"""应用配置：从环境变量加载，启动时校验必填项。"""
from functools import lru_cache
from typing import List

from pydantic import Field, field_validator
from pydantic_settings import BaseSettings, SettingsConfigDict


class Settings(BaseSettings):
    model_config = SettingsConfigDict(
        env_file=".env",
        env_file_encoding="utf-8",
        case_sensitive=True,
        extra="ignore",
    )

    # ===== 必填 =====
    SECRET_KEY: str = Field(..., description="JWT 签名密钥（>= 32 字符）")
    FERNET_KEY: str = Field(..., description="Fernet 字段加密密钥")
    INITIAL_ADMIN_PASSWORD: str = Field(..., min_length=8)

    # ===== 可选 =====
    JWT_EXPIRE_MINUTES: int = 1440
    DATABASE_URL: str = "sqlite:///./data/backup.db"
    STORAGE_LOCAL_ROOT: str = "./data/backups"
    LOG_LEVEL: str = "INFO"
    CORS_ORIGINS: str = "http://localhost:5173,http://localhost:8000"
    TZ: str = "UTC"

    @field_validator("SECRET_KEY")
    @classmethod
    def _check_secret_key(cls, v: str) -> str:
        if len(v) < 32:
            raise ValueError("SECRET_KEY 长度必须 >= 32 字符（建议 openssl rand -hex 32）")
        return v

    @property
    def cors_origins_list(self) -> List[str]:
        return [o.strip() for o in self.CORS_ORIGINS.split(",") if o.strip()]


@lru_cache
def get_settings() -> Settings:
    return Settings()  # type: ignore[call-arg]