"""FastAPI 应用入口"""

import asyncio
from contextlib import asynccontextmanager

from fastapi import FastAPI
from loguru import logger

from app.api.agent import router
from app.core.exceptions import register_exception_handlers
from app.core.logging import setup_logging


@asynccontextmanager
async def lifespan(application: FastAPI):
    setup_logging()
    from app.clients.decision import close_decision_engine
    from app.observability.tracing import flush_tracing
    from app.processor.graph import build_graph
    from app.services.agent import AgentService

    application.state.agent_service = AgentService(build_graph())
    try:
        yield
    finally:
        # 共享客户端只在应用退出时关闭，追踪刷新放到线程避免阻塞事件循环
        try:
            await close_decision_engine()
        finally:
            try:
                await asyncio.to_thread(flush_tracing)
            finally:
                await logger.complete()


def create_app() -> FastAPI:
    application = FastAPI(title="Screen Agent API", lifespan=lifespan)
    # 统一处理请求校验、HTTP 错误和未捕获异常
    register_exception_handlers(application)
    application.include_router(router)
    return application


app = create_app()