import RPi.GPIO as GPIO #This program must be executed as root.
from subprocess import check_output
from re import search
import csv
import datetime
import threading
from time import sleep

#Define file name here!
fileName = '/home/pi/Desktop/db.csv'
#Define timeout here!
#timeoutSecs = 5 * 60 #5 minutes
timeoutSecs = 5
#Define number of alarm seconds here!
cycles = 5

def readIWList():
	storage = []
	#now = datetime.datetime.strptime(str(datetime.datetime.utcnow()), "%Y-%m-%d %H:%M:%S.%f")
	now = datetime.datetime.utcnow()
	output = check_output("iwlist wlan0 scan |egrep ' - Address: '", shell=True) #Dependency: IWList
	for i in output.splitlines(True):
		arrayElement = search('([0-9A-F]{2}([:-]|$)){6}', i).group() #RegExp to obtain the MAC Address
		storage.append([arrayElement, now, 0]) #Dirty bit defaults to clean
	return storage

def writeFile(storage, file):
	with open (file, 'wb') as db:
		dbfile = csv.writer(db, delimiter='\t', quotechar='"')
		for j in storage:
			dbfile.writerow(j);

def readFile(file):
	storage = []
	with open(file, 'rb') as db:
		dbfile = csv.reader(db, delimiter='\t', quotechar='"')
		for dbrow in dbfile:
			then = datetime.datetime.strptime(dbrow[1], "%Y-%m-%d %H:%M:%S.%f") #Date reconversion
			storage.append([dbrow[0], then, dbrow[2]])
	return storage

def compareTime(time):
	now = datetime.datetime.utcnow()
	#Timeout is defined, in seconds, at the beginning of the file.
	timeout = datetime.timedelta(seconds = timeoutSecs)
	val = 0
	if ( abs(now - time) > timeout ):
		#print "Timeout: " + str(abs(now - time))
		return 1
	return val

def buttonPressed():
	#print "Button pressed."
	storage = readIWList()
	file = readFile(fileName)
	for x in file:
		for y in storage:
			if x[0] == y[0]:
				file.remove(x)
				#print "Removed " + x[0] + " from the list."
	for y in storage:
		file.append(y)
	writeFile(file, fileName)

def cyclicProcess():
	file = readFile(fileName)
	for x in file:
		if int(x[2]) == 0:
			if compareTime(x[1]) == 1:
				x[2] = 1 #Mark dirty bit, timeout achieved
				#print "Timeout achieved for " + str(x[0])
	isAlarmTriggered = False
	storage = readIWList()
	for x in file:
		for y in storage:
			if x[0] == y[0]:
				if x[2] == 1:
					isAlarmTriggered = True
					file.remove(x)
					#print "Removed " + x[0] + " from the list."
	if isAlarmTriggered:
		buzzAlarm()
		#print "Alarm activated!"
	writeFile(file, fileName)
	threading.Timer(timeoutSecs, cyclicProcess,()).start()

def buzzAlarm():
	for n in xrange(0, cycles):
		GPIO.output(18, 1)
		sleep(0.5)
		GPIO.output(18, 0)
		sleep(0.5)

#def main():
GPIO.setmode(GPIO.BCM)
GPIO.setup(24, GPIO.IN)
GPIO.setup(18, GPIO.OUT)
threading.Timer(timeoutSecs, cyclicProcess,()).start()
try:
	while True:
		sleep(0.1)
		if GPIO.input(24):
			buttonPressed()
except:
	GPIO.cleanup() #Resets the GPIO ports.