import { describe, it, expect, vi, beforeEach } from 'vitest';
import { SpamShieldService } from '../src/services/spamshield.service';
import { spamConfig } from '../src/config/spamshield.config';

const mockFetch = vi.fn();
global.fetch = mockFetch as unknown as typeof global.fetch;

describe('SpamShieldService', () => {
  let service: SpamShieldService;

  beforeEach(() => {
    service = SpamShieldService.getInstance();
    service.resetCircuits();
    mockFetch.mockReset();
    vi.clearAllMocks();
  });

  describe('checkReputation', () => {
    it('combines scores from both Hiya and Truecaller', async () => {
      mockFetch
        .mockResolvedValueOnce({
          ok: true,
          json: async () => ({ spamScore: 0.8 }),
        } as Response)
        .mockResolvedValueOnce({
          ok: true,
          json: async () => ({ spamProbability: 0.9 }),
        } as Response);

      const result = await service.checkReputation('+1234567890');

      expect(result.source).toBe('combined');
      expect(result.score).toBeCloseTo(0.85, 2);
      expect(result.isSpam).toBe(true);
      expect(result.hiyaScore).toBe(0.8);
      expect(result.truecallerScore).toBe(0.9);
      expect(mockFetch).toHaveBeenCalledTimes(2);
    });

    it('uses Hiya score + Truecaller fallback when Truecaller API fails', async () => {
      mockFetch
        .mockResolvedValueOnce({
          ok: true,
          json: async () => ({ spamScore: 0.6 }),
        } as Response)
        .mockResolvedValueOnce({
          ok: false,
          status: 500,
          statusText: 'Internal Server Error',
        } as Response);

      const result = await service.checkReputation('+1234567890');

      expect(result.source).toBe('combined');
      expect(result.hiyaScore).toBe(0.6);
      expect(result.truecallerScore).toBe(0.5);
    });

    it('uses Hiya fallback + Truecaller score when Hiya API fails', async () => {
      mockFetch
        .mockResolvedValueOnce({
          ok: false,
          status: 429,
          statusText: 'Too Many Requests',
        } as Response)
        .mockResolvedValueOnce({
          ok: true,
          json: async () => ({ spamProbability: 0.3 }),
        } as Response);

      const result = await service.checkReputation('+1234567890');

      expect(result.source).toBe('combined');
      expect(result.hiyaScore).toBe(0.5);
      expect(result.truecallerScore).toBe(0.3);
    });

    it('uses both fallbacks when both APIs fail', async () => {
      mockFetch
        .mockResolvedValueOnce({
          ok: false,
          status: 503,
          statusText: 'Service Unavailable',
        } as Response)
        .mockResolvedValueOnce({
          ok: false,
          status: 503,
          statusText: 'Service Unavailable',
        } as Response);

      const result = await service.checkReputation('+1234567890');

      expect(result.source).toBe('combined');
      expect(result.hiyaScore).toBe(0.5);
      expect(result.truecallerScore).toBe(0.5);
      expect(result.score).toBe(0.5);
      expect(result.isSpam).toBe(false);
    });

    it('validates phone number length', async () => {
      const shortNumber = '123';
      const result = service.checkReputation(shortNumber);
      await expect(result).rejects.toThrow('Invalid phone number format');
    });

    it('returns non-spam for low scores', async () => {
      mockFetch
        .mockResolvedValueOnce({
          ok: true,
          json: async () => ({ spamScore: 0.2 }),
        } as Response)
        .mockResolvedValueOnce({
          ok: true,
          json: async () => ({ spamProbability: 0.1 }),
        } as Response);

      const result = await service.checkReputation('+1234567890');

      expect(result.isSpam).toBe(false);
      expect(result.score).toBeCloseTo(0.15, 2);
    });
  });

  describe('circuit breaker integration', () => {
    it('opens circuit after consecutive failures', async () => {
      const metricsBefore = service.getCircuitMetrics();
      expect(metricsBefore.hiya.state).toBe('CLOSED');

      for (let i = 0; i < spamConfig.circuitBreakerThreshold; i++) {
        mockFetch
          .mockResolvedValueOnce({
            ok: false,
            status: 500,
            statusText: 'Server Error',
          } as Response)
          .mockResolvedValueOnce({
            ok: false,
            status: 500,
            statusText: 'Server Error',
          } as Response);
        await service.checkReputation('+1234567890');
      }

      const metricsAfter = service.getCircuitMetrics();
      expect(metricsAfter.hiya.totalFailures).toBeGreaterThanOrEqual(spamConfig.circuitBreakerThreshold);
      expect(metricsAfter.truecaller.totalFailures).toBeGreaterThanOrEqual(spamConfig.circuitBreakerThreshold);
    });

    it('exposes circuit metrics for monitoring', () => {
      const metrics = service.getCircuitMetrics();

      expect(metrics.hiya).toHaveProperty('state', 'CLOSED');
      expect(metrics.hiya).toHaveProperty('failureCount');
      expect(metrics.hiya).toHaveProperty('successCount');
      expect(metrics.hiya).toHaveProperty('totalExecutions');
      expect(metrics.hiya).toHaveProperty('totalFailures');
      expect(metrics.hiya).toHaveProperty('totalSuccesses');
      expect(metrics.hiya).toHaveProperty('lastFailureTime');
      expect(metrics.hiya).toHaveProperty('lastSuccessTime');
      expect(metrics.hiya).toHaveProperty('stateChangedAt');

      expect(metrics.truecaller).toHaveProperty('state', 'CLOSED');
    });

    it('resets circuits to CLOSED state', () => {
      service.resetCircuits();
      const metrics = service.getCircuitMetrics();
      expect(metrics.hiya.state).toBe('CLOSED');
      expect(metrics.truecaller.state).toBe('CLOSED');
    });

    it('returns fallback scores when circuits are open', async () => {
      service.resetCircuits();

      for (let i = 0; i < spamConfig.circuitBreakerThreshold; i++) {
        mockFetch
          .mockResolvedValueOnce({
            ok: false,
            status: 500,
            statusText: 'Server Error',
          } as Response)
          .mockResolvedValueOnce({
            ok: false,
            status: 500,
            statusText: 'Server Error',
          } as Response);
        await service.checkReputation('+1234567890');
      }

      const metrics = service.getCircuitMetrics();
      expect(metrics.hiya.state).toBe('OPEN');
      expect(metrics.truecaller.state).toBe('OPEN');

      const result = await service.checkReputation('+1234567890');
      expect(result.hiyaScore).toBe(0.5);
      expect(result.truecallerScore).toBe(0.5);
    });
  });
});