# Copyright (C) 2012-2016 by the Free Software Foundation, Inc.
#
# This file is part of GNU Mailman.
#
# GNU Mailman is free software: you can redistribute it and/or modify it under
# the terms of the GNU General Public License as published by the Free
# Software Foundation, either version 3 of the License, or (at your option)
# any later version.
#
# GNU Mailman is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
# more details.
#
# You should have received a copy of the GNU General Public License along with
# GNU Mailman.  If not, see <http://www.gnu.org/licenses/>.

"""Test the header chain."""

__all__ = [
    'TestHeaderChain',
    ]


import unittest

from mailman.app.lifecycle import create_list
from mailman.chains.headers import HeaderMatchRule, make_link
from mailman.config import config
from mailman.core.chains import process
from mailman.email.message import Message
from mailman.interfaces.action import Action
from mailman.interfaces.chain import LinkAction, HoldEvent, DiscardEvent
from mailman.interfaces.configuration import ConfigurationUpdatedEvent
from mailman.interfaces.mailinglist import IHeaderMatchList
from mailman.testing.helpers import (
    LogFileMark, configuration, event_subscribers,
    specialized_message_from_string as mfs)
from mailman.testing.layers import ConfigLayer



class TestHeaderChain(unittest.TestCase):
    """Test the header chain code."""

    layer = ConfigLayer

    def setUp(self):
        self._mlist = create_list('test@example.com')

    def test_make_link(self):
        # Test that make_link() with no given chain creates a Link with a
        # deferred link action.
        link = make_link('Subject', '[tT]esting')
        self.assertEqual(link.rule.header, 'Subject')
        self.assertEqual(link.rule.pattern, '[tT]esting')
        self.assertEqual(link.action, LinkAction.defer)
        self.assertIsNone(link.chain)

    def test_make_link_with_chain(self):
        # Test that make_link() with a given chain creates a Link with a jump
        # action to the chain.
        link = make_link('Subject', '[tT]esting', 'accept')
        self.assertEqual(link.rule.header, 'Subject')
        self.assertEqual(link.rule.pattern, '[tT]esting')
        self.assertEqual(link.action, LinkAction.jump)
        self.assertEqual(link.chain, config.chains['accept'])

    @configuration('antispam', header_checks="""
    Foo: a+
    Bar: bb?
    """)
    def test_config_checks(self):
        # Test that the header-match chain has the header checks from the
        # configuration file.
        chain = config.chains['header-match']
        # The links are created dynamically; the rule names will all start
        # with the same prefix, but have a variable suffix.  The actions will
        # all be to jump to the named chain.  Do these checks now, while we
        # collect other useful information.
        post_checks = []
        saw_any_rule = False
        for link in chain.get_links(self._mlist, Message(), {}):
            if link.rule.name == 'any':
                saw_any_rule = True
                self.assertEqual(link.action, LinkAction.jump)
            elif saw_any_rule:
                raise AssertionError("'any' rule was not last")
            else:
                self.assertEqual(link.rule.name[:13], 'header-match-')
                self.assertEqual(link.action, LinkAction.defer)
                post_checks.append((link.rule.header, link.rule.pattern))
        self.assertListEqual(post_checks, [
            ('Foo', 'a+'),
            ('Bar', 'bb?'),
            ])

    @configuration('antispam', header_checks="""
    Foo: foo
    A-bad-line
    Bar: bar
    """)
    def test_bad_configuration_line(self):
        # Take a mark on the error log file.
        mark = LogFileMark('mailman.error')
        # A bad value in [antispam]header_checks should just get ignored, but
        # with an error message logged.
        chain = config.chains['header-match']
        # The links are created dynamically; the rule names will all start
        # with the same prefix, but have a variable suffix.  The actions will
        # all be to jump to the named chain.  Do these checks now, while we
        # collect other useful information.
        post_checks = []
        saw_any_rule = False
        for link in chain.get_links(self._mlist, Message(), {}):
            if link.rule.name == 'any':
                saw_any_rule = True
                self.assertEqual(link.action, LinkAction.jump)
            elif saw_any_rule:
                raise AssertionError("'any' rule was not last")
            else:
                self.assertEqual(link.rule.name[:13], 'header-match-')
                self.assertEqual(link.action, LinkAction.defer)
                post_checks.append((link.rule.header, link.rule.pattern))
        self.assertListEqual(post_checks, [
            ('Foo', 'foo'),
            ('Bar', 'bar'),
            ])
        # Check the error log.
        self.assertEqual(mark.readline()[-77:-1],
                         'Configuration error: [antispam]header_checks '
                         'contains bogus line: A-bad-line')

    def test_duplicate_header_match_rule(self):
        # 100% coverage: test an assertion in a corner case.
        #
        # Save the existing rules so they can be restored later.
        saved_rules = config.rules.copy()
        next_rule_name = 'header-match-{0:02}'.format(HeaderMatchRule._count)
        config.rules[next_rule_name] = object()
        try:
            self.assertRaises(AssertionError,
                              HeaderMatchRule, 'x-spam-score', '.*')
        finally:
            config.rules = saved_rules

    def test_list_rule(self):
        # Test that the header-match chain has the header checks from the
        # mailing-list configuration.
        chain = config.chains['header-match']
        header_matches = IHeaderMatchList(self._mlist)
        header_matches.append('Foo', 'a+')
        links = [link for link in chain.get_links(self._mlist, Message(), {})
                 if link.rule.name != 'any']
        self.assertEqual(len(links), 1)
        self.assertEqual(links[0].action, LinkAction.jump)
        self.assertEqual(links[0].chain.name, config.antispam.jump_chain)
        self.assertEqual(links[0].rule.header, 'foo')
        self.assertEqual(links[0].rule.pattern, 'a+')

    def test_list_complex_rule(self):
        # Test that the mailing-list header-match complex rules are read
        # properly.
        chain = config.chains['header-match']
        header_matches = IHeaderMatchList(self._mlist)
        header_matches.append('Foo', 'a+', Action.reject)
        header_matches.append('Bar', 'b+', Action.discard)
        header_matches.append('Baz', 'z+', Action.accept)
        links = [link for link in chain.get_links(self._mlist, Message(), {})
                 if link.rule.name != 'any']
        self.assertEqual(len(links), 3)
        self.assertEqual([
            (link.rule.header, link.rule.pattern, link.action, link.chain.name)
            for link in links
            ],
            [('foo', 'a+', LinkAction.jump, 'reject'),
             ('bar', 'b+', LinkAction.jump, 'discard'),
             ('baz', 'z+', LinkAction.jump, 'accept'),
            ])

    @configuration('antispam', header_checks="""
    Foo: foo
    """, jump_chain='hold')
    def test_priority_site_over_list(self):
        # Test that the site-wide checks take precedence over the list-specific
        # checks.
        msg = mfs("""\
From: anne@example.com
To: test@example.com
Subject: A message
Message-ID: <ant>
Foo: foo
MIME-Version: 1.0

A message body.
""")
        msgdata = {}
        header_matches = IHeaderMatchList(self._mlist)
        header_matches.append('Foo', 'foo', Action.accept)
        # This event subscriber records the event that occurs when the message
        # is processed by the owner chain.
        events = []
        with event_subscribers(events.append):
            process(self._mlist, msg, msgdata, start_chain='header-match')
        self.assertEqual(len(events), 1)
        event = events[0]
        # Site-wide wants to hold the message, the list wants to accept it.
        self.assertTrue(isinstance(event, HoldEvent))
        self.assertEqual(event.chain, config.chains['hold'])

    def test_no_action_defaults_to_site_wide_action(self):
        # Test that list-specific checks with no action always follow the
        # site-wide antispam action.
        msg = mfs("""\
From: anne@example.com
To: test@example.com
Subject: A message
Message-ID: <ant>
Foo: foo
MIME-Version: 1.0

A message body.
""")
        msgdata = {}
        header_matches = IHeaderMatchList(self._mlist)
        header_matches.append('Foo', 'foo')
        # This event subscriber records the event that occurs when the message
        # is processed by the owner chain.
        events = []
        def record_event(event):
            if isinstance(event, ConfigurationUpdatedEvent):
                return
            events.append(event)
        with event_subscribers(record_event):
            # The site-wide default is hold.
            with configuration('antispam', header_checks="""
                Spam: [*]{3,}
                """, jump_chain='hold'):
                process(self._mlist, msg, msgdata, start_chain='header-match')
            self.assertEqual(len(events), 1)
            event = events[0]
            self.assertTrue(isinstance(event, HoldEvent))
            self.assertEqual(event.chain, config.chains['hold'])
            # The site-wide default is now discard.
            msg.replace_header('Message-Id', '<bee>')
            with configuration('antispam', header_checks="""
                Spam: [*]{3,}
                """, jump_chain='discard'):
                process(self._mlist, msg, msgdata, start_chain='header-match')
            self.assertEqual(len(events), 2)
            event = events[1]
            self.assertTrue(isinstance(event, DiscardEvent))
            self.assertEqual(event.chain, config.chains['discard'])