#!/usr/bin/env bash

set -o errexit -o nounset

# as suggested in https://github.com/koalaman/shellcheck/wiki/SC2044
shopt -s globstar nullglob

OCRMYPDF_CMD='docker run --rm -i ocrmypdf'

SCR_DIR=/mnt/docscans
DST_DIR=/mnt/documents

LOCKFILE=$DST_DIR/.lock
ARCHIVE_DIR=$DST_DIR/archive
FAILED_DIR=$DST_DIR/failed
LOG_DIR=$DST_DIR/logs

PROCESSED_COUNT=0
FAILED_COUNT=0

function ocrFile() {
  SRC=$1
  FILE_NAME=$(basename -- "$SRC")

  DST_PDF=$DST_DIR/${FILE_NAME%.*}.pdf
  DST_LOG=$LOG_DIR/${FILE_NAME%.*}.log

  $OCRMYPDF_CMD                \
    -l deu                     \
    --clean                    \
    --rotate-pages             \
    --deskew                   \
    - -                        \
    < "$FILE"                  \
    > "$DST_PDF" 2> "$DST_LOG"
}

exec 100>$LOCKFILE || exit 23

flock -n 100 || { echo $LOCKFILE is locked; exit 1; }

mkdir -p "$DST_DIR" "$ARCHIVE_DIR" "$FAILED_DIR" "$LOG_DIR"

while IFS= read -r -d '' file
do
  echo "processing $FILE ..."

  if ocrFile "$FILE" "$DST_DIR"
  then
    echo processed "$FILE"
    mv "$FILE" "$ARCHIVE_DIR"
    echo moved "$FILE" to "$ARCHIVE_DIR"
    (( PROCESSED_COUNT++ ))
  else
    echo failed to process "$FILE"
    mv "$FILE" "$FAILED_DIR"
    echo moved "$FILE" to "$FAILED_DIR"
    (( FAILED_COUNT++ ))
  fi
done <   <(find $SCR_DIR -maxdepth 1 -name '*.pdf' -print0)

echo Done
echo processed $PROCESSED_COUNT PDFs
[ $FAILED_COUNT -gt 0 ] && echo failed on $FAILED_COUNT PDFs