#!/usr/bin/env bash
  
  # This script validates a directory containing training or test images
  # for image-classification tasks with fixed-size images.
  
  
  if [ $# != 1 ]; then
    echo "Usage: $0 <image-dir-to-validate>"
    echo "e.g.: $0 data/cifar10_train"
  fi
  
  dir=$1
  
  [ -e ./path.sh ] && . ./path.sh
  
  if [ ! -d $dir ]; then
    echo "$0: directory $dir does not exist."
    exit 1
  fi
  
  for f in images.scp labels.txt classes.txt num_channels; do
    if [ ! -s "$dir/$f" ]; then
      echo "$0: expected file $dir/$f to exist and be nonempty"
      exit 1
    fi
  done
  
  
  num_channels=$(cat $dir/num_channels)
  
  if ! [[ $num_channels -gt 0 ]]; then
    echo "$0: expected the file $dir/num_channels to contain a number >0"
    exit 1
  fi
  
  paf="--print-args=false"
  
  num_cols=$(head -n 1 $dir/images.scp | feat-to-dim $paf scp:- -)
  if ! [[ $[$num_cols%$num_channels] == 0 ]]; then
    echo "$0: expected the number of columns in the image matrices ($num_cols) to "
    echo "    be a multiple of the number of channels ($num_channels)"
    exit 1
  fi
  
  num_rows=$(head -n 1 $dir/images.scp | feat-to-len $paf scp:- ark,t:- | awk '{print $2}')
  
  height=$[$num_cols/$num_channels]
  
  echo "$0: images are width=$num_rows by height=$height, with $num_channels channels (colors)."
  
  if ! cmp <(awk '{print $1}' $dir/images.scp) <(awk '{print $1}' $dir/labels.txt); then
    echo "$0: expected the first fields of $dir/images.scp and $dir/labels.txt to match up."
    exit 1;
  fi
  
  if ! [[ $num_cols -eq $(tail -n 1 $dir/images.scp | feat-to-dim $paf scp:- -) ]]; then
    echo "$0: the number of columns in the image matrices is not consistent."
    exit 1
  fi
  
  if ! [[ $num_rows -eq $(tail -n 1 $dir/images.scp | feat-to-len $paf scp:- ark,t:- | awk '{print $2}') ]]; then
    echo "$0: the number of rows in the image matrices is not consistent."
    exit 1
  fi
  
  # Note: we don't require images.scp and labels.txt to be sorted, but they
  # may not contain repeated keys.
  if ! awk '{if($1 in a) { print "validate_image_dir.sh: key " $1 " is repeated in labels.txt, line is: " $0; exit 1; } a[$1]=1; }' <$dir/labels.txt; then
    exit 1
  fi
  
  
  if ! utils/int2sym.pl -f 2 $dir/classes.txt <$dir/labels.txt >/dev/null; then
    echo "$0: classes.txt may have the wrong format or may not cover all labels in $dir/labels.txt"
    exit 1;
  fi
  
  
  if ! awk '{ if(NF != 2 || $2 != NR-1) { print "Bad line of classes.txt: " $0; exit(1); }}' $dir/classes.txt; then
    echo "$0: $dir/classes.txt doesn't look right."
    exit 1
  fi
  
  
  echo "$0: validated image-data directory $dir"
  exit 0