"""FastAPI 应用入口"""

import asyncio
from contextlib import asynccontextmanager

from fastapi import Depends, FastAPI
from loguru import logger

from app.api.agent import router
from app.api.conversations import router as conversation_router
from app.api.materials import router as material_router
from app.core.auth import get_current_user
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.agent.screen_agent import get_screen_agent
    from app.clients.decision import close_decision_engine
    from app.clients.mcp import start_mcp_servers, stop_mcp_servers
    from app.clients.user_center import close_user_center
    from app.observability.tracing import flush_tracing
    from app.processor.graph import build_graph
    from app.services.agent import AgentService
    from app.services.material_mongo import warm_material_cache
    from app.services.persistence import open_persistence

    # 按配置选择 MongoDB 或进程内存，会话记录与图检查点使用同一种存储
    persistence = await open_persistence()
    application.state.conversation_store = persistence.store
    mcp_processes = []
    try:
        # 物料目录启动时载入内存，动作校验与前端接口共用，避免重复查询数据库
        await warm_material_cache(persistence.db)
        # 拉起 mcp_servers.json 中由应用管理的服务；单个服务失败只记录，用到它的请求执行时报错
        mcp_processes = await start_mcp_servers()
        # 提前拉取 MCP 工具并组装 agent，问题在启动时暴露；失败只记录，首个请求会重试
        try:
            await get_screen_agent()
        except Exception as error:
            logger.opt(exception=error).error("screen agent 预先组装失败")
        application.state.agent_service = AgentService(
            build_graph(persistence.checkpointer), persistence.store
        )
        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 stop_mcp_servers(mcp_processes)
        finally:
            try:
                await persistence.close()
            finally:
                try:
                    await close_decision_engine()
                finally:
                    try:
                        await close_user_center()
                    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)
    # 统一 /api 前缀，方便前端代理和反向代理只配置一条规则
    # 会话和 agent 接口需登录，物料目录是全局公开数据
    authenticated = [Depends(get_current_user)]
    application.include_router(router, prefix="/api", dependencies=authenticated)
    application.include_router(
        conversation_router, prefix="/api", dependencies=authenticated
    )
    application.include_router(material_router, prefix="/api")
    return application


app = create_app()