#!/usr/bin/python2

#Checks facebook for updates, using beautifulsoup and urlgrabber.

#RSS URL for FB notifications
URL = "URL for Facebook RSS feed"
#Path to last message file. I think it needs to be fully qualified.
#i.e. "/home/ben/.config/fblast"
CONFIG = "/path/to/a/writable/file"
#Path to an icon for the notifications. Use "" to disable the icon. 
ICON = ""
#Time that the notification is visible for, in seconds. 
DELAY = 5

###
print "Loading Facebook Notifier"
from urllib import FancyURLopener
from bs4 import BeautifulSoup
import sys
import pynotify

#Overrides the URLReader with a sane browser ID. useragent. Thingey.
class URLReader(FancyURLopener):
	version = 'Mozilla/5.0 (Windows; U; Windows NT 5.1; it; rv:1.8.1.11) Gecko/20071127 Firefox/2.0.0.11'

def main():
	#Grab the RSS file
	print "Grabbing the RSS file:", URL
	soup = BeautifulSoup(grab(URL))
	
	#Pull out events
	events = soup.find_all('item')
	for num, data in enumerate(events):
		events[num] = data.description.get_text()
	print "Found", 

	#RSS lists them in reverse chronological order
	events.reverse()
	
	#Filter to new events, since last run
	events = new(events)
	
	#Notify for each.
	pynotify.init('Facebook Notifications')
	for event in events:
		print event
		notify(event)

def grab(url):
	"""Returns the text of the argument url."""
	browser = URLReader()
	try: 
		return browser.open(url).read()
	except: 
		print "Could not load "+URL
		exit(1)
    
def new(events):
	"""Trims the RSS list of events to include only events that haven't been 
	on the notify list yet."""
	#Open the last shown message. 
	try: last = open(CONFIG, 'r').read()
	except: last = ""
	
	#Find the index of the last notified message
	try: index = events.index(last)
	except: index = -1
	print "Removing oldest", index+1, "events"
	
	#Save the new most recent message to the config file
	try:
		recent = open(CONFIG, 'w')
		recent.write(events[-1])
	except:
		pass
	
	#Trim off events that've already been alerted. 
	return events[index+1:]
	
def notify(event):
	"""Creates a notify-osd bubble for the event, with an appropriate icon."""
	icon = ICON
	#Uncomment to use custom icons for friend requests, wall posts, pokes, etc.
	#if event.find('post'): icon = ''
	#if event.find('your friend request'): icon = ''
	note = pynotify.Notification(event, '', icon)
	note.set_timeout(1000*DELAY)
	note.show()
	
#Calling "fb.py 10" will check for updates every 10 minutes.
if len(sys.argv)>1:
	from time import sleep
	while True:
		main()
		print "Sleeping for", sys.argv[1], " minutes."
		sleep(60*float(sys.argv[1]))

#Calling "fb.py" will check once, then exit.
else:
	main()