# Copyright 2021 99cloud
#
# 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.

from __future__ import annotations

from collections.abc import MutableMapping
from typing import Any, Dict, Iterable, Iterator

import attr
from immutables import Map
from keystoneauth1.access.access import AccessInfoV3
from oslo_policy._checks import _check
from skyline_apiserver.config import CONF
from skyline_policy_manager.policies.base import APIRule


class UserContext(MutableMapping):
    def __init__(
        self,
        access: AccessInfoV3,
    ):
        self._data = {}
        self.access = access
        self._data.setdefault("auth_token", getattr(access, "auth_token", None))
        self._data.setdefault("user_id", getattr(access, "user_id", None))
        self._data.setdefault("project_id", getattr(access, "project_id", None))
        self._data.setdefault("domain_id", getattr(access, "domain_id", None))
        self._data.setdefault("user_domain_id", getattr(access, "user_domain_id", None))
        self._data.setdefault("project_domain_id", getattr(access, "project_domain_id", None))
        self._data.setdefault("username", getattr(access, "username", None))
        self._data.setdefault("project_name", getattr(access, "project_name", None))
        self._data.setdefault("domain_name", getattr(access, "domain_name", None))
        self._data.setdefault("user_domain_name", getattr(access, "user_domain_name", None))
        self._data.setdefault("project_domain_name", getattr(access, "project_domain_name", None))
        self._data.setdefault("system_scope", getattr(access, "system_scope", None))
        self._data.setdefault("role_ids", getattr(access, "role_ids", []))
        self._data.setdefault("roles", getattr(access, "role_names", []))

        is_admin = False
        for role in CONF.openstack.system_admin_roles:
            if role in self._data["roles"]:
                is_admin = True
                break

        self._data.setdefault("is_admin", is_admin)

        is_reader_admin = False
        for role in CONF.openstack.system_reader_roles:
            if role in self._data["roles"]:
                is_reader_admin = True
                break

        self._data.setdefault("is_reader_admin", is_reader_admin)

    def __getitem__(self, k: Any) -> Any:
        return self._data[k]

    def __setitem__(self, k: Any, v: Any) -> None:
        self._data[k] = v

    def __delitem__(self, k: Any) -> None:
        del self._data[k]

    def __iter__(self) -> Iterator[Any]:
        return iter(self._data)

    def __len__(self) -> int:
        return len(self._data)

    def __str__(self) -> str:
        return self._data.__str__()

    def __repr__(self) -> str:
        return self._data.__repr__()


@attr.s(kw_only=True, repr=True, frozen=False, slots=True, auto_attribs=True)
class Enforcer:
    rules: Map = attr.ib(factory=Map, repr=True, init=False)

    def register_rules(self, rules: Iterable[APIRule]) -> None:
        rule_map = {}
        for rule in rules:
            if rule.name in rule_map:
                raise ValueError(f"Duplicate policy rule {rule.name}.")

            rule_map[rule.name] = rule.basic_check

        self.rules = Map(rule_map)

    def authorize(self, rule: str, target: Dict[str, Any], context: UserContext) -> bool:
        result = False
        do_check = self.rules.get(rule)
        if do_check is None:
            raise ValueError(f"Policy {rule} not registered.")

        result = _check(
            rule=do_check,
            target=target,
            creds=context,
            enforcer=self,
            current_rule=rule,
        )
        return result
