#!/bin/bash
  
  set -euo pipefail
  
  # This script is called from local/nnet3/run_tdnn.sh and
  # local/chain/run_tdnn.sh (and may eventually be called by more
  # scripts).  It contains the common feature preparation and
  # iVector-related parts of the script.  See those scripts for examples
  # of usage.
  
  stage=0
  train_set=train
  test_sets="dev"
  gmm=tri3b
  
  . ./cmd.sh
  . ./path.sh
  . ./utils/parse_options.sh
  
  gmm_dir=exp/${gmm}
  ali_dir=exp/${gmm}_ali_${train_set}_sp
  
  for f in data/${train_set}/feats.scp ${gmm_dir}/final.mdl; do
    if [ ! -f $f ]; then
      echo "$0: expected file $f to exist"
      exit 1
    fi
  done
  
  if [ $stage -le 1 ]; then
    # Although the nnet will be trained by high resolution data, we still have to
    # perturb the normal data to get the alignment _sp stands for speed-perturbed
    echo "$0: preparing directory for low-resolution speed-perturbed data (for alignment)"
    utils/data/perturb_data_dir_speed_3way.sh data/${train_set} data/${train_set}_sp
    echo "$0: making MFCC features for low-resolution speed-perturbed data"
    steps/make_mfcc.sh --cmd "$train_cmd" --nj 17 data/${train_set}_sp || exit 1;
    steps/compute_cmvn_stats.sh data/${train_set}_sp || exit 1;
    utils/fix_data_dir.sh data/${train_set}_sp
  fi
  
  if [ $stage -le 2 ]; then
    echo "$0: aligning with the perturbed low-resolution data"
    steps/align_fmllr.sh --nj 16 --cmd "$train_cmd" \
      data/${train_set}_sp data/lang $gmm_dir $ali_dir || exit 1
  fi
  
  if [ $stage -le 3 ]; then
    # Create high-resolution MFCC features (with 40 cepstra instead of 13).
    # this shows how you can split across multiple file-systems.
    echo "$0: creating high-resolution MFCC features"
    mfccdir=data/${train_set}_sp_hires/data
  
    for datadir in ${train_set}_sp ${test_sets}; do
      utils/copy_data_dir.sh data/$datadir data/${datadir}_hires
    done
  
    # do volume-perturbation on the training data prior to extracting hires
    # features; this helps make trained nnets more invariant to test data volume.
    #utils/data/perturb_data_dir_volume.sh data/${train_set}_sp_hires || exit 1;
  
    for datadir in ${train_set}_sp ${test_sets}; do
      steps/make_mfcc.sh --nj 16 --mfcc-config conf/mfcc_hires.conf \
       --cmd "$train_cmd" data/${datadir}_hires || exit 1;
      steps/compute_cmvn_stats.sh data/${datadir}_hires || exit 1;
      utils/fix_data_dir.sh data/${datadir}_hires || exit 1;
    done
  fi
  
  if [ $stage -le 4 ]; then
    # Train a small system just for its LDA+MLLT transform.  We use --num-iters 13
    # because after we get the transform (12th iter is the last), any further
    # training is pointless.
    steps/train_lda_mllt.sh --cmd "$train_cmd" --num-iters 13 \
      --realign-iters "" --splice-opts "--left-context=3 --right-context=3" \
      5000 10000 data/${train_set}_sp_hires data/lang \
       $ali_dir exp/nnet3/tri5b || exit 1
  fi
  
  if [ $stage -le 5 ]; then
    echo "$0: training the diagonal UBM."
    steps/online/nnet2/train_diag_ubm.sh --cmd "$train_cmd" --nj 16  --num-frames 200000 \
       data/${train_set}_sp_hires 256 exp/nnet3/tri5b exp/nnet3/diag_ubm || exit 1
  fi
  
  if [ $stage -le 6 ]; then
    # Train the iVector extractor.  Use all of the speed-perturbed data since iVector extractors
    # can be sensitive to the amount of data. The iVector dimension of 50.
    # even though $nj is just 10, each job uses multiple processes and threads.
    echo "$0: training the iVector extractor"
    steps/online/nnet2/train_ivector_extractor.sh --cmd "$train_cmd" \
      --nj 10 --num-processes 1 --num-threads 2 --ivector-dim 50 \
      data/${train_set}_sp_hires exp/nnet3/diag_ubm exp/nnet3/extractor || exit 1;
  fi
  
  if [ $stage -le 7 ]; then
    # We extract iVectors on the speed-perturbed training data after combining
    # short segments, which will be what we train the system on.  With
    # --utts-per-spk-max 2, the script pairs the utterances into twos, and treats
    # each of these pairs as one speaker; this gives more diversity in iVectors..
    # Note that these are extracted 'online'.
  
    # note, we don't encode the 'max2' in the name of the ivectordir even though
    # that's the data we extract the ivectors from, as it's still going to be
    # valid for the non-'max2' data, the utterance list is the same.
  
    ivectordir=exp/nnet3/ivectors_${train_set}_sp_hires
  
    # having a larger number of speakers is helpful for generalization, and to
    # handle per-utterance decoding well (iVector starts at zero).
    temp_data_root=${ivectordir}
    utils/data/modify_speaker_info.sh --utts-per-spk-max 2 \
      data/${train_set}_sp_hires ${temp_data_root}/${train_set}_sp_hires_max2
  
    steps/online/nnet2/extract_ivectors_online.sh --cmd "$train_cmd" --nj 16 \
      ${temp_data_root}/${train_set}_sp_hires_max2 \
      exp/nnet3/extractor $ivectordir
  
    # Also extract iVectors for the test data, but in this case we don't need the speed
    # perturbation (sp).
    for data in $test_sets; do
      steps/online/nnet2/extract_ivectors_online.sh --cmd "$train_cmd" --nj 6 \
        data/${data}_hires exp/nnet3/extractor exp/nnet3/ivectors_${data}_hires
    done
  fi
  
  exit 0;