# Copyright 2010 Jacob Kaplan-Moss
#
# 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.

"""
Exception definitions.
"""


class UnsupportedVersion(Exception):
    """Indicates that the user is trying to use an unsupported
    version of the API.
    """
    pass


class InvalidAPIVersion(Exception):
    pass


class CommandError(Exception):
    pass


class AuthorizationFailure(Exception):
    pass


class NoUniqueMatch(Exception):
    pass


class AuthSystemNotFound(Exception):
    """When the user specifies an AuthSystem but not installed."""
    def __init__(self, auth_system):
        self.auth_system = auth_system

    def __str__(self):
        return "AuthSystemNotFound: %s" % repr(self.auth_system)


class NoTokenLookupException(Exception):
    """This form of authentication does not support looking up
       endpoints from an existing token.
    """
    pass


class EndpointNotFound(Exception):
    """Could not find Service or Region in Service Catalog."""
    pass


class ConnectionError(Exception):
    """Could not open a connection to the API service."""
    pass


class AmbiguousEndpoints(Exception):
    """Found more than one matching endpoint in Service Catalog."""
    def __init__(self, endpoints=None):
        self.endpoints = endpoints

    def __str__(self):
        return "AmbiguousEndpoints: %s" % repr(self.endpoints)


class ClientException(Exception):
    """
    The base exception class for all exceptions this library raises.
    """
    def __init__(self, code, message=None, details=None, request_id=None):
        self.code = code
        self.message = message or self.__class__.message
        self.details = details
        self.request_id = request_id

    def __str__(self):
        formatted_string = "%s (HTTP %s)" % (self.message, self.code)
        if self.request_id:
            formatted_string += " (Request-ID: %s)" % self.request_id

        return formatted_string


class BadRequest(ClientException):
    """
    HTTP 400 - Bad request: you sent some malformed data.
    """
    http_status = 400
    message = "Bad request"


class Unauthorized(ClientException):
    """
    HTTP 401 - Unauthorized: bad credentials.
    """
    http_status = 401
    message = "Unauthorized"


class Forbidden(ClientException):
    """
    HTTP 403 - Forbidden: your credentials don't give you access to this
    resource.
    """
    http_status = 403
    message = "Forbidden"


class NotFound(ClientException):
    """
    HTTP 404 - Not found
    """
    http_status = 404
    message = "Not found"


class OverLimit(ClientException):
    """
    HTTP 413 - Over limit: you're over the API limits for this time period.
    """
    http_status = 413
    message = "Over limit"


# NotImplemented is a python keyword.
class HTTPNotImplemented(ClientException):
    """
    HTTP 501 - Not Implemented: the server does not support this operation.
    """
    http_status = 501
    message = "Not Implemented"


# In Python 2.4 Exception is old-style and thus doesn't have a __subclasses__()
# so we can do this:
#     _code_map = dict((c.http_status, c)
#                      for c in ClientException.__subclasses__())
#
# Instead, we have to hardcode it:
_code_map = dict((c.http_status, c) for c in [BadRequest, Unauthorized,
                                              Forbidden, NotFound,
                                              OverLimit, HTTPNotImplemented])


def from_response(response, body):
    """
    Return an instance of a ClientException or subclass
    based on a requests response.

    Usage::

        resp, body = requests.request(...)
        if resp.status_code != 200:
            raise exceptions.from_response(resp, resp.text)
    """
    cls = _code_map.get(response.status_code, ClientException)
    if response.headers:
        request_id = response.headers.get('x-compute-request-id')
    else:
        request_id = None
    if body:
        message = "n/a"
        details = "n/a"
        if hasattr(body, 'keys'):
            error = body[list(body)[0]]
            message = error.get('message', None)
            details = error.get('details', None)
        return cls(code=response.status_code, message=message, details=details,
                   request_id=request_id)
    else:
        return cls(code=response.status_code, request_id=request_id,
                   message=response.reason)
