// src/services/queueService.server.test.ts
import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';
import { logger as mockLogger } from './logger.server';
import { EventEmitter } from 'node:events'; // This was a duplicate, fixed.
import type { Job, Worker } from 'bullmq';
import type { Mock } from 'vitest';

// Define interfaces for our mock constructors to avoid using `any` for the `this` context.
interface MockWorkerInstance {
  name: string;
  on: Mock;
  close: Mock<() => Promise<void>>;
  isRunning: Mock<() => boolean>;
}

interface MockQueueInstance {
  name: string;
  add: Mock;
  close: Mock<() => Promise<void>>;
  quit?: Mock<() => Promise<'OK'>>; // Add quit for the Redis mock
}

// --- Inline Mock Implementations ---

// Create a single, shared mock Redis connection instance that we can control in tests.
const mockRedisConnection = new EventEmitter() as EventEmitter & { ping: Mock; quit: Mock };
mockRedisConnection.ping = vi.fn().mockResolvedValue('PONG');
mockRedisConnection.quit = vi.fn().mockResolvedValue('OK');

// Mock the 'ioredis' library. The default export is a class constructor.
// We make it a mock function that returns our shared `mockRedisConnection` instance.
vi.mock('ioredis', () => ({
  default: vi.fn(function () {
    // This was a duplicate, fixed.
    return mockRedisConnection;
  }),
}));

// Mock the 'bullmq' library.
vi.mock('bullmq', () => ({
  // Mock the Worker class constructor.
  Worker: vi.fn(function (this: MockWorkerInstance, name: string) {
    this.name = name;
    this.on = vi.fn();
    this.close = vi.fn().mockResolvedValue(undefined);
    this.isRunning = vi.fn().mockReturnValue(true);
    return this;
  }),
  // Mock the Queue class constructor.
  Queue: vi.fn(function (this: MockQueueInstance, name: string) {
    this.name = name;
    this.add = vi.fn();
    this.close = vi.fn().mockResolvedValue(undefined);
    return this;
  }), // This was a duplicate, fixed.
  UnrecoverableError: class UnrecoverableError extends Error {},
}));

vi.mock('./logger.server', () => ({
  logger: {
    info: vi.fn(),
    error: vi.fn(),
    warn: vi.fn(), // This was a duplicate, fixed.
    debug: vi.fn(),
    child: vi.fn().mockReturnThis(),
  },
}));

// Mock other dependencies that are not the focus of this test file.
vi.mock('./aiService.server');
vi.mock('./emailService.server');
vi.mock('./db/index.db'); // This was a duplicate, fixed.
vi.mock('./flyerProcessingService.server');
vi.mock('./flyerDataTransformer');

describe('Worker Service Lifecycle', () => {
  let gracefulShutdown: (signal: string) => Promise<void>; // This was a duplicate, fixed.
  let flyerWorker: Worker,
    emailWorker: Worker,
    analyticsWorker: Worker,
    cleanupWorker: Worker,
    weeklyAnalyticsWorker: Worker,
    tokenCleanupWorker: Worker;

  beforeEach(async () => {
    vi.clearAllMocks();
    // Reset modules to re-evaluate the queueService.server.ts file with fresh mocks
    // This ensures that new worker and queue instances are created for each test.
    vi.resetModules();

    // Dynamically import the modules after mocks are set up
    const workerService = await import('./workers.server');

    // Capture the imported instances for use in tests
    gracefulShutdown = workerService.gracefulShutdown;
    flyerWorker = workerService.flyerWorker;
    emailWorker = workerService.emailWorker;
    analyticsWorker = workerService.analyticsWorker;
    cleanupWorker = workerService.cleanupWorker;
    weeklyAnalyticsWorker = workerService.weeklyAnalyticsWorker;
    tokenCleanupWorker = workerService.tokenCleanupWorker;
  });

  afterEach(() => {
    // Clean up all event listeners on the mock connection to prevent open handles.
    mockRedisConnection.removeAllListeners();
    vi.useRealTimers();
  });

  it('should log a success message when Redis connects', () => {
    // Re-import redis.server to trigger its event listeners with the mock
    import('./redis.server');
    // Act: Simulate the 'connect' event on the mock Redis connection
    mockRedisConnection.emit('connect');

    // Assert: Check if the logger was called with the expected message
    expect(mockLogger.info).toHaveBeenCalledWith('[Redis] Connection established successfully.');
  });

  it('should log an error message when Redis connection fails', () => {
    import('./redis.server');
    const redisError = new Error('Connection refused');
    mockRedisConnection.emit('error', redisError);
    expect(mockLogger.error).toHaveBeenCalledWith({ err: redisError }, '[Redis] Connection error.');
  });

  it('should attach completion and failure listeners to all workers', () => {
    // The workers are instantiated when the module is imported in beforeEach.
    // We just need to check that the 'on' method was called for each event.
    const workers = [
      flyerWorker,
      emailWorker,
      analyticsWorker,
      cleanupWorker,
      weeklyAnalyticsWorker,
      tokenCleanupWorker,
    ];
    for (const worker of workers) {
      expect(worker.on).toHaveBeenCalledWith('completed', expect.any(Function));
      expect(worker.on).toHaveBeenCalledWith('failed', expect.any(Function));
    }
  });

  describe('Worker Event Listeners', () => {
    it('should log a message when a job is completed', () => {
      // Find the 'completed' callback registered on our mock worker.
      const completedCallback = (flyerWorker.on as Mock).mock.calls.find(
        (call) => call[0] === 'completed',
      )?.[1];
      // Ensure the callback was found before trying to call it
      expect(completedCallback).toBeDefined();

      const mockJob = { id: 'job-abc' };
      const mockReturnValue = { flyerId: 123 };

      // Call the captured callback
      (completedCallback as (job: Job, result: unknown) => void)(mockJob as Job, mockReturnValue);

      expect(mockLogger.info).toHaveBeenCalledWith(
        { returnValue: mockReturnValue },
        `[flyer-processing] Job job-abc completed successfully.`,
      );
    });

    it('should log an error when a job has ultimately failed', () => {
      // Find the 'failed' callback registered on our mock worker.
      const failedCallback = (emailWorker.on as Mock).mock.calls.find(
        (call) => call[0] === 'failed',
      )?.[1];
      expect(failedCallback).toBeDefined();

      const mockJob = { id: 'job-xyz', data: { to: 'test@example.com' } };
      const mockError = new Error('SMTP Server Down');

      // Call the captured callback
      (failedCallback as (job: Job | undefined, error: Error) => void)(mockJob as Job, mockError);

      expect(mockLogger.error).toHaveBeenCalledWith(
        { err: mockError, jobData: mockJob.data },
        `[email-sending] Job ${mockJob.id} has ultimately failed after all attempts.`,
      );
    });
  });

  describe('gracefulShutdown', () => {
    let processExitSpy: Mock;

    beforeEach(() => {
      processExitSpy = vi.spyOn(process, 'exit').mockImplementation(() => undefined as never);
    });

    afterEach(() => {
      if (processExitSpy && typeof processExitSpy.mockRestore === 'function') {
        console.log('[DEBUG] queueService.server.test.ts: Restoring process.exit spy');
        processExitSpy.mockRestore();
      }
    });

    it('should close all workers, queues, the redis connection, and exit the process', async () => {
      // We need to import the queues to check if their close methods are called.
      const {
        flyerQueue,
        emailQueue,
        analyticsQueue,
        cleanupQueue,
        weeklyAnalyticsQueue,
        tokenCleanupQueue,
      } = await import('./queues.server');

      await gracefulShutdown('SIGINT');

      // Verify workers are closed
      expect((flyerWorker as unknown as MockWorkerInstance).close).toHaveBeenCalled();
      expect((emailWorker as unknown as MockWorkerInstance).close).toHaveBeenCalled();
      expect((analyticsWorker as unknown as MockWorkerInstance).close).toHaveBeenCalled();
      expect((cleanupWorker as unknown as MockWorkerInstance).close).toHaveBeenCalled();
      expect((weeklyAnalyticsWorker as unknown as MockWorkerInstance).close).toHaveBeenCalled();
      expect((tokenCleanupWorker as unknown as MockWorkerInstance).close).toHaveBeenCalled();

      // Verify queues are closed
      expect((flyerQueue as unknown as MockQueueInstance).close).toHaveBeenCalled();
      expect((emailQueue as unknown as MockQueueInstance).close).toHaveBeenCalled();
      expect((analyticsQueue as unknown as MockQueueInstance).close).toHaveBeenCalled();
      expect((cleanupQueue as unknown as MockQueueInstance).close).toHaveBeenCalled();
      expect((weeklyAnalyticsQueue as unknown as MockQueueInstance).close).toHaveBeenCalled();
      expect((tokenCleanupQueue as unknown as MockQueueInstance).close).toHaveBeenCalled();

      // Verify the redis connection is also closed
      expect(mockRedisConnection.quit).toHaveBeenCalledTimes(1);

      // Check for the correct success log message from workers.server.ts
      expect(mockLogger.info).toHaveBeenCalledWith(
        '[Shutdown] All resources closed successfully.',
      );
      expect(processExitSpy).toHaveBeenCalledWith(0);
    });

    it('should log an error if a worker fails to close', async () => {
      const closeError = new Error('Worker failed to close');
      // Simulate one worker failing to close
      (flyerWorker.close as Mock).mockRejectedValue(closeError);

      await gracefulShutdown('SIGTERM');

      // It should still attempt to close all workers
      expect((emailWorker as unknown as MockWorkerInstance).close).toHaveBeenCalled();
      expect(mockLogger.error).toHaveBeenCalledWith(
        { err: closeError, resource: 'flyerWorker' },
        `[Shutdown] Error closing flyerWorker.`,
      );
      expect(processExitSpy).toHaveBeenCalledWith(1);
    });

    it('should timeout if shutdown takes too long', async () => {
      vi.useFakeTimers();
      // Make one of the close calls hang indefinitely
      (flyerWorker.close as Mock).mockReturnValue(new Promise(() => {}));

      // Run shutdown but don't await it fully, as it will hang
      const shutdownPromise = gracefulShutdown('SIGTERM');

      // Advance timers past the timeout threshold
      await vi.advanceTimersByTimeAsync(31000);

      // Now await the promise to see the timeout result
      await shutdownPromise;

      expect(mockLogger.error).toHaveBeenCalledWith(
        `[Shutdown] Graceful shutdown timed out after 30 seconds. Forcing exit.`,
      );
      expect(processExitSpy).toHaveBeenCalledWith(1);

      vi.useRealTimers();
    });
  });
});