import os
from fastapi import FastAPI, Request
from fastapi.responses import PlainTextResponse, JSONResponse
import uvicorn

# HF Spaces 开启持久存储时 /data 可持久；否则退回容器本地目录（冷启动会丢，
# 靠本地 publisher 的心跳每 60s 重推自愈，开发机够用）。
try:
    os.makedirs("/data", exist_ok=True)
    STATE = "/data/current_url.txt"
except OSError:
    STATE = os.path.join(os.getcwd(), "current_url.txt")

app = FastAPI()


def read() -> str:
    try:
        with open(STATE) as f:
            return f.read().strip()
    except FileNotFoundError:
        return ""


@app.get("/")
@app.get("/url")
async def get_url():
    # no-store：保证设备/客户端每次都拿到最新地址，不被 CDN/浏览器缓存坑到
    return PlainTextResponse(read(), headers={"Cache-Control": "no-store"})


@app.post("/url")
async def set_url(request: Request):
    body = (await request.body()).decode().strip()
    if not body:
        return JSONResponse({"error": "empty body"}, status_code=400)
    with open(STATE, "w") as f:
        f.write(body)
    return JSONResponse({"ok": True, "url": body})


if __name__ == "__main__":
    uvicorn.run(app, host="0.0.0.0", port=7860)