class Config:
    """
    Configuration settings for SimpleVecDB, loaded from environment variables.

    Attributes:
        EMBEDDING_MODEL: The default embedding model repo id or alias.
        EMBEDDING_CACHE_DIR: Directory path for caching embedding models.
        EMBEDDING_MODEL_REGISTRY: Mapping of model aliases to repo ids.
        EMBEDDING_MODEL_REGISTRY_LOCKED: If True, only allow listed models.
        EMBEDDING_BATCH_SIZE: Optimal batch size for embedding requests.
        EMBEDDING_SERVER_MAX_REQUEST_ITEMS: Max items per embedding request.
        EMBEDDING_SERVER_API_KEYS: Set of valid API keys for the embedding server.
        DATABASE_PATH: Path to the SimpleVecDB database file.
        SERVER_HOST: Host address for the SimpleVecDB server.
        SERVER_PORT: Port number for the SimpleVecDB server.
    """

    # Embedding Model
    EMBEDDING_MODEL: str = os.getenv("EMBEDDING_MODEL", "TaylorAI/bge-micro-v2")
    EMBEDDING_CACHE_DIR: str = os.getenv(
        "EMBEDDING_CACHE_DIR", str(Path.home() / ".cache" / "simplevecdb")
    )
    _registry_env = os.getenv("EMBEDDING_MODEL_REGISTRY")
    EMBEDDING_MODEL_REGISTRY: dict[str, str] = _parse_registry(
        _registry_env, EMBEDDING_MODEL
    )
    EMBEDDING_MODEL_REGISTRY_LOCKED: bool = _parse_bool_env(
        os.getenv("EMBEDDING_MODEL_REGISTRY_LOCKED"), True
    )
    # Auto-detect optimal batch size if not explicitly set
    _batch_size_env = os.getenv("EMBEDDING_BATCH_SIZE")
    EMBEDDING_BATCH_SIZE: int = (
        int(_batch_size_env)
        if _batch_size_env is not None
        else get_optimal_batch_size()
    )
    _request_limit_env = os.getenv("EMBEDDING_SERVER_MAX_REQUEST_ITEMS") or os.getenv(
        "EMBEDDING_SERVER_MAX_BATCH"
    )
    EMBEDDING_SERVER_MAX_REQUEST_ITEMS: int = (
        int(_request_limit_env) if _request_limit_env else max(32, EMBEDDING_BATCH_SIZE)
    )
    EMBEDDING_SERVER_API_KEYS: set[str] = _parse_api_keys(
        os.getenv("EMBEDDING_SERVER_API_KEYS")
    )

    # Database
    DATABASE_PATH: str = os.getenv("DATABASE_PATH", ":memory:")

    # Server
    SERVER_HOST: str = os.getenv(
        "SERVER_HOST", "127.0.0.1"
    )  # Localhost only by default
    SERVER_PORT: int = int(os.getenv("SERVER_PORT", "8000"))

    @classmethod
    def from_env(cls) -> "Config":
        """Load configuration from environment variables."""
        return cls()