autohotspot

#!/bin/bash
if [ "$EUID" -ne 0 ]
        then echo "Must be root"
        exit
fi

CreateAdHocNetwork()
{
	echo "Create AdHoc network"
	echo "Put interface wlan0 down"
	ip link set dev wlan0 down

	echo "Set static ip on wlan0..."
	/sbin/ifconfig wlan0 10.0.50.1 netmask 255.255.255.0 up

	echo "Attempting to start dnsmasq..."
	systemctl start dnsmasq.service

	echo "Attempting to start hostapd..."
	systemctl start hostapd.service

	echo "Enable wlan0"
	ip link set dev wlan0 up
}

KillHotspot()
{
    echo "Shutting Down Hotspot"
	echo "Attempting to stop hostapd..."
	systemctl stop hostapd.service

	echo "Attempting to stop dnsmasq..."
	systemctl stop dnsmasq.service

	echo "Put interface wlan0 down"
	/sbin/dhclient -r wlan0
	ip link set dev wlan0 down
}

ChkWifiUp()
{
        sleep 10 #give time for ip to be assigned by router
        if ! wpa_cli status | grep 'ip_address' >/dev/null 2>&1
        then #Failed to connect to wifi (check your wifi settings, password etc)
               echo 'Wifi failed to connect, falling back to Hotspot'
               wpa_cli terminate >/dev/null 2>&1
               CreateAdHocNetwork
        fi
}

n=1
SSID=""
SSIDChk="NoSSid"
until [[ $SSID ]] || [[ $n -gt 5 ]]
do
		echo "Find optimal WiFi connection (try $n / 5)"
		sleep 5
		/sbin/wpa_cli scan
		# only select the SSID's that are actually configured
		SSID=`/sbin/wpa_cli scan_result | sort -k3 | grep -f /etc/wpa_supplicant/selectable.wlan -o | head -1`
		
		if [[ $SSID ]]
		then
			SSIDChk=$SSID
			NetworkID=`/sbin/wpa_cli list_network | grep -w "$SSID" | cut -f1`
			break
		else
			SSIDChk='NoSSid'
		fi
		n=$[$n+1]
done

#Create Hotspot or connect to valid wifi networks
if [ "$SSIDChk" != "NoSSid" ]
then
	echo 'Using SSID:' $SSIDChk
	if systemctl status hostapd | grep "(running)" >/dev/null 2>&1
	then #hotspot running and ssid in range
		KillHotspot
		echo "Hotspot Deactivated, Bringing Wifi Up"

		echo "Activate wifi connection $SSIDChk[$NetworkID]"
		/sbin/wpa_cli select_network $NetworkID

		echo "Enable wlan0"
		ip link set dev wlan0 up
		/sbin/dhclient wlan0

		_IP=$(hostname -I) || true
		if [ "$_IP" ]; then
			printf "My IP address is %s\n" "$_IP"
		fi

		ChkWifiUp
	elif { wpa_cli status | grep 'ip_address'; } >/dev/null 2>&1
	then #Already connected
		echo "Wifi already connected to network"
	else #ssid exists and no hotspot running connect to wifi network
		echo "Connecting to WiFi Network"

		echo "Activate wifi connection $SSIDChk[$NetworkID]"
		/sbin/wpa_cli select_network $NetworkID

		echo "Enable wlan0"
		ip link set dev wlan0 up
		/sbin/dhclient wlan0

		_IP=$(hostname -I) || true
		if [ "$_IP" ]; then
			printf "My IP address is %s\n" "$_IP"
		fi
		
		ChkWifiUp
	fi
else #ssid or MAC address not in range
	if systemctl status hostapd | grep "(running)" >/dev/null 2>&1
	then
		echo "Hostspot already active"
	elif { wpa_cli status | grep 'wlan0'; } >/dev/null 2>&1
	then
		echo "Cleaning wifi files and Activating Hotspot"
        NetworkID=`/sbin/wpa_cli list_network | grep "CURRENT" | cut -f1`

        echo "Deactivate wifi connection $NetworkID..."
        if ! [[ $NetworkID -ge 0 ]]; then
                echo "Failed to get current SSID. Rebooting..."
                sleep 5
                echo "Reboot..."
                /sbin/reboot
        fi

        /sbin/wpa_cli disable_network $NetworkID
		
		CreateAdHocNetwork
	else #"No SSID, activating Hotspot"
		CreateAdHocNetwork
	fi
fi