"""Shared clients that live for the lifetime of the FastAPI process.

We keep one AtomicClient, one EmbeddingClient, and one TagResolver in module
state. FastAPI dependencies pull them out so handlers stay clean.

Initialized from app.py's lifespan context manager at startup; closed on
shutdown.
"""

from __future__ import annotations

from dataclasses import dataclass

from shared.atomic_api import AtomicClient
from shared.embedding_client import EmbeddingClient
from shared.llm_client import LlmClient
from shared.taxonomy import TagResolver


@dataclass(slots=True)
class AppState:
    atomic: AtomicClient
    embed: EmbeddingClient
    llm: LlmClient
    resolver: TagResolver


# Module-level singleton, populated by the lifespan handler.
_state: AppState | None = None


def set_state(state: AppState) -> None:
    global _state
    _state = state


def get_state() -> AppState:
    if _state is None:
        raise RuntimeError(
            "brain_api state not initialized — FastAPI lifespan must run first"
        )
    return _state