#!/bin/sh

cmd_exists () {
    if which "$1" >/dev/null 2>&1; then
        return 0;
    else
        return 1;
    fi;
}

fork () {
    ( "$@" >/dev/null 2>&1 & )
}

cmd_running () {
    if pkill -0 -u "$(id -u)" "$1"; then
        return 0;
    else
        return 1;
    fi;
}

should_stop () {
    if [ "x$1" = "xoff" ] || [ "x$1" = "xstop" ] ; then
        return 0;
    else
        return 1;
    fi;
}


if cmd_exists slock && cmd_exists xautolock; then
    if cmd_running "xautolock"; then
        if should_stop "$1"; then
            xautolock -exit;
        fi;
    else
        if ! should_stop "$1"; then
            fork xautolock -notifier true -bell 0 -locker slock;
        fi;
    fi;
elif cmd_exists xscreensaver && [ -e ~/.xscreensaver ]; then
    if cmd_running "xscreensaver"; then
        if should_stop "$1"; then
            xscreensaver-command -exit;
        fi;
    else
        if ! should_stop "$1"; then
            fork XENVIRONMENT=~/.xscreensaver /usr/bin/xscreensaver;
        fi;
    fi;
elif cmd_exists xautolock; then
    if cmd_running "xautolock"; then
        if should_stop "$1"; then
            xautolock -exit;
        fi;
    else
        if ! should_stop "$1"; then
            fork xautolock -notifier true -bell 0;
        fi;
    fi;
fi;