import os
from dataclasses import dataclass


def as_bool(value: str | None, default: bool = False) -> bool:
    if value is None:
        return default
    return value.lower() in {"1", "true", "yes", "on"}


@dataclass(frozen=True)
class Settings:
    database_url: str
    app_env: str
    allowed_origins: tuple[str, ...]
    session_cookie_name: str
    session_cookie_secure: bool
    session_ttl_seconds: int
    csrf_secret: str
    email_verification_enabled: bool
    phone_verification_enabled: bool
    test_free_period_limit: int
    test_vip_period_limit: int

    @classmethod
    def from_env(cls) -> "Settings":
        database_url = os.getenv("DATABASE_URL")
        if not database_url:
            raise RuntimeError("DATABASE_URL is required")
        origins = tuple(item.strip().rstrip("/") for item in os.getenv("ALLOWED_ORIGINS", "").split(",") if item.strip())
        return cls(
            database_url=database_url,
            app_env=os.getenv("APP_ENV", "test"),
            allowed_origins=origins,
            session_cookie_name=os.getenv("SESSION_COOKIE_NAME", "kaotings_session"),
            session_cookie_secure=as_bool(os.getenv("SESSION_COOKIE_SECURE")),
            session_ttl_seconds=int(os.getenv("SESSION_TTL_SECONDS", "2592000")),
            csrf_secret=os.getenv("CSRF_SECRET", "development-only-change-me"),
            email_verification_enabled=as_bool(os.getenv("EMAIL_VERIFICATION_ENABLED")),
            phone_verification_enabled=as_bool(os.getenv("PHONE_VERIFICATION_ENABLED")),
            test_free_period_limit=int(os.getenv("TEST_FREE_PERIOD_LIMIT", "10000")),
            test_vip_period_limit=int(os.getenv("TEST_VIP_PERIOD_LIMIT", "100000")),
        )


settings = Settings.from_env()