import logging
from functools import lru_cache

from pydantic_settings import BaseSettings, SettingsConfigDict

logger = logging.getLogger(__name__)


class Settings(BaseSettings):
    model_config = SettingsConfigDict(env_file=".env")

    secret_key: str
    sqlalchemy_database_url: str = "sqlite:///./gatekeeper.db"
    mqtt_host: str = "localhost"
    mqtt_port: int = 1883
    mock: bool = True
    alembic_config: str = "./alembic.ini"

    disable_cards: bool = False
    mifare_app_master_key: str | None = None
    mifare_acl_read_base_key: str | None = None
    mifare_acl_write_base_key: str | None = None


@lru_cache(1)
def _create_settings():
    settings = Settings()
    if not settings.disable_cards:
        missing = [
            name.upper()
            for name in (
                "mifare_app_master_key",
                "mifare_acl_read_base_key",
                "mifare_acl_write_base_key",
            )
            if not getattr(settings, name)
        ]
        if missing:
            logger.critical(
                "Missing environment variable for scanner start: %s"
                "Card scanner and related funcionality is disabled!",
                ", ".join(missing),
            )
            settings.disable_cards = True
    return settings


class _SettingsProxy:
    _instance: Settings | None = None

    def _load(self) -> Settings:
        if self._instance is None:
            self._instance = _create_settings()
        return self._instance

    def __getattr__(self, name: str):
        return getattr(self._load(), name)

    def __setattr__(self, name: str, value):
        if name == "_instance":
            super().__setattr__(name, value)
        else:
            setattr(self._load(), name, value)

    def reset(self) -> None:
        self._instance = None
        _create_settings.cache_clear()


settings = _SettingsProxy()