#!/usr/bin/env python
# -*- coding: utf-8 -*-
#############################################
# check-gmail.py
#
# (c) 2006 Timothy Kilbourn
#
# A script to check for messages on a Gmail account
# Uses gmailatom.py by Juan Grande (juan.grande@gmail.com)
#
# 11.27.2006 created
# 11.29.2006 added username option, output for no new messages
#            added utf-8 character handling
# 12.04.2006 added summary hashes to print new messages only
#            the first time they appear
#            added graceful exiting from KeyboardInterrupts
# 12.05.2006 general code cleanups
#            added exception handling
#            added message filtering
#
# To do:
#   * Clean up all of the code so it is more object-oriented
#   * Fix filtering so it matches [SPAM] from CITES spam filtering
#   * Make filtering more flexible
#   * Add a configuration file (but not for passwords!)
#
#############################################

import gmailatom
import getpass
import time
import sre
import md5
from optparse import OptionParser
from datetime import datetime

# Constants
FirstTry = 1
UpdatePeriod = 5
DefaultTries = 1
DefaultDelay = 60
MinimumDelay = 15
DefaultTimeFormat = "%H:%M %P"
DefaultMessageEncoding = "utf-8"
Filter = False
Prog = "check-gmail"
Version = "0.6"
Desc = "A commandline program for checking a Gmail account for new messages"
Usage = "%prog -u USER [-t TIME] [-n NUM] [-f EXP]"
HTMLEscapes = { \
	"…": "...", \
	"&lt;": "<", \
	"&gt;": ">", \
	"&amp;": "&", \
	"&#39;": "'", \
	"&quot;": "\"", \
}

# Auxiliary functions
def uprint(s,enc=DefaultMessageEncoding):
	print s.encode(enc)

def now(format=DefaultTimeFormat):
	return datetime.now().strftime(format)

class GmailMessage:
	author_name=""
	subject=""
	summary=""
	md5=None

	def __init__(self,author,subject,summary):
		self.author_name=author
		self.subject=subject
		self.summary=summary
		self.normalize_summary()
		self.md5=md5.new(self.summary.encode(DefaultMessageEncoding))

	def normalize_summary(self):
		for (escape, str) in HTMLEscapes.items():
			self.summary = self.summary.replace(escape, str)

	def hash(self):
		return self.md5.hexdigest()

# Commandline parser
parser = OptionParser(usage=Usage, version="%s %s" % (Prog, Version), description=Desc, prog=Prog)
parser.add_option( "-n", "--number-of-tries", type="int", metavar="NUM", dest="tries", help="number of times to check for messages (0 for infinite)")
parser.add_option( "-t", "--time", type="int", metavar="TIME", dest="delay", help="time (in seconds) to wait between tries")
parser.add_option( "-u", "--user", type="string", metavar="USER", dest="username", help="Gmail account username (without the @gmail.com)")
parser.add_option( "-f", "--filter", type="string", metavar="EXP", dest="filter", help="prevent messages with EXP from being reported (uses regular expression syntax)" )


# Commandline defaults
parser.set_defaults(tries=DefaultTries)
parser.set_defaults(delay=DefaultDelay)

# Check commandline options
(options, args) = parser.parse_args()
if options.tries < 0:
	options.tries = 1
if options.delay < MinimumDelay:
	options.delay = MinimumDelay
if options.username == None:
	parser.error("a username is required for the -u option")
if options.filter != None:
	Filter = True
	msg_filter = sre.compile(options.filter)

# Get the password
password = getpass.getpass( "Enter the password for %s@gmail.com: " % options.username )

# Gmail check setup
g = gmailatom.GmailAtom( options.username, password )
tryno = FirstTry
prev_unread = False
hashes = []

# Loop
while (options.tries == 0) or (tryno <= options.tries):
	if tryno > FirstTry:
		try:
			time.sleep(options.delay)
		except KeyboardInterrupt:
			break

	try:
		g.refreshInfo()
	except Exception, e:
		print "An error has occurred: %s" % e
		print "(retrying in %d seconds...)" % options.delay
		continue

	unread = g.getUnreadMsgCount()

	if unread > 0:
		if unread > 1:
			unread_plural = "s"
		else:
			unread_plural = ""

		# iterate through the messages and look for new ones
		new_msgs=[]
		filtered_msgs = 0

		for i in range(0,unread):
			if Filter and (sre.match(msg_filter, g.getMsgTitle(i)) or \
					sre.match(msg_filter, g.getMsgSummary(i))):
				filtered_msgs = filtered_msgs + 1
				continue
			msg = GmailMessage(g.getMsgAuthorName(i),\
													g.getMsgTitle(i),\
													g.getMsgSummary(i))

			if hashes.count(msg.hash()) == 0:
				hashes.append(msg.hash())
				new_msgs.append(msg)

		if len(new_msgs) > 0:
			prev_unread = True
			if len(new_msgs) > 1:
				new_plural = "s"
			else:
				new_plural = ""

			if Filter and filtered_msgs > 0:
				filter_str = "%d filtered, " % filtered_msgs
			else:
				filter_str = ""

			print "%d new unread message%s! (%s%d total unread message%s) (%s)" % (len(new_msgs), new_plural, filter_str, unread, unread_plural, now())
			for msg in new_msgs:
				uprint("Message %d:" % (new_msgs.index(msg) + 1))
				uprint("  From: %s" % msg.author_name)
				uprint("  Subject: %s" % msg.subject)
				uprint("    %s" % msg.summary)
				print
		else:
			if (tryno % UpdatePeriod == 0) \
				or (tryno == options.tries):
					if Filter and filtered_msgs > 0:
						filter_str = "(%d filtered)" % filtered_msgs
					else:
						filter_str = ""
					print "%d unread message%s %s (%s)" % (unread, unread_plural, filter_str, now())
	else:
		# Print "No unread messages" under various circumstances
		if (prev_unread == True) \
			or (tryno == FirstTry) \
			or (tryno % UpdatePeriod == 0) \
			or (tryno == options.tries):
				print "No unread messages (%s)" % (now())
		prev_unread = False

	tryno = tryno + 1