#!/bin/sh

export STOW_DIR=/etc/portage/stow

err() {
	printf "bosun: %s\n" "$@" >&2
}

errx() {
	err "$@"
	exit 1
}

usage() {
	printf "usage: bosun add role ...\n" >&2
	printf "       bosun flush\n" >&2
	printf "       bosun [list [type ...]]\n" >&2
	printf "       bosun rebuild [role ...]\n" >&2
	printf "       bosun remove [role ...]\n" >&2
	exit 1
}

need_role() {
	test $# -gt 0 || errx "this command requires at least one role"
	for dir in "$@"; do
		test -d "$STOW_DIR/$dir" || errx "no such role '$dir' in $STOW_DIR"
	done
}

need_root() {
	test "$(id -u)" -eq 0 || errx "this action requires superuser access"
}

add() {
	need_root
	need_role "$@"
	stow -S "$@"
}

remove() {
	need_root
	need_role "$@"
	stow -D "$@"
}

flush() {
	need_root
	list | xargs -- stow -D
}

rebuild() {
	need_root
	if test $# -gt 0; then
		need_role "$@"
		stow -R "$@"
	else
		list | xargs -- stow -R
	fi
}

list() {
	subcmd="${1:-active}"
	case $subcmd in
		active) list_active;;
		all) list_all;;
		available) list_available;;
		*) errx "no such list type '$subcmd'. Try: active, all, available"
	esac
}

list_active() {
	# Note: we de not escape any special characters in $STOW_DIR since it is
	# assumed we are in full control of its contents.
	# XXX: -r for xargs is a GNU extension
	find "$STOW_DIR/.." -type l -print0 2>/dev/null \
		| xargs -r0 readlink -f \
		| sed -n ":^$STOW_DIR: s:^$STOW_DIR/\([^/]\+\)/.*:\1:p" \
		| sort -u
}

list_all() {
	ls -1 "$STOW_DIR"
}

list_available() {
	tmp="$(mktemp)" || exit 1
	list_active > "$tmp"
	list_all | comm -13 "$tmp" - 
	rm -f "$tmp"
}

cmd="${1:-list}"
test $# -gt 0 && shift
case $cmd in
	add) add "$@";;
	flush) flush;;
	list) list "$@";;
	rebuild) rebuild "$@";;
	del|delete|remove) remove "$@";;
	*) err "no such command '$cmd'"; usage;;
esac