#!/bin/bash
  
  # Copyright 2017  Luminar Technologies, Inc. (author: Daniel Galvez)
  # Apache 2.0
  
  # The following commands were used to generate the mini_librispeech dataset:
  #
  # Note that data generation is random. This could be fixed by
  # providing a seed argument to the shuf program.
  
  if [ "$#" -ne 3 ]; then
    echo "Usage: $0 <src-dir> <dst-dir> <num-hours>"
    echo "e.g.: $0 /export/a05/dgalvez/LibriSpeech/train-clean-100 \\
                   /export/a05/dgalvez/LibriSpeech/train-clean-5 5"
    exit 1
  fi
  
  src_dir=$1
  dest_dir=$2
  dest_num_hours=$3
  
  src=$(basename $src_dir)
  dest=$(basename $dest_dir)
  librispeech_dir=$(dirname $src_dir)
  
  # TODO: Possibly improve this to ensure gender balance and speaker
  # balance.
  # TODO: Use actual time values instead of assuming that to make sure we get $dest_num_hours of data
  src_num_hours=$(grep "$src" $librispeech_dir/CHAPTERS.TXT | awk -F'|' '{ print $3 }' | \
  python -c '
  from __future__ import print_function
  from sys import stdin
  minutes_str = stdin.read().split()
  print(int(round(sum([float(minutes) for minutes in minutes_str]) / 60.0)))')
  src_num_chapters=$(grep "$src" $librispeech_dir/CHAPTERS.TXT | \
                        awk -F'|' '{ print $1 }' | sort -u | wc -l)
  mkdir -p data/subset_tmp
  grep "$src" $librispeech_dir/CHAPTERS.TXT | \
    awk -F'|' '{ print $1 }' | \
    shuf -n $(((dest_num_hours * src_num_chapters) / src_num_hours)) > \
         data/subset_tmp/${dest}_chapter_id_list.txt
  
  while read -r chapter_id || [[ -n "$chapter_id" ]]; do
    chapter_dir=$(find $src_dir/ -mindepth 2 -name "$chapter_id" -type d)
    speaker_id=$(basename $(dirname $chapter_dir))
    mkdir -p $dest_dir/$speaker_id/
    cp -r $chapter_dir $dest_dir/$speaker_id/
  done  < data/subset_tmp/${dest}_chapter_id_list.txt