import { beforeEach, describe, expect, it, mock } from 'bun:test';
import { DeadLetterQueueHandler } from '../src/dlq-handler';
import type { Job, Queue } from 'bullmq';
import type { RedisConfig } from '../src/types';

describe('DeadLetterQueueHandler', () => {
  const mockLogger = {
    info: mock(() => {}),
    error: mock(() => {}),
    warn: mock(() => {}),
    debug: mock(() => {}),
    trace: mock(() => {}),
  };

  const mockQueue = {
    name: 'test-queue',
    add: mock(() => Promise.resolve({})),
    getCompleted: mock(() => Promise.resolve([])),
    getFailed: mock(() => Promise.resolve([])),
    getWaiting: mock(() => Promise.resolve([])),
  } as unknown as Queue;

  const mockRedisConfig: RedisConfig = {
    host: 'localhost',
    port: 6379,
  };

  let dlqHandler: DeadLetterQueueHandler;

  beforeEach(() => {
    dlqHandler = new DeadLetterQueueHandler(mockQueue, mockRedisConfig, {}, mockLogger);
    // Reset mocks
    mockLogger.info = mock(() => {});
    mockLogger.error = mock(() => {});
    mockLogger.warn = mock(() => {});
  });

  describe('handleFailedJob', () => {
    it('should log failed job details', async () => {
      const mockJob = {
        id: 'job-123',
        name: 'test-job',
        queueName: 'test-queue',
        data: {
          handler: 'testHandler',
          operation: 'testOp',
          payload: { test: true },
        },
        attemptsMade: 3,
        failedReason: 'Test error',
        finishedOn: Date.now(),
        processedOn: Date.now() - 5000,
      } as Job;

      const error = new Error('Job processing failed');

      await dlqHandler.handleFailedJob(mockJob, error);

      expect(mockLogger.error).toHaveBeenCalledWith(
        'Job moved to DLQ',
        expect.objectContaining({
          jobId: 'job-123',
          jobName: 'test-job',
          error: 'Job processing failed',
        })
      );
    });

    it('should handle jobs without data gracefully', async () => {
      const mockJob = {
        id: 'job-123',
        name: 'test-job',
        queueName: 'test-queue',
        data: null,
        attemptsMade: 1,
      } as any;

      const error = new Error('No data');

      await dlqHandler.handleFailedJob(mockJob, error);

      expect(mockLogger.error).toHaveBeenCalled();
    });

    it('should check alert threshold', async () => {
      const mockJob = {
        id: 'job-123',
        name: 'critical-job',
        queueName: 'critical-queue',
        data: { handler: 'critical', operation: 'process' },
        attemptsMade: 3,
        opts: { attempts: 3 },
      } as Job;

      const error = new Error('Critical failure');

      await dlqHandler.handleFailedJob(mockJob, error);

      expect(mockLogger.warn).toHaveBeenCalled();
    });
  });

  describe('getStats', () => {
    it('should return DLQ statistics', async () => {
      const mockJobs = [
        {
          id: 'job-1',
          data: { originalJob: { name: 'process' } },
          timestamp: Date.now(),
        },
        {
          id: 'job-2',
          data: { originalJob: { name: 'process' } },
          timestamp: Date.now() - 100000,
        },
        {
          id: 'job-3',
          data: { originalJob: { name: 'validate' } },
          timestamp: Date.now() - 200000,
        },
      ];

      (mockQueue.getCompleted as any) = mock(() => Promise.resolve(mockJobs));
      (mockQueue.getFailed as any) = mock(() => Promise.resolve([]));
      (mockQueue.getWaiting as any) = mock(() => Promise.resolve([]));

      const stats = await dlqHandler.getStats();

      expect(stats.total).toBe(3);
      expect(stats.byJobName['process']).toBe(2);
      expect(stats.byJobName['validate']).toBe(1);
      expect(stats.oldestJob).toBeDefined();
    });

    it('should handle empty DLQ', async () => {
      const stats = await dlqHandler.getStats();

      expect(stats.total).toBe(0);
      expect(stats.byJobName).toEqual({});
      expect(stats.oldestJob).toBeNull();
    });
  });

  describe('retryDLQJobs', () => {
    it('should retry jobs from DLQ', async () => {
      const mockDLQJobs = [
        {
          id: 'dlq-1',
          data: {
            originalJob: {
              id: 'orig-1',
              name: 'retry-job',
              data: { test: true },
              opts: {},
            },
          },
          remove: mock(() => Promise.resolve()),
        },
      ];

      (dlqHandler as any).dlq = {
        getCompleted: mock(() => Promise.resolve(mockDLQJobs)),
      };

      const retriedCount = await dlqHandler.retryDLQJobs(1);

      expect(retriedCount).toBe(1);
      expect(mockQueue.add).toHaveBeenCalledWith(
        'retry-job',
        { test: true },
        expect.objectContaining({ delay: expect.any(Number) })
      );
      expect(mockDLQJobs[0].remove).toHaveBeenCalled();
    });
  });

  describe('cleanup', () => {
    it('should clean up old DLQ entries', async () => {
      const oldJob = {
        id: 'old-1',
        timestamp: Date.now() - 8 * 24 * 60 * 60 * 1000, // 8 days old
        remove: mock(() => Promise.resolve()),
      };

      const newJob = {
        id: 'new-1',
        timestamp: Date.now() - 1 * 24 * 60 * 60 * 1000, // 1 day old
        remove: mock(() => Promise.resolve()),
      };

      (dlqHandler as any).dlq = {
        getCompleted: mock(() => Promise.resolve([oldJob, newJob])),
      };

      const removedCount = await dlqHandler.cleanup();

      expect(removedCount).toBe(1);
      expect(oldJob.remove).toHaveBeenCalled();
      expect(newJob.remove).not.toHaveBeenCalled();
    });
  });

  describe('inspectFailedJobs', () => {
    it('should return formatted failed jobs', async () => {
      const mockDLQJobs = [
        {
          data: {
            originalJob: {
              id: 'orig-1',
              name: 'test-job',
              data: { test: true },
              attemptsMade: 3,
            },
            error: {
              message: 'Test error',
              stack: 'Error stack',
            },
            movedToDLQAt: '2024-01-01T00:00:00Z',
          },
        },
      ];

      (dlqHandler as any).dlq = {
        getCompleted: mock(() => Promise.resolve(mockDLQJobs)),
      };

      const inspected = await dlqHandler.inspectFailedJobs(10);

      expect(inspected).toHaveLength(1);
      expect(inspected[0]).toEqual({
        id: 'orig-1',
        name: 'test-job',
        data: { test: true },
        error: { message: 'Test error', stack: 'Error stack' },
        failedAt: '2024-01-01T00:00:00Z',
        attempts: 3,
      });
    });
  });

  describe('shutdown', () => {
    it('should close DLQ and clear state', async () => {
      const mockClose = mock(() => Promise.resolve());
      (dlqHandler as any).dlq = {
        close: mockClose,
      };

      await dlqHandler.shutdown();

      expect(mockClose).toHaveBeenCalled();
    });
  });
})