from enum import Enum

from flask import url_for

from auth.auth_context import get_authenticated_user


class ApiErrorType(Enum):
  external_service_timeout = 'external_service_timeout'
  invalid_request = 'invalid_request'
  invalid_response = 'invalid_response'
  invalid_token = 'invalid_token'
  expired_token = 'expired_token'
  insufficient_scope = 'insufficient_scope'
  fresh_login_required = 'fresh_login_required'
  exceeds_license = 'exceeds_license'
  not_found = 'not_found'
  downstream_issue = 'downstream_issue'


ERROR_DESCRIPTION = {
  ApiErrorType.external_service_timeout.value: "An external service timed out. Retrying the request may resolve the issue.",
  ApiErrorType.invalid_request.value: "The request was invalid. It may have contained invalid values or was improperly formatted.",
  ApiErrorType.invalid_response.value: "The response was invalid.",
  ApiErrorType.invalid_token.value: "The access token provided was invalid.",
  ApiErrorType.expired_token.value: "The access token provided has expired.",
  ApiErrorType.insufficient_scope.value: "The access token did not have sufficient scope to access the requested resource.",
  ApiErrorType.fresh_login_required.value: "The action requires a fresh login to succeed.",
  ApiErrorType.exceeds_license.value: "The action was refused because the current license does not allow it.",
  ApiErrorType.not_found.value: "The resource was not found.",
  ApiErrorType.downstream_issue.value: "An error occurred in a downstream service.",
}


class ApiException(Exception):
  """
  Represents an error in the application/problem+json format.

  See: https://tools.ietf.org/html/rfc7807

   -  "type" (string) - A URI reference that identifies the
      problem type.

   -  "title" (string) - A short, human-readable summary of the problem
      type.  It SHOULD NOT change from occurrence to occurrence of the
      problem, except for purposes of localization

   -  "status" (number) - The HTTP status code

   -  "detail" (string) - A human-readable explanation specific to this
      occurrence of the problem.

   -  "instance" (string) - A URI reference that identifies the specific
      occurrence of the problem.  It may or may not yield further
      information if dereferenced.
  """

  def __init__(self, error_type, status_code, error_description, payload=None):
    Exception.__init__(self)
    self.error_description = error_description
    self.status_code = status_code
    self.payload = payload
    self.error_type = error_type

  def to_dict(self):
    rv = dict(self.payload or ())

    if self.error_description is not None:
      rv['detail'] = self.error_description
      rv['error_message'] = self.error_description  # TODO: deprecate

    rv['error_type'] = self.error_type.value  # TODO: deprecate
    rv['title'] = self.error_type.value
    rv['type'] = url_for('error', error_type=self.error_type.value, _external=True)
    rv['status'] = self.status_code

    return rv


class ExternalServiceTimeout(ApiException):
  def __init__(self, error_description, payload=None):
    ApiException.__init__(self, ApiErrorType.external_service_timeout, 520, error_description, payload)


class InvalidRequest(ApiException):
  def __init__(self, error_description, payload=None):
    ApiException.__init__(self, ApiErrorType.invalid_request, 400, error_description, payload)


class InvalidResponse(ApiException):
  def __init__(self, error_description, payload=None):
    ApiException.__init__(self, ApiErrorType.invalid_response, 400, error_description, payload)


class InvalidToken(ApiException):
  def __init__(self, error_description, payload=None):
    ApiException.__init__(self, ApiErrorType.invalid_token, 401, error_description, payload)

class ExpiredToken(ApiException):
  def __init__(self, error_description, payload=None):
    ApiException.__init__(self, ApiErrorType.expired_token, 401, error_description, payload)

class Unauthorized(ApiException):
  def __init__(self, payload=None):
    user = get_authenticated_user()
    if user is None or user.organization:
      ApiException.__init__(self, ApiErrorType.invalid_token, 401, "Requires authentication", payload)
    else:
      ApiException.__init__(self, ApiErrorType.insufficient_scope, 403, 'Unauthorized', payload)


class FreshLoginRequired(ApiException):
  def __init__(self, payload=None):
    ApiException.__init__(self, ApiErrorType.fresh_login_required, 401, "Requires fresh login", payload)


class ExceedsLicenseException(ApiException):
  def __init__(self, payload=None):
    ApiException.__init__(self, ApiErrorType.exceeds_license, 402, 'Payment Required', payload)


class NotFound(ApiException):
  def __init__(self, payload=None):
    ApiException.__init__(self, ApiErrorType.not_found, 404, 'Not Found', payload)


class DownstreamIssue(ApiException):
  def __init__(self, payload=None):
    ApiException.__init__(self, ApiErrorType.downstream_issue, 520, 'Downstream Issue', payload)