#
# Copyright 2010 United States Government as represented by the
# Administrator of the National Aeronautics and Space Administration.
#
#    Licensed under the Apache License, Version 2.0 (the "License"); you may
#    not use this file except in compliance with the License. You may obtain
#    a copy of the License at
#
#         http://www.apache.org/licenses/LICENSE-2.0
#
#    Unless required by applicable law or agreed to in writing, software
#    distributed under the License 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.

"""Heat API exception subclasses - maps API response errors to AWS Errors."""

import six
import webob.exc

from heat.common.i18n import _
from heat.common import serializers


class HeatAPIException(webob.exc.HTTPError):

    """webob HTTPError subclass that creates a serialized body.

    Subclass webob HTTPError so we can correctly serialize the wsgi response
    into the http response body, using the format specified by the request.
    Note this should not be used directly, instead use the subclasses
    defined below which map to AWS API errors
    """

    code = 400
    title = "HeatAPIException"
    explanation = _("Generic HeatAPIException, please use specific "
                    "subclasses!")
    err_type = "Sender"

    def __init__(self, detail=None):
        """Overload HTTPError constructor to create a default serialized body.

        This is required because not all error responses are processed
        by the wsgi controller (such as auth errors), which are further up the
        paste pipeline.  We serialize in XML by default (as AWS does).
        """
        webob.exc.HTTPError.__init__(self, detail=detail)
        serializer = serializers.XMLResponseSerializer()
        serializer.default(self, self.get_unserialized_body())

    def get_unserialized_body(self):
        """Return a dict suitable for serialization in the wsgi controller.

        This wraps the exception details in a format which maps to the
        expected format for the AWS API.
        """
        # Note the aws response format specifies a "Code" element which is not
        # the html response code, but the AWS API error code, e.g self.title
        if self.detail:
            message = ":".join([self.explanation, self.detail])
        else:
            message = self.explanation
        return {'ErrorResponse': {'Error': {'Type': self.err_type,
                'Code': self.title, 'Message': message}}}


# Common Error Subclasses:

class HeatIncompleteSignatureError(HeatAPIException):

    """The request signature does not conform to AWS standards."""

    code = 400
    title = "IncompleteSignature"
    explanation = _("The request signature does not conform to AWS standards")


class HeatInternalFailureError(HeatAPIException):

    """The request processing has failed due to some unknown error."""

    code = 500
    title = "InternalFailure"
    explanation = _("The request processing has failed due to an "
                    "internal error")
    err_type = "Server"


class HeatInvalidActionError(HeatAPIException):

    """The action or operation requested is invalid."""

    code = 400
    title = "InvalidAction"
    explanation = _("The action or operation requested is invalid")


class HeatInvalidClientTokenIdError(HeatAPIException):

    """The X.509 certificate or AWS Access Key ID provided does not exist."""

    code = 403
    title = "InvalidClientTokenId"
    explanation = _("The certificate or AWS Key ID provided does not exist")


class HeatInvalidParameterCombinationError(HeatAPIException):

    """Parameters that must not be used together were used together."""

    code = 400
    title = "InvalidParameterCombination"
    explanation = _("Incompatible parameters were used together")


class HeatInvalidParameterValueError(HeatAPIException):

    """A bad or out-of-range value was supplied for the input parameter."""

    code = 400
    title = "InvalidParameterValue"
    explanation = _("A bad or out-of-range value was supplied")


class HeatInvalidQueryParameterError(HeatAPIException):

    """AWS query string is malformed, does not adhere to AWS standards."""

    code = 400
    title = "InvalidQueryParameter"
    explanation = _("AWS query string is malformed, does not adhere to "
                    "AWS spec")


class HeatMalformedQueryStringError(HeatAPIException):

    """The query string is malformed."""

    code = 404
    title = "MalformedQueryString"
    explanation = _("The query string is malformed")


class HeatMissingActionError(HeatAPIException):

    """The request is missing an action or operation parameter."""

    code = 400
    title = "MissingAction"
    explanation = _("The request is missing an action or operation parameter")


class HeatMissingAuthenticationTokenError(HeatAPIException):

    """Does not contain a valid AWS Access Key or certificate.

    Request must contain either a valid (registered) AWS Access Key ID
    or X.509 certificate.
    """

    code = 403
    title = "MissingAuthenticationToken"
    explanation = _("Does not contain a valid AWS Access Key or certificate")


class HeatMissingParameterError(HeatAPIException):

    """A mandatory input parameter is missing.

    An input parameter that is mandatory for processing the request is missing.
    """

    code = 400
    title = "MissingParameter"
    explanation = _("A mandatory input parameter is missing")


class HeatOptInRequiredError(HeatAPIException):

    """The AWS Access Key ID needs a subscription for the service."""

    code = 403
    title = "OptInRequired"
    explanation = _("The AWS Access Key ID needs a subscription for the "
                    "service")


class HeatRequestExpiredError(HeatAPIException):

    """Request expired or more than 15mins in the future.

    Request is past expires date or the request date (either with 15 minute
    padding), or the request date occurs more than 15 minutes in the future.
    """

    code = 400
    title = "RequestExpired"
    explanation = _("Request expired or more than 15mins in the future")


class HeatServiceUnavailableError(HeatAPIException):

    """The request has failed due to a temporary failure of the server."""

    code = 503
    title = "ServiceUnavailable"
    explanation = _("Service temporarily unavailable")
    err_type = "Server"


class HeatThrottlingError(HeatAPIException):

    """Request was denied due to request throttling."""

    code = 400
    title = "Throttling"
    explanation = _("Request was denied due to request throttling")


class AlreadyExistsError(HeatAPIException):

    """Resource with the name requested already exists."""

    code = 400
    title = 'AlreadyExists'
    explanation = _("Resource with the name requested already exists")


# Not documented in the AWS docs, authentication failure errors
class HeatAccessDeniedError(HeatAPIException):

    """Authentication fails due to user IAM group memberships.

    This is the response given when authentication fails due to user
    IAM group memberships meaning we deny access.
    """

    code = 403
    title = "AccessDenied"
    explanation = _("User is not authorized to perform action")


class HeatSignatureError(HeatAPIException):

    """Authentication fails due to a bad signature."""

    code = 403
    title = "SignatureDoesNotMatch"
    explanation = _("The request signature we calculated does not match the "
                    "signature you provided")


# Heat-specific errors
class HeatAPINotImplementedError(HeatAPIException):

    """API action is not yet implemented."""

    code = 500
    title = "APINotImplemented"
    explanation = _("The requested action is not yet implemented")
    err_type = "Server"


class HeatActionInProgressError(HeatAPIException):

    """Cannot perform action on stack in its current state."""

    code = 400
    title = 'InvalidAction'
    explanation = ("Cannot perform action on stack while other actions are " +
                   "in progress")


def map_remote_error(ex):
    """Map rpc_common.RemoteError exceptions to HeatAPIException subclasses.

    Map rpc_common.RemoteError exceptions returned by the engine
    to HeatAPIException subclasses which can be used to return
    properly formatted AWS error responses.
    """
    inval_param_errors = (
        'AttributeError',
        'ValueError',
        'InvalidTenant',
        'StackNotFound',
        'ResourceActionNotSupported',
        'ResourceNotFound',
        'ResourceNotAvailable',
        'ResourceTypeNotFound',
        'PhysicalResourceNotFound',
        'WatchRuleNotFound',
        'StackValidationFailed',
        'InvalidSchemaError',
        'InvalidTemplateReference',
        'InvalidTemplateVersion',
        'InvalidTemplateSection',
        'UnknownUserParameter',
        'UserParameterMissing',
        'InvalidTemplateParameter',
        'MissingCredentialError',
    )
    denied_errors = ('Forbidden', 'NotAuthorized')
    already_exists_errors = ('StackExists')
    invalid_action_errors = ('ActionInProgress',)

    ex_type = ex.__class__.__name__

    if ex_type.endswith('_Remote'):
        ex_type = ex_type[:-len('_Remote')]

    if ex_type in inval_param_errors:
        return HeatInvalidParameterValueError(detail=six.text_type(ex))
    elif ex_type in denied_errors:
        return HeatAccessDeniedError(detail=six.text_type(ex))
    elif ex_type in already_exists_errors:
        return AlreadyExistsError(detail=six.text_type(ex))
    elif ex_type in invalid_action_errors:
        return HeatActionInProgressError(detail=six.text_type(ex))
    else:
        # Map everything else to internal server error for now
        return HeatInternalFailureError(detail=six.text_type(ex))
