#!/bin/bash


LOGFILE="/home/sats/satsd/log/dwc.log";
slog(){
	echo -e "$1" | sudo -u sats tee -a $LOGFILE > /dev/null;
}

failexit(){
	slog " > failed";
	exit 127;
}

connectedexit(){
	slog " > connected";
	slog "<<< Finished\n";
	exit 0;
}

test ! -f $LOGFILE && sudo -u sats touch $LOGFILE;

HSALT="***SALT***";
HPEPPER="***PEPPER***";


slog ">>> Dynamic Wireless Credentials";


# [1] Checking connectivity
#========================================================#
slog " * 1. Checking connectivity"
[ -z "`ping xdrm.io -q -c 1 -i 1 2>&1 > /dev/null`" ] \
	&& connectedexit \
	|| slog " > offline";



# [2] Wifi scan for "SATS_*" APs
#========================================================#

# (1) Get interface name #
slog " * 2. Looking for wireless interface";
IFACE=`sudo ifconfig -a | grep -P "^w" | awk '{print $1}' | head -n 1`;
sudo ifconfig $IFACE up;

# (2) Manage no IFACE found #
test -z "$IFACE" && failexit;
slog " > done (got '$IFACE')";


# (3) Get nearest AP matching "SATS_*" and extract HASH #
slog " * 3. Looking for nearest AP matching 'SATS_.+'";
AP_HASH=`sudo iwlist $IFACE scan | grep -P "^\s*ESSID:\"SATS_.+\"\s*$" | sed 's/^[ \t]*ESSID:"SATS_//' | sed 's/"[ \t]*$//' | head -n 1`;

# (4) Manage no AP found #
test -z "$AP_HASH" && failexit;
slog " > done (got 'SATS_$AP_HASH')";




# [3] Calculate WIFI PASS from SSID hash
#========================================================#
slog " * 4. Processing WPA2 passphrase"
PASS=`echo -ne "$HPEPPER$(echo -ne "${HSALT}${AP_HASH}" | sha512sum | sed 's/[ \t]*-$//')" | sha512sum | sed 's/[ \t]*-//' | cut -b 1-63`;
slog " > done";


# [4] Update 'wpa_supplicant' configuration
#========================================================#
echo -e "network={\n\tssid=\"SATS_$AP_HASH\"\n\tpsk=\"$PASS\"\n}" | sudo tee /etc/wpa_supplicant/$IFACE.conf;


# [5] Restart connection
#========================================================#
# (1) Starting wpa_supplicant #
slog " * 5. Starting wpa_supplicant"
sudo pkill wpa_supplicant;
sudo wpa_supplicant -B -Dwext -i$IFACE -c/etc/wpa_supplicant/$IFACE.conf \
	&& slog " > done" \
	|| failexit;


# (2) Starting dhclient #
slog " * 6. Starting dhclient"
if [ ! -z "`pgrep dhclient`" ]; then
	slog " > already running";
else
	sudo dhclient $IFACE \
		&& slog " > done" \
		|| failexit;
fi;


slog "<<< Finished\n";