"""KiloStar 集中式环境变量管理。

所有散落在各模块的 os.getenv/os.environ 收敛到此处，
通过 pydantic-settings 统一校验、类型转换、默认值管理。
"""

from __future__ import annotations

from functools import lru_cache

from pydantic import Field
from pydantic_settings import BaseSettings


class DatabaseSettings(BaseSettings):
    postgres_user: str = "postgres"
    postgres_password: str = ""
    postgres_host: str = "db"
    postgres_port: int = 5432
    postgres_db: str = "postgres"


class SecuritySettings(BaseSettings):
    secret_key: str = ""
    kilostar_secret_key: str = ""
    kilostar_env: str = "production"


class LogSettings(BaseSettings):
    kilostar_log_level: str = "DEBUG"
    kilostar_log_format: str = ""
    kilostar_log_json: str = ""


class OnebotSettings(BaseSettings):
    onebot_access_token: str = ""
    onebot_http_url: str = "http://127.0.0.1:5700"


class AppSettings(BaseSettings):
    kilostar_mode: str = "distributed"
    kilostar_lang: str = "zh"
    kilostar_cors_origins: str = ""

    db: DatabaseSettings = Field(default_factory=DatabaseSettings)
    security: SecuritySettings = Field(default_factory=SecuritySettings)
    log: LogSettings = Field(default_factory=LogSettings)
    onebot: OnebotSettings = Field(default_factory=OnebotSettings)

    model_config = {"env_nested_delimiter": "__"}


@lru_cache(maxsize=1)
def get_settings() -> AppSettings:
    return AppSettings()