import assert from "node:assert/strict";
import { test } from "node:test";
import { realtimeRefresh } from "../lib/realtime-refresh";

test("Realtime refresh coalesces bursts and retains changes arriving during a request", async () => {
  const releases: Array<() => void> = [];
  let calls = 0;
  const queue = realtimeRefresh(
    () => {
      calls++;
      return new Promise<void>((resolve) => releases.push(resolve));
    },
    () => assert.fail("unexpected failure"),
  );
  const first = queue.request();
  await queue.request();
  await queue.request();
  assert.equal(calls, 1);
  releases.shift()!();
  await Promise.resolve();
  assert.equal(calls, 2, "One follow-up fetch captures the newest state");
  releases.shift()!();
  await first;
  assert.equal(calls, 2);
  queue.close();
  await queue.request();
  assert.equal(calls, 2);
});

test("Realtime refresh recovers after a failed fetch and cancels queued work on unmount", async () => {
  const errors: unknown[] = [];
  let calls = 0;
  let release: () => void = () => {};
  const queue = realtimeRefresh(
    async () => {
      calls++;
      if (calls === 1) throw Error("offline");
      await new Promise<void>((resolve) => {
        release = resolve;
      });
    },
    (e) => errors.push(e),
  );
  await queue.request();
  assert.equal(errors.length, 1);
  const second = queue.request();
  await queue.request();
  queue.close();
  release();
  await second;
  assert.equal(calls, 2, "Closing prevents the pending follow-up request");
});