#!/bin/sh
set -e

# Print the command and run it
run() {
	echo "$@"
	"$@"
}


	# Absolute path to busybox, if found
	busybox=
	for i in /bin/busybox /usr/bin/busybox; do [ -x "$i" ] && busybox=$i; done

	while read LINE
	do
		# "eval set" to do proper splitting while respecting quotes
		eval set -- $LINE
		case "${1-}" in
		\#*|"")
		;;
		g)
			shift
			ARGUMENTS="$1"
			if [ -n "${2-}" ] && [ "$2" != "-" ]; then
				ARGUMENTS="-g $2 $ARGUMENTS"
			fi

			if ! /usr/bin/getent group "$1" >> /dev/null; then
				if [ -x "/usr/sbin/groupadd" ]; then
					run /usr/sbin/groupadd -r $ARGUMENTS
				elif [ -x "$busybox" ]; then
					run $busybox addgroup -S $ARGUMENTS
				else
					echo "ERROR: neither groupadd nor busybox found!"
					exit 1
				fi
			fi
		;;
		u)
			shift
			ARGUMENTS="$1"
			if [ -n "${2-}" ] && [ "$2" != "-" ]; then
				ARGUMENTS="-u $2 $ARGUMENTS"
			fi
			homedir="/" # If null, empty or '-'
			if [ "${4:--}" != "-" ]; then
				homedir="$4"
			fi

			# Set shell only if not null, empty nor '-'
			if [ "${5:--}" != "-" ]; then
				ARGUMENTS="$ARGUMENTS -s $5"
			else
				ARGUMENTS="$ARGUMENTS -s /usr/sbin/nologin"
			fi

			if [ -x /usr/sbin/useradd ]; then
				if ! /usr/bin/getent passwd "$1" >> /dev/null; then
					# this is useradd/shadow specific
					if /usr/bin/getent group "$1" >> /dev/null; then
						ARGUMENTS="-g $1 $ARGUMENTS"
					else
						ARGUMENTS="-U $ARGUMENTS"
					fi

					run /usr/sbin/useradd -r -c "$3" -d "${homedir}" $ARGUMENTS
				fi
				if ! /usr/bin/getent group "$1" >> /dev/null; then
					if [ -x /usr/sbin/groupadd ]; then
						run /usr/sbin/groupadd -r "$1"
					else
						echo "ERROR: groupadd not found!"
						exit 1
					fi
				fi
			elif [ -x "$busybox" ]; then
				/usr/bin/getent group "$1" >> /dev/null || $busybox addgroup -S "$1"

				if ! /usr/bin/getent passwd "$1" >> /dev/null; then
					run $busybox adduser -S -H -g "$3" -G "$1" -h "${homedir}" $ARGUMENTS
				fi
			else
				echo "ERROR: neither useradd nor busybox found!"
				exit 1
			fi
		;;
		m)
			shift
			if [ -x /usr/sbin/usermod ] ; then
				run /usr/sbin/usermod -a -G $2 $1
			elif [ -x "$busybox" ]; then
				run $busybox addgroup $1 $2
			else
				echo "ERROR: neither usermod nor busybox found!"
				exit 1
			fi
		;;
		r)
			echo "range option ignored: \"$LINE\""
		;;
		*)
			echo "Syntax Error: \"$LINE\""
			exit 1
		;;
		esac
	done
