#!/bin/bash

set -e

if test -n "$1" ; then
    # tell another machine to sleep.
    host=$1
    ssh $host osascript -e \'tell application \"Finder\" to sleep\'

elif test -n "$SSH_TTY" ; then
    # sleep the machine you are ssh'ed into and also log out of the ssh session.
    # this was trickier than I would have guessed.

    # turns out you can't just 'logout' from within a shell script.
    # instead, we have to find the $PID of our bash shell and kill it.
    # I tried killing the PID of our ssh session but that seems to
    # also kill the osascript call.
    ipid=$PID
    ippid=$PPID
    tmp=$(mktemp /tmp/sleep.XXXX)
    ps -x -o user,pid,ppid,command \
        | sed -E 's/ +/ /g' \
        | grep -v '^USER PID PPID COMMAND$' \
        > $tmp
    while true ; do
        notfound=1
        while read line ; do
            lpid=$(echo $line | awk '{print $2}')
            if test "$ippid" = "$lpid" ; then
                cmd=$(echo $line | cut -d' ' -f4-)
                if test "$cmd" = "/usr/sbin/sshd -i" ; then
                    # found it.
                    tokill=$ipid
                    break 2
                else
                    # ascend to ppid and start again.
                    lppid=$(echo $line | awk '{print $3}')
                    ipid=$lpid
                    ippid=$lppid
                    unset notfound
                    break 1
                fi
            else
                continue
            fi
        done < $tmp

        if test -n "$notfound" ; then
            echo "Error: couldn't determine \$PID of your ssh session." >&2
            exit 1
        else
            continue
        fi
    done
    rm -f $tmp

    # now fork off a sleep script into the background and kill ssh.
    cd /tmp
    cat > /tmp/sleep2.sh << "EOF"
#!/bin/bash
set -e
sleep 0.2
osascript -e 'tell application "Finder" to sleep'
EOF
    chmod +x /tmp/sleep2.sh
    # turns out we have to redirect nohup's stdout and stderr to prevent ssh from killing it.
    nohup /tmp/sleep2.sh >/dev/null 2>&1 </dev/null &
    disown
    sleep 0.1
    # argh, it turns out we have to 'kill -9' bash, which means we lose bash history.
    kill -9 $tokill

else
    # sleep this machine.
    osascript -e 'tell application "Finder" to sleep'

fi