// gmmbin/gmm-decode-simple.cc
  
  // Copyright 2009-2011  Microsoft Corporation
  //                2013  Johns Hopkins University
  
  // 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 "base/kaldi-common.h"
  #include "util/common-utils.h"
  #include "gmm/am-diag-gmm.h"
  #include "tree/context-dep.h"
  #include "hmm/transition-model.h"
  #include "fstext/fstext-lib.h"
  #include "decoder/simple-decoder.h"
  #include "gmm/decodable-am-diag-gmm.h"
  #include "fstext/lattice-utils.h"
  #include "lat/kaldi-lattice.h"
  #include "base/timer.h"
  
  
  int main(int argc, char *argv[]) {
    try {
      using namespace kaldi;
      typedef kaldi::int32 int32;
      using fst::SymbolTable;
      using fst::VectorFst;
      using fst::Fst;
      using fst::StdArc;
      using fst::ReadFstKaldiGeneric;
  
      const char *usage =
          "Decode features using GMM-based model.
  "
          "Viterbi decoding, Only produces linear sequence; any lattice
  "
          "produced is linear
  "
          "
  "
          "Usage:   gmm-decode-simple [options] <model-in> <fst-in> "
          "<features-rspecifier> <words-wspecifier> [<alignments-wspecifier>] "
          "[<lattice-wspecifier>]";
      ParseOptions po(usage);
      Timer timer;
      bool allow_partial = true; 
      BaseFloat acoustic_scale = 0.1;
  
      std::string word_syms_filename;
      BaseFloat beam = 16.0;
      po.Register("beam", &beam, "Decoding log-likelihood beam");
      po.Register("acoustic-scale", &acoustic_scale,
                  "Scaling factor for acoustic likelihoods");
      po.Register("word-symbol-table", &word_syms_filename,
                  "Symbol table for words [for debug output]");
      po.Register("allow-partial", &allow_partial,
                  "Produce output even when final state was not reached");
      po.Read(argc, argv);
  
      if (po.NumArgs() < 4 || po.NumArgs() > 6) {
        po.PrintUsage();
        exit(1);
      }
  
      std::string model_in_filename = po.GetArg(1),
          fst_in_filename = po.GetArg(2),
          feature_rspecifier = po.GetArg(3),
          words_wspecifier = po.GetArg(4),
          alignment_wspecifier = po.GetOptArg(5),
          lattice_wspecifier = po.GetOptArg(6);
  
      TransitionModel trans_model;
      AmDiagGmm am_gmm;
      {
        bool binary;
        Input ki(model_in_filename, &binary);
        trans_model.Read(ki.Stream(), binary);
        am_gmm.Read(ki.Stream(), binary);
      }
  
      Fst<StdArc> *decode_fst = ReadFstKaldiGeneric(fst_in_filename);
  
      Int32VectorWriter words_writer(words_wspecifier);
  
      Int32VectorWriter alignment_writer(alignment_wspecifier);
  
      CompactLatticeWriter clat_writer(lattice_wspecifier);
  
      fst::SymbolTable *word_syms = NULL;
      if (word_syms_filename != "") 
        if (!(word_syms = fst::SymbolTable::ReadText(word_syms_filename)))
          KALDI_ERR << "Could not read symbol table from file "
                     << word_syms_filename;
  
      SequentialBaseFloatMatrixReader feature_reader(feature_rspecifier);
  
      BaseFloat tot_like = 0.0;
      kaldi::int64 frame_count = 0;
      int num_success = 0, num_fail = 0;
      SimpleDecoder decoder(*decode_fst, beam);
  
      for (; !feature_reader.Done(); feature_reader.Next()) {
        std::string utt = feature_reader.Key();
        Matrix<BaseFloat> features (feature_reader.Value());
        feature_reader.FreeCurrent();
        if (features.NumRows() == 0) {
          KALDI_WARN << "Zero-length utterance: " << utt;
          num_fail++;
          continue;
        }
  
        DecodableAmDiagGmmScaled gmm_decodable(am_gmm, trans_model, features,
                                               acoustic_scale);
        decoder.Decode(&gmm_decodable);
  
        VectorFst<LatticeArc> decoded;  // linear FST.
  
        if ( (allow_partial || decoder.ReachedFinal())
             && decoder.GetBestPath(&decoded) ) {
          if (!decoder.ReachedFinal())
            KALDI_WARN << "Decoder did not reach end-state, "
                       << "outputting partial traceback since --allow-partial=true";
          num_success++;
  
          std::vector<int32> alignment;
          std::vector<int32> words;
          LatticeWeight weight;
          frame_count += features.NumRows();
  
          GetLinearSymbolSequence(decoded, &alignment, &words, &weight);
  
          words_writer.Write(utt, words);
          if (alignment_wspecifier != "")
            alignment_writer.Write(utt, alignment);
          if (lattice_wspecifier != "") {
            // We'll write the lattice without acoustic scaling.
            if (acoustic_scale != 0.0)
              fst::ScaleLattice(fst::AcousticLatticeScale(1.0 / acoustic_scale),
                                &decoded);
            fst::VectorFst<CompactLatticeArc> clat;
            ConvertLattice(decoded, &clat, true);
            clat_writer.Write(utt, clat);
          }
          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 << '
  ';
          }
          BaseFloat like = -ConvertToCost(weight);
          tot_like += like;
          KALDI_LOG << "Log-like per frame for utterance " << utt << " is "
                    << (like / features.NumRows()) << " over "
                    << features.NumRows() << " frames.";
        } else {
          num_fail++;
          KALDI_WARN << "Did not successfully decode utterance " << utt
                     << ", len = " << features.NumRows();
        }
      }
  
      double elapsed = timer.Elapsed();
      KALDI_LOG << "Time taken "<< elapsed
                << "s: real-time factor assuming 100 frames/sec is "
                << (elapsed*100.0/frame_count);
      KALDI_LOG << "Done " << num_success << " utterances, failed for "
                << num_fail;
      KALDI_LOG << "Overall log-likelihood per frame is " << (tot_like/frame_count) << " over "
                << frame_count<<" frames.";
  
      delete word_syms;
      delete decode_fst;
      if (num_success != 0) return 0;
      else return 1;
    } catch(const std::exception &e) {
      std::cerr << e.what();
      return -1;
    }
  }