from contextlib import asynccontextmanager

from fastapi import FastAPI
from fastapi.staticfiles import StaticFiles
from sqlalchemy import text
from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker, create_async_engine

from app.config import settings, ensure_dirs, STATIC_DIR
from app.models.database import Base


# 后台推送任务的独立连接写结果可能撞上 SMTP 窗口内持有的写锁,默认 5s
# 忙等上限低于 SMTP 最坏时长,抬到 30s;等待发生在 aiosqlite 工作线程,不阻塞事件循环
engine = create_async_engine(settings.DATABASE_URL, echo=settings.APP_DEBUG,
                             connect_args={"timeout": 30})
async_session = async_sessionmaker(engine, class_=AsyncSession, expire_on_commit=False)


async def _migrate(conn):
    result = await conn.execute(text("PRAGMA table_info(conversations)"))
    columns = {row[1] for row in result}
    if "page_token" not in columns:
        await conn.execute(text(
            "ALTER TABLE conversations ADD COLUMN page_token VARCHAR(64)"
        ))

    result = await conn.execute(text("PRAGMA table_info(evaluations)"))
    columns = {row[1] for row in result}
    if "correction_count" not in columns:
        await conn.execute(text(
            "ALTER TABLE evaluations ADD COLUMN correction_count INTEGER DEFAULT 0"
        ))


@asynccontextmanager
async def lifespan(app: FastAPI):
    ensure_dirs()
    async with engine.begin() as conn:
        await conn.run_sync(Base.metadata.create_all)
        await _migrate(conn)
    # 询盘推送(设计 8.2): 清扫崩溃遗留的 stale pending → failed
    # 函数内导入: lead_push_service 顶部 from app.main import async_session,
    # 顶层互相导入会循环
    from app.services.lead_push_service import sweep_stale_pending
    await sweep_stale_pending()
    yield


app = FastAPI(title="HESUPIPE AI 客服", lifespan=lifespan)

from app.api.routes.chat import router as chat_router
from app.api.routes.admin import router as admin_router
from app.api.routes.chat_rest import router as chat_rest_router
app.include_router(chat_router)
app.include_router(admin_router)
app.include_router(chat_rest_router)

app.mount("/static", StaticFiles(directory=str(STATIC_DIR)), name="static")


@app.middleware("http")
async def static_no_cache(request, call_next):
    """静态资源协商缓存(2026-09-30 线上事件): 无 Cache-Control 时浏览器对
    widget.js 走启发式缓存,修复部署后用户端仍跑旧脚本。no-cache=每次用
    etag 轻量协商,有更新即时生效,未变则 304 几乎零开销。"""
    resp = await call_next(request)
    if request.url.path.startswith("/static/"):
        resp.headers["Cache-Control"] = "no-cache"
    return resp


@app.get("/")
async def index():
    from fastapi.responses import FileResponse
    return FileResponse(str(STATIC_DIR / "chat.html"))


@app.get("/admin")
async def admin_page():
    from fastapi.responses import FileResponse
    return FileResponse(str(STATIC_DIR / "admin.html"))


@app.get("/health")
async def health():
    return {"status": "ok"}