# Copyright 2011 Piston Cloud Computing, Inc.
# All Rights Reserved.

#    Licensed under the Apache License, Version 2.0 (the "License"); you may
#    not use this file except in compliance with the License. You may obtain
#    a copy of the License at
#
#         http://www.apache.org/licenses/LICENSE-2.0
#
#    Unless required by applicable law or agreed to in writing, software
#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
#    License for the specific language governing permissions and limitations
#    under the License.

import json
import os

import mock
from oslo_policy import policy as common_policy
import six
from six.moves.urllib import request as urlrequest
from testtools import matchers

from keystone import exception
from keystone.policy.backends import rules
from keystone.tests import unit
from keystone.tests.unit.ksfixtures import temporaryfile


class BasePolicyTestCase(unit.TestCase):
    def setUp(self):
        super(BasePolicyTestCase, self).setUp()
        rules.reset()
        self.addCleanup(rules.reset)
        self.addCleanup(self.clear_cache_safely)

    def clear_cache_safely(self):
        if rules._ENFORCER:
            rules._ENFORCER.clear()


class PolicyFileTestCase(BasePolicyTestCase):
    def setUp(self):
        # self.tmpfilename should exist before setUp super is called
        # this is to ensure it is available for the config_fixture in
        # the config_overrides call.
        self.tempfile = self.useFixture(temporaryfile.SecureTempFile())
        self.tmpfilename = self.tempfile.file_name
        super(PolicyFileTestCase, self).setUp()
        self.target = {}

    def config_overrides(self):
        super(PolicyFileTestCase, self).config_overrides()
        self.config_fixture.config(group='oslo_policy',
                                   policy_file=self.tmpfilename)

    def test_modified_policy_reloads(self):
        action = "example:test"
        empty_credentials = {}
        with open(self.tmpfilename, "w") as policyfile:
            policyfile.write("""{"example:test": []}""")
        rules.enforce(empty_credentials, action, self.target)
        with open(self.tmpfilename, "w") as policyfile:
            policyfile.write("""{"example:test": ["false:false"]}""")
        rules._ENFORCER.clear()
        self.assertRaises(exception.ForbiddenAction, rules.enforce,
                          empty_credentials, action, self.target)

    def test_invalid_policy_raises_error(self):
        action = "example:test"
        empty_credentials = {}
        invalid_json = '{"example:test": [],}'
        with open(self.tmpfilename, "w") as policyfile:
            policyfile.write(invalid_json)
        self.assertRaises(ValueError, rules.enforce,
                          empty_credentials, action, self.target)


class PolicyTestCase(BasePolicyTestCase):
    def setUp(self):
        super(PolicyTestCase, self).setUp()
        # NOTE(vish): preload rules to circumvent reloading from file
        rules.init()
        self.rules = {
            "true": [],
            "example:allowed": [],
            "example:denied": [["false:false"]],
            "example:get_http": [["http:http://www.example.com"]],
            "example:my_file": [["role:compute_admin"],
                                ["project_id:%(project_id)s"]],
            "example:early_and_fail": [["false:false", "rule:true"]],
            "example:early_or_success": [["rule:true"], ["false:false"]],
            "example:lowercase_admin": [["role:admin"], ["role:sysadmin"]],
            "example:uppercase_admin": [["role:ADMIN"], ["role:sysadmin"]],
        }

        # NOTE(vish): then overload underlying policy engine
        self._set_rules()
        self.credentials = {}
        self.target = {}

    def _set_rules(self):
        these_rules = common_policy.Rules.from_dict(self.rules)
        rules._ENFORCER.set_rules(these_rules)

    def test_enforce_nonexistent_action_throws(self):
        action = "example:noexist"
        self.assertRaises(exception.ForbiddenAction, rules.enforce,
                          self.credentials, action, self.target)

    def test_enforce_bad_action_throws(self):
        action = "example:denied"
        self.assertRaises(exception.ForbiddenAction, rules.enforce,
                          self.credentials, action, self.target)

    def test_enforce_good_action(self):
        action = "example:allowed"
        rules.enforce(self.credentials, action, self.target)

    def test_enforce_http_true(self):

        def fakeurlopen(url, post_data):
            return six.StringIO("True")

        action = "example:get_http"
        target = {}
        with mock.patch.object(urlrequest, 'urlopen', fakeurlopen):
            result = rules.enforce(self.credentials, action, target)
        self.assertTrue(result)

    def test_enforce_http_false(self):

        def fakeurlopen(url, post_data):
            return six.StringIO("False")

        action = "example:get_http"
        target = {}
        with mock.patch.object(urlrequest, 'urlopen', fakeurlopen):
            self.assertRaises(exception.ForbiddenAction, rules.enforce,
                              self.credentials, action, target)

    def test_templatized_enforcement(self):
        target_mine = {'project_id': 'fake'}
        target_not_mine = {'project_id': 'another'}
        credentials = {'project_id': 'fake', 'roles': []}
        action = "example:my_file"
        rules.enforce(credentials, action, target_mine)
        self.assertRaises(exception.ForbiddenAction, rules.enforce,
                          credentials, action, target_not_mine)

    def test_early_AND_enforcement(self):
        action = "example:early_and_fail"
        self.assertRaises(exception.ForbiddenAction, rules.enforce,
                          self.credentials, action, self.target)

    def test_early_OR_enforcement(self):
        action = "example:early_or_success"
        rules.enforce(self.credentials, action, self.target)

    def test_ignore_case_role_check(self):
        lowercase_action = "example:lowercase_admin"
        uppercase_action = "example:uppercase_admin"
        # NOTE(dprince) we mix case in the Admin role here to ensure
        # case is ignored
        admin_credentials = {'roles': ['AdMiN']}
        rules.enforce(admin_credentials, lowercase_action, self.target)
        rules.enforce(admin_credentials, uppercase_action, self.target)


class DefaultPolicyTestCase(BasePolicyTestCase):
    def setUp(self):
        super(DefaultPolicyTestCase, self).setUp()
        rules.init()

        self.rules = {
            "default": [],
            "example:exist": [["false:false"]]
        }
        self._set_rules('default')
        self.credentials = {}

        # FIXME(gyee): latest Oslo policy Enforcer class reloads the rules in
        # its enforce() method even though rules has been initialized via
        # set_rules(). To make it easier to do our tests, we're going to
        # monkeypatch load_roles() so it does nothing. This seem like a bug in
        # Oslo policy as we shoudn't have to reload the rules if they have
        # already been set using set_rules().
        self._old_load_rules = rules._ENFORCER.load_rules
        self.addCleanup(setattr, rules._ENFORCER, 'load_rules',
                        self._old_load_rules)
        rules._ENFORCER.load_rules = lambda *args, **kwargs: None

    def _set_rules(self, default_rule):
        these_rules = common_policy.Rules.from_dict(self.rules, default_rule)
        rules._ENFORCER.set_rules(these_rules)

    def test_policy_called(self):
        self.assertRaises(exception.ForbiddenAction, rules.enforce,
                          self.credentials, "example:exist", {})

    def test_not_found_policy_calls_default(self):
        rules.enforce(self.credentials, "example:noexist", {})

    def test_default_not_found(self):
        new_default_rule = "default_noexist"
        # FIXME(gyee): need to overwrite the Enforcer's default_rule first
        # as it is recreating the rules with its own default_rule instead
        # of the default_rule passed in from set_rules(). I think this is a
        # bug in Oslo policy.
        rules._ENFORCER.default_rule = new_default_rule
        self._set_rules(new_default_rule)
        self.assertRaises(exception.ForbiddenAction, rules.enforce,
                          self.credentials, "example:noexist", {})


class PolicyJsonTestCase(unit.TestCase):

    def _load_entries(self, filename):
        return set(json.load(open(filename)))

    def test_json_examples_have_matching_entries(self):
        policy_keys = self._load_entries(unit.dirs.etc('policy.json'))
        cloud_policy_keys = self._load_entries(
            unit.dirs.etc('policy.v3cloudsample.json'))

        policy_extra_keys = ['admin_or_token_subject',
                             'service_admin_or_token_subject',
                             'token_subject', ]
        expected_policy_keys = list(cloud_policy_keys) + policy_extra_keys
        diffs = set(policy_keys).difference(set(expected_policy_keys))

        self.assertThat(diffs, matchers.Equals(set()))

    def test_all_targets_documented(self):
        # All the targets in the sample policy file must be documented in
        # doc/source/policy_mapping.rst.

        policy_keys = self._load_entries(unit.dirs.etc('policy.json'))

        # These keys are in the policy.json but aren't targets.
        policy_rule_keys = [
            'admin_or_owner', 'admin_or_token_subject', 'admin_required',
            'default', 'owner', 'service_admin_or_token_subject',
            'service_or_admin', 'service_role', 'token_subject', ]

        def read_doc_targets():
            # Parse the doc/source/policy_mapping.rst file and return the
            # targets.

            doc_path = os.path.join(
                unit.ROOTDIR, 'doc', 'source', 'policy_mapping.rst')
            with open(doc_path) as doc_file:
                for line in doc_file:
                    if line.startswith('Target'):
                        break
                for line in doc_file:
                    # Skip === line
                    if line.startswith('==='):
                        break
                for line in doc_file:
                    line = line.rstrip()
                    if not line or line.startswith(' '):
                        continue
                    if line.startswith('=='):
                        break
                    target, dummy, dummy = line.partition(' ')
                    yield six.text_type(target)

        doc_targets = list(read_doc_targets())
        self.assertItemsEqual(policy_keys, doc_targets + policy_rule_keys)