// onlinebin/online-server-gmm-decode-faster.cc
  
  // Copyright 2012 Cisco Systems (author: Matthias Paulik)
  //           2012 Vassil Panayotov
  //           2013 Johns Hopkins University (author: Daniel Povey)
  
  // 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/feature-mfcc.h"
  #include "online/online-feat-input.h"
  #include "online/online-decodable.h"
  #include "online/online-faster-decoder.h"
  #include "online/onlinebin-util.h"
  
  namespace kaldi {
  
  void SendPartialResult(const std::vector<int32>& words,
                         const fst::SymbolTable *word_syms,
                         const bool line_break,
                         const int32 serv_sock,
                         const sockaddr_in &client_addr) {
    KALDI_ASSERT(word_syms != NULL);
    std::stringstream sstream;
    for (size_t i = 0; i < words.size(); i++) {
      std::string word = word_syms->Find(words[i]);
      if (word == "")
        KALDI_ERR << "Word-id " << words[i] <<" not in symbol table.";
      sstream << word << ' ';
    }
    if (line_break)
      sstream << "
  
  ";
  
    ssize_t sent = sendto(serv_sock, sstream.str().c_str(), sstream.str().size(),
                          0, reinterpret_cast<const sockaddr*>(&client_addr),
                          sizeof(client_addr));
    if (sent == -1)
      KALDI_WARN << "sendto() call failed when tried to send recognition results";
  }
  
  } // namespace kaldi
  
  
  int main(int argc, char *argv[]) {
    try {
      using namespace kaldi;
      using namespace fst;
  
      typedef kaldi::int32 int32;
  
      // Up to delta-delta derivative features are calculated (unless LDA is used)
      const int32 kDeltaOrder = 2;
  
      const char *usage =
          "Decode speech, using feature batches received over a network connection
  
  "
          "Utterance segmentation is done on-the-fly.
  "
          "Feature splicing/LDA transform is used, if the optional(last) argument "
          "is given.
  "
          "Otherwise delta/delta-delta(2-nd order) features are produced.
  
  "
          "Usage: online-server-gmm-decode-faster [options] model-in"
          "fst-in word-symbol-table silence-phones udp-port [lda-matrix-in]
  
  "
          "Example: online-server-gmm-decode-faster --rt-min=0.3 --rt-max=0.5 "
          "--max-active=4000 --beam=12.0 --acoustic-scale=0.0769 "
          "model HCLG.fst words.txt '1:2:3:4:5' 1234 lda-matrix";
      ParseOptions po(usage);
      BaseFloat acoustic_scale = 0.1;
      int32 cmn_window = 600,
        min_cmn_window = 100; // adds 1 second latency, only at utterance start.
      int32 right_context = 4, left_context = 4;
  
      kaldi::DeltaFeaturesOptions delta_opts;
      delta_opts.Register(&po);
      OnlineFasterDecoderOpts decoder_opts;
      OnlineFeatureMatrixOptions feature_reading_opts;
      decoder_opts.Register(&po, true);
      feature_reading_opts.Register(&po);
  
      po.Register("left-context", &left_context, "Number of frames of left context");
      po.Register("right-context", &right_context, "Number of frames of right context");
      po.Register("acoustic-scale", &acoustic_scale,
                  "Scaling factor for acoustic likelihoods");
      po.Register("cmn-window", &cmn_window,
          "Number of feat. vectors used in the running average CMN calculation");
      po.Register("min-cmn-window", &min_cmn_window,
                  "Minumum CMN window used at start of decoding (adds "
                  "latency only at start)");
  
      po.Read(argc, argv);
      if (po.NumArgs() != 5 && po.NumArgs() != 6) {
        po.PrintUsage();
        return 1;
      }
  
      std::string model_rxfilename = po.GetArg(1),
          fst_rxfilename = po.GetArg(2),
          word_syms_filename = po.GetArg(3),
          silence_phones_str = po.GetArg(4),
          lda_mat_rspecifier = po.GetOptArg(6);
      int32 udp_port = atoi(po.GetArg(5).c_str());
  
      Matrix<BaseFloat> lda_transform;
      if (lda_mat_rspecifier != "") {
        bool binary_in;
        Input ki(lda_mat_rspecifier, &binary_in);
        lda_transform.Read(ki.Stream(), binary_in);
      }
  
      std::vector<int32> silence_phones;
      if (!SplitStringToIntegers(silence_phones_str, ":", false, &silence_phones))
          KALDI_ERR << "Invalid silence-phones string " << silence_phones_str;
      if (silence_phones.empty())
          KALDI_ERR << "No silence phones given!";
  
      TransitionModel trans_model;
      AmDiagGmm am_gmm;
      {
          bool binary;
          Input ki(model_rxfilename, &binary);
          trans_model.Read(ki.Stream(), binary);
          am_gmm.Read(ki.Stream(), binary);
      }
  
      fst::SymbolTable *word_syms = NULL;
      if (!(word_syms = fst::SymbolTable::ReadText(word_syms_filename)))
          KALDI_ERR << "Could not read symbol table from file "
                      << word_syms_filename;
  
      fst::Fst<fst::StdArc> *decode_fst = ReadDecodeGraph(fst_rxfilename);
  
      // We are not properly registering/exposing MFCC and frame extraction options,
      // because there are parts of the online decoding code, where some of these
      // options are hardwired(ToDo: we should fix this at some point)
      MfccOptions mfcc_opts;
      mfcc_opts.use_energy = false;
  
      OnlineFasterDecoder decoder(*decode_fst, decoder_opts,
                                  silence_phones, trans_model);
      VectorFst<LatticeArc> out_fst;
      int32 feature_dim = mfcc_opts.num_ceps; // default to 13 right now.
      OnlineUdpInput udp_input(udp_port, feature_dim);
      OnlineCmnInput cmn_input(&udp_input, cmn_window, min_cmn_window);
      OnlineFeatInputItf *feat_transform = 0;
  
      if (lda_mat_rspecifier != "") {
        feat_transform = new OnlineLdaInput(
                                 &cmn_input, lda_transform,
                                 left_context, right_context);
      } else {
        DeltaFeaturesOptions opts;
        opts.order = kDeltaOrder;
        feat_transform = new OnlineDeltaInput(opts, &cmn_input);
      }
  
      // feature_reading_opts contains number of retries, batch size.
      OnlineFeatureMatrix feature_matrix(feature_reading_opts,
                                         feat_transform);
  
      OnlineDecodableDiagGmmScaled decodable(am_gmm, trans_model, acoustic_scale,
                                             &feature_matrix);
  
      std::cerr << std::endl << "Listening on UDP port "
                << udp_port << " ... " << std::endl;
      bool partial_res = false;
      while (1) {
        OnlineFasterDecoder::DecodeState dstate = decoder.Decode(&decodable);
        std::vector<int32> word_ids;
        if (dstate & (decoder.kEndFeats | decoder.kEndUtt)) {
          decoder.FinishTraceBack(&out_fst);
          fst::GetLinearSymbolSequence(out_fst,
                                       static_cast<vector<int32> *>(0),
                                       &word_ids,
                                       static_cast<LatticeArc::Weight*>(0));
          SendPartialResult(word_ids, word_syms, partial_res || word_ids.size(),
                            udp_input.descriptor(), udp_input.client_addr());
          partial_res = false;
        } else {
          if (decoder.PartialTraceback(&out_fst)) {
            fst::GetLinearSymbolSequence(out_fst,
                                         static_cast<vector<int32> *>(0),
                                         &word_ids,
                                         static_cast<LatticeArc::Weight*>(0));
            SendPartialResult(word_ids, word_syms, false,
                              udp_input.descriptor(), udp_input.client_addr());
            if (!partial_res)
              partial_res = (word_ids.size() > 0);
          }
        }
      }
  
      delete feat_transform;
      delete word_syms;
      delete decode_fst;
      return 0;
    } catch(const std::exception& e) {
      std::cerr << e.what();
      return -1;
    }
  } // main()