// LaunchDarkly TestData source - from launchdarkly.com/docs/sdk/features/test-data-sources:
// "The test data source allows you to mock the behavior of a LaunchDarkly
//  SDK so it has predictable behavior when evaluating flags."
import { TestData } from '@launchdarkly/node-server-sdk';

describe('checkout-kill-switch: switch-OFF', () => {
  let td: TestData;

  beforeEach(() => {
    td = TestData.dataSource();
    // Flag starts ON (normal production state)
    td.update(td.flag('checkout-kill').boolVariation(true));
  });

  test('flag OFF - checkout shows maintenance message, not an error', async () => {
    td.update(td.flag('checkout-kill').boolVariation(false));
    const result = await renderCheckout({ flagClient: clientWith(td) });
    expect(result.status).toBe('degraded');
    expect(result.userMessage).toMatch(/temporarily unavailable/i);
    expect(result.errorThrown).toBe(false);
  });

  test('flag OFF - degraded path does not call payment provider', async () => {
    td.update(td.flag('checkout-kill').boolVariation(false));
    const paymentSpy = jest.spyOn(paymentProvider, 'charge');
    await renderCheckout({ flagClient: clientWith(td) });
    expect(paymentSpy).not.toHaveBeenCalled();
  });
});

// Simulate an unreachable flag service by providing a failing provider
// OpenFeature InMemory provider with forced error, then OpenFeature hook
// verifies error code is surfaced (openfeature.dev/docs/reference/concepts/hooks):
// "The error hook runs only in the case that flag evaluation has proceeded
//  abnormally."
import { OpenFeature, InMemoryProvider } from '@openfeature/server-sdk';

describe('checkout-kill-switch: fail-static default', () => {
  test('provider unavailable - default OFF is served, app does not crash', async () => {
    // Register a provider that always throws
    await OpenFeature.setProviderAndWait(new AlwaysErrorProvider());
    const client = OpenFeature.getClient();

    // Default is false (feature disabled) - the safe side for a kill-switch
    const value = await client.getBooleanValue('checkout-kill', false);
    expect(value).toBe(false);

    // Application layer must handle the default without throwing
    await expect(renderCheckout({ featureEnabled: value })).resolves.not.toThrow();
  });

  test('provider unavailable - error hook fires and is logged', async () => {
    const errorEvents: string[] = [];
    OpenFeature.addHooks({
      error: (_ctx, err) => { errorEvents.push(err.message); }
    });
    await OpenFeature.setProviderAndWait(new AlwaysErrorProvider());
    const client = OpenFeature.getClient();
    await client.getBooleanValue('checkout-kill', false);
    expect(errorEvents.length).toBeGreaterThan(0);
  });
});

describe('checkout-kill-switch: kill latency', () => {
  test('flag re-evaluated per request - not cached application-side', async () => {
    const td = TestData.dataSource();
    td.update(td.flag('checkout-kill').boolVariation(true));
    const client = clientWith(td);

    const before = await isCheckoutEnabled(client);
    expect(before).toBe(true);

    // Flip the kill-switch
    td.update(td.flag('checkout-kill').boolVariation(false));

    // Next evaluation reflects the flip without a process restart
    const after = await isCheckoutEnabled(client);
    expect(after).toBe(false);
  });

  // Integration note: with LaunchDarkly streaming (server SDK default),
  // flag changes propagate in near-real-time over the SSE stream.
  // With Unleash polling (default 15s interval per unleash.io/docs),
  // the worst-case lag equals the polling interval.
  // Agree on the acceptable window with SRE and add a staging smoke test.
});

describe('checkout-kill-switch: mid-flight flip', () => {
  test('in-progress order is not corrupted when kill-switch flips mid-checkout', async () => {
    const td = TestData.dataSource();
    td.update(td.flag('checkout-kill').boolVariation(true));
    const client = clientWith(td);

    // Begin a multi-step checkout; flip the flag after step 1
    const order = await startCheckout(client);  // Step 1: reserve inventory

    // Simulate operator flipping the kill-switch during step 2
    td.update(td.flag('checkout-kill').boolVariation(false));

    const result = await completeCheckout(order);  // Step 2: charge + confirm

    // Either fully committed or fully rolled back - never partial
    expect(['committed', 'rolled_back']).toContain(result.state);
    if (result.state === 'rolled_back') {
      // Inventory reservation must be released
      expect(await inventoryReserved(order.itemId)).toBe(false);
    }
  });
});

// tests/feature-flags/checkout-kill.test.ts
//
// Kill-switch flag: checkout-kill
// Safe default: false (checkout disabled)
// Streaming SDK: LaunchDarkly server SDK (near-real-time propagation)

import { TestData } from '@launchdarkly/node-server-sdk';

describe('checkout-kill-switch', () => {
  let td: TestData;
  let client: LDClient;

  beforeEach(async () => {
    td = TestData.dataSource();
    client = buildTestClient(td);
    await client.waitForInitialization();
  });

  afterEach(() => client.close());

  // Category 1: switch-OFF degrades gracefully
  test('OFF - renders maintenance banner, not error page', async () => {
    td.update(td.flag('checkout-kill').boolVariation(false));
    const page = await renderCheckoutPage(client);
    expect(page.banner).toBe('maintenance');
    expect(page.httpStatus).toBe(200);
  });

  // Category 2: fail-static default
  test('SDK error - default false served, page still renders', async () => {
    const page = await renderCheckoutPage(brokenClient());
    expect(page.checkoutEnabled).toBe(false);
    expect(page.httpStatus).toBe(200);
  });

  // Category 3: re-evaluated per request
  test('flag flip reflected on next evaluation without restart', async () => {
    td.update(td.flag('checkout-kill').boolVariation(true));
    expect(await checkoutEnabled(client)).toBe(true);
    td.update(td.flag('checkout-kill').boolVariation(false));
    expect(await checkoutEnabled(client)).toBe(false);
  });

  // Category 4: no mid-flight corruption
  test('kill mid-checkout leaves order committed or fully rolled back', async () => {
    td.update(td.flag('checkout-kill').boolVariation(true));
    const order = await startCheckout(client);
    td.update(td.flag('checkout-kill').boolVariation(false));
    const result = await completeCheckout(order);
    expect(['committed', 'rolled_back']).toContain(result.state);
  });
});