#!/bin/sh
set -e

die() {
	ec=$1
	[ -n "$1" ] && shift
	[ -n "$1" ] && notify-send "$@"
	exit $ec
}

command -v systemctl > /dev/null || die 1 "VPN Error" "this script is designed for systemd based systems"

vpnunits() {
	# TODO currently this only lists wg-quick-* which is generated on nixos
	for f in $(systemctl list-unit-files 'wg-quick-*.service' --no-legend | cut -d' ' -f1); do
		systemctl show "$f" -p Id -p Description -p ActiveState --value | paste -sd '\t' -
	done | sed 's/\.service//;s/\t/ (/;s/\t/) (/;s/$/)/'
}

# get unit
s="$(vpnunits | dmenu -l 8 -p "Toggle VPN")"
[ -z "$s" ] && die
unit=$(cut -d' ' -f1 <<< "$s")

# check if unit exits
systemctl cat "$unit" > /dev/null || die 1 "VPN Error" "Unit $unit.service does not exist"

# toggle state
if [ "$(systemctl show "$unit" -p ActiveState --value)" = "active" ]; then
	[ "$(printf '%s\n' 'yes' 'no' | dmenu -p "Disable VPN $unit?")" != "yes" ] && die  # confirm

	pkexec systemctl stop "$unit" \
		&& die 0 "VPN Disabled" "$unit stopped successfully" \
		|| die 1 "VPN Error" "$unit threw an error when stopping"
else
	pkexec systemctl start "$unit" \
		&& die 0 "VPN Enabled" "$unit started successfully" \
		|| die 1 "VPN Error" "$unit threw an error when starting"
fi