# 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 subprocess
import uuid

import mock
from oslo_policy import policy as common_policy
import six
from testtools import matchers

from keystone.common import policies
from keystone.common import policy
import keystone.conf
from keystone import exception
from keystone.tests import unit
from keystone.tests.unit import ksfixtures
from keystone.tests.unit.ksfixtures import temporaryfile


CONF = keystone.conf.CONF


class PolicyFileTestCase(unit.TestCase):
    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 _policy_fixture(self):
        return ksfixtures.Policy(self.tmpfilename, self.config_fixture)

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


class PolicyTestCase(unit.TestCase):
    def setUp(self):
        super(PolicyTestCase, self).setUp()
        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)
        policy._ENFORCER.set_rules(these_rules)

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

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

    def test_enforce_good_action(self):
        action = "example:allowed"
        policy.enforce(self.credentials, action, self.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"
        policy.enforce(credentials, action, target_mine)
        self.assertRaises(exception.ForbiddenAction, policy.enforce,
                          credentials, action, target_not_mine)

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

    def test_early_OR_enforcement(self):
        action = "example:early_or_success"
        policy.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']}
        policy.enforce(admin_credentials, lowercase_action, self.target)
        policy.enforce(admin_credentials, uppercase_action, self.target)


class PolicyScopeTypesEnforcementTestCase(unit.TestCase):

    def setUp(self):
        super(PolicyScopeTypesEnforcementTestCase, self).setUp()
        policy.init()
        rule = common_policy.RuleDefault(
            name='foo',
            check_str='',
            scope_types=['system']
        )
        policy._ENFORCER.register_default(rule)
        self.credentials = {}
        self.action = 'foo'
        self.target = {}

    def test_forbidden_is_raised_if_enforce_scope_is_true(self):
        self.config_fixture.config(group='oslo_policy', enforce_scope=True)
        self.assertRaises(
            exception.ForbiddenAction, policy.enforce, self.credentials,
            self.action, self.target
        )

    def test_warning_message_is_logged_if_enforce_scope_is_false(self):
        self.config_fixture.config(group='oslo_policy', enforce_scope=False)
        expected_msg = (
            'Policy foo failed scope check. The token used to make the '
            'request was project scoped but the policy requires [\'system\'] '
            'scope. This behavior may change in the future where using the '
            'intended scope is required'
        )
        with mock.patch('warnings.warn') as mock_warn:
            policy.enforce(self.credentials, self.action, self.target)
            mock_warn.assert_called_once_with(expected_msg)


class PolicyJsonTestCase(unit.TestCase):

    def _get_default_policy_rules(self):
        """Return a dictionary of all in-code policies.

        All policies have a default value that is maintained in code.
        This method returns a dictionary containing all default policies.
        """
        rules = dict()
        for rule in policies.list_rules():
            rules[rule.name] = rule.check_str
        return rules

    def test_json_examples_have_matching_entries(self):
        policy_keys = self._get_default_policy_rules()
        cloud_policy_keys = set(
            json.load(open(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_policies_loads(self):
        action = 'identity:list_projects'
        target = {'user_id': uuid.uuid4().hex,
                  'user.domain_id': uuid.uuid4().hex,
                  'group.domain_id': uuid.uuid4().hex,
                  'project.domain_id': uuid.uuid4().hex,
                  'project_id': uuid.uuid4().hex,
                  'domain_id': uuid.uuid4().hex}
        credentials = {'username': uuid.uuid4().hex, 'token': uuid.uuid4().hex,
                       'project_name': None, 'user_id': uuid.uuid4().hex,
                       'roles': [u'admin'], 'is_admin': True,
                       'is_admin_project': True, 'project_id': None,
                       'domain_id': uuid.uuid4().hex}

        # Since we are moving policy.json defaults to code, we instead call
        # `policy.init()` which does the enforce setup for us with the added
        # bonus of registering the in code default policies.
        policy.init()
        result = policy._ENFORCER.enforce(action, target, credentials)
        self.assertTrue(result)

        domain_policy = unit.dirs.etc('policy.v3cloudsample.json')
        enforcer = common_policy.Enforcer(CONF, policy_file=domain_policy)
        result = enforcer.enforce(action, target, credentials)
        self.assertTrue(result)

    def test_all_targets_documented(self):
        policy_keys = self._get_default_policy_rules()

        # These keys are in the policy.json but aren't targets.
        policy_rule_keys = [
            'admin_or_owner', 'admin_or_token_subject', 'admin_required',
            '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', 'getting-started',
                '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)


class GeneratePolicyFileTestCase(unit.TestCase):

    def test_policy_generator_from_command_line(self):
        # This test ensures keystone.common.policy:get_enforcer ignores
        # unexpected arguments before handing them off to oslo.config, which
        # will fail and prevent users from generating policy files.
        ret_val = subprocess.Popen(
            ['oslopolicy-policy-generator', '--namespace', 'keystone'],
            stdout=subprocess.PIPE,
            stderr=subprocess.PIPE
        )
        ret_val.communicate()
        self.assertEqual(ret_val.returncode, 0)
