/**
 * Tests de performance et charge
 * Validation des KPIs selon CDC: < 5s response time, > 99.5% uptime
 */

const request = require('supertest');
const SourceFinderApp = require('../../src/app');

describe('Performance & Load Tests', () => {
  let app;
  let server;

  beforeAll(async () => {
    const sourceFinderApp = new SourceFinderApp();
    app = await sourceFinderApp.initialize();
    server = app.listen(0);
  });

  afterAll(async () => {
    if (server) {
      await new Promise(resolve => server.close(resolve));
    }
  });

  describe('Response Time Requirements (CDC: < 5s)', () => {
    test('API search devrait répondre en moins de 5 secondes', async () => {
      const startTime = Date.now();

      const response = await request(app)
        .post('/api/v1/news/search')
        .send({
          race_code: '352-1',
          max_results: 3,
          min_score: 40,
          client_id: 'perf-test-1'
        })
        .timeout(6000);

      const responseTime = Date.now() - startTime;

      expect([200, 202]).toContain(response.status);
      expect(responseTime).toBeLessThan(5000); // CDC requirement

      if (response.status === 200) {
        expect(response.body.metadata.processingTime).toBeLessThan(5000);
      }

      console.log(`✓ Response time: ${responseTime}ms (target: <5000ms)`);
    }, 10000);

    test('Health check devrait répondre en moins de 1 seconde', async () => {
      const times = [];

      for (let i = 0; i < 5; i++) {
        const startTime = Date.now();

        await request(app)
          .get('/api/v1/health')
          .expect(200);

        times.push(Date.now() - startTime);
      }

      const avgTime = times.reduce((a, b) => a + b, 0) / times.length;
      const maxTime = Math.max(...times);

      expect(maxTime).toBeLessThan(1000);
      expect(avgTime).toBeLessThan(500);

      console.log(`✓ Health check avg: ${avgTime}ms, max: ${maxTime}ms`);
    });

    test('Metrics endpoint devrait être rapide', async () => {
      const startTime = Date.now();

      const response = await request(app)
        .get('/api/v1/metrics')
        .expect(200);

      const responseTime = Date.now() - startTime;

      expect(responseTime).toBeLessThan(1000);
      expect(response.body.metrics).toBeDefined();

      console.log(`✓ Metrics response time: ${responseTime}ms`);
    });
  });

  describe('Concurrent Request Handling', () => {
    test('devrait gérer 10 requêtes simultanées', async () => {
      const concurrentRequests = 10;
      const requests = Array(concurrentRequests).fill().map((_, i) =>
        request(app)
          .post('/api/v1/news/search')
          .send({
            race_code: '352-1',
            max_results: 1,
            client_id: `concurrent-test-${i}`
          })
          .timeout(10000)
      );

      const startTime = Date.now();
      const responses = await Promise.allSettled(requests);
      const totalTime = Date.now() - startTime;

      const successful = responses.filter(r =>
        r.status === 'fulfilled' && [200, 202].includes(r.value.status)
      );

      // Au moins 80% des requêtes doivent réussir
      expect(successful.length).toBeGreaterThanOrEqual(concurrentRequests * 0.8);

      // Temps total ne doit pas dépasser 15 secondes
      expect(totalTime).toBeLessThan(15000);

      console.log(`✓ ${successful.length}/${concurrentRequests} requests succeeded in ${totalTime}ms`);
    }, 20000);

    test('devrait maintenir performance sous charge soutenue', async () => {
      const rounds = 3;
      const requestsPerRound = 5;
      const results = [];

      for (let round = 0; round < rounds; round++) {
        const roundStart = Date.now();

        const roundRequests = Array(requestsPerRound).fill().map((_, i) =>
          request(app)
            .get('/api/v1/health')
            .timeout(2000)
        );

        const responses = await Promise.allSettled(roundRequests);
        const successful = responses.filter(r =>
          r.status === 'fulfilled' && r.value.status === 200
        );

        const roundTime = Date.now() - roundStart;

        results.push({
          round: round + 1,
          successful: successful.length,
          total: requestsPerRound,
          time: roundTime
        });

        // Petite pause entre les rounds
        await new Promise(resolve => setTimeout(resolve, 1000));
      }

      // Vérifier que la performance reste stable
      results.forEach((result, index) => {
        expect(result.successful).toBeGreaterThanOrEqual(requestsPerRound * 0.9);
        expect(result.time).toBeLessThan(3000);

        console.log(`✓ Round ${result.round}: ${result.successful}/${result.total} in ${result.time}ms`);
      });

      // Vérifier que le système ne se dégrade pas
      const firstRoundTime = results[0].time;
      const lastRoundTime = results[results.length - 1].time;
      expect(lastRoundTime).toBeLessThan(firstRoundTime * 1.5); // Max 50% de dégradation
    }, 25000);
  });

  describe('Memory and Resource Management', () => {
    test('devrait maintenir usage mémoire stable', async () => {
      const initialMemory = process.memoryUsage();

      // Effectuer plusieurs requêtes pour charger le système
      for (let i = 0; i < 10; i++) {
        await request(app)
          .get('/api/v1/metrics')
          .timeout(2000);
      }

      const afterRequestsMemory = process.memoryUsage();

      // La mémoire ne devrait pas augmenter de manière excessive
      const memoryIncrease = afterRequestsMemory.heapUsed - initialMemory.heapUsed;
      const memoryIncreasePercent = (memoryIncrease / initialMemory.heapUsed) * 100;

      expect(memoryIncreasePercent).toBeLessThan(50); // Max 50% d'augmentation

      console.log(`✓ Memory increase: ${(memoryIncrease / 1024 / 1024).toFixed(2)}MB (${memoryIncreasePercent.toFixed(1)}%)`);

      // Forcer garbage collection si disponible
      if (global.gc) {
        global.gc();
      }
    });

    test('devrait gérer nettoyage des ressources temporaires', async () => {
      // Vérifier que les caches se nettoient correctement
      const metricsResponse = await request(app)
        .get('/api/v1/metrics')
        .expect(200);

      const { metrics } = metricsResponse.body;

      // Les caches ne devraient pas grandir indéfiniment
      if (metrics.search && metrics.search.cacheSize !== undefined) {
        expect(metrics.search.cacheSize).toBeLessThan(1000);
      }

      if (metrics.security && metrics.security.cache) {
        expect(metrics.security.cache.size).toBeLessThan(500);
      }
    });
  });

  describe('Stress Testing', () => {
    test('devrait résister à une charge élevée ponctuelle', async () => {
      const highLoad = 20;
      const timeout = 15000;

      const startTime = Date.now();

      const stressRequests = Array(highLoad).fill().map((_, i) => {
        // Mélanger différents types de requêtes
        if (i % 3 === 0) {
          return request(app).get('/api/v1/health').timeout(timeout);
        } else if (i % 3 === 1) {
          return request(app).get('/api/v1/metrics').timeout(timeout);
        } else {
          return request(app)
            .post('/api/v1/news/search')
            .send({
              race_code: '352-1',
              max_results: 1,
              client_id: `stress-${i}`
            })
            .timeout(timeout);
        }
      });

      const responses = await Promise.allSettled(stressRequests);
      const totalTime = Date.now() - startTime;

      const successful = responses.filter(r =>
        r.status === 'fulfilled' &&
        [200, 202].includes(r.value.status)
      );

      const failed = responses.filter(r => r.status === 'rejected');
      const errorRate = failed.length / responses.length;

      // Critères de réussite du stress test
      expect(successful.length).toBeGreaterThanOrEqual(highLoad * 0.7); // 70% de réussite minimum
      expect(errorRate).toBeLessThan(0.3); // Moins de 30% d'erreurs
      expect(totalTime).toBeLessThan(20000); // Moins de 20 secondes

      console.log(`✓ Stress test: ${successful.length}/${highLoad} successful, ${(errorRate * 100).toFixed(1)}% error rate, ${totalTime}ms total`);

      // Vérifier que le système récupère après le stress
      await new Promise(resolve => setTimeout(resolve, 2000));

      const recoveryResponse = await request(app)
        .get('/api/v1/health')
        .expect(200);

      expect(recoveryResponse.body.status).toMatch(/healthy|degraded/);
    }, 30000);

    test('devrait gérer requêtes avec payload volumineux', async () => {
      const largePayload = {
        race_code: '352-1',
        product_context: 'A'.repeat(5000), // 5KB de contexte
        content_type: 'education',
        max_results: 1,
        client_id: 'large-payload-test'
      };

      const startTime = Date.now();

      const response = await request(app)
        .post('/api/v1/news/search')
        .send(largePayload)
        .timeout(10000);

      const responseTime = Date.now() - startTime;

      expect([200, 202, 400]).toContain(response.status); // 400 si payload trop grand
      expect(responseTime).toBeLessThan(8000);

      if (response.status === 400) {
        expect(response.body.error).toBeDefined();
        console.log('✓ Large payload correctly rejected');
      } else {
        console.log(`✓ Large payload processed in ${responseTime}ms`);
      }
    });
  });

  describe('Performance Regression Testing', () => {
    test('devrait maintenir temps de réponse baseline', async () => {
      // Baseline pour différents types de requêtes
      const baselines = [
        {
          name: 'Health check',
          request: () => request(app).get('/api/v1/health'),
          maxTime: 500
        },
        {
          name: 'Metrics',
          request: () => request(app).get('/api/v1/metrics'),
          maxTime: 1000
        },
        {
          name: 'Stock status',
          request: () => request(app).get('/api/v1/stock/status'),
          maxTime: 2000
        }
      ];

      for (const baseline of baselines) {
        const measurements = [];

        // Effectuer 5 mesures
        for (let i = 0; i < 5; i++) {
          const startTime = Date.now();
          const response = await baseline.request().timeout(baseline.maxTime + 1000);
          const responseTime = Date.now() - startTime;

          measurements.push(responseTime);
          expect(response.status).toBe(200);
        }

        const avgTime = measurements.reduce((a, b) => a + b, 0) / measurements.length;
        const maxTime = Math.max(...measurements);

        expect(avgTime).toBeLessThan(baseline.maxTime);
        expect(maxTime).toBeLessThan(baseline.maxTime * 1.5);

        console.log(`✓ ${baseline.name}: avg=${avgTime}ms, max=${maxTime}ms (baseline=${baseline.maxTime}ms)`);
      }
    });

    test('devrait détecter les fuites mémoire potentielles', async () => {
      const iterations = 50;
      const memorySnapshots = [];

      for (let i = 0; i < iterations; i++) {
        await request(app)
          .get('/api/v1/health')
          .timeout(2000);

        if (i % 10 === 0) {
          memorySnapshots.push(process.memoryUsage().heapUsed);
        }
      }

      // Vérifier que la mémoire ne croît pas linéairement
      const memoryGrowth = memorySnapshots.map((current, index) => {
        if (index === 0) return 0;
        return current - memorySnapshots[index - 1];
      }).slice(1);

      const avgGrowth = memoryGrowth.reduce((a, b) => a + b, 0) / memoryGrowth.length;

      // La croissance moyenne ne devrait pas dépasser 1MB par tranche
      expect(Math.abs(avgGrowth)).toBeLessThan(1024 * 1024);

      console.log(`✓ Memory growth check: avg=${(avgGrowth / 1024).toFixed(2)}KB per 10 requests`);
    }, 20000);
  });

  describe('Database and I/O Performance', () => {
    test('devrait maintenir performance des opérations de stock', async () => {
      const operations = [
        () => request(app).get('/api/v1/stock/status'),
        () => request(app).get('/api/v1/stock/status?race_code=352-1'),
        () => request(app).post('/api/v1/stock/refresh').send({ race_code: '352-1' })
      ];

      for (const operation of operations) {
        const startTime = Date.now();
        const response = await operation().timeout(5000);
        const responseTime = Date.now() - startTime;

        expect([200, 202]).toContain(response.status);
        expect(responseTime).toBeLessThan(3000); // Opérations de stock < 3s

        console.log(`✓ Stock operation completed in ${responseTime}ms`);
      }
    });

    test('devrait gérer opérations concurrentes sur le stock', async () => {
      const concurrentStockOps = Array(5).fill().map(() =>
        request(app)
          .get('/api/v1/stock/status')
          .timeout(5000)
      );

      const startTime = Date.now();
      const responses = await Promise.allSettled(concurrentStockOps);
      const totalTime = Date.now() - startTime;

      const successful = responses.filter(r =>
        r.status === 'fulfilled' && r.value.status === 200
      );

      expect(successful.length).toBe(5); // Toutes les lectures doivent réussir
      expect(totalTime).toBeLessThan(8000); // Moins de 8 secondes au total

      console.log(`✓ Concurrent stock operations: ${successful.length}/5 in ${totalTime}ms`);
    });
  });

  describe('Performance Monitoring', () => {
    test('devrait exposer métriques de performance détaillées', async () => {
      const response = await request(app)
        .get('/api/v1/metrics')
        .expect(200);

      const { metrics } = response.body;

      // Vérifier présence des métriques de performance
      expect(metrics.search).toHaveProperty('averageResponseTime');
      expect(metrics.search).toHaveProperty('totalSearches');
      expect(metrics.system).toHaveProperty('uptime');
      expect(metrics.system).toHaveProperty('memory');

      // Les métriques doivent être numériques et positives
      expect(typeof metrics.search.averageResponseTime).toBe('number');
      expect(metrics.search.averageResponseTime).toBeGreaterThanOrEqual(0);
      expect(typeof metrics.system.uptime).toBe('number');
      expect(metrics.system.uptime).toBeGreaterThan(0);

      console.log('✓ Performance metrics available and valid');
    });

    test('devrait permettre monitoring continu', async () => {
      // Effectuer quelques opérations pour générer des métriques
      await request(app)
        .post('/api/v1/news/search')
        .send({
          race_code: '352-1',
          max_results: 1,
          client_id: 'monitoring-test'
        })
        .timeout(10000);

      const metricsAfter = await request(app)
        .get('/api/v1/metrics')
        .expect(200);

      // Les compteurs doivent avoir été incrémentés
      expect(metricsAfter.body.metrics.search.totalSearches).toBeGreaterThanOrEqual(1);

      console.log('✓ Continuous monitoring functional');
    }, 15000);
  });
});