# -*- coding: utf-8 -*-

import re
import mock
from typing import Dict, Any, Set

from django.conf import settings

import zerver.lib.openapi as openapi
from zerver.lib.test_classes import ZulipTestCase
from zerver.lib.openapi import (
    get_openapi_fixture, get_openapi_parameters,
    validate_against_openapi_schema, to_python_type,
    SchemaError, openapi_spec, get_openapi_paths
)
from zerver.lib.request import arguments_map

TEST_ENDPOINT = '/messages/{message_id}'
TEST_METHOD = 'patch'
TEST_RESPONSE_BAD_REQ = '400'
TEST_RESPONSE_SUCCESS = '200'


class OpenAPIToolsTest(ZulipTestCase):
    """Make sure that the tools we use to handle our OpenAPI specification
    (located in zerver/lib/openapi.py) work as expected.

    These tools are mostly dedicated to fetching parts of the -already parsed-
    specification, and comparing them to objects returned by our REST API.
    """
    def test_get_openapi_fixture(self) -> None:
        actual = get_openapi_fixture(TEST_ENDPOINT, TEST_METHOD,
                                     TEST_RESPONSE_BAD_REQ)
        expected = {
            'code': 'BAD_REQUEST',
            'msg': 'You don\'t have permission to edit this message',
            'result': 'error'
        }
        self.assertEqual(actual, expected)

    def test_get_openapi_parameters(self) -> None:
        actual = get_openapi_parameters(TEST_ENDPOINT, TEST_METHOD)
        expected_item = {
            'name': 'message_id',
            'in': 'path',
            'description':
                'The ID of the message that you wish to edit/update.',
            'example': 42,
            'required': True,
            'schema': {'type': 'integer'}
        }
        assert(expected_item in actual)

    def test_validate_against_openapi_schema(self) -> None:
        with self.assertRaises(SchemaError,
                               msg=('Extraneous key "foo" in '
                                    'the response\'scontent')):
            bad_content = {
                'msg': '',
                'result': 'success',
                'foo': 'bar'
            }  # type: Dict[str, Any]
            validate_against_openapi_schema(bad_content,
                                            TEST_ENDPOINT,
                                            TEST_METHOD,
                                            TEST_RESPONSE_SUCCESS)

        with self.assertRaises(SchemaError,
                               msg=("Expected type <class 'str'> for key "
                                    "\"msg\", but actually got "
                                    "<class 'int'>")):
            bad_content = {
                'msg': 42,
                'result': 'success',
            }
            validate_against_openapi_schema(bad_content,
                                            TEST_ENDPOINT,
                                            TEST_METHOD,
                                            TEST_RESPONSE_SUCCESS)

        with self.assertRaises(SchemaError,
                               msg='Expected to find the "msg" required key'):
            bad_content = {
                'result': 'success',
            }
            validate_against_openapi_schema(bad_content,
                                            TEST_ENDPOINT,
                                            TEST_METHOD,
                                            TEST_RESPONSE_SUCCESS)

        # No exceptions should be raised here.
        good_content = {
            'msg': '',
            'result': 'success',
        }
        validate_against_openapi_schema(good_content,
                                        TEST_ENDPOINT,
                                        TEST_METHOD,
                                        TEST_RESPONSE_SUCCESS)

        # Overwrite the exception list with a mocked one
        openapi.EXCLUDE_PROPERTIES = {
            TEST_ENDPOINT: {
                TEST_METHOD: {
                    TEST_RESPONSE_SUCCESS: ['foo']
                }
            }
        }
        good_content = {
            'msg': '',
            'result': 'success',
            'foo': 'bar'
        }
        validate_against_openapi_schema(good_content,
                                        TEST_ENDPOINT,
                                        TEST_METHOD,
                                        TEST_RESPONSE_SUCCESS)

    def test_to_python_type(self) -> None:
        TYPES = {
            'string': str,
            'number': float,
            'integer': int,
            'boolean': bool,
            'array': list,
            'object': dict
        }

        for oa_type, py_type in TYPES.items():
            self.assertEqual(to_python_type(oa_type), py_type)

    def test_live_reload(self) -> None:
        # Force the reload by making the last update date < the file's last
        # modified date
        openapi_spec.last_update = 0
        get_openapi_fixture(TEST_ENDPOINT, TEST_METHOD)

        # Check that the file has been reloaded by verifying that the last
        # update date isn't zero anymore
        self.assertNotEqual(openapi_spec.last_update, 0)

        # Now verify calling it again doesn't call reload
        with mock.patch('zerver.lib.openapi.openapi_spec.reload') as mock_reload:
            get_openapi_fixture(TEST_ENDPOINT, TEST_METHOD)
            self.assertFalse(mock_reload.called)

class OpenAPIArgumentsTest(ZulipTestCase):
    # This will be filled during test_openapi_arguments:
    checked_endpoints = set()  # type: Set[str]
    # TODO: These endpoints need to be documented:
    pending_endpoints = set([
        '/users/me/avatar',
        '/settings/display',
        '/users/me/profile_data',
        '/users/me/pointer',
        '/users/me/presence',
        '/users/me',
        '/bot_storage',
        '/users/me/api_key/regenerate',
        '/default_streams',
        '/default_stream_groups/create',
        '/users/me/alert_words',
        '/users/me/status',
        # This endpoint is legacy; documented using the old system
        # defined in ./templates/zerver/api/fixtures.json, not
        # zulip.yaml.  Needs migrating.
        '/users/me/subscriptions',
        '/messages/matches_narrow',
        '/settings',
        '/submessage',
        '/attachments',
        '/calls/create',
        '/export/realm',
        '/zcommand',
        '/realm',
        '/realm/deactivate',
        '/realm/domains',
        '/realm/icon',
        '/realm/logo',
        '/realm/presence',
        '/realm/profile_fields',
        '/queue_id',
        '/invites',
        '/invites/multiuse',
        '/bots',
        # Mobile-app only endpoints
        '/users/me/android_gcm_reg_id',
        '/users/me/apns_device_token',
        # Regex based urls
        '/realm/domains/{domain}',
        '/realm/profile_fields/{field_id}',
        '/users/{user_id}/reactivate',
        '/users/{user_id}',
        '/bots/{bot_id}/api_key/regenerate',
        '/bots/{bot_id}',
        '/invites/{prereg_id}',
        '/invites/{prereg_id}/resend',
        '/invites/multiuse/{invite_id}',
        '/users/me/subscriptions/{stream_id}',
        '/messages/{message_id}/reactions',
        '/messages/{message_id}/emoji_reactions/{emoji_name}',
        '/attachments/{attachment_id}',
        '/user_groups/{user_group_id}/members',
        '/streams/{stream_id}/members',
        '/streams/{stream_id}/delete_topic',
        '/default_stream_groups/{group_id}',
        '/default_stream_groups/{group_id}/streams',
        # Regex with an unnamed capturing group.
        '/users/(?!me/)(?P<email>[^/]*)/presence',
        # Actually '/user_groups/<user_group_id>' in urls.py but fails the reverse mapping
        # test because of the variable name mismatch. So really, it's more of a buggy endpoint.
        '/user_groups/{group_id}',  # Equivalent of what's in urls.py
        '/user_groups/{user_group_id}',  # What's in the OpenAPI docs
    ])
    # TODO: These endpoints have a mismatch between the
    # documentation and the actual API and need to be fixed:
    buggy_documentation_endpoints = set([
        '/events',
        '/users/me/subscriptions/muted_topics',
        # List of flags is broader in actual code; fix is to just add them
        '/settings/notifications',
        # Endpoint is documented; parameters aren't detected properly.
        '/realm/filters',
        '/realm/filters/{filter_id}',
        # Docs need update for subject -> topic migration
        '/messages/{message_id}',
        # stream_id parameter incorrectly appears in both URL and endpoint parameters?
        '/streams/{stream_id}',
        # pattern starts with /api/v1 and thus fails reverse mapping test.
        '/dev_fetch_api_key',
        '/server_settings',
        # Because of the unnamed capturing group, this fails the reverse mapping test.
        '/users/{email}/presence',
    ])

    def convert_regex_to_url_pattern(self, regex_pattern: str) -> str:
        """ Convert regular expressions style URL patterns to their
            corresponding OpenAPI style formats. All patterns are
            expected to start with ^ and end with $.
            Examples:
                1. /messages/{message_id} <-> r'^messages/(?P<message_id>[0-9]+)$'
                2. /events <-> r'^events$'
        """
        self.assertTrue(regex_pattern.startswith("^"))
        self.assertTrue(regex_pattern.endswith("$"))
        url_pattern = '/' + regex_pattern[1:][:-1]
        url_pattern = re.sub(r"\(\?P<(\w+)>[^/]+\)", r"{\1}", url_pattern)
        return url_pattern

    def ensure_no_documentation_if_intentionally_undocumented(self, url_pattern: str,
                                                              method: str) -> None:
        try:
            get_openapi_parameters(url_pattern, method)
            raise AssertionError("We found some OpenAPI \
documentation for %s %s, so maybe we shouldn't mark it as intentionally \
undocumented in the urls." % (method, url_pattern))  # nocoverage
        except KeyError:
            return

    def check_for_non_existant_openapi_endpoints(self) -> None:
        """ Here, we check to see if every endpoint documented in the openapi
        documentation actually exists in urls.py and thus in actual code.
        Note: We define this as a helper called at the end of
        test_openapi_arguments instead of as a separate test to ensure that
        this test is only executed after test_openapi_arguments so that it's
        results can be used here in the set operations. """
        openapi_paths = set(get_openapi_paths())
        undocumented_paths = openapi_paths - self.checked_endpoints
        undocumented_paths -= self.buggy_documentation_endpoints
        undocumented_paths -= self.pending_endpoints
        try:
            self.assertEqual(len(undocumented_paths), 0)
        except AssertionError:  # nocoverage
            msg = "The following endpoints have been documented but can't be found in urls.py:"
            for undocumented_path in undocumented_paths:
                msg += "\n + {}".format(undocumented_path)
            raise AssertionError(msg)

    def test_openapi_arguments(self) -> None:
        """This end-to-end API documentation test compares the arguments
        defined in the actual code using @has_request_variables and
        REQ(), with the arguments declared in our API documentation
        for every API endpoint in Zulip.

        First, we import the fancy-Django version of zproject/urls.py
        by doing this, each has_request_variables wrapper around each
        imported view function gets called to generate the wrapped
        view function and thus filling the global arguments_map variable.
        Basically, we're exploiting code execution during import.

            Then we need to import some view modules not already imported in
        urls.py. We use this different syntax because of the linters complaining
        of an unused import (which is correct, but we do this for triggering the
        has_request_variables decorator).

            At the end, we perform a reverse mapping test that verifies that
        every url pattern defined in the openapi documentation actually exists
        in code.
        """

        urlconf = __import__(getattr(settings, "ROOT_URLCONF"), {}, {}, [''])
        __import__('zerver.views.typing')
        __import__('zerver.views.events_register')
        __import__('zerver.views.realm_emoji')

        # We loop through all the API patterns, looking in particular
        # for those using the rest_dispatch decorator; we then parse
        # its mapping of (HTTP_METHOD -> FUNCTION).
        for p in urlconf.v1_api_and_json_patterns:
            if p.lookup_str != 'zerver.lib.rest.rest_dispatch':
                continue
            for method, value in p.default_args.items():
                if isinstance(value, str):
                    function = value
                    tags = set()  # type: Set[str]
                else:
                    function, tags = value

                # Our accounting logic in the `has_request_variables()`
                # code means we have the list of all arguments
                # accepted by every view function in arguments_map.
                #
                # TODO: Probably with a bit more work, we could get
                # the types, too; `check_int` -> `int`, etc., and
                # verify those too!
                accepted_arguments = set(arguments_map[function])

                regex_pattern = p.regex.pattern
                url_pattern = self.convert_regex_to_url_pattern(regex_pattern)

                if url_pattern == "/users/me/subscriptions":
                    # Hack to workaround legacy pre-openapi docs.
                    # TODO: Migrate get-subscriptions out of
                    # ./templates/zerver/api/fixtures.json and into
                    # zerver/openapi/zulip.yaml.
                    continue

                if "intentionally_undocumented" in tags or url_pattern in self.pending_endpoints:
                    self.ensure_no_documentation_if_intentionally_undocumented(url_pattern, method)
                    continue

                try:
                    openapi_parameters = get_openapi_parameters(url_pattern, method)
                except Exception:  # nocoverage
                    raise AssertionError("Could not find OpenAPI docs for %s %s" %
                                         (method, url_pattern))

                # We now have everything we need to understand the
                # function as defined in our urls.py:
                #
                # * method is the HTTP method, e.g. GET, POST, or PATCH
                #
                # * p.regex.pattern is the URL pattern; might require
                #   some processing to match with OpenAPI rules
                #
                # * accepted_arguments is the full set of arguments
                #   this method accepts (from the REQ declarations in
                #   code).
                #
                # * The documented parameters for the endpoint as recorded in our
                #   OpenAPI data in zerver/openapi/zulip.yaml.
                #
                # We now compare these to confirm that the documented
                # argument list matches what actually appears in the
                # codebase.

                openapi_parameter_names = set(
                    [parameter['name'] for parameter in openapi_parameters]
                )

                if len(openapi_parameter_names - accepted_arguments) > 0:
                    print("Documented invalid parameters for",
                          url_pattern, method, function)
                    print(" +", openapi_parameter_names)
                    print(" -", accepted_arguments)
                    assert(url_pattern in self.buggy_documentation_endpoints)
                elif len(accepted_arguments - openapi_parameter_names) > 0:
                    print("Undocumented parameters for",
                          url_pattern, method, function)
                    print(" -", openapi_parameter_names)
                    print(" +", accepted_arguments)
                    assert(url_pattern in self.buggy_documentation_endpoints)
                else:
                    self.assertEqual(openapi_parameter_names, accepted_arguments)
                    self.checked_endpoints.add(url_pattern)

        self.check_for_non_existant_openapi_endpoints()