#!/usr/bin/env bash

set -euo pipefail

function mk-nixos-cmd-args() {
	hostname="$1"
	pkgs=$(nix-instantiate --eval -E "let sources = import ./npins; in sources.nixpkgs.outPath" | tr -d '"')
	args=(
		"-I" "nixpkgs=$pkgs"
		"-I" "nixos-config=./nix/configurations/$hostname.nix"
		"--file" "./default.nix"
		"--attr" "nixosConfigurations.$hostname"
	)
	echo "${args[@]}"
}

function wrapped-nixos-rebuild() {
	hostname="$1"
	action="$2"
	# shellcheck disable=SC2046
	nixos-rebuild "$action" $(mk-nixos-cmd-args "$hostname") --no-reexec
}

function wrapped-nixos-install() {
	hostname="$1"
	# shellcheck disable=SC2046
	nixos-install $(mk-nixos-cmd-args "$hostname")
}

function help() {
	cat <<EOF
manage.sh

manage.sh is a thin wrapper to make nixos-{install,rebuild} easier to use.
Black lives matter. Trans rights are human rights. No nazi bullsh*t.

Available commands:
	os <hostname> <action>:	run perhost action with nixos-rebuild
	install <hostname>:	run perhost action with nixos-install
	--help:	show this help menu
EOF
}

if [ $# -lt 1 ]; then
	help
	exit 1
fi
mode="$1"
shift

case $mode in
os)
	if [ $# -lt 2 ]; then
		help
		exit 1
	fi
	wrapped-nixos-rebuild "$1" "$2"
	;;

install)
	if [ $# -lt 1 ]; then
		help
		exit 1
	fi
	wrapped-nixos-install "$1"
	;;

help | *)
	help
	;;
esac