"""IMAP4 client.

Based on RFC 2060.

Author: Piers Lauder <piers@cs.su.oz.au> December 1997.

Public class:		IMAP4
Public variable:	Debug
Public functions:	Internaldate2tuple
			Int2AP
			ParseFlags
			Time2Internaldate
"""

import re, socket, string, time, random

#	Globals

CRLF = '\r\n'
Debug = 0
IMAP4_PORT = 143
AllowedVersions = ('IMAP4REV1', 'IMAP4')	# Most recent first

#	Commands

Commands = {
	# name		  valid states
	'APPEND':	('AUTH', 'SELECTED'),
	'AUTHENTICATE':	('NONAUTH',),
	'CAPABILITY':	('NONAUTH', 'AUTH', 'SELECTED', 'LOGOUT'),
	'CHECK':	('SELECTED',),
	'CLOSE':	('SELECTED',),
	'COPY':		('SELECTED',),
	'CREATE':	('AUTH', 'SELECTED'),
	'DELETE':	('AUTH', 'SELECTED'),
	'EXAMINE':	('AUTH', 'SELECTED'),
	'EXPUNGE':	('SELECTED',),
	'FETCH':	('SELECTED',),
	'LIST':		('AUTH', 'SELECTED'),
	'LOGIN':	('NONAUTH',),
	'LOGOUT':	('NONAUTH', 'AUTH', 'SELECTED', 'LOGOUT'),
	'LSUB':		('AUTH', 'SELECTED'),
	'NOOP':		('NONAUTH', 'AUTH', 'SELECTED', 'LOGOUT'),
	'RENAME':	('AUTH', 'SELECTED'),
	'SEARCH':	('SELECTED',),
	'SELECT':	('AUTH', 'SELECTED'),
	'STATUS':	('AUTH', 'SELECTED'),
	'STORE':	('SELECTED',),
	'SUBSCRIBE':	('AUTH', 'SELECTED'),
	'UID':		('SELECTED',),
	'UNSUBSCRIBE':	('AUTH', 'SELECTED'),
	}

#	Patterns to match server responses

Continuation = re.compile(r'\+ (?P<data>.*)')
Flags = re.compile(r'.*FLAGS \((?P<flags>[^\)]*)\)')
InternalDate = re.compile(r'.*INTERNALDATE "'
	r'(?P<day>[ 123][0-9])-(?P<mon>[A-Z][a-z][a-z])-(?P<year>[0-9][0-9][0-9][0-9])'
	r' (?P<hour>[0-9][0-9]):(?P<min>[0-9][0-9]):(?P<sec>[0-9][0-9])'
	r' (?P<zonen>[-+])(?P<zoneh>[0-9][0-9])(?P<zonem>[0-9][0-9])'
	r'"')
Literal = re.compile(r'(?P<data>.*) {(?P<size>\d+)}$')
Response_code = re.compile(r'\[(?P<type>[A-Z-]+)( (?P<data>[^\]]*))?\]')
Untagged_response = re.compile(r'\* (?P<type>[A-Z-]+) (?P<data>.*)')
Untagged_status = re.compile(r'\* (?P<data>\d+) (?P<type>[A-Z-]+)( (?P<data2>.*))?')



class IMAP4:

	"""IMAP4 client class.

	Instantiate with: IMAP4([host[, port]])

		host - host's name (default: localhost);
		port - port number (default: standard IMAP4 port).

	All IMAP4rev1 commands are supported by methods of the same
	name (in lower-case).

	All arguments to commands are converted to strings, except for
	the last argument to APPEND which is passed as an IMAP4
	literal.  If necessary (the string isn't enclosed with either
	parentheses or double quotes) each converted string is quoted.

	Each command returns a tuple: (type, [data, ...]) where 'type'
	is usually 'OK' or 'NO', and 'data' is either the text from the
	tagged response, or untagged results from command.

	Errors raise the exception class <instance>.error("<reason>").
	IMAP4 server errors raise <instance>.abort("<reason>"),
	which is a sub-class of 'error'.
	"""

	class error(Exception): pass	# Logical errors - debug required
	class abort(error): pass	# Service errors - close and retry


	def __init__(self, host = '', port = IMAP4_PORT):
		self.host = host
		self.port = port
		self.debug = Debug
		self.state = 'LOGOUT'
		self.literal = None		# A literal argument to a command
		self.tagged_commands = {}	# Tagged commands awaiting response
		self.untagged_responses = {}	# {typ: [data, ...], ...}
		self.continuation_response = ''	# Last continuation response
		self.tagnum = 0

		# Open socket to server.

		self.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
		self.sock.connect(self.host, self.port)
		self.file = self.sock.makefile('r')

		# Create unique tag for this session,
		# and compile tagged response matcher.

		self.tagpre = Int2AP(random.randint(0, 31999))
		self.tagre = re.compile(r'(?P<tag>'
				+ self.tagpre
				+ r'\d+) (?P<type>[A-Z]+) (?P<data>.*)')

		# Get server welcome message,
		# request and store CAPABILITY response.

		if __debug__ and self.debug >= 1:
			print '\tnew IMAP4 connection, tag=%s' % self.tagpre

		self.welcome = self._get_response()
		if self.untagged_responses.has_key('PREAUTH'):
			self.state = 'AUTH'
		elif self.untagged_responses.has_key('OK'):
			self.state = 'NONAUTH'
#		elif self.untagged_responses.has_key('BYE'):
		else:
			raise self.error(self.welcome)

		cap = 'CAPABILITY'
		self._simple_command(cap)
		if not self.untagged_responses.has_key(cap):
			raise self.error('no CAPABILITY response from server')
		self.capabilities = tuple(string.split(self.untagged_responses[cap][-1]))

		if __debug__ and self.debug >= 3:
			print '\tCAPABILITIES: %s' % `self.capabilities`

		self.PROTOCOL_VERSION = None
		for version in AllowedVersions:
			if not version in self.capabilities:
				continue
			self.PROTOCOL_VERSION = version
			break
		if not self.PROTOCOL_VERSION:
			raise self.error('server not IMAP4 compliant')


	def __getattr__(self, attr):
		"""Allow UPPERCASE variants of all following IMAP4 commands."""
		if Commands.has_key(attr):
			return eval("self.%s" % string.lower(attr))
		raise AttributeError("Unknown IMAP4 command: '%s'" % attr)


	#	Public methods


	def append(self, mailbox, flags, date_time, message):
		"""Append message to named mailbox.

		(typ, [data]) = <instance>.append(mailbox, flags, date_time, message)
		"""
		name = 'APPEND'
		if flags:
			flags = '(%s)' % flags
		else:
			flags = None
		if date_time:
			date_time = Time2Internaldate(date_time)
		else:
			date_time = None
		self.literal = message
		return self._simple_command(name, mailbox, flags, date_time)


	def authenticate(self, func):
		"""Authenticate command - requires response processing.

		UNIMPLEMENTED
		"""
		raise self.error('UNIMPLEMENTED')


	def check(self):
		"""Checkpoint mailbox on server.

		(typ, [data]) = <instance>.check()
		"""
		return self._simple_command('CHECK')


	def close(self):
		"""Close currently selected mailbox.

		Deleted messages are removed from writable mailbox.
		This is the recommended command before 'LOGOUT'.

		(typ, [data]) = <instance>.close()
		"""
		try:
			try: typ, dat = self._simple_command('CLOSE')
			except EOFError: typ, dat = None, [None]
		finally:
			self.state = 'AUTH'
		return typ, dat


	def copy(self, message_set, new_mailbox):
		"""Copy 'message_set' messages onto end of 'new_mailbox'.

		(typ, [data]) = <instance>.copy(message_set, new_mailbox)
		"""
		return self._simple_command('COPY', message_set, new_mailbox)


	def create(self, mailbox):
		"""Create new mailbox.

		(typ, [data]) = <instance>.create(mailbox)
		"""
		return self._simple_command('CREATE', mailbox)


	def delete(self, mailbox):
		"""Delete old mailbox.

		(typ, [data]) = <instance>.delete(mailbox)
		"""
		return self._simple_command('DELETE', mailbox)


	def expunge(self):
		"""Permanently remove deleted items from selected mailbox.

		Generates 'EXPUNGE' response for each deleted message.

		(typ, [data]) = <instance>.expunge()

		'data' is list of 'EXPUNGE'd message numbers in order received.
		"""
		name = 'EXPUNGE'
		typ, dat = self._simple_command(name)
		return self._untagged_response(typ, name)


	def fetch(self, message_set, message_parts):
		"""Fetch (parts of) messages.

		(typ, [data, ...]) = <instance>.fetch(message_set, message_parts)

		'data' are tuples of message part envelope and data.
		"""
		name = 'FETCH'
		typ, dat = self._simple_command(name, message_set, message_parts)
		return self._untagged_response(typ, name)


	def list(self, directory='""', pattern='*'):
		"""List mailbox names in directory matching pattern.

		(typ, [data]) = <instance>.list(directory='""', pattern='*')

		'data' is list of LIST responses.
		"""
		name = 'LIST'
		typ, dat = self._simple_command(name, directory, pattern)
		return self._untagged_response(typ, name)


	def login(self, user, password):
		"""Identify client using plaintext password.

		(typ, [data]) = <instance>.list(user, password)
		"""
		typ, dat = self._simple_command('LOGIN', user, password)
		if typ != 'OK':
			raise self.error(dat)
		self.state = 'AUTH'
		return typ, dat


	def logout(self):
		"""Shutdown connection to server.

		(typ, [data]) = <instance>.logout()

		Returns server 'BYE' response.
		"""
		self.state = 'LOGOUT'
		try: typ, dat = self._simple_command('LOGOUT')
		except EOFError: typ, dat = None, [None]
		self.file.close()
		self.sock.close()
		if self.untagged_responses.has_key('BYE'):
			return 'BYE', self.untagged_responses['BYE']
		return typ, dat


	def lsub(self, directory='""', pattern='*'):
		"""List 'subscribed' mailbox names in directory matching pattern.

		(typ, [data, ...]) = <instance>.lsub(directory='""', pattern='*')

		'data' are tuples of message part envelope and data.
		"""
		name = 'LSUB'
		typ, dat = self._simple_command(name, directory, pattern)
		return self._untagged_response(typ, name)


	def noop(self):
		"""Send NOOP command.

		(typ, data) = <instance>.noop()
		"""
		return self._simple_command('NOOP')


	def recent(self):
		"""Return most recent 'RECENT' response if it exists,
		else prompt server for an update using the 'NOOP' command,
		and flush all untagged responses.

		(typ, [data]) = <instance>.recent()

		'data' is None if no new messages,
		else value of RECENT response.
		"""
		name = 'RECENT'
		typ, dat = self._untagged_response('OK', name)
		if dat[-1]:
			return typ, dat
		self.untagged_responses = {}
		typ, dat = self._simple_command('NOOP')
		return self._untagged_response(typ, name)


	def rename(self, oldmailbox, newmailbox):
		"""Rename old mailbox name to new.

		(typ, data) = <instance>.rename(oldmailbox, newmailbox)
		"""
		return self._simple_command('RENAME', oldmailbox, newmailbox)


	def response(self, code):
		"""Return data for response 'code' if received, or None.

		Old value for response 'code' is cleared.

		(code, [data]) = <instance>.response(code)
		"""
		return self._untagged_response(code, code)


	def search(self, charset, criteria):
		"""Search mailbox for matching messages.

		(typ, [data]) = <instance>.search(charset, criteria)

		'data' is space separated list of matching message numbers.
		"""
		name = 'SEARCH'
		if charset:
			charset = 'CHARSET ' + charset
		typ, dat = self._simple_command(name, charset, criteria)
		return self._untagged_response(typ, name)


	def select(self, mailbox='INBOX', readonly=None):
		"""Select a mailbox.

		Flush all untagged responses.

		(typ, [data]) = <instance>.select(mailbox='INBOX', readonly=None)

		'data' is count of messages in mailbox ('EXISTS' response).
		"""
		# Mandated responses are ('FLAGS', 'EXISTS', 'RECENT', 'UIDVALIDITY')
		self.untagged_responses = {}	# Flush old responses.
		if readonly:
			name = 'EXAMINE'
		else:
			name = 'SELECT'
		typ, dat = self._simple_command(name, mailbox)
		if typ == 'OK':
			self.state = 'SELECTED'
		elif typ == 'NO':
			self.state = 'AUTH'
		if not readonly and not self.untagged_responses.has_key('READ-WRITE'):
			raise self.error('%s is not writable' % mailbox)
		return typ, self.untagged_responses.get('EXISTS', [None])


	def status(self, mailbox, names):
		"""Request named status conditions for mailbox.

		(typ, [data]) = <instance>.status(mailbox, names)
		"""
		name = 'STATUS'
		if self.PROTOCOL_VERSION == 'IMAP4':
			raise self.error('%s unimplemented in IMAP4 (obtain IMAP4rev1 server, or re-code)' % name)
		typ, dat = self._simple_command(name, mailbox, names)
		return self._untagged_response(typ, name)


	def store(self, message_set, command, flag_list):
		"""Alters flag dispositions for messages in mailbox.

		(typ, [data]) = <instance>.store(message_set, command, flag_list)
		"""
		typ, dat = self._simple_command('STORE', message_set, command, flag_list)
		return self._untagged_response(typ, 'FETCH')


	def subscribe(self, mailbox):
		"""Subscribe to new mailbox.

		(typ, [data]) = <instance>.subscribe(mailbox)
		"""
		return self._simple_command('SUBSCRIBE', mailbox)


	def uid(self, command, *args):
		"""Execute "command arg ..." with messages identified by UID,
			rather than message number.

		(typ, [data]) = <instance>.uid(command, arg1, arg2, ...)

		Returns response appropriate to 'command'.
		"""
		name = 'UID'
		typ, dat = apply(self._simple_command, ('UID', command) + args)
		if command == 'SEARCH':
			name = 'SEARCH'
		else:
			name = 'FETCH'
		typ, dat2 = self._untagged_response(typ, name)
		if dat2[-1]: dat = dat2
		return typ, dat


	def unsubscribe(self, mailbox):
		"""Unsubscribe from old mailbox.

		(typ, [data]) = <instance>.unsubscribe(mailbox)
		"""
		return self._simple_command('UNSUBSCRIBE', mailbox)


	def xatom(self, name, *args):
		"""Allow simple extension commands
			notified by server in CAPABILITY response.

		(typ, [data]) = <instance>.xatom(name, arg, ...)
		"""
		if name[0] != 'X' or not name in self.capabilities:
			raise self.error('unknown extension command: %s' % name)
		return apply(self._simple_command, (name,) + args)



	#	Private methods


	def _append_untagged(self, typ, dat):

		if self.untagged_responses.has_key(typ):
			self.untagged_responses[typ].append(dat)
		else:
			self.untagged_responses[typ] = [dat]

		if __debug__ and self.debug >= 5:
			print '\tuntagged_responses[%s] += %.20s..' % (typ, `dat`)


	def _command(self, name, *args):

		if self.state not in Commands[name]:
			self.literal = None
			raise self.error(
			'command %s illegal in state %s' % (name, self.state))

		tag = self._new_tag()
		data = '%s %s' % (tag, name)
		for d in args:
			if d is None: continue
			if type(d) is type(''):
				l = len(string.split(d))
			else:
				l = 1
			if l == 0 or l > 1 and (d[0],d[-1]) not in (('(',')'),('"','"')):
				data = '%s "%s"' % (data, d)
			else:
				data = '%s %s' % (data, d)

		literal = self.literal
		if literal is not None:
			self.literal = None
			data = '%s {%s}' % (data, len(literal))

		try:
			self.sock.send('%s%s' % (data, CRLF))
		except socket.error, val:
			raise self.abort('socket error: %s' % val)

		if __debug__ and self.debug >= 4:
			print '\t> %s' % data

		if literal is None:
			return tag

		# Wait for continuation response

		while self._get_response():
			if self.tagged_commands[tag]:	# BAD/NO?
				return tag

		# Send literal

		if __debug__ and self.debug >= 4:
			print '\twrite literal size %s' % len(literal)

		try:
			self.sock.send(literal)
			self.sock.send(CRLF)
		except socket.error, val:
			raise self.abort('socket error: %s' % val)

		return tag


	def _command_complete(self, name, tag):
		try:
			typ, data = self._get_tagged_response(tag)
		except self.abort, val:
			raise self.abort('command: %s => %s' % (name, val))
		except self.error, val:
			raise self.error('command: %s => %s' % (name, val))
		if self.untagged_responses.has_key('BYE') and name != 'LOGOUT':
			raise self.abort(self.untagged_responses['BYE'][-1])
		if typ == 'BAD':
			raise self.error('%s command error: %s %s' % (name, typ, data))
		return typ, data


	def _get_response(self):

		# Read response and store.
		#
		# Returns None for continuation responses,
		# otherwise first response line received.

		resp = self._get_line()

		# Command completion response?

		if self._match(self.tagre, resp):
			tag = self.mo.group('tag')
			if not self.tagged_commands.has_key(tag):
				raise self.abort('unexpected tagged response: %s' % resp)

			typ = self.mo.group('type')
			dat = self.mo.group('data')
			self.tagged_commands[tag] = (typ, [dat])
		else:
			dat2 = None

			# '*' (untagged) responses?

			if not self._match(Untagged_response, resp):
				if self._match(Untagged_status, resp):
					dat2 = self.mo.group('data2')

			if self.mo is None:
				# Only other possibility is '+' (continuation) rsponse...

				if self._match(Continuation, resp):
					self.continuation_response = self.mo.group('data')
					return None	# NB: indicates continuation

				raise self.abort('unexpected response: %s' % resp)

			typ = self.mo.group('type')
			dat = self.mo.group('data')
			if dat2: dat = dat + ' ' + dat2

			# Is there a literal to come?

			while self._match(Literal, dat):

				# Read literal direct from connection.

				size = string.atoi(self.mo.group('size'))
				if __debug__ and self.debug >= 4:
					print '\tread literal size %s' % size
				data = self.file.read(size)

				# Store response with literal as tuple

				self._append_untagged(typ, (dat, data))

				# Read trailer - possibly containing another literal

				dat = self._get_line()

			self._append_untagged(typ, dat)

		# Bracketed response information?

		if typ in ('OK', 'NO', 'BAD') and self._match(Response_code, dat):
			self._append_untagged(self.mo.group('type'), self.mo.group('data'))

		return resp


	def _get_tagged_response(self, tag):

		while 1:
			result = self.tagged_commands[tag]
			if result is not None:
				del self.tagged_commands[tag]
				return result
			self._get_response()


	def _get_line(self):

		line = self.file.readline()
		if not line:
			raise EOFError

		# Protocol mandates all lines terminated by CRLF

		line = line[:-2]
		if __debug__ and self.debug >= 4:
			print '\t< %s' % line
		return line


	def _match(self, cre, s):

		# Run compiled regular expression match method on 's'.
		# Save result, return success.

		self.mo = cre.match(s)
		if __debug__ and self.mo is not None and self.debug >= 5:
			print "\tmatched r'%s' => %s" % (cre.pattern, `self.mo.groups()`)
		return self.mo is not None


	def _new_tag(self):

		tag = '%s%s' % (self.tagpre, self.tagnum)
		self.tagnum = self.tagnum + 1
		self.tagged_commands[tag] = None
		return tag


	def _simple_command(self, name, *args):

		return self._command_complete(name, apply(self._command, (name,) + args))


	def _untagged_response(self, typ, name):

		if not self.untagged_responses.has_key(name):
			return typ, [None]
		data = self.untagged_responses[name]
		if __debug__ and self.debug >= 5:
			print '\tuntagged_responses[%s] => %.20s..' % (name, `data`)
		del self.untagged_responses[name]
		return typ, data



Mon2num = {'Jan': 1, 'Feb': 2, 'Mar': 3, 'Apr': 4, 'May': 5, 'Jun': 6,
	'Jul': 7, 'Aug': 8, 'Sep': 9, 'Oct': 10, 'Nov': 11, 'Dec': 12}

def Internaldate2tuple(resp):

	"""Convert IMAP4 INTERNALDATE to UT.

	Returns Python time module tuple.
	"""

	mo = InternalDate.match(resp)
	if not mo:
		return None

	mon = Mon2num[mo.group('mon')]
	zonen = mo.group('zonen')

	for name in ('day', 'year', 'hour', 'min', 'sec', 'zoneh', 'zonem'):
		exec "%s = string.atoi(mo.group('%s'))" % (name, name)

	# INTERNALDATE timezone must be subtracted to get UT

	zone = (zoneh*60 + zonem)*60
	if zonen == '-':
		zone = -zone

	tt = (year, mon, day, hour, min, sec, -1, -1, -1)

	utc = time.mktime(tt)

	# Following is necessary because the time module has no 'mkgmtime'.
	# 'mktime' assumes arg in local timezone, so adds timezone/altzone.

	lt = time.localtime(utc)
	if time.daylight and lt[-1]:
		zone = zone + time.altzone
	else:
		zone = zone + time.timezone

	return time.localtime(utc - zone)



def Int2AP(num):

	"""Convert integer to A-P string representation."""

	val = ''; AP = 'ABCDEFGHIJKLMNOP'
	num = int(abs(num))
	while num:
		num, mod = divmod(num, 16)
		val = AP[mod] + val
	return val



def ParseFlags(resp):

	"""Convert IMAP4 flags response to python tuple."""

	mo = Flags.match(resp)
	if not mo:
		return ()

	return tuple(string.split(mo.group('flags')))


def Time2Internaldate(date_time):

	"""Convert 'date_time' to IMAP4 INTERNALDATE representation.

	Return string in form: '"DD-Mmm-YYYY HH:MM:SS +HHMM"'
	"""

	dttype = type(date_time)
	if dttype is type(1):
		tt = time.localtime(date_time)
	elif dttype is type(()):
		tt = date_time
	elif dttype is type(""):
		return date_time	# Assume in correct format
	else: raise ValueError

	dt = time.strftime("%d-%b-%Y %H:%M:%S", tt)
	if dt[0] == '0':
		dt = ' ' + dt[1:]
	if time.daylight and tt[-1]:
		zone = -time.altzone
	else:
		zone = -time.timezone
	return '"' + dt + " %+02d%02d" % divmod(zone/60, 60) + '"'



if __debug__ and __name__ == '__main__':

	import getpass
	USER = getpass.getuser()
	PASSWD = getpass.getpass()

	test_seq1 = (
	('login', (USER, PASSWD)),
	('create', ('/tmp/xxx 1',)),
	('rename', ('/tmp/xxx 1', '/tmp/yyy')),
	('CREATE', ('/tmp/yyz 2',)),
	('append', ('/tmp/yyz 2', None, None, 'From: anon@x.y.z\n\ndata...')),
	('select', ('/tmp/yyz 2',)),
	('uid', ('SEARCH', 'ALL')),
	('fetch', ('1', '(INTERNALDATE RFC822)')),
	('store', ('1', 'FLAGS', '(\Deleted)')),
	('expunge', ()),
	('recent', ()),
	('close', ()),
	)

	test_seq2 = (
	('select', ()),
	('response',('UIDVALIDITY',)),
	('uid', ('SEARCH', 'ALL')),
	('response', ('EXISTS',)),
	('recent', ()),
	('logout', ()),
	)

	def run(cmd, args):
		typ, dat = apply(eval('M.%s' % cmd), args)
		print ' %s %s\n  => %s %s' % (cmd, args, typ, dat)
		return dat

	Debug = 4
	M = IMAP4()
	print 'PROTOCOL_VERSION = %s' % M.PROTOCOL_VERSION

	for cmd,args in test_seq1:
		run(cmd, args)

	for ml in run('list', ('/tmp/', 'yy%')):
		mo = re.match(r'.*"([^"]+)"$', ml)
		if mo: path = mo.group(1)
		else: path = string.split(ml)[-1]
		run('delete', (path,))

	for cmd,args in test_seq2:
		dat = run(cmd, args)

		if (cmd,args) != ('uid', ('SEARCH', 'ALL')):
			continue

		uid = string.split(dat[0])[-1]
		run('uid', ('FETCH', '%s' % uid,
			'(FLAGS INTERNALDATE RFC822.SIZE RFC822.HEADER RFC822)'))