#!/bin/sh
# Stolen from and based on Robert Cutajar
# https://askubuntu.com/a/421718

if [ "$#" == "0" ] ;
then
    echo "Session daemon missing command" >&2
    echo "USAGE: $0 command [args...]"
    echo "Executes given command with args only once per XDG seat (session)."
    echo "Keeps PID and log of the executed command."
    exit 1
fi

COMMAND=$1
shift

NAME="${COMMAND##*/}"
PIDFILE=~/.cache/xsession-daemon/$NAME-$XDG_SEAT.pid
LOGFILE=~/.cache/xsession-daemon/$NAME-$XDG_SEAT.log
PID=""
PIDDIR="${PIDFILE%/*}"
LOGDIR="${LOGFILE%/*}"

mkdir -p $PIDDIR
if [ $? -ne 0 ]; then
    echo "Session daemon PIDDIR not there: $PIDDIR" >&2
    exit 2
fi

mkdir -p $LOGDIR
if [ $? -ne 0 ]; then
    echo "Session daemon LOGDIR not there: $LOGDIR" >&2
    exit 2
fi

if [ -e "$PIDFILE" ] ; then
    PID=`cat "$PIDFILE"`
    echo "Session daemon '$NAME' PID found: $PID"

    if pgrep -F "$PIDFILE" "${NAME}" >/dev/null ; then
        echo "Session daemon '$NAME' was already running with PID $PID" >&2
        exit 3
    fi
else
    echo "Session daemon '$NAME' PIDFILE NOT found: $PIDFILE"
fi


echo "Session daemon running $COMMAND $* > $LOGFILE 2>&1"
$COMMAND $* > "$LOGFILE" 2>&1 &
PID=$!
ERR=$?
sleep 1

if [ "$PID" ] && [  $ERR == 0 ] && kill -0 "$PID" 2>/dev/null; then
    echo -n $PID > "$PIDFILE"
    echo "Session daemon '$NAME' started with PID $PID"
else
    echo "Session daemon '$NAME' did not start or finished early. PID: $PID, ERR: $ERR" >&2
    cat "$LOGFILE" >&2
    exit 4
fi