#!/bin/sh

# arguments
if [ "$#" -ne 0 ]; then
	echo "usage: $0" >&2
	exit 1
fi

# write input into temporary file
TMP=$(mktemp)
trap 'rm "$TMP"' EXIT
cat > "$TMP"

# determine the mime-type
if [ "$(dd if="$TMP" bs=1 count=8 2>/dev/null | tr -d '\0')" = "farbfeld" ]; then
	cat "$TMP"
else
	MIME=$(file -ib "$TMP" | cut -d ";" -f 1)

	case "$MIME" in
	image/png)
		png2ff < "$TMP"
		;;
	image/jpeg)
		jpg2ff < "$TMP"
		;;
	*)
		if [ ! -x /usr/bin/convert ] ; then
			printf "%s: cant convert from %s -- missing \`convert' program" "$0" "$FORMAT" >&2
			printf "Run \`apt install imagemagick' to install it" >&2
			exit 1
		fi

		convert "$TMP" png:- | png2ff
		;;
	esac
fi

# errors
if [ $? -ne 0 ]; then
	exit 1
else
	exit 0
fi