#!/bin/bash

# syntax: $0 [-o <keyring outfile>] [--] <keyfiles...>

# export a key from your keyring:
# gpg -a --export --export-options export-minimal your@id

set -e

tmpdir=$(mktemp --tmpdir -d create-gpgring-XXXXXXX)
trap 'rm -rf "${tmpdir}"' EXIT

mygpg() {
	gpg --homedir "${tmpdir}/.gnupg" --batch --no-tty --no-options --no-default-keyring --no-auto-check-trustdb --trustdb-name "${tmpdir}/trustdb.gpg" "$@"
}

unset INFILES
INFILES=()

OUTFILE=

while [ $# -gt 0 ]; do
	case "$1" in
	-o)
		shift
		if [ $# -eq 0 ]; then
			echo "Missing parameter value for -o" >&2
			exit 2
		fi
		OUTFILE="$1"
		;;
	--)
		shift
		INFILES+=("$@")
		shift $#
		;;
	-*)
		echo "Uknown option: '$1'" >&2
		exit 2
		;;
	*)
		INFILES+=("$1")
		;;
	esac
	shift || true
done

if [ -z "${OUTFILE}" -o "${OUTFILE}" = "-" ]; then
	OUTFILE="${tmpdir}/stdout"
fi

if [ -z "${INFILES[*]}" -o "${INFILES[*]}" = "-" ]; then
	INFILES=("${tmpdir}/stdin")
	cat > "${INFILES[0]}"
fi

export HOME="${tmpdir}"

KEYRING="${tmpdir}/keyring"

mygpg --keyring "${KEYRING}" --import -- "${INFILES[@]}"
mygpg --keyring "${KEYRING}" --list-keys

mv "${KEYRING}" "${OUTFILE}"

if [ -f "${tmpdir}/stdout" ]; then
	cat "${tmpdir}/stdout"
fi