"""Runtime checks shared by the controller's interpreter probe and workers."""

from __future__ import annotations

import importlib


def storage_backend(config) -> str:
    """Return the effective LangGraph persistence adapter selected by config."""
    checkpoint = getattr(config, "checkpointer", None)
    if checkpoint is not None:
        if checkpoint.type == "postgres":
            from deerflow.runtime.checkpointer.async_provider import _use_postgres_enabled

            return "postgres" if _use_postgres_enabled(checkpoint) else "sqlite"
        if checkpoint.type == "sqlite":
            return "sqlite"
        return "memory"

    database = getattr(config, "database", None)
    backend = getattr(database, "backend", "memory")
    return backend if backend in {"postgres", "sqlite"} else "memory"


def verify_storage_dependencies(config) -> str:
    """Verify the adapters the configured runtime will import, without DB access."""
    backend = storage_backend(config)
    modules = {
        "postgres": (
            "langgraph.checkpoint.postgres.aio",
            "langgraph.store.postgres.aio",
            "psycopg.rows",
            "psycopg_pool",
        ),
        "sqlite": (
            "langgraph.checkpoint.sqlite.aio",
            "langgraph.store.sqlite.aio",
        ),
    }.get(backend, ())
    for module in modules:
        try:
            importlib.import_module(module)
        except ImportError as exc:
            install = (
                "langgraph-checkpoint-postgres psycopg[binary] psycopg-pool"
                if backend == "postgres"
                else "langgraph-checkpoint-sqlite aiosqlite"
            )
            raise RuntimeError(
                f"Worker Python is missing {module} required by the configured "
                f"{backend} chat store; install {install} in the main service "
                "runtime and ensure Workers use that same Python environment"
            ) from exc
    return backend