# Thresholds - these may depend on what you do with your computer and what 
# you want it to stay awake for.
CPUTHRESH=5        # in percent 
DISKTHRESH=500     # in blocks/sec (the sar manpage says blocks are 512 bytes in normal cases) 
NETTHRESH=10       # in kB/s
# (no sound playing is ~25 while playing mp3 w/ pcm+master turned all the way to zero is ~250)

# Sample times (in seconds) - again needs may vary
CPUTIME=1   
DISKTIME=2  
NETTIME=2 


# Check CPU usage defined as non-idle time.
echo "Check CPU"
CPU=`sar $CPUTIME 1 | awk '/Durchschn/ { printf "%d\n",100-$8}'`
echo "CPU = $CPU%"
if [ $CPUTHRESH -lt $CPU ];then
    echo CPU is working, not sleeping
    exit;
fi

# Check disk usage (read + write)
echo "CheckDisk"
DISK=`sar -b $DISKTIME 1 | awk '/Durchschn.:/ { printf "%d\n",$5 + $6 }'`
echo "DISK = $DISK"
if [ $DISKTHRESH -lt $DISK ];then
    echo Disk is working, not sleeping
    exit;
fi

# Check net usage (exclude wifi0 which appears to have activity all the time for some weird reason)
NET=`sar -n DEV $NETTIME 1 | awk '/Durchschn.:/ { SUM += $5 + $6 } END { printf ("%d\n",SUM)}'`
echo "NETWORK = $NET"
if [ $NETTHRESH -lt $NET ]; then
    echo Network is in use, not sleeping
    exit;
fi

#check for samba logins
SAMBAUSERS=`smbstatus -p | awk /^[0123456789]+/'{printf("%d\n",$1)}'`

if [ -n "$SAMBAUSERS" ]; then
        echo Some SAMBA users connected
	exit;
fi


# check for remote login
REMOTELOGIN=`last | head | grep "pts/.*still logged in"`
if [ -n "$REMOTELOGIN" ];then
    echo Remote login active:
    echo $REMOTELOGIN
    echo Not sleeping
    exit;
fi

if [ -e /tmp/suspend.last ];then
 if [ $(($(date +%s) - $(date -r /tmp/suspend.last +%s))) -lt 1800 ]; then 
  echo between two suspends need to be a half hour
  exit
 fi
fi

if [ -e /tmp/suspend.lock ]; then
 echo some other suspend is running
 exit
fi

# Go into standby
touch /tmp/suspend.lock
echo "go into standby"
echo 3 > /proc/acpi/sleep

rm /tmp/suspend.lock
touch /tmp/suspend.last