#!/usr/bin/env python3

import difflib
import email.parser
import itertools
import mailbox
import sys


def flexible_eq(expected, got):
    """Compare two strings, supporting wildcards.

    This functions compares two strings, but supports wildcards on the
    expected string. The following characters have special meaning:

     - ?  matches any character.
     - *  matches anything until the end of the line.

    Returns True if equal (considering wildcards), False otherwise.
    """
    posG = 0
    for c in expected:
        if posG >= len(got):
            return False

        if c == '?':
            posG += 1
            continue
        if c == '*':
            while posG < len(got) and got[posG] != '\n':
                posG += 1
                continue
            continue

        if c != got[posG]:
            return False

        posG += 1

    if posG != len(got):
        # We got more than we expected.
        return False

    return True


def msg_equals(expected, msg):
	"""Compare two messages recursively, using flexible_eq()."""
	diff = False
	for h, val in expected.items():
		if h not in msg:
			print("Header missing: %r" % h)
			diff = True
			continue

		if expected[h] == '*':
			continue

		if not flexible_eq(val, msg[h]):
			print("Header %r differs:" % h)
			print("Exp: %r" % val)
			print("Got: %r" % msg[h])
			diff = True

	if diff:
		return False

	if expected.is_multipart() != msg.is_multipart():
		print("Multipart differs, expected %s, got %s" % (
			expected.is_multipart(), msg.is_multipart()))
		return False

	if expected.is_multipart():
		for exp, got in itertools.zip_longest(expected.get_payload(), msg.get_payload()):
			if not msg_equals(exp, got):
				return False
	else:
		if not flexible_eq(expected.get_payload(), msg.get_payload()):
			exp = expected.get_payload().splitlines()
			got = msg.get_payload().splitlines()
			print("Payload differs:")
			for l in difflib.ndiff(exp, got):
				print(l)
			return False

	return True


if __name__ == "__main__":
	f1, f2 = sys.argv[1:3]

	expected = email.parser.Parser().parse(open(f1))
	msg = email.parser.Parser().parse(open(f2))

	sys.exit(0 if msg_equals(expected, msg) else 1)