# -*- coding: utf-8 -*-

# Copyright 2018 Whitestack, LLC
#
# 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.
#
# For those usages not covered by the Apache License, Version 2.0 please
# contact: esousa@whitestack.com or glavado@whitestack.com
##

"""
Authconn implements an Abstract class for the Auth backend connector
plugins with the definition of the methods to be implemented.
"""

__author__ = "Eduardo Sousa <esousa@whitestack.com>, " \
             "Pedro de la Cruz Ramos <pdelacruzramos@altran.com>"
__date__ = "$27-jul-2018 23:59:59$"

from http import HTTPStatus
from osm_nbi.base_topic import BaseTopic


class AuthException(Exception):
    """
    Authentication error, because token, user password not recognized
    """
    def __init__(self, message, http_code=HTTPStatus.UNAUTHORIZED):
        super(AuthException, self).__init__(message)
        self.http_code = http_code


class AuthExceptionUnauthorized(AuthException):
    """
    Authentication error, because not having rights to make this operation
    """
    pass


class AuthconnException(Exception):
    """
    Common and base class Exception for all authconn exceptions.
    """
    def __init__(self, message, http_code=HTTPStatus.UNAUTHORIZED):
        super(AuthconnException, self).__init__(message)
        self.http_code = http_code


class AuthconnConnectionException(AuthconnException):
    """
    Connectivity error with Auth backend.
    """
    def __init__(self, message, http_code=HTTPStatus.BAD_GATEWAY):
        super(AuthconnConnectionException, self).__init__(message, http_code)


class AuthconnNotSupportedException(AuthconnException):
    """
    The request is not supported by the Auth backend.
    """
    def __init__(self, message, http_code=HTTPStatus.NOT_IMPLEMENTED):
        super(AuthconnNotSupportedException, self).__init__(message, http_code)


class AuthconnNotImplementedException(AuthconnException):
    """
    The method is not implemented by the Auth backend.
    """
    def __init__(self, message, http_code=HTTPStatus.NOT_IMPLEMENTED):
        super(AuthconnNotImplementedException, self).__init__(message, http_code)


class AuthconnOperationException(AuthconnException):
    """
    The operation executed failed.
    """
    def __init__(self, message, http_code=HTTPStatus.INTERNAL_SERVER_ERROR):
        super(AuthconnOperationException, self).__init__(message, http_code)


class AuthconnNotFoundException(AuthconnException):
    """
    The operation executed failed because element not found.
    """
    def __init__(self, message, http_code=HTTPStatus.NOT_FOUND):
        super().__init__(message, http_code)


class AuthconnConflictException(AuthconnException):
    """
    The operation has conflicts.
    """
    def __init__(self, message, http_code=HTTPStatus.CONFLICT):
        super().__init__(message, http_code)


class Authconn:
    """
    Abstract base class for all the Auth backend connector plugins.
    Each Auth backend connector plugin must be a subclass of
    Authconn class.
    """
    def __init__(self, config, db, role_permissions):
        """
        Constructor of the Authconn class.
        :param config: configuration dictionary containing all the
        necessary configuration parameters.
        :param db: internal database classs
        :param role_permissions: read only role permission list
        """
        self.config = config
        self.role_permissions = role_permissions

    def authenticate(self, credentials, token_info=None):
        """
        Authenticate a user using username/password or token_info, plus project
        :param credentials: dictionary that contains:
            username: name, id or None
            password: password or None
            project_id: name, id, or None. If None first found project will be used to get an scope token
            other items are allowed for specific auth backends
        :param token_info: previous token_info to obtain authorization
        :return: the scoped token info or raises an exception. The token is a dictionary with:
            _id:  token string id,
            username: username,
            project_id: scoped_token project_id,
            project_name: scoped_token project_name,
            expires: epoch time when it expires,

        """
        raise AuthconnNotImplementedException("Should have implemented this")

    def validate_token(self, token):
        """
        Check if the token is valid.

        :param token: token to validate
        :return: dictionary with information associated with the token. If the
        token is not valid, returns None.
        """
        raise AuthconnNotImplementedException("Should have implemented this")

    def revoke_token(self, token):
        """
        Invalidate a token.

        :param token: token to be revoked
        """
        raise AuthconnNotImplementedException("Should have implemented this")

    def create_user(self, user_info):
        """
        Create a user.

        :param user_info: full user info.
        :raises AuthconnOperationException: if user creation failed.
        """
        raise AuthconnNotImplementedException("Should have implemented this")

    def update_user(self, user_info):
        """
        Change the user name and/or password.

        :param user_info:  user info modifications
        :raises AuthconnNotImplementedException: if function not implemented
        """
        raise AuthconnNotImplementedException("Should have implemented this")

    def delete_user(self, user_id):
        """
        Delete user.

        :param user_id: user identifier.
        :raises AuthconnOperationException: if user deletion failed.
        """
        raise AuthconnNotImplementedException("Should have implemented this")

    def get_user_list(self, filter_q=None):
        """
        Get user list.

        :param filter_q: dictionary to filter user list by name (username is also admited) and/or _id
        :return: returns a list of users.
        """

    def get_user(self, _id, fail=True):
        """
        Get one user
        :param _id:  id or name
        :param fail: True to raise exception on not found. False to return None on not found
        :return: dictionary with the user information
        """
        filt = {BaseTopic.id_field("users", _id): _id}
        users = self.get_user_list(filt)
        if not users:
            if fail:
                raise AuthconnNotFoundException("User with {} not found".format(filt), http_code=HTTPStatus.NOT_FOUND)
            else:
                return None
        return users[0]

    def create_role(self, role_info):
        """
        Create a role.

        :param role_info: full role info.
        :raises AuthconnOperationException: if role creation failed.
        """
        raise AuthconnNotImplementedException("Should have implemented this")

    def delete_role(self, role_id):
        """
        Delete a role.

        :param role_id: role identifier.
        :raises AuthconnOperationException: if user deletion failed.
        """
        raise AuthconnNotImplementedException("Should have implemented this")

    def get_role_list(self, filter_q=None):
        """
        Get all the roles.

        :param filter_q: dictionary to filter role list by _id and/or name.
        :return: list of roles
        """
        raise AuthconnNotImplementedException("Should have implemented this")

    def get_role(self, _id, fail=True):
        """
        Get one role
        :param _id: id or name
        :param fail: True to raise exception on not found. False to return None on not found
        :return: dictionary with the role information
        """
        filt = {BaseTopic.id_field("roles", _id): _id}
        roles = self.get_role_list(filt)
        if not roles:
            if fail:
                raise AuthconnNotFoundException("Role with {} not found".format(filt))
            else:
                return None
        return roles[0]

    def update_role(self, role_info):
        """
        Change the information of a role
        :param role_info: full role info
        :return: None
        """
        raise AuthconnNotImplementedException("Should have implemented this")

    def create_project(self, project_info):
        """
        Create a project.

        :param project_info: full project info.
        :return: the internal id of the created project
        :raises AuthconnOperationException: if project creation failed.
        """
        raise AuthconnNotImplementedException("Should have implemented this")

    def delete_project(self, project_id):
        """
        Delete a project.

        :param project_id: project identifier.
        :raises AuthconnOperationException: if project deletion failed.
        """
        raise AuthconnNotImplementedException("Should have implemented this")

    def get_project_list(self, filter_q=None):
        """
        Get all the projects.

        :param filter_q: dictionary to filter project list, by "name" and/or "_id"
        :return: list of projects
        """
        raise AuthconnNotImplementedException("Should have implemented this")

    def get_project(self, _id, fail=True):
        """
        Get one project
        :param _id:  id or name
        :param fail: True to raise exception on not found. False to return None on not found
        :return: dictionary with the project information
        """
        filt = {BaseTopic.id_field("projects", _id): _id}
        projs = self.get_project_list(filt)
        if not projs:
            if fail:
                raise AuthconnNotFoundException("project with {} not found".format(filt))
            else:
                return None
        return projs[0]

    def update_project(self, project_id, project_info):
        """
        Change the information of a project
        :param project_id: project to be changed
        :param project_info: full project info
        :return: None
        """
        raise AuthconnNotImplementedException("Should have implemented this")