import { describe, expect, it, vi } from 'vitest';
import { render, screen, waitFor } from '@testing-library/react';
import userEvent from '@testing-library/user-event';
import { QueryClientProvider } from '@tanstack/react-query';

import { NotificationsSettingsSection } from '@/pages/settings/NotificationsSettingsSection';
import {
  createTestQueryClient,
  installFetch,
  json,
  recordedRequests,
  type FetchRoute,
} from './helpers';

/**
 * Web Push в настройках уведомлений (AGENT.md 7.16, Фаза 7): раздел с
 * тумблером, запросом разрешения и честной деградацией, когда браузер или
 * инстанс push не поддерживают.
 */

const ENDPOINT = 'https://fcm.googleapis.com/fcm/send/settings-device';

/** Подписка, которую «выдаёт» браузер после subscribe(). */
function fakeSubscription(
  endpoint = ENDPOINT,
  unsubscribe: () => Promise<boolean> = () => Promise.resolve(true),
) {
  const buffer = (bytes: number[]): ArrayBuffer => new Uint8Array(bytes).buffer;
  return {
    endpoint,
    getKey: (name: string) =>
      name === 'p256dh'
        ? buffer(Array.from({ length: 65 }, (_, index) => index))
        : buffer(Array.from({ length: 16 }, (_, index) => index + 1)),
    unsubscribe,
  } as unknown as PushSubscription;
}

interface BrowserOptions {
  subscription?: PushSubscription | null;
  permission?: NotificationPermission;
  requestPermission?: () => Promise<NotificationPermission>;
}

/** stubBrowser подменяет Notification, PushManager и service worker. */
function stubBrowser(options: BrowserOptions = {}) {
  const unsubscribe = vi.fn(() => Promise.resolve(true));
  const subscription =
    options.subscription === undefined
      ? fakeSubscription(ENDPOINT, unsubscribe)
      : options.subscription;
  const registration = {
    pushManager: {
      getSubscription: vi.fn(() => Promise.resolve(subscription)),
      subscribe: vi.fn(() => Promise.resolve(subscription ?? fakeSubscription())),
    },
  };
  const serviceWorker = {
    getRegistration: vi.fn(() => Promise.resolve(registration)),
    register: vi.fn(() => Promise.resolve(registration)),
    addEventListener: vi.fn(),
    removeEventListener: vi.fn(),
  };
  vi.stubGlobal('PushManager', class PushManagerStub {});
  vi.stubGlobal('Notification', {
    permission: options.permission ?? 'granted',
    requestPermission: vi.fn(
      options.requestPermission ?? (() => Promise.resolve('granted' as const)),
    ),
  });
  Object.defineProperty(navigator, 'serviceWorker', { value: serviceWorker, configurable: true });
  return {
    registration,
    serviceWorker,
    subscription: subscription ?? fakeSubscription(),
    unsubscribe,
  };
}

function renderSection(routes: FetchRoute[]) {
  const fetchMock = installFetch(routes);
  const client = createTestQueryClient();
  render(
    <QueryClientProvider client={client}>
      <NotificationsSettingsSection />
    </QueryClientProvider>,
  );
  return fetchMock;
}

describe('раздел push в настройках уведомлений', () => {
  it('без поддержки push показывает пояснение и не спрашивает сервер', async () => {
    const fetchMock = renderSection([]);
    expect(await screen.findByText(/не поддерживает push-уведомления/i)).toBeInTheDocument();
    expect(screen.queryByTestId('push-toggle')).not.toBeInTheDocument();
    expect(recordedRequests(fetchMock)).toHaveLength(0);
  });

  it('на инстансе без ключей честно сообщает, что push выключен', async () => {
    stubBrowser({ subscription: null });
    renderSection([{ match: '/push/config', response: () => json({ enabled: false }) }]);
    expect(await screen.findByText(/push-уведомления не настроены/i)).toBeInTheDocument();
    expect(screen.queryByTestId('push-toggle')).not.toBeInTheDocument();
  });

  it('включает push: подписывает браузер и отправляет подписку на сервер', async () => {
    stubBrowser({ subscription: null });
    const fetchMock = renderSection([
      {
        match: '/push/config',
        response: () => json({ enabled: true, public_key: 'BPv_public_key' }),
      },
      { match: '/push/subscriptions', method: 'POST', response: () => json({ ok: true }) },
    ]);

    const toggle = await screen.findByTestId('push-toggle');
    await waitFor(() => expect(toggle).toBeEnabled());
    await userEvent.click(toggle);

    expect(await screen.findByTestId('push-active')).toBeInTheDocument();
    const request = recordedRequests(fetchMock).find(
      (item) => item.method === 'POST' && item.url.includes('/push/subscriptions'),
    );
    expect(request?.body).toMatchObject({ endpoint: ENDPOINT });
  });

  it('показывает активное состояние, если устройство уже подписано', async () => {
    stubBrowser();
    renderSection([
      {
        match: '/push/config',
        response: () => json({ enabled: true, public_key: 'BPv_public_key' }),
      },
    ]);
    expect(await screen.findByTestId('push-active')).toBeInTheDocument();
    expect(await screen.findByTestId('push-toggle')).toHaveTextContent(/выключить/i);
  });

  it('выключает push: отписывает браузер и сервер', async () => {
    const { unsubscribe } = stubBrowser();
    const fetchMock = renderSection([
      {
        match: '/push/config',
        response: () => json({ enabled: true, public_key: 'BPv_public_key' }),
      },
      {
        match: '/push/subscriptions',
        method: 'DELETE',
        response: () => json({ ok: true }),
      },
    ]);

    const toggle = await screen.findByTestId('push-toggle');
    await waitFor(() => expect(toggle).toHaveTextContent(/выключить/i));
    await userEvent.click(toggle);

    await waitFor(() => expect(screen.queryByTestId('push-active')).not.toBeInTheDocument());
    expect(unsubscribe).toHaveBeenCalled();
    const request = recordedRequests(fetchMock).find(
      (item) => item.method === 'DELETE' && item.url.includes('/push/subscriptions'),
    );
    expect(request?.url).toContain(encodeURIComponent(ENDPOINT));
  });

  it('объясняет отказ браузера в разрешении', async () => {
    stubBrowser({
      subscription: null,
      permission: 'denied',
      requestPermission: () => Promise.resolve('denied' as const),
    });
    renderSection([
      {
        match: '/push/config',
        response: () => json({ enabled: true, public_key: 'BPv_public_key' }),
      },
    ]);
    expect(await screen.findByTestId('push-denied')).toBeInTheDocument();
  });

  it('показывает ошибку загрузки параметров и умеет повторить', async () => {
    stubBrowser({ subscription: null });
    renderSection([
      {
        match: '/push/config',
        response: () => json({ error: { code: 'internal.error', message: 'x' } }, 500),
      },
    ]);
    expect(await screen.findByRole('alert')).toBeInTheDocument();
  });
});