#!/usr/bin/env bash

set -o errexit -o nounset

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

SRC_DIR=/mnt/docscans
DST_DIR=/mnt/documents

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

PROCESSED_COUNT=0
FAILED_FILES=

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

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

  echo "Started at $(date -Isec)" >> "$DST_LOG"

  $OCRMYPDF_CMD                \
    -l deu                     \
    --clean                    \
    --rotate-pages             \
    --deskew                   \
    - -                        \
    < "$SRC"                   \
    > "$DST_PDF" 2>> "$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 "$FILE"
  then
    echo processed "$FILE"
    mv "$FILE" "$ARCHIVE_DIR"
    echo moved "$FILE" to "$ARCHIVE_DIR"
    (( PROCESSED_COUNT+=1 ))
  else
    echo failed to process "$FILE"
    mv "$FILE" "$FAILED_DIR"
    echo moved "$FILE" to "$FAILED_DIR"
    FAILED_FILES+="${FILE}\n"
  fi
  echo
done <   <(find "$SRC_DIR" -maxdepth 1 -name '*.pdf' -print0)

echo Done
echo
echo processed "$PROCESSED_COUNT" PDFs

if [ -n "$FAILED_FILES" ]
then
  echo failed on PDFs
  echo "$FAILED_FILES"

  sendmail -t thomasruoff@gmail.com <<MAILTEXT
Subject: [$(hostname)] OCR on PDFs failed

Hey,
following PDFs failed to be OCR'd:
${FAILED_FILES}

Cheers
MAILTEXT

fi