# 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

import os
import warnings
from dataclasses import InitVar, dataclass, field
from pathlib import Path, PurePath
from typing import TYPE_CHECKING, Any, Dict, Iterator, Sequence, Tuple, Type

import yaml
from immutables import Map
from pydantic import BaseModel, create_model

if TYPE_CHECKING:
    from immutables._map import MapItems, MapKeys, MapValues


@dataclass(frozen=True)
class Opt:
    name: str
    description: str
    schema: Any
    default: Any = None
    deprecated: bool = False
    value: Any = field(init=False, default=None)
    _schema_model: Type[BaseModel] = field(init=False, repr=False)

    def __post_init__(self) -> None:
        object.__setattr__(
            self,
            "_schema_model",
            create_model(f"Opt(name='{self.name}')", value=(self.schema, ...)),
        )

    def load(self, value: Any) -> None:
        value = self.default if value is None else value
        self._schema_model(value=value)
        object.__setattr__(self, "value", value)
        if self.deprecated:
            warnings.warn(
                f"The config opt {self.name} is deprecated, will be deleted in the"
                " future version",
                DeprecationWarning,
            )


@dataclass(repr=False, frozen=True)
class Group:
    name: str
    init_opts: InitVar[Sequence[Opt]] = tuple()
    _opts: Map[str, Opt] = field(init=False, repr=False)

    def __post_init__(self, init_opts: Sequence[Opt]) -> None:
        object.__setattr__(self, "_opts", Map({opt.name: opt for opt in init_opts}))

    def __getattr__(self, name: str) -> Any:
        if name in self._opts:
            return self._opts[name].value
        raise AttributeError(name)

    def __contains__(self, key: Any) -> bool:
        return self._opts.__contains__(key)

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

    def __len__(self) -> int:
        return self._opts.__len__()

    def __repr__(self) -> str:
        items = ", ".join((f"{opt}=Opt(name='{opt}')" for opt in self._opts))
        return f"Group({items})"

    def items(self) -> MapItems[str, Opt]:
        return self._opts.items()

    def keys(self) -> MapKeys[str]:
        return self._opts.keys()

    def values(self) -> MapValues[Opt]:
        return self._opts.values()


@dataclass(repr=False, frozen=True)
class Configuration:
    init_groups: InitVar[Sequence[Group]] = tuple()
    config: Dict[str, Any] = field(init=False, default_factory=dict, repr=False)
    _groups: Map[str, Group] = field(init=False, repr=False)

    def __post_init__(self, init_groups: Sequence[Group]) -> None:
        object.__setattr__(self, "_groups", Map({group.name: group for group in init_groups}))

    @staticmethod
    def _get_config_file(project: str, env: Dict[str, str]) -> Tuple[str, str]:
        config_dir = env.get("OS_CONFIG_DIR", PurePath("/etc", project).as_posix()).strip()

        config_file = env.get(
            "OS_CONFIG_FILE",
            os.path.join(config_dir, f"{project}.yaml"),
        ).strip()

        return (config_dir, config_file)

    def setup(self, project: str, env: Dict[str, str]) -> None:
        config_dir, config_file = self._get_config_file(project, env)
        if not Path(config_file).exists():
            raise ValueError("Not found config file: %s" % config_file)

        with open(config_file) as f:
            try:
                object.__setattr__(self, "config", yaml.safe_load(f))
            except Exception:
                raise ValueError("Load config file error")

        for group in self._groups.values():
            for opt in group._opts.values():
                value = self.config.get(group.name, {}).get(opt.name)
                opt.load(value)

    def cleanup(self) -> None:
        for group in self._groups.values():
            for opt in group._opts.values():
                object.__setattr__(opt, "value", None)
        object.__setattr__(self, "_groups", Map())
        object.__setattr__(self, "config", {})

    def __getattr__(self, name: str) -> Group:
        if name in self._groups:
            return self._groups[name]
        raise AttributeError(name)

    def __call__(self, init_groups: Sequence[Group]) -> Any:
        object.__setattr__(self, "_groups", Map({group.name: group for group in init_groups}))

    def __contains__(self, key: Any) -> bool:
        return self._groups.__contains__(key)

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

    def __len__(self) -> int:
        return self._groups.__len__()

    def __repr__(self) -> str:
        items = ", ".join((f"{group}=Group(name='{group}')" for group in self._groups))
        return f"Configuration({items})"

    def items(self) -> MapItems[str, Group]:
        return self._groups.items()

    def keys(self) -> MapKeys[str]:
        return self._groups.keys()

    def values(self) -> MapValues[Group]:
        return self._groups.values()


__all__ = ("Opt", "Group", "Configuration")