#!/usr/bin/python

import sys
from email.message import Message, _unquotevalue
import email.utils


def de_comment(field):
	"""Parse a header field fragment and remove comments.

	copied from AddrlistClass.getdelimited() in email/_parseaddr.py
	"""

	slist = ['']
	quote = False
	pos = 0
	depth = 0
	while pos < len(field):
		if quote:
			quote = False
		elif field[pos] == '(':
			depth += 1
		elif field[pos] == ')':
			depth = max(depth - 1, 0)
			pos += 1
			continue
		elif field[pos] == '\\':
			quote = True
		if depth == 0:
			slist.append(field[pos])
		pos += 1

	return ''.join(slist)

#####################################################
# the rest shows a possible use of the above function

def is_quoted(value):
	""" Check whether a value (string or tuple) is quoted
	"""
	if isinstance(value, tuple):
		return value[2].startswith('"')
	else:
		return value.startswith('"')

class MyMessage(Message):
	"""Email message with comments stripped
	"""

	def __init__(self, *args, **kwargs):
		Message.__init__(self, *args, **kwargs)

	def get_filename(self, failobj=None):
		"""Return the filename associated with the payload if present.

		The filename is extracted from the Content-Disposition header's
		`filename' parameter.  If that header is missing the `filename'
		parameter, this method falls back to looking for the `name' parameter.
		"""
		# changed from original: get the unquoted string
		missing = object()
		filename = self.get_param('filename', missing, 'content-disposition',
			unquote=False)
		if filename is missing:
			filename = self.get_param('name', missing, 'content-type', unquote=False)
		if filename is missing:
			return failobj

		# added to original: non quoted comments are removed
		bare = is_quoted(filename)
		if not bare:
			filename = _unquotevalue(filename)
		filename = email.utils.collapse_rfc2231_value(filename)
		if bare and '(' in filename:
			filename = de_comment(filename)
		return filename.strip()


if __name__ == '__main__':
	if len(sys.argv) != 2:
		print "Usage: attachments.py <message_body_file>"
		sys.exit(0)
	msg = email.message_from_file(open(sys.argv[1]), _class=MyMessage)
	for part in msg.walk():
		print part.get_filename()