"""Backend detection — SQLITE (default) or POSTGRES based on DATABASE_URL."""
from __future__ import annotations

import os
from enum import Enum


class Backend(Enum):
    SQLITE = "sqlite"
    POSTGRES = "postgres"


def _detect() -> Backend:
    url = os.environ.get("DATABASE_URL", "")
    if url.startswith(("postgresql://", "postgres://", "postgresql+psycopg://")):
        return Backend.POSTGRES
    return Backend.SQLITE


BACKEND: Backend = _detect()