "")
        if (!(word_syms = fst::SymbolTable::ReadText(word_syms_rxfilename)))
          KALDI_ERR << "Could not read symbol table from file "
                    << word_syms_rxfilename;
  
      int32 num_done = 0, num_err = 0;
      double tot_like = 0.0;
      int64 num_frames = 0;
  
      SequentialTokenVectorReader spk2utt_reader(spk2utt_rspecifier);
      RandomAccessTableReader<WaveHolder> wav_reader(wav_rspecifier);
      CompactLatticeWriter clat_writer(clat_wspecifier);
  
      OnlineTimingStats timing_stats;
  
      for (; !spk2utt_reader.Done(); spk2utt_reader.Next()) {
        std::string spk = spk2utt_reader.Key();
        const std::vector<std::string> &uttlist = spk2utt_reader.Value();
        OnlineIvectorExtractorAdaptationState adaptation_state(
            feature_info.ivector_extractor_info);
        for (size_t i = 0; i < uttlist.size(); i++) {
          std::string utt = uttlist[i];
          if (!wav_reader.HasKey(utt)) {
            KALDI_WARN << "Did not find audio for utterance " << utt;
            num_err++;
            continue;
          }
          const WaveData &wave_data = wav_reader.Value(utt);
          // get the data for channel zero (if the signal is not mono, we only
          // take the first channel).
          SubVector<BaseFloat> data(wave_data.Data(), 0);
  
          OnlineNnet2FeaturePipeline feature_pipeline(feature_info);
          feature_pipeline.SetAdaptationState(adaptation_state);
  
          OnlineSilenceWeighting silence_weighting(
              trans_model,
              feature_info.silence_weighting_config,
              decodable_opts.frame_subsampling_factor);
  
          SingleUtteranceNnet3DecoderTpl<fst::GrammarFst> decoder(
              decoder_opts, trans_model,
              decodable_info, fst, &feature_pipeline);
  
          OnlineTimer decoding_timer(utt);
  
          BaseFloat samp_freq = wave_data.SampFreq();
          int32 chunk_length;
          if (chunk_length_secs > 0) {
            chunk_length = int32(samp_freq * chunk_length_secs);
            if (chunk_length == 0) chunk_length = 1;
          } else {
            chunk_length = std::numeric_limits<int32>::max();
          }
  
          int32 samp_offset = 0;
          std::vector<std::pair<int32, BaseFloat> > delta_weights;
  
          while (samp_offset < data.Dim()) {
            int32 samp_remaining = data.Dim() - samp_offset;
            int32 num_samp = chunk_length < samp_remaining ? chunk_length
                                                           : samp_remaining;
  
            SubVector<BaseFloat> wave_part(data, samp_offset, num_samp);
            feature_pipeline.AcceptWaveform(samp_freq, wave_part);
  
            samp_offset += num_samp;
            decoding_timer.WaitUntil(samp_offset / samp_freq);
            if (samp_offset == data.Dim()) {
              // no more input. flush out last frames
              feature_pipeline.InputFinished();
            }
  
            if (silence_weighting.Active() &&
                feature_pipeline.IvectorFeature() != NULL) {
              silence_weighting.ComputeCurrentTraceback(decoder.Decoder());
              silence_weighting.GetDeltaWeights(feature_pipeline.NumFramesReady(),
                                                &delta_weights);
              feature_pipeline.IvectorFeature()->UpdateFrameWeights(delta_weights);
            }
  
            decoder.AdvanceDecoding();
  
            if (do_endpointing && decoder.EndpointDetected(endpoint_opts)) {
              break;
            }
          }
          decoder.FinalizeDecoding();
  
          CompactLattice clat;
          bool end_of_utterance = true;
          decoder.GetLattice(end_of_utterance, &clat);
  
          GetDiagnosticsAndPrintOutput(utt, word_syms, clat,
                                       &num_frames, &tot_like);
  
          decoding_timer.OutputStats(&timing_stats);
  
          // In an application you might avoid updating the adaptation state if
          // you felt the utterance had low confidence.  See lat/confidence.h
          feature_pipeline.GetAdaptationState(&adaptation_state);
  
          // we want to output the lattice with un-scaled acoustics.
          BaseFloat inv_acoustic_scale =
              1.0 / decodable_opts.acoustic_scale;
          ScaleLattice(AcousticLatticeScale(inv_acoustic_scale), &clat);
  
          clat_writer.Write(utt, clat);
          KALDI_LOG << "Decoded utterance " << utt;
          num_done++;
        }
      }
      timing_stats.Print(online);
  
      KALDI_LOG << "Decoded " << num_done << " utterances, "
                << num_err << " with errors.";
      KALDI_LOG << "Overall likelihood per frame was " << (tot_like / num_frames)
                << " per frame over " << num_frames << " frames.";
      delete word_syms; // will delete if non-NULL.
      return (num_done != 0 ? 0 : 1);
    } catch(const std::exception& e) {
      std::cerr << e.what();
      return -1;
    }
  } // main()