Source

// Pairing a parent device with a baby station: a 6-digit code resolves to the station's room id
// (one rate-limited try per code), or a QR code carries the room id itself.
import { get, set, serverTimestamp } from "@bounded-sh/client";
import { me, explain } from "./lib/bounded";
import { randomId } from "./lib/rtc";
import { pairings, type Pairing } from "./lib/store";

export async function resolveCode(code: string): Promise<string> {
  const uid = await me();
  const tryPath = `codetries/${uid}/t/${code}`;
  if (!(await get(tryPath))) {
    try {
      await set(tryPath, { n: 1 });
    } catch (err) {
      const e = err as { decline?: { boundary?: { cause?: string } }; message?: string };
      if (e?.decline?.boundary?.cause === "cap_exceeded" || /code_tries|invariant|409/.test(String(e?.message))) {
        throw new Error("Too many codes tried. Wait a few minutes, or scan the QR code instead.");
      }
      throw new Error(explain(err));
    }
  }
  const doc = await get(`codes/${code}`);
  if (!doc?.room) throw new Error("That code did not work. Check the code on the baby station. Each code lasts 10 minutes.");
  return String(doc.room);
}

export async function joinRoom(room: string, deviceName: string): Promise<Pairing> {
  const uid = await me();
  const path = `rooms/${room}/joins/${uid}`;
  const joined = await get(path);
  if (joined?.role === "baby") throw new Error("This device is that baby station. Pair from another phone or laptop.");
  if (joined) {
    if (joined.name !== deviceName) await set(path, { name: deviceName });
  } else {
    try {
      await set(path, { role: "parent", name: deviceName, at: serverTimestamp() });
    } catch {
      const banned = await get(`rooms/${room}/bans/${uid}`).catch(() => null);
      throw new Error(banned ? "This baby station removed this device, so it cannot pair again." : "That baby station could not be found. Ask for a new code.");
    }
  }
  const station = await get(`rooms/${room}`);
  return pairings.save(room, String(station?.name || "Baby station"), randomId(8));
}