# Copyright 2016 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.
"""Internal module to help with normalizing botocore client args.

This module (and all function/classes within this module) should be
considered internal, and *not* a public API.

"""
import copy
import logging
import socket

import botocore.exceptions
import botocore.parsers
import botocore.serialize
import botocore.utils
from botocore.config import Config
from botocore.endpoint import EndpointCreator
from botocore.regions import EndpointResolverBuiltins as EPRBuiltins
from botocore.signers import RequestSigner

logger = logging.getLogger(__name__)


VALID_REGIONAL_ENDPOINTS_CONFIG = [
    'legacy',
    'regional',
]
LEGACY_GLOBAL_STS_REGIONS = [
    'ap-northeast-1',
    'ap-south-1',
    'ap-southeast-1',
    'ap-southeast-2',
    'aws-global',
    'ca-central-1',
    'eu-central-1',
    'eu-north-1',
    'eu-west-1',
    'eu-west-2',
    'eu-west-3',
    'sa-east-1',
    'us-east-1',
    'us-east-2',
    'us-west-1',
    'us-west-2',
]


class ClientArgsCreator:
    def __init__(
        self,
        event_emitter,
        user_agent,
        response_parser_factory,
        loader,
        exceptions_factory,
        config_store,
    ):
        self._event_emitter = event_emitter
        self._user_agent = user_agent
        self._response_parser_factory = response_parser_factory
        self._loader = loader
        self._exceptions_factory = exceptions_factory
        self._config_store = config_store

    def get_client_args(
        self,
        service_model,
        region_name,
        is_secure,
        endpoint_url,
        verify,
        credentials,
        scoped_config,
        client_config,
        endpoint_bridge,
        auth_token=None,
    ):
        final_args = self.compute_client_args(
            service_model,
            client_config,
            endpoint_bridge,
            region_name,
            endpoint_url,
            is_secure,
            scoped_config,
        )

        service_name = final_args['service_name']  # noqa
        parameter_validation = final_args['parameter_validation']
        endpoint_config = final_args['endpoint_config']
        protocol = final_args['protocol']
        config_kwargs = final_args['config_kwargs']
        s3_config = final_args['s3_config']
        partition = endpoint_config['metadata'].get('partition', None)
        socket_options = final_args['socket_options']

        signing_region = endpoint_config['signing_region']
        endpoint_region_name = endpoint_config['region_name']

        event_emitter = copy.copy(self._event_emitter)
        signer = RequestSigner(
            service_model.service_id,
            signing_region,
            endpoint_config['signing_name'],
            endpoint_config['signature_version'],
            credentials,
            event_emitter,
            auth_token,
        )

        config_kwargs['s3'] = s3_config
        new_config = Config(**config_kwargs)
        endpoint_creator = EndpointCreator(event_emitter)

        endpoint = endpoint_creator.create_endpoint(
            service_model,
            region_name=endpoint_region_name,
            endpoint_url=endpoint_config['endpoint_url'],
            verify=verify,
            response_parser_factory=self._response_parser_factory,
            max_pool_connections=new_config.max_pool_connections,
            proxies=new_config.proxies,
            timeout=(new_config.connect_timeout, new_config.read_timeout),
            socket_options=socket_options,
            client_cert=new_config.client_cert,
            proxies_config=new_config.proxies_config,
        )

        serializer = botocore.serialize.create_serializer(
            protocol, parameter_validation
        )
        response_parser = botocore.parsers.create_parser(protocol)
        return {
            'serializer': serializer,
            'endpoint': endpoint,
            'response_parser': response_parser,
            'event_emitter': event_emitter,
            'request_signer': signer,
            'service_model': service_model,
            'loader': self._loader,
            'client_config': new_config,
            'partition': partition,
            'exceptions_factory': self._exceptions_factory,
        }

    def compute_client_args(
        self,
        service_model,
        client_config,
        endpoint_bridge,
        region_name,
        endpoint_url,
        is_secure,
        scoped_config,
    ):
        service_name = service_model.endpoint_prefix
        protocol = service_model.metadata['protocol']
        parameter_validation = True
        if client_config and not client_config.parameter_validation:
            parameter_validation = False
        elif scoped_config:
            raw_value = scoped_config.get('parameter_validation')
            if raw_value is not None:
                parameter_validation = botocore.utils.ensure_boolean(raw_value)

        # Override the user agent if specified in the client config.
        user_agent = self._user_agent
        if client_config is not None:
            if client_config.user_agent is not None:
                user_agent = client_config.user_agent
            if client_config.user_agent_extra is not None:
                user_agent += ' %s' % client_config.user_agent_extra

        s3_config = self.compute_s3_config(client_config)
        endpoint_config = self._compute_endpoint_config(
            service_name=service_name,
            region_name=region_name,
            endpoint_url=endpoint_url,
            is_secure=is_secure,
            endpoint_bridge=endpoint_bridge,
            s3_config=s3_config,
        )
        endpoint_variant_tags = endpoint_config['metadata'].get('tags', [])
        # Create a new client config to be passed to the client based
        # on the final values. We do not want the user to be able
        # to try to modify an existing client with a client config.
        config_kwargs = dict(
            region_name=endpoint_config['region_name'],
            signature_version=endpoint_config['signature_version'],
            user_agent=user_agent,
        )
        if 'dualstack' in endpoint_variant_tags:
            config_kwargs.update(use_dualstack_endpoint=True)
        if 'fips' in endpoint_variant_tags:
            config_kwargs.update(use_fips_endpoint=True)
        if client_config is not None:
            config_kwargs.update(
                connect_timeout=client_config.connect_timeout,
                read_timeout=client_config.read_timeout,
                max_pool_connections=client_config.max_pool_connections,
                proxies=client_config.proxies,
                proxies_config=client_config.proxies_config,
                retries=client_config.retries,
                client_cert=client_config.client_cert,
                inject_host_prefix=client_config.inject_host_prefix,
                tcp_keepalive=client_config.tcp_keepalive,
            )
        self._compute_retry_config(config_kwargs)
        self._compute_connect_timeout(config_kwargs)
        s3_config = self.compute_s3_config(client_config)

        is_s3_service = service_name in ['s3', 's3-control']

        if is_s3_service and 'dualstack' in endpoint_variant_tags:
            if s3_config is None:
                s3_config = {}
            s3_config['use_dualstack_endpoint'] = True

        return {
            'service_name': service_name,
            'parameter_validation': parameter_validation,
            'user_agent': user_agent,
            'endpoint_config': endpoint_config,
            'protocol': protocol,
            'config_kwargs': config_kwargs,
            's3_config': s3_config,
            'socket_options': self._compute_socket_options(
                scoped_config, client_config
            ),
        }

    def compute_s3_config(self, client_config):
        s3_configuration = self._config_store.get_config_variable('s3')

        # Next specific client config values takes precedence over
        # specific values in the scoped config.
        if client_config is not None:
            if client_config.s3 is not None:
                if s3_configuration is None:
                    s3_configuration = client_config.s3
                else:
                    # The current s3_configuration dictionary may be
                    # from a source that only should be read from so
                    # we want to be safe and just make a copy of it to modify
                    # before it actually gets updated.
                    s3_configuration = s3_configuration.copy()
                    s3_configuration.update(client_config.s3)

        return s3_configuration

    def _compute_endpoint_config(
        self,
        service_name,
        region_name,
        endpoint_url,
        is_secure,
        endpoint_bridge,
        s3_config,
    ):
        resolve_endpoint_kwargs = {
            'service_name': service_name,
            'region_name': region_name,
            'endpoint_url': endpoint_url,
            'is_secure': is_secure,
            'endpoint_bridge': endpoint_bridge,
        }
        if service_name == 's3':
            return self._compute_s3_endpoint_config(
                s3_config=s3_config, **resolve_endpoint_kwargs
            )
        if service_name == 'sts':
            return self._compute_sts_endpoint_config(**resolve_endpoint_kwargs)
        return self._resolve_endpoint(**resolve_endpoint_kwargs)

    def _compute_s3_endpoint_config(
        self, s3_config, **resolve_endpoint_kwargs
    ):
        force_s3_global = self._should_force_s3_global(
            resolve_endpoint_kwargs['region_name'], s3_config
        )
        if force_s3_global:
            resolve_endpoint_kwargs['region_name'] = None
        endpoint_config = self._resolve_endpoint(**resolve_endpoint_kwargs)
        self._set_region_if_custom_s3_endpoint(
            endpoint_config, resolve_endpoint_kwargs['endpoint_bridge']
        )
        # For backwards compatibility reasons, we want to make sure the
        # client.meta.region_name will remain us-east-1 if we forced the
        # endpoint to be the global region. Specifically, if this value
        # changes to aws-global, it breaks logic where a user is checking
        # for us-east-1 as the global endpoint such as in creating buckets.
        if force_s3_global and endpoint_config['region_name'] == 'aws-global':
            endpoint_config['region_name'] = 'us-east-1'
        return endpoint_config

    def _should_force_s3_global(self, region_name, s3_config):
        s3_regional_config = 'legacy'
        if s3_config and 'us_east_1_regional_endpoint' in s3_config:
            s3_regional_config = s3_config['us_east_1_regional_endpoint']
            self._validate_s3_regional_config(s3_regional_config)

        is_global_region = region_name in ('us-east-1', None)
        return s3_regional_config == 'legacy' and is_global_region

    def _validate_s3_regional_config(self, config_val):
        if config_val not in VALID_REGIONAL_ENDPOINTS_CONFIG:
            raise botocore.exceptions.InvalidS3UsEast1RegionalEndpointConfigError(
                s3_us_east_1_regional_endpoint_config=config_val
            )

    def _set_region_if_custom_s3_endpoint(
        self, endpoint_config, endpoint_bridge
    ):
        # If a user is providing a custom URL, the endpoint resolver will
        # refuse to infer a signing region. If we want to default to s3v4,
        # we have to account for this.
        if (
            endpoint_config['signing_region'] is None
            and endpoint_config['region_name'] is None
        ):
            endpoint = endpoint_bridge.resolve('s3')
            endpoint_config['signing_region'] = endpoint['signing_region']
            endpoint_config['region_name'] = endpoint['region_name']

    def _compute_sts_endpoint_config(self, **resolve_endpoint_kwargs):
        endpoint_config = self._resolve_endpoint(**resolve_endpoint_kwargs)
        if self._should_set_global_sts_endpoint(
            resolve_endpoint_kwargs['region_name'],
            resolve_endpoint_kwargs['endpoint_url'],
            endpoint_config,
        ):
            self._set_global_sts_endpoint(
                endpoint_config, resolve_endpoint_kwargs['is_secure']
            )
        return endpoint_config

    def _should_set_global_sts_endpoint(
        self, region_name, endpoint_url, endpoint_config
    ):
        has_variant_tags = endpoint_config and endpoint_config.get(
            'metadata', {}
        ).get('tags')
        if endpoint_url or has_variant_tags:
            return False
        return (
            self._get_sts_regional_endpoints_config() == 'legacy'
            and region_name in LEGACY_GLOBAL_STS_REGIONS
        )

    def _get_sts_regional_endpoints_config(self):
        sts_regional_endpoints_config = self._config_store.get_config_variable(
            'sts_regional_endpoints'
        )
        if not sts_regional_endpoints_config:
            sts_regional_endpoints_config = 'legacy'
        if (
            sts_regional_endpoints_config
            not in VALID_REGIONAL_ENDPOINTS_CONFIG
        ):
            raise botocore.exceptions.InvalidSTSRegionalEndpointsConfigError(
                sts_regional_endpoints_config=sts_regional_endpoints_config
            )
        return sts_regional_endpoints_config

    def _set_global_sts_endpoint(self, endpoint_config, is_secure):
        scheme = 'https' if is_secure else 'http'
        endpoint_config['endpoint_url'] = '%s://sts.amazonaws.com' % scheme
        endpoint_config['signing_region'] = 'us-east-1'

    def _resolve_endpoint(
        self,
        service_name,
        region_name,
        endpoint_url,
        is_secure,
        endpoint_bridge,
    ):
        return endpoint_bridge.resolve(
            service_name, region_name, endpoint_url, is_secure
        )

    def _compute_socket_options(self, scoped_config, client_config=None):
        # This disables Nagle's algorithm and is the default socket options
        # in urllib3.
        socket_options = [(socket.IPPROTO_TCP, socket.TCP_NODELAY, 1)]
        client_keepalive = client_config and client_config.tcp_keepalive
        scoped_keepalive = scoped_config and self._ensure_boolean(
            scoped_config.get("tcp_keepalive", False)
        )
        # Enables TCP Keepalive if specified in client config object or shared config file.
        if client_keepalive or scoped_keepalive:
            socket_options.append((socket.SOL_SOCKET, socket.SO_KEEPALIVE, 1))
        return socket_options

    def _compute_retry_config(self, config_kwargs):
        self._compute_retry_max_attempts(config_kwargs)
        self._compute_retry_mode(config_kwargs)

    def _compute_retry_max_attempts(self, config_kwargs):
        # There's a pre-existing max_attempts client config value that actually
        # means max *retry* attempts.  There's also a `max_attempts` we pull
        # from the config store that means *total attempts*, which includes the
        # intitial request.  We can't change what `max_attempts` means in
        # client config so we try to normalize everything to a new
        # "total_max_attempts" variable.  We ensure that after this, the only
        # configuration for "max attempts" is the 'total_max_attempts' key.
        # An explicitly provided max_attempts in the client config
        # overrides everything.
        retries = config_kwargs.get('retries')
        if retries is not None:
            if 'total_max_attempts' in retries:
                retries.pop('max_attempts', None)
                return
            if 'max_attempts' in retries:
                value = retries.pop('max_attempts')
                # client config max_attempts means total retries so we
                # have to add one for 'total_max_attempts' to account
                # for the initial request.
                retries['total_max_attempts'] = value + 1
                return
        # Otherwise we'll check the config store which checks env vars,
        # config files, etc.  There is no default value for max_attempts
        # so if this returns None and we don't set a default value here.
        max_attempts = self._config_store.get_config_variable('max_attempts')
        if max_attempts is not None:
            if retries is None:
                retries = {}
                config_kwargs['retries'] = retries
            retries['total_max_attempts'] = max_attempts

    def _compute_retry_mode(self, config_kwargs):
        retries = config_kwargs.get('retries')
        if retries is None:
            retries = {}
            config_kwargs['retries'] = retries
        elif 'mode' in retries:
            # If there's a retry mode explicitly set in the client config
            # that overrides everything.
            return
        retry_mode = self._config_store.get_config_variable('retry_mode')
        if retry_mode is None:
            retry_mode = 'legacy'
        retries['mode'] = retry_mode

    def _compute_connect_timeout(self, config_kwargs):
        # Checking if connect_timeout is set on the client config.
        # If it is not, we check the config_store in case a
        # non legacy default mode has been configured.
        connect_timeout = config_kwargs.get('connect_timeout')
        if connect_timeout is not None:
            return
        connect_timeout = self._config_store.get_config_variable(
            'connect_timeout'
        )
        if connect_timeout:
            config_kwargs['connect_timeout'] = connect_timeout

    def _ensure_boolean(self, val):
        if isinstance(val, bool):
            return val
        else:
            return val.lower() == 'true'

    def compute_endpoint_resolver_builtin_defaults(
        self,
        region_name,
        service_name,
        s3_config,
        endpoint_bridge,
        client_endpoint_url,
        legacy_endpoint_url,
    ):
        # EndpointResolverv2 rulesets may accept an "SDK::Endpoint" as input.
        # If the endpoint_url argument of create_client() is set, it always
        # takes priority.
        if client_endpoint_url:
            given_endpoint = client_endpoint_url
        # If an endpoints.json data file other than the one bundled within
        # the botocore/data directory is used, the output of legacy
        # endpoint resolution is provided to EndpointResolverv2.
        elif not endpoint_bridge.endpoint_resolver.uses_builtin_data:
            given_endpoint = legacy_endpoint_url
        else:
            given_endpoint = None

        return {
            EPRBuiltins.AWS_REGION: region_name,
            EPRBuiltins.AWS_USE_FIPS: (
                endpoint_bridge._resolve_endpoint_variant_config_var(
                    'use_fips_endpoint'
                )
                or False
                and not given_endpoint
            ),
            EPRBuiltins.AWS_USE_DUALSTACK: (
                endpoint_bridge._resolve_use_dualstack_endpoint(service_name)
                or False
                and not given_endpoint
            ),
            EPRBuiltins.AWS_STS_USE_GLOBAL_ENDPOINT: (
                self._should_set_global_sts_endpoint(
                    region_name=region_name,
                    endpoint_url=None,
                    endpoint_config=None,
                )
            ),
            EPRBuiltins.AWS_S3_USE_GLOBAL_ENDPOINT: (
                self._should_force_s3_global(region_name, s3_config)
            ),
            EPRBuiltins.AWS_S3_ACCELERATE: s3_config.get(
                'use_accelerate_endpoint', False
            ),
            EPRBuiltins.AWS_S3_FORCE_PATH_STYLE: (
                s3_config.get('addressing_style') == 'path'
            ),
            EPRBuiltins.AWS_S3_USE_ARN_REGION: s3_config.get(
                'use_arn_region', True
            ),
            EPRBuiltins.AWS_S3CONTROL_USE_ARN_REGION: s3_config.get(
                'use_arn_region', False
            ),
            EPRBuiltins.AWS_S3_DISABLE_MRAP: s3_config.get(
                's3_disable_multiregion_access_points', False
            ),
            EPRBuiltins.SDK_ENDPOINT: given_endpoint,
        }
