import { Router, type Router as ExpressRouter } from "express";
import { z } from "zod";
import { setPreviewPort } from "../preview-sink.js";

export const previewRouter: ExpressRouter = Router();

const portSchema = z.object({
  port: z.number().int().min(1).max(65535),
});

// Called by the frontend after the LSP `tinymist.startDefaultPreview` command
// returns its (random) data-plane port. The backend stores it so that the
// `/preview` WS and `/preview-app` HTTP proxies know where to dial.
previewRouter.post("/sink", (req, res) => {
  const parsed = portSchema.safeParse(req.body);
  if (!parsed.success) {
    res.status(400).json({ error: parsed.error.issues });
    return;
  }
  setPreviewPort(parsed.data.port);
  res.json({ ok: true, port: parsed.data.port });
});