"""全局配置：从 .env 读取，Pydantic v2 settings 风格。"""

from functools import lru_cache

from pydantic_settings import BaseSettings, SettingsConfigDict


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

    # ---------- 应用 ----------
    APP_NAME: str = "沃林学生管理系统"
    APP_DESC: str = "基于 FastAPI + SQLAlchemy 2.0 + MySQL 的教务管理系统"
    VERSION: str = "1.0.0"
    DEBUG: bool = True

    # ---------- 数据库 ----------
    DB_DRIVER: str = "mysql+pymysql"          # mysql+pymysql | sqlite
    DB_HOST: str = "127.0.0.1"
    DB_PORT: int = 3306
    DB_USER: str = "root"
    DB_PASSWORD: str = "123456"
    DB_NAME: str = "wolin_sms"
    SQLITE_PATH: str = "./wolin_sms.db"

    DB_ECHO: bool = False
    DB_POOL_SIZE: int = 10
    DB_POOL_RECYCLE: int = 3600

    # ---------- 鉴权 ----------
    JWT_SECRET: str = "wolin-sms-dev-secret-change-me"
    JWT_ALGORITHM: str = "HS256"
    JWT_EXPIRE_MINUTES: int = 720
    AUTH_ENABLED: bool = True                  # 关闭后所有接口免登录（本地排错用）

    # ---------- 初始管理员 ----------
    ADMIN_USERNAME: str = "admin"
    ADMIN_PASSWORD: str = "admin123"

    # ---------- 业务规则 ----------
    SCORE_PASS_LINE: float = 60.0              # 及格线
    SCORE_WARN_LINE: float = 60.0              # 红线预警线（低于即标记"需重点关注"）
    HIGH_SALARY_LINE: float = 10000.0          # 高薪线
    STU_NO_PREFIX: str = "WL"                  # 学号前缀

    @property
    def database_url(self) -> str:
        if self.DB_DRIVER.startswith("sqlite"):
            return f"sqlite:///{self.SQLITE_PATH}"
        return (
            f"{self.DB_DRIVER}://{self.DB_USER}:{self.DB_PASSWORD}"
            f"@{self.DB_HOST}:{self.DB_PORT}/{self.DB_NAME}?charset=utf8mb4"
        )

    @property
    def server_url_without_db(self) -> str:
        """用于首次自动建库（数据库还不存在时）。"""
        return (
            f"{self.DB_DRIVER}://{self.DB_USER}:{self.DB_PASSWORD}"
            f"@{self.DB_HOST}:{self.DB_PORT}/?charset=utf8mb4"
        )


@lru_cache
def get_settings() -> Settings:
    return Settings()


settings = get_settings()