# Copyright 2014 Amazon.com, Inc. or its affiliates. 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. A copy of
# the License is located at
#
# http://aws.amazon.com/apache2.0/
#
# or in the "license" file accompanying this file. This file 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 logging
import functools

from botocore import waiter, xform_name
from botocore.auth import AUTH_TYPE_MAPS
from botocore.awsrequest import prepare_request_dict
from botocore.docs.docstring import ClientMethodDocstring
from botocore.docs.docstring import PaginatorDocstring
from botocore.exceptions import ClientError, DataNotFoundError
from botocore.exceptions import OperationNotPageableError
from botocore.exceptions import UnknownSignatureVersionError
from botocore.hooks import first_non_none_response
from botocore.model import ServiceModel
from botocore.paginate import Paginator
from botocore.utils import CachedProperty
from botocore.utils import get_service_module_name
from botocore.utils import switch_host_s3_accelerate
from botocore.utils import S3RegionRedirector
from botocore.utils import fix_s3_host
from botocore.utils import switch_to_virtual_host_style
from botocore.utils import S3_ACCELERATE_WHITELIST
from botocore.args import ClientArgsCreator
from botocore.compat import urlsplit
# Keep this imported.  There's pre-existing code that uses
# "from botocore.client import Config".
from botocore.config import Config


logger = logging.getLogger(__name__)


class ClientCreator(object):
    """Creates client objects for a service."""
    def __init__(self, loader, endpoint_resolver, user_agent, event_emitter,
                 retry_handler_factory, retry_config_translator,
                 response_parser_factory=None):
        self._loader = loader
        self._endpoint_resolver = endpoint_resolver
        self._user_agent = user_agent
        self._event_emitter = event_emitter
        self._retry_handler_factory = retry_handler_factory
        self._retry_config_translator = retry_config_translator
        self._response_parser_factory = response_parser_factory

    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):
        service_model = self._load_service_model(service_name, api_version)
        cls = self._create_client_class(service_name, service_model)
        endpoint_bridge = ClientEndpointBridge(
            self._endpoint_resolver, scoped_config, client_config,
            service_signing_name=service_model.metadata.get('signingName'))
        client_args = self._get_client_args(
            service_model, region_name, is_secure, endpoint_url,
            verify, credentials, scoped_config, client_config, endpoint_bridge)
        service_client = cls(**client_args)
        self._register_s3_events(service_client, endpoint_bridge, endpoint_url)
        return service_client

    def create_client_class(self, service_name, api_version=None):
        service_model = self._load_service_model(service_name, api_version)
        return self._create_client_class(service_name, service_model)

    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 = [BaseClient]
        self._event_emitter.emit('creating-client-class.%s' % service_name,
                                 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 _load_service_model(self, service_name, api_version=None):
        json_model = self._loader.load_service_model(service_name, 'service-2',
                                                     api_version=api_version)
        service_model = ServiceModel(json_model, service_name=service_name)
        self._register_retries(service_model)
        return service_model

    def _register_retries(self, service_model):
        endpoint_prefix = service_model.endpoint_prefix

        # 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

        retry_config = self._retry_config_translator.build_retry_config(
            endpoint_prefix, original_config.get('retry', {}),
            original_config.get('definitions', {}))

        logger.debug("Registering retry handlers for service: %s",
                     service_model.service_name)
        handler = self._retry_handler_factory.create_retry_handler(
            retry_config, endpoint_prefix)
        unique_id = 'retry-config-%s' % endpoint_prefix
        self._event_emitter.register('needs-retry.%s' % endpoint_prefix,
                                     handler, unique_id=unique_id)

    def _register_s3_events(self, client, endpoint_bridge, endpoint_url):
        if client.meta.service_model.service_name != 's3':
            return
        S3RegionRedirector(endpoint_bridge, client).register()
        self._set_s3_addressing_style(
            endpoint_url, client.meta.config.s3, client.meta.events)
        # Enable accelerate if the configuration is set to to true or the
        # endpoint being used matches one of the accelerate endpoints.
        if self._is_s3_accelerate(endpoint_url, client.meta.config.s3):
            # Also make sure that the hostname gets switched to
            # s3-accelerate.amazonaws.com
            client.meta.events.register_first(
                'request-created.s3', switch_host_s3_accelerate)

    def _set_s3_addressing_style(self, endpoint_url, s3_config, event_emitter):
        if s3_config is None:
            s3_config = {}

        addressing_style = self._get_s3_addressing_style(
            endpoint_url, s3_config)
        handler = self._get_s3_addressing_handler(
            endpoint_url, s3_config, addressing_style)
        if handler is not None:
            event_emitter.register('before-sign.s3', handler)

    def _get_s3_addressing_style(self, endpoint_url, s3_config):
        # Use virtual host style addressing if accelerate is enabled or if
        # the given endpoint url is an accelerate endpoint.
        accelerate = s3_config.get('use_accelerate_endpoint', False)
        if accelerate or self._is_s3_accelerate(endpoint_url, s3_config):
            return 'virtual'

        # If a particular addressing style is configured, use it.
        configured_addressing_style = s3_config.get('addressing_style')
        if configured_addressing_style:
            return configured_addressing_style

    def _get_s3_addressing_handler(self, endpoint_url, s3_config,
                                   addressing_style):
        # If virtual host style was configured, use it regardless of whether
        # or not the bucket looks dns compatible.
        if addressing_style == 'virtual':
            logger.debug("Using S3 virtual host style addressing.")
            return switch_to_virtual_host_style

        # If path style is configured, no additional steps are needed. If
        # endpoint_url was specified, don't default to virtual. We could
        # potentially default provided endpoint urls to virtual hosted
        # style, but for now it is avoided.
        if addressing_style == 'path' or endpoint_url is not None:
            logger.debug("Using S3 path style addressing.")
            return None

        logger.debug("Defaulting to S3 virtual host style addressing with "
                     "path style addressing fallback.")

        # For dual stack mode, we need to clear the default endpoint url in
        # order to use the existing netloc if the bucket is dns compatible.
        if s3_config.get('use_dualstack_endpoint', False):
            return functools.partial(
                fix_s3_host, default_endpoint_url=None)

        # By default, try to use virtual style with path fallback.
        return fix_s3_host

    def _is_s3_accelerate(self, endpoint_url, s3_config):
        # Accelerate has been explicitly configured.
        if s3_config is not None and s3_config.get('use_accelerate_endpoint'):
            return True

        # Accelerate mode is turned on automatically if an endpoint url is
        # provided that matches the accelerate scheme.
        if endpoint_url is None:
            return False

        # Accelerate is only valid for Amazon endpoints.
        netloc = urlsplit(endpoint_url).netloc
        if not netloc.endswith('amazonaws.com'):
            return False

        # The first part of the url should always be s3-accelerate.
        parts = netloc.split('.')
        if parts[0] != 's3-accelerate':
            return False

        # Url parts between 's3-accelerate' and 'amazonaws.com' which
        # represent different url features.
        feature_parts = parts[1:-2]

        # There should be no duplicate url parts.
        if len(feature_parts) != len(set(feature_parts)):
            return False

        # Remaining parts must all be in the whitelist.
        return all(p in S3_ACCELERATE_WHITELIST for p in feature_parts)

    def _get_client_args(self, service_model, region_name, is_secure,
                         endpoint_url, verify, credentials,
                         scoped_config, client_config, endpoint_bridge):
        args_creator = ClientArgsCreator(
            self._event_emitter, self._user_agent,
            self._response_parser_factory, self._loader)
        return args_creator.get_client_args(
            service_model, region_name, is_secure, endpoint_url,
            verify, credentials, scoped_config, client_config, endpoint_bridge)

    def _create_methods(self, service_model):
        op_dict = {}
        for operation_name in service_model.operation_names:
            py_operation_name = xform_name(operation_name)
            op_dict[py_operation_name] = self._create_api_method(
                py_operation_name, operation_name, service_model)
        return op_dict

    def _create_name_mapping(self, service_model):
        # py_name -> OperationName, for every operation available
        # for a service.
        mapping = {}
        for operation_name in service_model.operation_names:
            py_operation_name = xform_name(operation_name)
            mapping[py_operation_name] = operation_name
        return mapping

    def _create_api_method(self, py_operation_name, operation_name,
                           service_model):
        def _api_call(self, *args, **kwargs):
            # We're accepting *args so that we can give a more helpful
            # error message than TypeError: _api_call takes exactly
            # 1 argument.
            if args:
                raise TypeError(
                    "%s() only accepts keyword arguments." % py_operation_name)
            # The "self" in this scope is referring to the BaseClient.
            return self._make_api_call(operation_name, kwargs)

        _api_call.__name__ = str(py_operation_name)

        # Add the docstring to the client method
        operation_model = service_model.operation_model(operation_name)
        docstring = ClientMethodDocstring(
            operation_model=operation_model,
            method_name=operation_name,
            event_emitter=self._event_emitter,
            method_description=operation_model.documentation,
            example_prefix='response = client.%s' % py_operation_name,
            include_signature=False
        )
        _api_call.__doc__ = docstring
        return _api_call


class ClientEndpointBridge(object):
    """Bridges endpoint data and client creation

    This class handles taking out the relevant arguments from the endpoint
    resolver and determining which values to use, taking into account any
    client configuration options and scope configuration options.

    This class also handles determining what, if any, region to use if no
    explicit region setting is provided. For example, Amazon S3 client will
    utilize "us-east-1" by default if no region can be resolved."""

    DEFAULT_ENDPOINT = '{service}.{region}.amazonaws.com'

    def __init__(self, endpoint_resolver, scoped_config=None,
                 client_config=None, default_endpoint=None,
                 service_signing_name=None):
        self.service_signing_name = service_signing_name
        self.endpoint_resolver = endpoint_resolver
        self.scoped_config = scoped_config
        self.client_config = client_config
        self.default_endpoint = default_endpoint or self.DEFAULT_ENDPOINT

    def resolve(self, service_name, region_name=None, endpoint_url=None,
                is_secure=True):
        region_name = self._check_default_region(service_name, region_name)
        resolved = self.endpoint_resolver.construct_endpoint(
            service_name, region_name)
        if resolved:
            return self._create_endpoint(
                resolved, service_name, region_name, endpoint_url, is_secure)
        else:
            return self._assume_endpoint(service_name, region_name,
                                         endpoint_url, is_secure)

    def _check_default_region(self, service_name, region_name):
        if region_name is not None:
            return region_name
        # Use the client_config region if no explicit region was provided.
        if self.client_config and self.client_config.region_name is not None:
            return self.client_config.region_name

    def _create_endpoint(self, resolved, service_name, region_name,
                         endpoint_url, is_secure):
        region_name, signing_region = self._pick_region_values(
            resolved, region_name, endpoint_url)
        if endpoint_url is None:
            if self._is_s3_dualstack_mode(service_name):
                endpoint_url = self._create_dualstack_endpoint(
                    service_name, region_name,
                    resolved['dnsSuffix'], is_secure)
            else:
                # Use the sslCommonName over the hostname for Python 2.6 compat.
                hostname = resolved.get('sslCommonName', resolved.get('hostname'))
                endpoint_url = self._make_url(hostname, is_secure,
                                            resolved.get('protocols', []))
        signature_version = self._resolve_signature_version(
            service_name, resolved)
        signing_name = self._resolve_signing_name(service_name, resolved)
        return self._create_result(
            service_name=service_name, region_name=region_name,
            signing_region=signing_region, signing_name=signing_name,
            endpoint_url=endpoint_url, metadata=resolved,
            signature_version=signature_version)

    def _is_s3_dualstack_mode(self, service_name):
        if service_name != 's3':
            return False
        # TODO: This normalization logic is duplicated from the
        # ClientArgsCreator class.  Consolidate everything to
        # ClientArgsCreator.  _resolve_signature_version also has similarly
        # duplicated logic.
        client_config = self.client_config
        if client_config is not None and client_config.s3 is not None and \
                'use_dualstack_endpoint' in client_config.s3:
            # Client config trumps scoped config.
            return client_config.s3['use_dualstack_endpoint']
        if self.scoped_config is None: