os/pkgs/scan2paperless.nix

self: with self; ''
  echo "$@"
  DUPLEX=,Duplex
  removeempty="true"

  [[ $1 == "-s" ]] && {
  	DUPLEX=""
  	removeempty=false
  	shift
  }

  [[ $1 == "-a" ]] && {
  	DUPLEX=,Duplex
    removeempty="true"
  	shift
  }

  [[ $1 == "-d" ]] && {
  	DUPLEX=,Duplex
  	shift
  }

  cleanup() {
  	echo finalizing pdf file.
  	${img2pdf}/bin/img2pdf --pdfa --output /tmp/scan2paperless_$$.pdf /tmp/scan2paperless_$$_*.png && \
  	rm -f /tmp/scan2paperless_$$_*.png

    scp /tmp/scan2paperless_$$.pdf pub-solar@paperless.faenix.eu:~/.local/share/scandir \
  		&& rm -f /tmp/scan2paperless_$$* \
  		|| echo upload failed, retaining file /tmp/scan2paperless_$$.pdf >&2
  }

  trap 'cleanup; exit 1' EXIT

  ${sane-backends}/bin/scanimage --device 'brother5:bus1;dev5' --format=png --resolution 300 --batch=/tmp/scan2paperless_$$_%d.png --AutoDeskew=yes --batch-start=10 --source="Automatic Document Feeder(left aligned''${DUPLEX})" -x 210 -y 297

  if $removeempty
  then
  	threshold=99
  	images=( )
  	values=( )
  	for f in /tmp/scan2paperless_$$_*.png
  	do
  		images[''${#images[@]}]=$f
  		values[''${#values[@]}]=$(${imagemagick}/bin/convert "$f" -fuzz 02% -fill black +opaque white -fill white -opaque white -format "%[fx:100*mean]" info:)
  	done

  	for ((i=0;i<''${#images[@]};i++))
  	do
  		if [[ $(echo "''${values[i]} > $threshold" | ${bc}/bin/bc -l) == "1" ]]
  		then
  			# bc will output 1 if the comparison is true, 0 otherwise
  			echo image "''${images[i]}" was found to be mostly white, removing.
  			rm "''${images[i]}"
  		fi
  	done
  fi
''