from botocore.awsrequest import prepare_request_dict
from botocore.client import (
    BaseClient,
    ClientCreator,
    ClientEndpointBridge,
    PaginatorDocstring,
    logger,
    resolve_checksum_context,
)
from botocore.compress import maybe_compress_request
from botocore.discovery import block_endpoint_discovery_required_operations
from botocore.exceptions import OperationNotPageableError, UnknownServiceError
from botocore.history import get_global_history_recorder
from botocore.hooks import first_non_none_response
from botocore.utils import get_service_module_name
from botocore.waiter import xform_name

from . import waiter
from .args import AioClientArgsCreator
from .discovery import AioEndpointDiscoveryHandler, AioEndpointDiscoveryManager
from .httpchecksum import apply_request_checksum
from .paginate import AioPaginator
from .retries import adaptive, standard
from .utils import AioS3RegionRedirectorv2

history_recorder = get_global_history_recorder()


class AioClientCreator(ClientCreator):
    async def create_client(
        self,
        service_name,
        region_name,
        is_secure=True,
        endpoint_url=None,
        verify=None,
        credentials=None,
        scoped_config=None,
        api_version=None,
        client_config=None,
        auth_token=None,
    ):
        responses = await self._event_emitter.emit(
            'choose-service-name', service_name=service_name
        )
        service_name = first_non_none_response(responses, default=service_name)
        service_model = self._load_service_model(service_name, api_version)
        try:
            endpoints_ruleset_data = self._load_service_endpoints_ruleset(
                service_name, api_version
            )
            partition_data = self._loader.load_data('partitions')
        except UnknownServiceError:
            endpoints_ruleset_data = None
            partition_data = None
            logger.info(
                'No endpoints ruleset found for service %s, falling back to '
                'legacy endpoint routing.',
                service_name,
            )

        cls = await self._create_client_class(service_name, service_model)
        region_name, client_config = self._normalize_fips_region(
            region_name, client_config
        )
        endpoint_bridge = ClientEndpointBridge(
            self._endpoint_resolver,
            scoped_config,
            client_config,
            service_signing_name=service_model.metadata.get('signingName'),
            config_store=self._config_store,
            service_signature_version=service_model.metadata.get(
                'signatureVersion'
            ),
        )
        client_args = self._get_client_args(
            service_model,
            region_name,
            is_secure,
            endpoint_url,
            verify,
            credentials,
            scoped_config,
            client_config,
            endpoint_bridge,
            auth_token,
            endpoints_ruleset_data,
            partition_data,
        )
        service_client = cls(**client_args)
        self._register_retries(service_client)
        self._register_s3_events(
            client=service_client,
            endpoint_bridge=None,
            endpoint_url=None,
            client_config=client_config,
            scoped_config=scoped_config,
        )
        self._register_s3_control_events(client=service_client)
        self._register_endpoint_discovery(
            service_client, endpoint_url, client_config
        )
        return service_client

    async def _create_client_class(self, service_name, service_model):
        class_attributes = self._create_methods(service_model)
        py_name_to_operation_name = self._create_name_mapping(service_model)
        class_attributes['_PY_TO_OP_NAME'] = py_name_to_operation_name
        bases = [AioBaseClient]
        service_id = service_model.service_id.hyphenize()
        await self._event_emitter.emit(
            'creating-client-class.%s' % service_id,
            class_attributes=class_attributes,
            base_classes=bases,
        )
        class_name = get_service_module_name(service_model)
        cls = type(str(class_name), tuple(bases), class_attributes)
        return cls

    def _register_retries(self, client):
        # botocore retry handlers may block. We add our own implementation here.
        # botocore provides three implementations:
        #
        # 1) standard
        # This one doesn't block. A threading.Lock is used in quota.RetryQuota,
        # but it's only used to protect concurrent modifications of internal
        # state inside multithreaded programs. When running under a single
        # asyncio thread, this lock will be acquired and released in the same
        # coroutine, and the coroutine will never block waiting for the lock.
        # Thus, we don't need to redefine this strategy.
        #
        # 2) adaptive
        # This one blocks when the client is applying self rate limiting.
        # We override the corresponding definition to replace it with async
        # objects.
        #
        # 3) legacy
        # This one probably doesn't block.
        #
        # The code for this method comes directly from botocore. We could
        # override `_register_v2_adaptive_retries` only. The override for
        # `_register_retries` is only included for clarity.
        retry_mode = client.meta.config.retries['mode']
        if retry_mode == 'standard':
            self._register_v2_standard_retries(client)
        elif retry_mode == 'adaptive':
            self._register_v2_standard_retries(client)
            self._register_v2_adaptive_retries(client)
        elif retry_mode == 'legacy':
            self._register_legacy_retries(client)

    def _register_v2_standard_retries(self, client):
        max_attempts = client.meta.config.retries.get('total_max_attempts')
        kwargs = {'client': client}
        if max_attempts is not None:
            kwargs['max_attempts'] = max_attempts
        standard.register_retry_handler(**kwargs)

    def _register_v2_adaptive_retries(self, client):
        # See comment in `_register_retries`.
        # Note that this `adaptive` module is an aiobotocore reimplementation.
        adaptive.register_retry_handler(client)

    def _register_legacy_retries(self, client):
        endpoint_prefix = client.meta.service_model.endpoint_prefix
        service_id = client.meta.service_model.service_id
        service_event_name = service_id.hyphenize()

        # First, we load the entire retry config for all services,
        # then pull out just the information we need.
        original_config = self._loader.load_data('_retry')
        if not original_config:
            return

        retries = self._transform_legacy_retries(client.meta.config.retries)
        retry_config = self._retry_config_translator.build_retry_config(
            endpoint_prefix,
            original_config.get('retry', {}),
            original_config.get('definitions', {}),
            retries,
        )

        logger.debug(
            "Registering retry handlers for service: %s",
            client.meta.service_model.service_name,
        )
        handler = self._retry_handler_factory.create_retry_handler(
            retry_config, endpoint_prefix
        )
        unique_id = 'retry-config-%s' % service_event_name
        client.meta.events.register(
            f"needs-retry.{service_event_name}", handler, unique_id=unique_id
        )

    def _register_endpoint_discovery(self, client, endpoint_url, config):
        if endpoint_url is not None:
            # Don't register any handlers in the case of a custom endpoint url
            return
        # Only attach handlers if the service supports discovery
        if client.meta.service_model.endpoint_discovery_operation is None:
            return
        events = client.meta.events
        service_id = client.meta.service_model.service_id.hyphenize()
        enabled = False
        if config and config.endpoint_discovery_enabled is not None:
            enabled = config.endpoint_discovery_enabled
        elif self._config_store:
            enabled = self._config_store.get_config_variable(
                'endpoint_discovery_enabled'
            )

        enabled = self._normalize_endpoint_discovery_config(enabled)
        if enabled and self._requires_endpoint_discovery(client, enabled):
            discover = enabled is True
            manager = AioEndpointDiscoveryManager(
                client, always_discover=discover
            )
            handler = AioEndpointDiscoveryHandler(manager)
            handler.register(events, service_id)
        else:
            events.register(
                'before-parameter-build',
                block_endpoint_discovery_required_operations,
            )

    def _register_s3_events(
        self,
        client,
        endpoint_bridge,
        endpoint_url,
        client_config,
        scoped_config,
    ):
        if client.meta.service_model.service_name != 's3':
            return
        AioS3RegionRedirectorv2(None, client).register()
        self._set_s3_presign_signature_version(
            client.meta, client_config, scoped_config
        )

    def _get_client_args(
        self,
        service_model,
        region_name,
        is_secure,
        endpoint_url,
        verify,
        credentials,
        scoped_config,
        client_config,
        endpoint_bridge,
        auth_token,
        endpoints_ruleset_data,
        partition_data,
    ):
        # This is a near copy of ClientCreator. What's replaced
        # is ClientArgsCreator->AioClientArgsCreator
        args_creator = AioClientArgsCreator(
            self._event_emitter,
            self._user_agent,
            self._response_parser_factory,
            self._loader,
            self._exceptions_factory,
            config_store=self._config_store,
            user_agent_creator=self._user_agent_creator,
        )
        return args_creator.get_client_args(
            service_model,
            region_name,
            is_secure,
            endpoint_url,
            verify,
            credentials,
            scoped_config,
            client_config,
            endpoint_bridge,
            auth_token,
            endpoints_ruleset_data,
            partition_data,
        )


class AioBaseClient(BaseClient):
    async def _async_getattr(self, item):
        event_name = 'getattr.{}.{}'.format(
            self._service_model.service_id.hyphenize(), item
        )
        handler, event_response = await self.meta.events.emit_until_response(
            event_name, client=self
        )

        return event_response

    def __getattr__(self, item):
        # NOTE: we can not reliably support this because if we were to make this a
        # deferred attrgetter (See #803), it would resolve in hasattr always returning
        # true.  This ends up breaking ddtrace for example when it tries to set a pin.
        raise AttributeError(
            "'{}' object has no attribute '{}'".format(
                self.__class__.__name__, item
            )
        )

    async def close(self):
        """Closes underlying endpoint connections."""
        await self._endpoint.close()

    async def _make_api_call(self, operation_name, api_params):
        operation_model = self._service_model.operation_model(operation_name)
        service_name = self._service_model.service_name
        history_recorder.record(
            'API_CALL',
            {
                'service': service_name,
                'operation': operation_name,
                'params': api_params,
            },
        )
        if operation_model.deprecated:
            logger.debug(
                'Warning: %s.%s() is deprecated', service_name, operation_name
            )
        request_context = {
            'client_region': self.meta.region_name,
            'client_config': self.meta.config,
            'has_streaming_input': operation_model.has_streaming_input,
            'auth_type': operation_model.auth_type,
        }
        api_params = await self._emit_api_params(
            api_params=api_params,
            operation_model=operation_model,
            context=request_context,
        )
        # fmt: off
        endpoint_url, additional_headers = await self._resolve_endpoint_ruleset(
            operation_model, api_params, request_context
        )
        # fmt: on
        request_dict = await self._convert_to_request_dict(
            api_params=api_params,
            operation_model=operation_model,
            endpoint_url=endpoint_url,
            context=request_context,
            headers=additional_headers,
        )
        resolve_checksum_context(request_dict, operation_model, api_params)

        service_id = self._service_model.service_id.hyphenize()
        handler, event_response = await self.meta.events.emit_until_response(
            'before-call.{service_id}.{operation_name}'.format(
                service_id=service_id, operation_name=operation_name
            ),
            model=operation_model,
            params=request_dict,
            request_signer=self._request_signer,
            context=request_context,
        )

        if event_response is not None:
            http, parsed_response = event_response
        else:
            maybe_compress_request(
                self.meta.config, request_dict, operation_model
            )
            apply_request_checksum(request_dict)
            http, parsed_response = await self._make_request(
                operation_model, request_dict, request_context
            )

        await self.meta.events.emit(
            'after-call.{service_id}.{operation_name}'.format(
                service_id=service_id, operation_name=operation_name
            ),
            http_response=http,
            parsed=parsed_response,
            model=operation_model,
            context=request_context,
        )

        if http.status_code >= 300:
            error_code = parsed_response.get("Error", {}).get("Code")
            error_class = self.exceptions.from_code(error_code)
            raise error_class(parsed_response, operation_name)
        else:
            return parsed_response

    async def _make_request(
        self, operation_model, request_dict, request_context
    ):
        try:
            return await self._endpoint.make_request(
                operation_model, request_dict
            )
        except Exception as e:
            await self.meta.events.emit(
                'after-call-error.{service_id}.{operation_name}'.format(
                    service_id=self._service_model.service_id.hyphenize(),
                    operation_name=operation_model.name,
                ),
                exception=e,
                context=request_context,
            )
            raise

    async def _convert_to_request_dict(
        self,
        api_params,
        operation_model,
        endpoint_url,
        context=None,
        headers=None,
        set_user_agent_header=True,
    ):
        request_dict = self._serializer.serialize_to_request(
            api_params, operation_model
        )
        if not self._client_config.inject_host_prefix:
            request_dict.pop('host_prefix', None)
        if headers is not None:
            request_dict['headers'].update(headers)
        if set_user_agent_header:
            user_agent = self._user_agent_creator.to_string()
        else:
            user_agent = None
        prepare_request_dict(
            request_dict,
            endpoint_url=endpoint_url,
            user_agent=user_agent,
            context=context,
        )
        return request_dict

    async def _emit_api_params(self, api_params, operation_model, context):
        # Given the API params provided by the user and the operation_model
        # we can serialize the request to a request_dict.
        operation_name = operation_model.name

        # Emit an event that allows users to modify the parameters at the
        # beginning of the method. It allows handlers to modify existing
        # parameters or return a new set of parameters to use.
        service_id = self._service_model.service_id.hyphenize()
        responses = await self.meta.events.emit(
            f'provide-client-params.{service_id}.{operation_name}',
            params=api_params,
            model=operation_model,
            context=context,
        )
        api_params = first_non_none_response(responses, default=api_params)

        await self.meta.events.emit(
            f'before-parameter-build.{service_id}.{operation_name}',
            params=api_params,
            model=operation_model,
            context=context,
        )
        return api_params

    async def _resolve_endpoint_ruleset(
        self,
        operation_model,
        params,
        request_context,
        ignore_signing_region=False,
    ):
        """Returns endpoint URL and list of additional headers returned from
        EndpointRulesetResolver for the given operation and params. If the
        ruleset resolver is not available, for example because the service has
        no endpoints ruleset file, the legacy endpoint resolver's value is
        returned.

        Use ignore_signing_region for generating presigned URLs or any other
        situtation where the signing region information from the ruleset
        resolver should be ignored.

        Returns tuple of URL and headers dictionary. Additionally, the
        request_context dict is modified in place with any signing information
        returned from the ruleset resolver.
        """
        if self._ruleset_resolver is None:
            endpoint_url = self.meta.endpoint_url
            additional_headers = {}
        else:
            endpoint_info = await self._ruleset_resolver.construct_endpoint(
                operation_model=operation_model,
                call_args=params,
                request_context=request_context,
            )
            endpoint_url = endpoint_info.url
            additional_headers = endpoint_info.headers
            # If authSchemes is present, overwrite default auth type and
            # signing context derived from service model.
            auth_schemes = endpoint_info.properties.get('authSchemes')
            if auth_schemes is not None:
                auth_info = self._ruleset_resolver.auth_schemes_to_signing_ctx(
                    auth_schemes
                )
                auth_type, signing_context = auth_info
                request_context['auth_type'] = auth_type
                if 'region' in signing_context and ignore_signing_region:
                    del signing_context['region']
                if 'signing' in request_context:
                    request_context['signing'].update(signing_context)
                else:
                    request_context['signing'] = signing_context

        return endpoint_url, additional_headers

    def get_paginator(self, operation_name):
        """Create a paginator for an operation.

        :type operation_name: string
        :param operation_name: The operation name.  This is the same name
            as the method name on the client.  For example, if the
            method name is ``create_foo``, and you'd normally invoke the
            operation as ``client.create_foo(**kwargs)``, if the
            ``create_foo`` operation can be paginated, you can use the
            call ``client.get_paginator("create_foo")``.

        :raise OperationNotPageableError: Raised if the operation is not
            pageable.  You can use the ``client.can_paginate`` method to
            check if an operation is pageable.

        :rtype: L{botocore.paginate.Paginator}
        :return: A paginator object.

        """
        if not self.can_paginate(operation_name):
            raise OperationNotPageableError(operation_name=operation_name)
        else:
            actual_operation_name = self._PY_TO_OP_NAME[operation_name]

            # Create a new paginate method that will serve as a proxy to
            # the underlying Paginator.paginate method. This is needed to
            # attach a docstring to the method.
            def paginate(self, **kwargs):
                return AioPaginator.paginate(self, **kwargs)

            paginator_config = self._cache['page_config'][
                actual_operation_name
            ]
            # Add the docstring for the paginate method.
            paginate.__doc__ = PaginatorDocstring(
                paginator_name=actual_operation_name,
                event_emitter=self.meta.events,
                service_model=self.meta.service_model,
                paginator_config=paginator_config,
                include_signature=False,
            )

            # Rename the paginator class based on the type of paginator.
            service_module_name = get_service_module_name(
                self.meta.service_model
            )
            paginator_class_name = (
                f"{service_module_name}.Paginator.{actual_operation_name}"
            )

            # Create the new paginator class
            documented_paginator_cls = type(
                paginator_class_name, (AioPaginator,), {'paginate': paginate}
            )

            operation_model = self._service_model.operation_model(
                actual_operation_name
            )
            paginator = documented_paginator_cls(
                getattr(self, operation_name),
                paginator_config,
                operation_model,
            )
            return paginator

    # NOTE: this method does not differ from botocore, however it's important to keep
    #   as the "waiter" value points to our own asyncio waiter module
    def get_waiter(self, waiter_name):
        """Returns an object that can wait for some condition.

        :type waiter_name: str
        :param waiter_name: The name of the waiter to get. See the waiters
            section of the service docs for a list of available waiters.

        :returns: The specified waiter object.
        :rtype: botocore.waiter.Waiter
        """
        config = self._get_waiter_config()
        if not config:
            raise ValueError("Waiter does not exist: %s" % waiter_name)
        model = waiter.WaiterModel(config)
        mapping = {}
        for name in model.waiter_names:
            mapping[xform_name(name)] = name
        if waiter_name not in mapping:
            raise ValueError("Waiter does not exist: %s" % waiter_name)

        return waiter.create_waiter_with_client(
            mapping[waiter_name], model, self
        )

    async def __aenter__(self):
        await self._endpoint.http_session.__aenter__()
        return self

    async def __aexit__(self, exc_type, exc_val, exc_tb):
        await self._endpoint.http_session.__aexit__(exc_type, exc_val, exc_tb)
