import { describe, it, expect, beforeEach, afterEach, vi } from 'vitest';
import { getScenarioRuntime, RudderClient } from '../../src/client/RudderClient.js';
import { createFakeTokenStore } from '../helpers/FakeTokenStore.js';
import { createFakeGateway, type FakeGateway } from '../helpers/fakeGateway.js';
import { createMemoryPlanStore, stubDeterministicUuid } from '../helpers/memoryPlanStore.js';
import { plan } from '../helpers/plan.js';
import type { StoreSession, WaitSession } from '../../src/scenario/engine/sessions.js';

const MINUTE = 60_000;

describe('E2E: scenario state survives a reload', () => {
  let gateway: FakeGateway;
  // Shared backing store mimics IndexedDB persisting across page loads.
  const backing = { value: null as string | null };

  function clientWithSharedStore(): RudderClient {
    return new RudderClient({
      baseUrl: 'https://api.test.rudder.build',
      projectKey: 'test-project',
      tokenStore: createFakeTokenStore(),
      runtime: { planStateStore: createMemoryPlanStore(backing), loginEvent: null },
    });
  }

  beforeEach(() => {
    stubDeterministicUuid();
    vi.useFakeTimers();
    backing.value = null;
    gateway = createFakeGateway();
    gateway.onEvent(
      'session_start',
      plan('offer_flow')
        .node('wait_intro', 'wait', { duration: 1, unit: 'minutes' })
        .node('offer', 'store', { message: 'Limited starter pack!' })
        .edge('wait_intro', 'onComplete', 'offer')
        .build(),
    );
    gateway.install();
  });

  afterEach(() => {
    vi.useRealTimers();
    vi.unstubAllGlobals();
  });

  it('a wait started before reload resumes and fires the offer after reload', async () => {
    // --- Session 1: trigger the scenario, then "close the tab" mid-wait ---
    const client1 = clientWithSharedStore();
    await client1.auth.loginWithDevice();
    const runtime1 = await getScenarioRuntime(client1);
    await runtime1.send('session_start');
    expect(runtime1.isRunning).toBe(true);
    expect(backing.value).toBeTruthy(); // run was persisted

    // --- Session 2: fresh client, same persisted state (page reload) ---
    const client2 = clientWithSharedStore();
    const runtime2 = await getScenarioRuntime(client2);
    const resumedWaits: WaitSession[] = [];
    let offer: StoreSession | undefined;
    runtime2.onWait = (s) => resumedWaits.push(s);
    runtime2.onStore = (s) => { offer = s; };

    await client2.auth.loginWithDevice();

    // The wait node was rehydrated and re-dispatched.
    expect(runtime2.isRunning).toBe(true);
    expect(resumedWaits).toHaveLength(1);
    expect(offer).toBeUndefined();

    // The remaining wait time still elapses → the offer surfaces on the new client.
    await vi.advanceTimersByTimeAsync(MINUTE);
    expect(offer).toBeDefined();
    expect(offer!.get('message', '')).toBe('Limited starter pack!');
  });
});