#!/bin/bash
# Usage: scan_perpage <imagefile>
#   where imagefile is the data just scanned
# (specify this script to scanadf via -S)

usage()
{
  echo "Usage: $0 <imagefile>"
  echo "Set the following environment variables:"
  echo "  UNPAPER"
  echo "  SEARCHABLE"
  echo "  RESOLUTION"
  echo "  PGWIDTHIN"
  echo "  PGHEIGHTIN"
  echo "  PS2PDF_OPTS (optional)"
  echo "  VERBOSE (optional)"
  echo "  LOCKFILE (required if VERBOSE=1)"
}

log()
{
  if [ $VERBOSE = 1 ]; then
    echo "scan_perpage: $1"
  fi
}

logstdout()
{
  if [ $VERBOSE = 1 ]; then
    cat
  else
    cat > /dev/null
  fi
}

if [ $# -lt 1 ]; then
  usage
  exit 1
fi

if [ "$UNPAPER" == "" -o "$SEARCHABLE" == "" -o "$RESOLUTION" == "" -o "$RESOLUTION" == "" ]; then
  usage
  exit 1
fi

IMAGE_FILE=$1

process_page() {
  log ""
  log "-------------------------------------------------------------------------------"
  log "Post-processing scanned page ${IMAGE_FILE}, deskew=$UNPAPER, searchable=$SEARCHABLE..."

  PP_PREFIX=
  if [ $UNPAPER -eq 1 ]; then
    log "Applying unpaper post-processing to image data..."
    PP_PREFIX="unpaper-"
    if [ $VERBOSE = 1 ]; then
      UNPAPERVERBOSE="-v"
    fi
    #unpaper $UNPAPERVERBOSE --no-mask-scan --overwrite --dpi $RESOLUTION --no-blackfilter $IMAGE_FILE $PP_PREFIX$IMAGE_FILE | logstdout
    unpaper $UNPAPERVERBOSE --overwrite --dpi $RESOLUTION $IMAGE_FILE $PP_PREFIX$IMAGE_FILE | logstdout
  fi
  log ""
  log "-------------------------------------------------------------------------------"
  log "Converting image data to pdf..."
  if [ $SEARCHABLE -eq 1 ]; then
    log "Converting image data to searchable pdf..."
    tesseract $PP_PREFIX$IMAGE_FILE ${IMAGE_FILE%.*} -l eng pdf | logstdout
  else
    log "Converting image data to pdf..."
    PNMVERBOSE=
    if [ $VERBOSE = 1 ]; then
      PNMVERBOSE="-verbose"
    fi
    if [ "$PGWIDTHIN" == "" -o "$PGHEIGHTIN" == "" ]; then
      PAGEOPTS="-equalpixels -dpi=$RESOLUTION -noturn"
    else
      PAGEOPTS="-imagewidth $PGWIDTHIN -imageheight $PGHEIGHTIN"
    fi
    log "Using page options: $PAGEOPTS"
    pnmtops $PNMVERBOSE $PAGEOPTS $PP_PREFIX$IMAGE_FILE | ps2pdf $PS2PDF_OPTS - > ${IMAGE_FILE%.*}.pdf | logstdout
  fi
  
  status=$?
  rm $IMAGE_FILE
  if [ -f $PP_PREFIX$IMAGE_FILE ]; then
    rm $PP_PREFIX$IMAGE_FILE
  fi

  log ""
  log "Scan processing done, status = $status"
}

if [ $VERBOSE = 1 ]; then
  (
    flock 200
    process_page
  ) 200>$LOCKFILE
else
  process_page
fi;

exit $status