from contextlib import contextmanager
from typing import (
    Any, Callable, Dict, Generator, Iterable, Iterator, List, Mapping,
    Optional, Tuple, Union, IO, TypeVar, TYPE_CHECKING
)

from django.urls import URLResolver
from django.conf import settings
from django.test import override_settings
from django.http import HttpResponse, HttpResponseRedirect
from django.db.migrations.state import StateApps
import boto3
from boto3.resources.base import ServiceResource

import zerver.lib.upload
from zerver.lib.actions import do_set_realm_property
from zerver.lib.upload import S3UploadBackend, LocalUploadBackend
from zerver.lib.avatar import avatar_url
from zerver.lib.cache import get_cache_backend
from zerver.lib.db import Params, ParamsT, Query, TimeTrackingCursor
from zerver.lib import cache
from zerver.tornado import event_queue
from zerver.tornado.handlers import allocate_handler_id
from zerver.worker import queue_processors
from zerver.lib.integrations import WEBHOOK_INTEGRATIONS

from zerver.models import (
    get_realm,
    get_stream,
    Client,
    Message,
    Realm,
    Subscription,
    UserMessage,
    UserProfile,
)

from zproject.backends import ExternalAuthResult, ExternalAuthDataDict

if TYPE_CHECKING:
    # Avoid an import cycle; we only need these for type annotations.
    from zerver.lib.test_classes import ZulipTestCase, MigrationsTestCase

import collections
from unittest import mock
import os
import re
import sys
import time
import ujson
from moto import mock_s3

import fakeldap
import ldap

class MockLDAP(fakeldap.MockLDAP):
    class LDAPError(ldap.LDAPError):
        pass

    class INVALID_CREDENTIALS(ldap.INVALID_CREDENTIALS):
        pass

    class NO_SUCH_OBJECT(ldap.NO_SUCH_OBJECT):
        pass

    class ALREADY_EXISTS(ldap.ALREADY_EXISTS):
        pass

@contextmanager
def stub_event_queue_user_events(event_queue_return: Any, user_events_return: Any) -> Iterator[None]:
    with mock.patch('zerver.lib.events.request_event_queue',
                    return_value=event_queue_return):
        with mock.patch('zerver.lib.events.get_user_events',
                        return_value=user_events_return):
            yield

@contextmanager
def simulated_queue_client(client: Callable[..., Any]) -> Iterator[None]:
    real_SimpleQueueClient = queue_processors.SimpleQueueClient
    queue_processors.SimpleQueueClient = client  # type: ignore[assignment, misc] # https://github.com/JukkaL/mypy/issues/1152
    yield
    queue_processors.SimpleQueueClient = real_SimpleQueueClient  # type: ignore[misc] # https://github.com/JukkaL/mypy/issues/1152

@contextmanager
def tornado_redirected_to_list(lst: List[Mapping[str, Any]]) -> Iterator[None]:
    real_event_queue_process_notification = event_queue.process_notification
    event_queue.process_notification = lambda notice: lst.append(notice)
    # process_notification takes a single parameter called 'notice'.
    # lst.append takes a single argument called 'object'.
    # Some code might call process_notification using keyword arguments,
    # so mypy doesn't allow assigning lst.append to process_notification
    # So explicitly change parameter name to 'notice' to work around this problem
    yield
    event_queue.process_notification = real_event_queue_process_notification

class EventInfo:
    def populate(self, call_args_list: List[Any]) -> None:
        args = call_args_list[0][0]
        self.realm_id = args[0]
        self.payload = args[1]
        self.user_ids = args[2]

@contextmanager
def capture_event(event_info: EventInfo) -> Iterator[None]:
    # Use this for simple endpoints that throw a single event
    # in zerver.lib.actions.
    with mock.patch('zerver.lib.actions.send_event') as m:
        yield

    if len(m.call_args_list) == 0:
        raise AssertionError('No event was sent inside actions.py')

    if len(m.call_args_list) > 1:
        raise AssertionError('Too many events sent by action')

    event_info.populate(m.call_args_list)

@contextmanager
def simulated_empty_cache() -> Generator[
        List[Tuple[str, Union[str, List[str]], str]], None, None]:
    cache_queries: List[Tuple[str, Union[str, List[str]], str]] = []

    def my_cache_get(key: str, cache_name: Optional[str]=None) -> Optional[Dict[str, Any]]:
        cache_queries.append(('get', key, cache_name))
        return None

    def my_cache_get_many(keys: List[str], cache_name: Optional[str]=None) -> Dict[str, Any]:  # nocoverage -- simulated code doesn't use this
        cache_queries.append(('getmany', keys, cache_name))
        return {}

    old_get = cache.cache_get
    old_get_many = cache.cache_get_many
    cache.cache_get = my_cache_get
    cache.cache_get_many = my_cache_get_many
    yield cache_queries
    cache.cache_get = old_get
    cache.cache_get_many = old_get_many

@contextmanager
def queries_captured(include_savepoints: Optional[bool]=False) -> Generator[
        List[Dict[str, Union[str, bytes]]], None, None]:
    '''
    Allow a user to capture just the queries executed during
    the with statement.
    '''

    queries: List[Dict[str, Union[str, bytes]]] = []

    def wrapper_execute(self: TimeTrackingCursor,
                        action: Callable[[str, ParamsT], None],
                        sql: Query,
                        params: ParamsT) -> None:
        cache = get_cache_backend(None)
        cache.clear()
        start = time.time()
        try:
            return action(sql, params)
        finally:
            stop = time.time()
            duration = stop - start
            if include_savepoints or not isinstance(sql, str) or 'SAVEPOINT' not in sql:
                queries.append({
                    'sql': self.mogrify(sql, params).decode('utf-8'),
                    'time': "%.3f" % (duration,),
                })

    old_execute = TimeTrackingCursor.execute
    old_executemany = TimeTrackingCursor.executemany

    def cursor_execute(self: TimeTrackingCursor, sql: Query,
                       params: Optional[Params]=None) -> None:
        return wrapper_execute(self, super(TimeTrackingCursor, self).execute, sql, params)
    TimeTrackingCursor.execute = cursor_execute  # type: ignore[assignment] # https://github.com/JukkaL/mypy/issues/1167

    def cursor_executemany(self: TimeTrackingCursor, sql: Query,
                           params: Iterable[Params]) -> None:
        return wrapper_execute(self, super(TimeTrackingCursor, self).executemany, sql, params)  # nocoverage -- doesn't actually get used in tests
    TimeTrackingCursor.executemany = cursor_executemany  # type: ignore[assignment] # https://github.com/JukkaL/mypy/issues/1167

    yield queries

    TimeTrackingCursor.execute = old_execute  # type: ignore[assignment] # https://github.com/JukkaL/mypy/issues/1167
    TimeTrackingCursor.executemany = old_executemany  # type: ignore[assignment] # https://github.com/JukkaL/mypy/issues/1167

@contextmanager
def stdout_suppressed() -> Iterator[IO[str]]:
    """Redirect stdout to /dev/null."""

    with open(os.devnull, 'a') as devnull:
        stdout, sys.stdout = sys.stdout, devnull
        yield stdout
        sys.stdout = stdout

def reset_emails_in_zulip_realm() -> None:
    realm = get_realm('zulip')
    do_set_realm_property(realm, 'email_address_visibility',
                          Realm.EMAIL_ADDRESS_VISIBILITY_EVERYONE)

def get_test_image_file(filename: str) -> IO[Any]:
    test_avatar_dir = os.path.abspath(os.path.join(os.path.dirname(__file__), '../tests/images'))
    return open(os.path.join(test_avatar_dir, filename), 'rb')

def avatar_disk_path(user_profile: UserProfile, medium: bool=False, original: bool=False) -> str:
    avatar_url_path = avatar_url(user_profile, medium)
    avatar_disk_path = os.path.join(settings.LOCAL_UPLOADS_DIR, "avatars",
                                    avatar_url_path.split("/")[-2],
                                    avatar_url_path.split("/")[-1].split("?")[0])
    if original:
        return avatar_disk_path.replace(".png", ".original")
    return avatar_disk_path

def make_client(name: str) -> Client:
    client, _ = Client.objects.get_or_create(name=name)
    return client

def find_key_by_email(address: str) -> Optional[str]:
    from django.core.mail import outbox
    key_regex = re.compile("accounts/do_confirm/([a-z0-9]{24})>")
    for message in reversed(outbox):
        if address in message.to:
            return key_regex.search(message.body).groups()[0]
    return None  # nocoverage -- in theory a test might want this case, but none do

def message_stream_count(user_profile: UserProfile) -> int:
    return UserMessage.objects. \
        select_related("message"). \
        filter(user_profile=user_profile). \
        count()

def most_recent_usermessage(user_profile: UserProfile) -> UserMessage:
    query = UserMessage.objects. \
        select_related("message"). \
        filter(user_profile=user_profile). \
        order_by('-message')
    return query[0]  # Django does LIMIT here

def most_recent_message(user_profile: UserProfile) -> Message:
    usermessage = most_recent_usermessage(user_profile)
    return usermessage.message

def get_subscription(stream_name: str, user_profile: UserProfile) -> Subscription:
    stream = get_stream(stream_name, user_profile.realm)
    recipient_id = stream.recipient_id
    return Subscription.objects.get(user_profile=user_profile,
                                    recipient_id=recipient_id, active=True)

def get_user_messages(user_profile: UserProfile) -> List[Message]:
    query = UserMessage.objects. \
        select_related("message"). \
        filter(user_profile=user_profile). \
        order_by('message')
    return [um.message for um in query]

class DummyHandler:
    def __init__(self) -> None:
        allocate_handler_id(self)  # type: ignore[arg-type] # this is a testing mock

class POSTRequestMock:
    method = "POST"

    def __init__(self, post_data: Dict[str, Any], user_profile: Optional[UserProfile]) -> None:
        self.GET: Dict[str, Any] = {}

        # Convert any integer parameters passed into strings, even
        # though of course the HTTP API would do so.  Ideally, we'd
        # get rid of this abstraction entirely and just use the HTTP
        # API directly, but while it exists, we need this code.
        self.POST: Dict[str, str] = {}
        for key in post_data:
            self.POST[key] = str(post_data[key])

        self.user = user_profile
        self._tornado_handler = DummyHandler()
        self._log_data: Dict[str, Any] = {}
        self.META = {'PATH_INFO': 'test'}
        self.path = ''

class HostRequestMock:
    """A mock request object where get_host() works.  Useful for testing
    routes that use Zulip's subdomains feature"""

    def __init__(self, user_profile: UserProfile=None, host: str=settings.EXTERNAL_HOST) -> None:
        self.host = host
        self.GET: Dict[str, Any] = {}
        self.POST: Dict[str, Any] = {}
        self.META = {'PATH_INFO': 'test'}
        self.path = ''
        self.user = user_profile
        self.method = ''
        self.body = ''
        self.content_type = ''

    def get_host(self) -> str:
        return self.host

class MockPythonResponse:
    def __init__(self, text: str, status_code: int, headers: Optional[Dict[str, str]]=None) -> None:
        self.text = text
        self.status_code = status_code
        if headers is None:
            headers = {'content-type': 'text/html'}
        self.headers = headers

    @property
    def ok(self) -> bool:
        return self.status_code == 200

    def iter_content(self, n: int) -> Generator[str, Any, None]:
        yield self.text[:n]


INSTRUMENTING = os.environ.get('TEST_INSTRUMENT_URL_COVERAGE', '') == 'TRUE'
INSTRUMENTED_CALLS: List[Dict[str, Any]] = []

UrlFuncT = Callable[..., HttpResponse]  # TODO: make more specific

def append_instrumentation_data(data: Dict[str, Any]) -> None:
    INSTRUMENTED_CALLS.append(data)

def instrument_url(f: UrlFuncT) -> UrlFuncT:
    if not INSTRUMENTING:  # nocoverage -- option is always enabled; should we remove?
        return f
    else:
        def wrapper(self: 'ZulipTestCase', url: str, info: Dict[str, Any]={},
                    **kwargs: Any) -> HttpResponse:
            start = time.time()
            result = f(self, url, info, **kwargs)
            delay = time.time() - start
            test_name = self.id()
            if '?' in url:
                url, extra_info = url.split('?', 1)
            else:
                extra_info = ''

            append_instrumentation_data(dict(
                url=url,
                status_code=result.status_code,
                method=f.__name__,
                delay=delay,
                extra_info=extra_info,
                info=info,
                test_name=test_name,
                kwargs=kwargs))
            return result
        return wrapper

def write_instrumentation_reports(full_suite: bool, include_webhooks: bool) -> None:
    if INSTRUMENTING:
        calls = INSTRUMENTED_CALLS

        from zproject.urls import urlpatterns, v1_api_and_json_patterns

        # Find our untested urls.
        pattern_cnt: Dict[str, int] = collections.defaultdict(int)

        def re_strip(r: Any) -> str:
            return str(r).lstrip('^').rstrip('$')

        def find_patterns(patterns: List[Any], prefixes: List[str]) -> None:
            for pattern in patterns:
                find_pattern(pattern, prefixes)

        def cleanup_url(url: str) -> str:
            if url.startswith('/'):
                url = url[1:]
            if url.startswith('http://testserver/'):
                url = url[len('http://testserver/'):]
            if url.startswith('http://zulip.testserver/'):
                url = url[len('http://zulip.testserver/'):]
            if url.startswith('http://testserver:9080/'):
                url = url[len('http://testserver:9080/'):]
            return url

        def find_pattern(pattern: Any, prefixes: List[str]) -> None:

            if isinstance(pattern, type(URLResolver)):
                return  # nocoverage -- shouldn't actually happen

            if hasattr(pattern, 'url_patterns'):
                return

            canon_pattern = prefixes[0] + re_strip(pattern.pattern.regex.pattern)
            cnt = 0
            for call in calls:
                if 'pattern' in call:
                    continue

                url = cleanup_url(call['url'])

                for prefix in prefixes:
                    if url.startswith(prefix):
                        match_url = url[len(prefix):]
                        if pattern.resolve(match_url):
                            if call['status_code'] in [200, 204, 301, 302]:
                                cnt += 1
                            call['pattern'] = canon_pattern
            pattern_cnt[canon_pattern] += cnt

        find_patterns(urlpatterns, ['', 'en/', 'de/'])
        find_patterns(v1_api_and_json_patterns, ['api/v1/', 'json/'])

        assert len(pattern_cnt) > 100
        untested_patterns = {p.replace("\\", "") for p in pattern_cnt if pattern_cnt[p] == 0}

        exempt_patterns = set([
            # We exempt some patterns that are called via Tornado.
            'api/v1/events',
            'api/v1/events/internal',
            'api/v1/register',
            # We also exempt some development environment debugging
            # static content URLs, since the content they point to may
            # or may not exist.
            'coverage/(?P<path>.*)',
            'node-coverage/(?P<path>.*)',
            'docs/(?P<path>.*)',
            'casper/(?P<path>.*)',
            'static/(?P<path>.*)',
        ] + [webhook.url for webhook in WEBHOOK_INTEGRATIONS if not include_webhooks])

        untested_patterns -= exempt_patterns

        var_dir = 'var'  # TODO make sure path is robust here
        fn = os.path.join(var_dir, 'url_coverage.txt')
        with open(fn, 'w') as f:
            for call in calls:
                try:
                    line = ujson.dumps(call)
                    f.write(line + '\n')
                except OverflowError:  # nocoverage -- test suite error handling
                    print('''
                        A JSON overflow error was encountered while
                        producing the URL coverage report.  Sometimes
                        this indicates that a test is passing objects
                        into methods like client_post(), which is
                        unnecessary and leads to false positives.
                        ''')
                    print(call)

        if full_suite:
            print('INFO: URL coverage report is in %s' % (fn,))
            print('INFO: Try running: ./tools/create-test-api-docs')

        if full_suite and len(untested_patterns):  # nocoverage -- test suite error handling
            print("\nERROR: Some URLs are untested!  Here's the list of untested URLs:")
            for untested_pattern in sorted(untested_patterns):
                print("   %s" % (untested_pattern,))
            sys.exit(1)

def load_subdomain_token(response: HttpResponse) -> ExternalAuthDataDict:
    assert isinstance(response, HttpResponseRedirect)
    token = response.url.rsplit('/', 1)[1]
    data = ExternalAuthResult(login_token=token, delete_stored_data=False).data_dict
    assert data is not None
    return data

FuncT = TypeVar('FuncT', bound=Callable[..., None])

def use_s3_backend(method: FuncT) -> FuncT:
    @mock_s3
    @override_settings(LOCAL_UPLOADS_DIR=None)
    def new_method(*args: Any, **kwargs: Any) -> Any:
        zerver.lib.upload.upload_backend = S3UploadBackend()
        try:
            return method(*args, **kwargs)
        finally:
            zerver.lib.upload.upload_backend = LocalUploadBackend()
    return new_method

def create_s3_buckets(*bucket_names: Tuple[str]) -> List[ServiceResource]:
    session = boto3.Session(settings.S3_KEY, settings.S3_SECRET_KEY)
    s3 = session.resource('s3')
    buckets = [s3.create_bucket(Bucket=name) for name in bucket_names]
    return buckets

def use_db_models(method: Callable[..., None]) -> Callable[..., None]:  # nocoverage
    def method_patched_with_mock(self: 'MigrationsTestCase', apps: StateApps) -> None:
        ArchivedAttachment = apps.get_model('zerver', 'ArchivedAttachment')
        ArchivedMessage = apps.get_model('zerver', 'ArchivedMessage')
        ArchivedUserMessage = apps.get_model('zerver', 'ArchivedUserMessage')
        Attachment = apps.get_model('zerver', 'Attachment')
        BotConfigData = apps.get_model('zerver', 'BotConfigData')
        BotStorageData = apps.get_model('zerver', 'BotStorageData')
        Client = apps.get_model('zerver', 'Client')
        CustomProfileField = apps.get_model('zerver', 'CustomProfileField')
        CustomProfileFieldValue = apps.get_model('zerver', 'CustomProfileFieldValue')
        DefaultStream = apps.get_model('zerver', 'DefaultStream')
        DefaultStreamGroup = apps.get_model('zerver', 'DefaultStreamGroup')
        EmailChangeStatus = apps.get_model('zerver', 'EmailChangeStatus')
        Huddle = apps.get_model('zerver', 'Huddle')
        Message = apps.get_model('zerver', 'Message')
        MultiuseInvite = apps.get_model('zerver', 'MultiuseInvite')
        MutedTopic = apps.get_model('zerver', 'MutedTopic')
        PreregistrationUser = apps.get_model('zerver', 'PreregistrationUser')
        PushDeviceToken = apps.get_model('zerver', 'PushDeviceToken')
        Reaction = apps.get_model('zerver', 'Reaction')
        Realm = apps.get_model('zerver', 'Realm')
        RealmAuditLog = apps.get_model('zerver', 'RealmAuditLog')
        RealmDomain = apps.get_model('zerver', 'RealmDomain')
        RealmEmoji = apps.get_model('zerver', 'RealmEmoji')
        RealmFilter = apps.get_model('zerver', 'RealmFilter')
        Recipient = apps.get_model('zerver', 'Recipient')
        Recipient.PERSONAL = 1
        Recipient.STREAM = 2
        Recipient.HUDDLE = 3
        ScheduledEmail = apps.get_model('zerver', 'ScheduledEmail')
        ScheduledMessage = apps.get_model('zerver', 'ScheduledMessage')
        Service = apps.get_model('zerver', 'Service')
        Stream = apps.get_model('zerver', 'Stream')
        Subscription = apps.get_model('zerver', 'Subscription')
        UserActivity = apps.get_model('zerver', 'UserActivity')
        UserActivityInterval = apps.get_model('zerver', 'UserActivityInterval')
        UserGroup = apps.get_model('zerver', 'UserGroup')
        UserGroupMembership = apps.get_model('zerver', 'UserGroupMembership')
        UserHotspot = apps.get_model('zerver', 'UserHotspot')
        UserMessage = apps.get_model('zerver', 'UserMessage')
        UserPresence = apps.get_model('zerver', 'UserPresence')
        UserProfile = apps.get_model('zerver', 'UserProfile')

        zerver_models_patch = mock.patch.multiple(
            'zerver.models',
            ArchivedAttachment=ArchivedAttachment,
            ArchivedMessage=ArchivedMessage,
            ArchivedUserMessage=ArchivedUserMessage,
            Attachment=Attachment,
            BotConfigData=BotConfigData,
            BotStorageData=BotStorageData,
            Client=Client,
            CustomProfileField=CustomProfileField,
            CustomProfileFieldValue=CustomProfileFieldValue,
            DefaultStream=DefaultStream,
            DefaultStreamGroup=DefaultStreamGroup,
            EmailChangeStatus=EmailChangeStatus,
            Huddle=Huddle,
            Message=Message,
            MultiuseInvite=MultiuseInvite,
            MutedTopic=MutedTopic,
            PreregistrationUser=PreregistrationUser,
            PushDeviceToken=PushDeviceToken,
            Reaction=Reaction,
            Realm=Realm,
            RealmAuditLog=RealmAuditLog,
            RealmDomain=RealmDomain,
            RealmEmoji=RealmEmoji,
            RealmFilter=RealmFilter,
            Recipient=Recipient,
            ScheduledEmail=ScheduledEmail,
            ScheduledMessage=ScheduledMessage,
            Service=Service,
            Stream=Stream,
            Subscription=Subscription,
            UserActivity=UserActivity,
            UserActivityInterval=UserActivityInterval,
            UserGroup=UserGroup,
            UserGroupMembership=UserGroupMembership,
            UserHotspot=UserHotspot,
            UserMessage=UserMessage,
            UserPresence=UserPresence,
            UserProfile=UserProfile
        )
        zerver_test_helpers_patch = mock.patch.multiple(
            'zerver.lib.test_helpers',
            Client=Client,
            Message=Message,
            Subscription=Subscription,
            UserMessage=UserMessage,
            UserProfile=UserProfile,
        )

        zerver_test_classes_patch = mock.patch.multiple(
            'zerver.lib.test_classes',
            Client=Client,
            Message=Message,
            Realm=Realm,
            Recipient=Recipient,
            Stream=Stream,
            Subscription=Subscription,
            UserProfile=UserProfile,
        )

        with zerver_models_patch,\
                zerver_test_helpers_patch,\
                zerver_test_classes_patch:
            method(self, apps)
    return method_patched_with_mock

def create_dummy_file(filename: str) -> str:
    filepath = os.path.join(settings.TEST_WORKER_DIR, filename)
    with open(filepath, 'w') as f:
        f.write('zulip!')
    return filepath