#! /bin/sh
###################################################################################
# Choose and enable wifi-interface with uci
# Usage: choose_wifi.sh [ssid]
# when argument is passed, script tries to activate wifi interface with that ssid
# else script tries to activate first match from iwlist scanning results
#
# author: Christian Ulrich
# version: 0.1
###################################################################################


# function search_ssid( ssid, number_of_ifaces )
#################################################
search_ssid(){
    found=false
    current=0
    index_to_return=0
    while [ $found = false -a $current -lt $2 ]
    do
        uci_result=`uci get wireless.@wifi-iface[$current].ssid 2>&1`
        if [ $uci_result = $1 ]; then
            index_to_return=`expr $current + 1`
	    found=true
        fi
        current=`expr $current + 1` #increment counter
    done
    return $index_to_return
}

# Count interfaces in /etc/config/wireless (result in $iface_counter) 
# and check if any of them is enabled
######################################################################
uci_result="0"
value_exists=true
iface_counter=0
enabled_iface_exists=false
while [ $value_exists = true ]
do
    uci_result=`uci get wireless.@wifi-iface[$iface_counter].ssid 2>&1`
    if [ $? -eq 0 ]; then
                #iface_counter=`expr $iface_counter + 1` #increment iface_counter
		#uci_result=`uci get wireless.@wifi-iface[$iface_counter].disabled 2>/dev/null`
	if [ `uci get wireless.@wifi-iface[$iface_counter].disabled 2>/dev/null` = 0 ]; then
	    enabled_iface_exists=true
	fi
	iface_counter=`expr $iface_counter + 1` #increment iface_counter	
    else
        value_exists=false
    fi
done

# Get Wifi interface
#####################
#wifi_iface=$(cat /proc/net/wireless | grep : )
#wifi_iface=$(echo $wifi_iface | cut -c1-$(expr $(expr index "$wifi_iface" :) - 1 ))

# Check commandline options and start searching
################################################
if [ $# -eq 0 ]; then
    if [ $enabled_iface_exists = false ]; then # if no interface is enabled, enable first one
	uci set wireless.@wifi-iface[0].disabled=0
	/etc/init.d/network reload
	sleep 1
    fi

	#scan_result=`iwlist ${wifi_iface} scanning | grep ESSID`
    scan_result=`iwlist scanning 2>/dev/null | grep ESSID`
    if [ $? -eq 1 ]; then
	sleep 1
	scan_result=`iwlist scanning 2>/dev/null | grep ESSID`
    fi
	#echo ${scan_result[1]}
    scan_result=`echo $scan_result | tr -d 'ESSID:"'`
	#scan_result=`echo $scan_result | tr -d '" '`
    
    index_of_ssid_to_activate=0
    for j in $scan_result
    do
	if [ $index_of_ssid_to_activate -eq 0 ]; then		
	    search_ssid $j $iface_counter
	    index_of_ssid_to_activate=$?
	    if [ $index_of_ssid_to_activate -ne 0 ]; then
				#ssid=$j
		break
	    fi
	fi			
    done
    
elif [ $# -eq 1 ]; then
    index_of_ssid_to_activate=0
    search_ssid $1 $iface_counter
    index_of_ssid_to_activate=$?

else
    echo "usage: choose_wifi.sh [ssid]"
    exit 1
fi


# Evaluate results and enable the right interface with uci
###########################################################

if [ $index_of_ssid_to_activate -eq 0 ]; then
    echo "Network with SSID ${1} not defined in /etc/config/wireless."
    exit 1
fi

i=1
while [ $i -le $iface_counter ]
do
    if [ $i -eq $index_of_ssid_to_activate ]; then
	uci set wireless.@wifi-iface[`expr $i - 1`].disabled=0
	ssid=$(uci get wireless.@wifi-iface[`expr $i - 1`].ssid)
    else
	uci set wireless.@wifi-iface[`expr $i - 1`].disabled=1
    fi
    i=`expr $i + 1`
done

# Activate interface
##########################################
echo "Activating wifi-interface ${ssid}..."
/etc/init.d/network reload