#!/bin/sh

cfpid="${XDG_RUNTIME_DIR:-${TMPDIR:-/tmp}}/caffeine.pid"

usage()
{
	cat <<- EOF
	Usage: ${0##*/} [ -s ] [ -t timeout ]
	Keep your computer awake

	Options:
	  -s silent or quiet mode
	  -t <timeout in minutes>

	EOF
}

note()
{
	command -v notify-send > /dev/null &&
		notify-send "   caffeine" "$1"
}

die()
{
	note "err: $1"
	printf "\033[31;1merr: %b\033[0m\n" "$1" 1>&2
	exit "${2:-1}"
}

dep_check()
{
	: "${1:?}"

	for dep; do
		command -v "$dep" > /dev/null ||
			die "${dep} not installed"
	done

	unset dep
}

set_menu()
{
	if [ -n "$WAYLAND_DISPLAY" ]; then
		menu="bemenu"
	elif [ -n "$DISPLAY" ]; then
		menu="dmenu"
	else
		die "can't be ran from tty, setup xorg or wayland"
	fi
}

caf_time()
{
	dep_check "$menu"

	time="$(printf "1m\n3m\n5m\n10m\n15m\n30m" | "$menu" -p "  sleep after ")"
	echo "${time%m}"
}

drink()
{
	# usage: drink <time in mins>
	: "${1:?}"

	dep_check swayidle brightnessctl swaylock

	[ -s "$cfpid" ] &&
		kill "$(cat "$cfpid")"

	swayidle \
		timeout "$(($1 - 10))" "brightnessctl --save; brightnessctl set 10%-" \
		resume "brightnessctl --restore" \
		timeout "$(($1 - 5))" "swaylock" \
		timeout "$1" "swaymsg --type command 'output * dpms off'" \
		resume "swaymsg --type command 'output * dpms on'" &
	echo $! > "$cfpid"
	
	[ "$silent" != true ] &&
		note "$(uname -n) will sleep after $(($1 / 60)) m of inactivity"
}

########
# MAIN #
########

timeout=
silent=
menu=

set_menu

while getopts "t:sh" f; do
	case "$f" in
	t)
		timeout="$OPTARG"
		;;
	s)
		silent=true
		;;
	h)
		usage
		exit
		;;
	?)
		printf "try '%s -h' for more information\n" "${0##*/}"
		exit 1
		;;
	esac
done

[ -z "$timeout" ] &&
	timeout="$(caf_time)"
[ -z "$timeout" ] &&
	exit 1
[ "$((timeout))" -le 0 ] &&
	die "invalid input time"

drink "$((timeout * 60))"