import { Queue, QueueEvents, Worker } from 'bullmq';
import { afterEach, beforeEach, describe, expect, test } from 'bun:test';
import { QueueMetricsCollector } from '../src/queue-metrics';
import { getRedisConnection } from '../src/utils';

// Suppress Redis connection errors in tests
process.on('unhandledRejection', (reason, promise) => {
  if (reason && typeof reason === 'object' && 'message' in reason) {
    const message = (reason as Error).message;
    if (
      message.includes('Connection is closed') ||
      message.includes('Connection is in monitoring mode')
    ) {
      return;
    }
  }
  console.error('Unhandled Rejection at:', promise, 'reason:', reason);
});

describe('QueueMetricsCollector', () => {
  let queue: Queue;
  let queueEvents: QueueEvents;
  let metricsCollector: QueueMetricsCollector;
  let worker: Worker;
  let connection: any;

  const redisConfig = {
    host: 'localhost',
    port: 6379,
    password: '',
    db: 0,
  };

  beforeEach(async () => {
    connection = getRedisConnection(redisConfig);

    // Create queue and events
    queue = new Queue('metrics-test-queue', { connection });
    queueEvents = new QueueEvents('metrics-test-queue', { connection });

    // Create metrics collector
    metricsCollector = new QueueMetricsCollector(queue, queueEvents);

    // Wait for connections
    await queue.waitUntilReady();
    await queueEvents.waitUntilReady();
  });

  afterEach(async () => {
    try {
      if (worker) {
        await worker.close();
      }
      await queueEvents.close();
      await queue.close();
    } catch {
      // Ignore cleanup errors
    }
    await new Promise(resolve => setTimeout(resolve, 50));
  });

  describe('Job Count Metrics', () => {
    test('should collect basic job counts', async () => {
      // Add jobs in different states
      await queue.add('waiting-job', { test: true });
      await queue.add('delayed-job', { test: true }, { delay: 60000 });

      const metrics = await metricsCollector.collect();

      expect(metrics.waiting).toBe(1);
      expect(metrics.delayed).toBe(1);
      expect(metrics.active).toBe(0);
      expect(metrics.completed).toBe(0);
      expect(metrics.failed).toBe(0);
    });

    test('should track completed and failed jobs', async () => {
      let jobCount = 0;

      // Create worker that alternates between success and failure
      worker = new Worker(
        'metrics-test-queue',
        async () => {
          jobCount++;
          if (jobCount % 2 === 0) {
            throw new Error('Test failure');
          }
          return { success: true };
        },
        { connection }
      );

      // Add jobs
      await queue.add('job1', { test: 1 });
      await queue.add('job2', { test: 2 });
      await queue.add('job3', { test: 3 });
      await queue.add('job4', { test: 4 });

      // Wait for processing
      await new Promise(resolve => setTimeout(resolve, 200));

      const metrics = await metricsCollector.collect();

      expect(metrics.completed).toBe(2);
      expect(metrics.failed).toBe(2);
    });
  });

  describe('Processing Time Metrics', () => {
    test('should track processing times', async () => {
      const processingTimes = [50, 100, 150, 200, 250];
      let jobIndex = 0;

      // Create worker with variable processing times
      worker = new Worker(
        'metrics-test-queue',
        async () => {
          const delay = processingTimes[jobIndex++] || 100;
          await new Promise(resolve => setTimeout(resolve, delay));
          return { processed: true };
        },
        { connection }
      );

      // Add jobs
      for (let i = 0; i < processingTimes.length; i++) {
        await queue.add(`job${i}`, { index: i });
      }

      // Wait for processing
      await new Promise(resolve => setTimeout(resolve, 1500));

      const metrics = await metricsCollector.collect();

      expect(metrics.processingTime.avg).toBeGreaterThan(0);
      expect(metrics.processingTime.min).toBeGreaterThanOrEqual(50);
      expect(metrics.processingTime.max).toBeLessThanOrEqual(300);
      expect(metrics.processingTime.p95).toBeGreaterThan(metrics.processingTime.avg);
    });

    test('should handle empty processing times', async () => {
      const metrics = await metricsCollector.collect();

      expect(metrics.processingTime).toEqual({
        avg: 0,
        min: 0,
        max: 0,
        p95: 0,
        p99: 0,
      });
    });
  });

  describe('Throughput Metrics', () => {
    test('should calculate throughput correctly', async () => {
      // Create fast worker
      worker = new Worker(
        'metrics-test-queue',
        async () => {
          return { success: true };
        },
        { connection, concurrency: 5 }
      );

      // Add multiple jobs
      const jobPromises = [];
      for (let i = 0; i < 10; i++) {
        jobPromises.push(queue.add(`job${i}`, { index: i }));
      }
      await Promise.all(jobPromises);

      // Wait for processing
      await new Promise(resolve => setTimeout(resolve, 500));

      const metrics = await metricsCollector.collect();

      expect(metrics.throughput.completedPerMinute).toBeGreaterThan(0);
      expect(metrics.throughput.totalPerMinute).toBe(
        metrics.throughput.completedPerMinute + metrics.throughput.failedPerMinute
      );
    });
  });

  describe('Queue Health', () => {
    test('should report healthy queue', async () => {
      const metrics = await metricsCollector.collect();

      expect(metrics.isHealthy).toBe(true);
      expect(metrics.healthIssues).toEqual([]);
    });

    test('should detect high failure rate', async () => {
      // Create worker that always fails
      worker = new Worker(
        'metrics-test-queue',
        async () => {
          throw new Error('Always fails');
        },
        { connection }
      );

      // Add jobs
      for (let i = 0; i < 10; i++) {
        await queue.add(`job${i}`, { index: i });
      }

      // Wait for failures
      await new Promise(resolve => setTimeout(resolve, 500));

      const metrics = await metricsCollector.collect();

      expect(metrics.isHealthy).toBe(false);
      expect(metrics.healthIssues).toContain(expect.stringMatching(/High failure rate/));
    });

    test('should detect large queue backlog', async () => {
      // Add many jobs without workers
      for (let i = 0; i < 1001; i++) {
        await queue.add(`job${i}`, { index: i });
      }

      const metrics = await metricsCollector.collect();

      expect(metrics.isHealthy).toBe(false);
      expect(metrics.healthIssues).toContain(expect.stringMatching(/Large queue backlog/));
    });
  });

  describe('Oldest Waiting Job', () => {
    test('should track oldest waiting job', async () => {
      const beforeAdd = Date.now();

      // Add jobs with delays
      await queue.add('old-job', { test: true });
      await new Promise(resolve => setTimeout(resolve, 100));
      await queue.add('new-job', { test: true });

      const metrics = await metricsCollector.collect();

      expect(metrics.oldestWaitingJob).toBeDefined();
      expect(metrics.oldestWaitingJob!.getTime()).toBeGreaterThanOrEqual(beforeAdd);
    });

    test('should return null when no waiting jobs', async () => {
      // Create worker that processes immediately
      worker = new Worker(
        'metrics-test-queue',
        async () => {
          return { success: true };
        },
        { connection }
      );

      const metrics = await metricsCollector.collect();
      expect(metrics.oldestWaitingJob).toBe(null);
    });
  });

  describe('Metrics Report', () => {
    test('should generate formatted report', async () => {
      // Add some jobs
      await queue.add('job1', { test: true });
      await queue.add('job2', { test: true }, { delay: 5000 });

      const report = await metricsCollector.getReport();

      expect(report).toContain('Queue Metrics Report');
      expect(report).toContain('Status:');
      expect(report).toContain('Job Counts:');
      expect(report).toContain('Performance:');
      expect(report).toContain('Throughput:');
      expect(report).toContain('Waiting: 1');
      expect(report).toContain('Delayed: 1');
    });

    test('should include health issues in report', async () => {
      // Add many jobs to trigger health issue
      for (let i = 0; i < 1001; i++) {
        await queue.add(`job${i}`, { index: i });
      }

      const report = await metricsCollector.getReport();

      expect(report).toContain('Issues Detected');
      expect(report).toContain('Health Issues:');
      expect(report).toContain('Large queue backlog');
    });
  });

  describe('Prometheus Metrics', () => {
    test('should export metrics in Prometheus format', async () => {
      // Add some jobs and process them
      worker = new Worker(
        'metrics-test-queue',
        async () => {
          await new Promise(resolve => setTimeout(resolve, 50));
          return { success: true };
        },
        { connection }
      );

      await queue.add('job1', { test: true });
      await queue.add('job2', { test: true });

      // Wait for processing
      await new Promise(resolve => setTimeout(resolve, 200));

      const prometheusMetrics = await metricsCollector.getPrometheusMetrics();

      // Check format
      expect(prometheusMetrics).toContain('# HELP queue_jobs_total');
      expect(prometheusMetrics).toContain('# TYPE queue_jobs_total gauge');
      expect(prometheusMetrics).toContain(
        'queue_jobs_total{queue="metrics-test-queue",status="completed"}'
      );

      expect(prometheusMetrics).toContain('# HELP queue_processing_time_seconds');
      expect(prometheusMetrics).toContain('# TYPE queue_processing_time_seconds summary');

      expect(prometheusMetrics).toContain('# HELP queue_throughput_per_minute');
      expect(prometheusMetrics).toContain('# TYPE queue_throughput_per_minute gauge');

      expect(prometheusMetrics).toContain('# HELP queue_health');
      expect(prometheusMetrics).toContain('# TYPE queue_health gauge');
    });
  });
});