#!/bin/sh
set -eu

usage() {
	cat <<-'EOF'
		Usage:
		  reconfigure [-U]
		  reconfigure -h
	EOF
}

help() {
	cat <<-'EOF'


		Options:
		  -U            run update(1) before acting
		  -h, --help    show this message


		Switches the system:
		- reconfigure the Guix "home" environment;
		- Guix "system" if it exists;
		- NixOS if it exists.


		Examples:

		  Just use it:

		    $ reconfigure


		  Update before reconfiguring:

		    $ reconfigure -U
	EOF
}


for flag in "$@"; do
	case "$flag" in
		(--)
			break
			;;
		(--help)
			usage
			help
			exit
			;;
		(*)
			;;
	esac
done

UPDATE=false
while getopts 'Uh' flag; do
	case "$flag" in
		U)
			UPDATE=true
			;;
		(h)
			usage
			help
			exit
			;;
		(*)
			usage >&2
			exit 2
			;;
	esac
done
shift $((OPTIND - 1))


if [ "$(id -un)" = 'root' ]; then
	printf 'This script must *not* be run as root.\n\n' >&2
	usage >&2
	exit 2
fi

set -x

if [ "$UPDATE" = true ]; then
	update
fi


trap 'bins > /dev/null' EXIT


HOSTNAME="$(hostname)"

pass show "$(hostname)"/andreh |
	head -n1 |
	sudo -ES guix system -v3 reconfigure "$XDG_CONFIG_HOME"/guix/system.scm

if [ -e /etc/nixos/configuration.nix ]; then
	pass show "$HOSTNAME"/andreh |
		head -n1 |
		sudo -S nixos-rebuild switch
fi

bins > /dev/null


guix home -v3 reconfigure "$XDG_CONFIG_HOME"/guix/home.scm