#!/bin/bash
# ----------------------------------------
# DESCRIPTION:
# 
# Keep airport associated with a specific
# access point
# 
# 
# Copyright (c) 2008 Ali Rantakari
# http://hasseg.org
# 
# ----------------------------------------





# settings begin here:
# --------------------

# SSID of WLAN AP to connect to
TOSSID="MYSSID"

# WLAN AP password
WITHPW="0xf0f0f0f0f0f0f0f0f0f0f0f0f0"


# where to find the airport utility (it's here in Tiger and Leopard, at least)
AP="/System/Library/PrivateFrameworks/Apple80211.framework/Versions/Current/Resources/airport"

CHECKINTERVAL=5 # how often to check AirPort status
CHECKINTERVALWHENOFF=20 # how often to check AirPort status if it's been off

TRIES=7 # how many times to retry connecting if not successful
RETRYDELAY=3 # how many seconds to wait before retrying


# ------ settings end here. implementation begins below





#if [ "$1" == "-xv" ];then
#	VERBOSE="true"
#else
#	VERBOSE="false"
#fi
VERBOSE="true"




is_on()
{
	if [ "`$AP --getinfo | grep -c \"AirPort: Off\"`" == "1" ];then
		echo "false"
	else
		echo "true"
	fi
}

is_associated()
{
	if [ "`$AP --getinfo | grep SSID | grep -v BSSID | grep -c $TOSSID`" == "0" ];then
		echo "false"
	else
		echo "true"
	fi
}

connect()
{
	if [ "$VERBOSE" == "true" ];then
		echo " "
	fi
	
	I=0
	while [ "$I" -lt "$TRIES" ]
	do
		if [ "$VERBOSE" == "true" ];then
		#	if [ "$I" == "1" ];then
		#		echo " "
		#		echo "    (trying $(($TRIES-1)) more times)"
		#		echo " "
		#	fi
			echo -n "    Trying to connect to $TOSSID... "
		fi
		$AP --associate=$TOSSID --password=$WITHPW
		if [ "`is_associated`" == "true" ];then
			# ok
			I=$TRIES
			if [ "$VERBOSE" == "true" ];then
				echo "...done!"
			fi
		else
			# not ok -> retry
			I=$(($I + 1))
			if [ "$VERBOSE" == "true" ];then
				if [ "$I" == "$TRIES" ];then
					echo "...unsuccessful."
				else
					echo -n "...unsuccessful."
				fi
			fi
			
			if [ "$I" -lt "$TRIES" ];then
				if [ "$VERBOSE" == "true" ];then
					echo -n " Retrying in "
				fi
				
				J=$RETRYDELAY
				while [ "$J" -gt "-1" ]
				do
					J=$(($J - 1))
					sleep 1
					if [ "$VERBOSE" == "true" ];then
						echo -n "$(($J+1))"
					fi
				done
				
				if [ "$VERBOSE" == "true" ];then
					echo " "
				fi
			fi
			
		fi
	done
	
	if [ "$VERBOSE" == "true" ];then
		echo " "
	fi
}





CURRCHECKINTERVAL=$CHECKINTERVAL
LASTONSTATUS="on"
LASTASSOCIATEDSTATUS="false"
FIRSTRUN="true"

# main loop
while [ "1" == "1" ]
do
	if [ "`is_on`" == "false" ];then
		if [ "$VERBOSE" == "true" ]&&[ "$LASTONSTATUS" == "on" ];then
			echo "- Airport turned off, will not try to connect until it's turned on again."
		fi
		LASTONSTATUS="off"
		CURRCHECKINTERVAL=$CHECKINTERVALWHENOFF
	else
		if [ "`is_associated`" == "true" ];then
			if [ "$VERBOSE" == "true" ]&&[ "$LASTASSOCIATEDSTATUS" == "false" ];then
				echo "- Already connected to $TOSSID."
			fi
			LASTASSOCIATEDSTATUS="true"
		else
			if [ "$VERBOSE" == "true" ]&&[ "$FIRSTRUN" == "false" ];then
				if [ "$LASTONSTATUS" == "off" ];then
					echo "- Airport is on again, initiating connect procedure:"
				else
					if [ "$LASTASSOCIATEDSTATUS" == "true" ];then
						echo "- Connection to $TOSSID lost. Initiating connect procedure:"
					else
						echo "- Trying to connect again:"
					fi
				fi
			fi
			connect
			if [ "`is_associated`" == "true" ];then
				LASTASSOCIATEDSTATUS="true"
			else
				LASTASSOCIATEDSTATUS="false"
			fi
		fi
		LASTONSTATUS="on"
		CURRCHECKINTERVAL=$CHECKINTERVAL
	fi
	sleep $CURRCHECKINTERVAL
	FIRSTRUN="false"
done