#
# Declare variables
#
DEVICE="${SANE_DEFAULT_DEVICE:-}"
OUTPUT_FILE=

while [[ $# -gt 0 ]]; do
	case $1 in
	-d | --device)
		# Allows user to override the device used, since scanimage is
		# slow and the printer might not even change between runs
		DEVICE="$2"
		shift
		shift
		;;
	-*)
		echo "Unknown option $1"
		exit 1
		;;
	*)
		OUTPUT_FILE="$1"
		shift
		;;
	esac
done

#
# Handle defaults
#
if [ -z "$OUTPUT_FILE" ]; then
	OUTPUT_FILE=./scan_"$(date)".pdf
fi

if [ -z "$DEVICE" ]; then
	DEVICE=$(scanimage --formatted-device-list="%d (%v %m)" --list-devices |
		fzf --header "Pick a device:" |
		cut -d ' ' -f 1)
fi

tempdir="$(mktemp -d)"

do_scan() {
	filename="$tempdir/$(date).pdf"
	while ! scanimage --format=pdf --device="$DEVICE" --resolution 300 >"$filename"; do
		:
	done
	echo "$filename"
}

do_fix() {
	read -r filename
	fixed_name="${filename%.pdf}_fixed.pdf"
	gs -o "$fixed_name" -sDEVICE=pdfwrite -dPDFSETTINGS=/prepress "$filename"
	rm "$filename"
	mv "$fixed_name" "$filename"
	echo "$filename"
}

while :; do
	do_scan | do_fix

	IFS= read -r -p "Continue scanning ? [Y/n] " cont
	case "$cont" in
	[nN])
		echo "Exiting..."
		break
		;;
	[yY] | *) ;;
	esac
done

# Multiple files are scanned, join them
merged_filename="$tempdir/$(date)_final.pdf"
pdfunite "$tempdir"/*.pdf "$merged_filename"
echo "$merged_filename" | do_fix

# Copy scan to current directory
cp "$merged_filename" "$OUTPUT_FILE"

# Make sure I don't remove things other than pdf
rm "$tempdir/"*.pdf
rm -d "$tempdir"