import { afterEach, describe, expect, mock, test } from "bun:test";
import {
  startRealtimeRefresh,
  type RealtimeRefreshHandlers,
} from "@/lib/realtime-refresh";

const cleanups: Array<() => void> = [];

afterEach(() => {
  for (const clean of cleanups.splice(0)) clean();
});

function setup(
  filter: Parameters<typeof startRealtimeRefresh>[0]["filter"],
  debounceMs = 10,
) {
  let handlers: RealtimeRefreshHandlers | undefined;
  const refresh = mock(() => {});
  const cleanSubscription = mock(() => {});
  const clean = startRealtimeRefresh({
    filter,
    debounceMs,
    refresh,
    subscribe(nextHandlers) {
      handlers = nextHandlers;
      return { clean: cleanSubscription };
    },
  });
  cleanups.push(clean);
  return {
    get handlers() {
      if (!handlers) throw new Error("Handlers were not registered.");
      return handlers;
    },
    refresh,
    clean,
    cleanSubscription,
  };
}

describe("leaderboard realtime refresh", () => {
  test("filters XP and VC events by leaderboard scope", async () => {
    const xp = setup({ kind: "xp" });
    xp.handlers.onVc({ channelId: "1" });
    xp.handlers.onXp();
    await Bun.sleep(20);
    expect(xp.refresh).toHaveBeenCalledTimes(1);

    const selectedVc = setup({ kind: "vc", channelId: "2" });
    selectedVc.handlers.onVc({ channelId: "1" });
    await Bun.sleep(20);
    expect(selectedVc.refresh).not.toHaveBeenCalled();
    selectedVc.handlers.onVc({ channelId: "2" });
    await Bun.sleep(20);
    expect(selectedVc.refresh).toHaveBeenCalledTimes(1);

    const allVc = setup({ kind: "vc" });
    allVc.handlers.onVc({ channelId: "any" });
    await Bun.sleep(20);
    expect(allVc.refresh).toHaveBeenCalledTimes(1);
  });

  test("refreshes after reconnect but not the initial connection", async () => {
    const subscription = setup({ kind: "xp" });
    subscription.handlers.onOpen();
    await Bun.sleep(20);
    expect(subscription.refresh).not.toHaveBeenCalled();

    subscription.handlers.onOpen();
    await Bun.sleep(20);
    expect(subscription.refresh).toHaveBeenCalledTimes(1);
  });

  test("debounces event bursts and cleans timers and subscriptions", async () => {
    const subscription = setup({ kind: "xp" }, 20);
    subscription.handlers.onXp();
    subscription.handlers.onXp();
    subscription.handlers.onXp();
    await Bun.sleep(30);
    expect(subscription.refresh).toHaveBeenCalledTimes(1);

    subscription.handlers.onXp();
    subscription.clean();
    await Bun.sleep(30);
    expect(subscription.refresh).toHaveBeenCalledTimes(1);
    expect(subscription.cleanSubscription).toHaveBeenCalledTimes(1);
  });
});