from contextlib import asynccontextmanager

from core_shared.observability import add_observability
from core_shared.security import add_internal_service_auth
from fastapi import FastAPI

from app.api.routes import router
from app.bootstrap.settings import KnowledgeServiceSettings
from app.db.session import build_session_factory
from app.worker import BackgroundKnowledgeWorker, build_worker_key


@asynccontextmanager
async def lifespan(app: FastAPI):
    settings: KnowledgeServiceSettings = app.state.settings
    worker: BackgroundKnowledgeWorker | None = None
    if settings.auto_worker_enabled:
        worker = BackgroundKnowledgeWorker(
            settings=settings,
            session_factory=app.state.session_factory,
            worker_key=f"api-{build_worker_key()}")
        app.state.background_knowledge_worker = worker
        worker.start()
    try:
        yield
    finally:
        if worker is not None:
            worker.stop(timeout_seconds=settings.auto_worker_stop_timeout_seconds)


def create_app() -> FastAPI:
    settings = KnowledgeServiceSettings()
    app = FastAPI(
        title="agent-platform knowledge-service",
        version="0.1.0",
        lifespan=lifespan)
    app.state.settings = settings
    app.state.session_factory = build_session_factory(settings)
    add_observability(app, settings.service_name)
    add_internal_service_auth(app, settings)
    app.include_router(router, prefix="/knowledge", tags=["knowledge"])
    return app