#!/usr/bin/env node
/**
 * Production Performance Benchmarks
 * Establishes baseline performance metrics and SLA targets
 */

const fs = require('fs');
const path = require('path');
const { execSync } = require('child_process');

console.log('📊 Establishing Production Performance Benchmarks...\n');

// Production Performance SLA Targets
const PERFORMANCE_SLA = {
  // Response time targets (milliseconds)
  responseTime: {
    p50: 100,     // 50th percentile < 100ms
    p95: 300,     // 95th percentile < 300ms
    p99: 500,     // 99th percentile < 500ms
    max: 1000     // Maximum < 1000ms
  },

  // Throughput targets (requests/second)
  throughput: {
    read: 1000,   // GET requests/sec
    write: 100,   // POST/PUT/DELETE requests/sec
    mixed: 500    // Mixed workload requests/sec
  },

  // Cache performance targets
  cache: {
    hitRate: 0.80,        // 80% cache hit rate
    writeOpsPerSec: 50000, // Cache write operations/sec
    readOpsPerSec: 100000, // Cache read operations/sec
    memoryUsage: 512      // Max memory usage MB
  },

  // Resource utilization targets
  resources: {
    cpuUsage: 0.70,       // Max 70% CPU utilization
    memoryUsage: 0.80,    // Max 80% memory utilization
    diskIO: 100,          // Max 100 MB/s disk I/O
    networkIO: 500        // Max 500 MB/s network I/O
  },

  // Availability targets
  availability: {
    uptime: 0.999,        // 99.9% uptime SLA
    healthCheckTimeout: 5000, // Health check timeout
    maxDowntime: 43200    // Max downtime per month (12 hours)
  }
};

// Test Scenarios
const TEST_SCENARIOS = [
  {
    name: 'WordPress API Load Test',
    description: 'Test WordPress REST API performance under load',
    duration: 60,
    concurrency: 50,
    target: 'posts'
  },
  {
    name: 'Cache Performance Test',
    description: 'Validate cache hit rates and performance',
    duration: 30,
    operations: 10000,
    type: 'mixed'
  },
  {
    name: 'Memory Stress Test',
    description: 'Test memory usage under sustained load',
    duration: 120,
    payloadSize: '1mb',
    operations: 1000
  },
  {
    name: 'Concurrent User Simulation',
    description: 'Simulate real-world concurrent user patterns',
    duration: 180,
    users: 100,
    rampUp: 30
  }
];

function getCurrentMetrics() {
  console.log('📈 Collecting current performance metrics...');

  const metrics = {
    timestamp: new Date().toISOString(),
    system: {
      nodeVersion: process.version,
      platform: process.platform,
      arch: process.arch,
      cpus: require('os').cpus().length,
      totalMemory: Math.round(require('os').totalmem() / 1024 / 1024 / 1024) + ' GB'
    },
    application: {}
  };

  try {
    // Run performance tests to get baseline
    console.log('  ⚡ Running cache performance test...');
    const cacheTest = execSync('NODE_OPTIONS="--experimental-vm-modules" npx jest tests/cache/cache-performance.test.js --verbose --testTimeout=60000', {
      encoding: 'utf8',
      timeout: 120000,
      stdio: ['pipe', 'pipe', 'pipe']
    });

    // Extract cache performance metrics from test output
    const cacheMetrics = extractCacheMetrics(cacheTest);
    metrics.application.cache = cacheMetrics;

    console.log('  🔍 Cache write throughput:', cacheMetrics.writeThroughput.toLocaleString(), 'ops/sec');
    console.log('  🔍 Cache read throughput:', cacheMetrics.readThroughput.toLocaleString(), 'ops/sec');

  } catch (error) {
    console.warn('  ⚠️ Could not collect all performance metrics:', error.message);
  }

  return metrics;
}

function extractCacheMetrics(testOutput) {
  const metrics = {
    writeThroughput: 0,
    readThroughput: 0,
    mixedThroughput: 0,
    latencyP50: 0,
    latencyP95: 0,
    latencyP99: 0,
    memoryEfficiency: 0
  };

  try {
    // Parse cache throughput from test output
    const writeMatch = testOutput.match(/Cache write throughput: ([\d,]+) ops\/sec/);
    if (writeMatch) {
      metrics.writeThroughput = parseInt(writeMatch[1].replace(/,/g, ''));
    }

    const readMatch = testOutput.match(/Cache read throughput: ([\d,]+) ops\/sec/);
    if (readMatch) {
      metrics.readThroughput = parseInt(readMatch[1].replace(/,/g, ''));
    }

    const mixedMatch = testOutput.match(/Mixed workload throughput: ([\d,]+) ops\/sec/);
    if (mixedMatch) {
      metrics.mixedThroughput = parseInt(mixedMatch[1].replace(/,/g, ''));
    }

    // Parse latency metrics
    const latencyMatch = testOutput.match(/P50: ([\d.]+)ms, P95: ([\d.]+)ms, P99: ([\d.]+)ms/);
    if (latencyMatch) {
      metrics.latencyP50 = parseFloat(latencyMatch[1]);
      metrics.latencyP95 = parseFloat(latencyMatch[2]);
      metrics.latencyP99 = parseFloat(latencyMatch[3]);
    }

  } catch (error) {
    console.warn('  ⚠️ Could not parse all cache metrics');
  }

  return metrics;
}

function validateAgainstSLA(metrics) {
  console.log('\n🎯 Validating performance against SLA targets...');

  const results = {
    overall: 'PASS',
    details: [],
    score: 100
  };

  // Validate cache performance
  if (metrics.application.cache) {
    const cache = metrics.application.cache;

    // Cache write throughput
    if (cache.writeThroughput >= PERFORMANCE_SLA.cache.writeOpsPerSec) {
      results.details.push({
        metric: 'Cache Write Throughput',
        status: 'PASS',
        value: cache.writeThroughput,
        target: PERFORMANCE_SLA.cache.writeOpsPerSec
      });
    } else {
      results.details.push({
        metric: 'Cache Write Throughput',
        status: 'FAIL',
        value: cache.writeThroughput,
        target: PERFORMANCE_SLA.cache.writeOpsPerSec
      });
      results.overall = 'FAIL';
      results.score -= 15;
    }

    // Cache read throughput
    if (cache.readThroughput >= PERFORMANCE_SLA.cache.readOpsPerSec) {
      results.details.push({
        metric: 'Cache Read Throughput',
        status: 'PASS',
        value: cache.readThroughput,
        target: PERFORMANCE_SLA.cache.readOpsPerSec
      });
    } else {
      results.details.push({
        metric: 'Cache Read Throughput',
        status: 'FAIL',
        value: cache.readThroughput,
        target: PERFORMANCE_SLA.cache.readOpsPerSec
      });
      results.overall = 'FAIL';
      results.score -= 15;
    }

    // Response time validation
    if (cache.latencyP95 <= PERFORMANCE_SLA.responseTime.p95) {
      results.details.push({
        metric: 'Response Time P95',
        status: 'PASS',
        value: cache.latencyP95 + 'ms',
        target: PERFORMANCE_SLA.responseTime.p95 + 'ms'
      });
    } else {
      results.details.push({
        metric: 'Response Time P95',
        status: 'FAIL',
        value: cache.latencyP95 + 'ms',
        target: PERFORMANCE_SLA.responseTime.p95 + 'ms'
      });
      results.overall = 'FAIL';
      results.score -= 20;
    }
  }

  return results;
}

function generateBenchmarkReport(metrics, validation) {
  console.log('\n📋 Generating benchmark report...');

  const report = {
    metadata: {
      version: '2.4.2',
      timestamp: new Date().toISOString(),
      environment: 'production',
      testDuration: '5 minutes'
    },
    sla: PERFORMANCE_SLA,
    testScenarios: TEST_SCENARIOS,
    currentMetrics: metrics,
    validation: validation,
    recommendations: []
  };

  // Generate recommendations based on validation results
  validation.details.forEach(detail => {
    if (detail.status === 'FAIL') {
      report.recommendations.push({
        priority: 'HIGH',
        metric: detail.metric,
        issue: `Performance below SLA target: ${detail.value} < ${detail.target}`,
        recommendations: generateRecommendations(detail.metric)
      });
    }
  });

  return report;
}

function generateRecommendations(metric) {
  const recommendations = {
    'Cache Write Throughput': [
      'Optimize cache write operations with batching',
      'Consider using Redis for distributed caching',
      'Review cache serialization performance',
      'Implement async cache writes where possible'
    ],
    'Cache Read Throughput': [
      'Implement cache warming strategies',
      'Optimize cache key generation and lookup',
      'Consider memory-based caching for hot data',
      'Review cache hit rate and eviction policies'
    ],
    'Response Time P95': [
      'Enable request compression and caching',
      'Optimize database queries and indexing',
      'Implement connection pooling',
      'Consider CDN for static assets'
    ]
  };

  return recommendations[metric] || ['Review and optimize this metric'];
}

function displayResults(validation) {
  console.log('\n🎯 Performance Validation Results:');
  console.log('====================================');
  console.log(`Overall Status: ${validation.overall === 'PASS' ? '✅' : '❌'} ${validation.overall}`);
  console.log(`Performance Score: ${validation.score}/100`);
  console.log('');

  validation.details.forEach(detail => {
    const status = detail.status === 'PASS' ? '✅' : '❌';
    console.log(`${status} ${detail.metric}: ${detail.value} (target: ${detail.target})`);
  });
}

async function main() {
  try {
    // Step 1: Collect current metrics
    const metrics = getCurrentMetrics();

    // Step 2: Validate against SLA
    const validation = validateAgainstSLA(metrics);

    // Step 3: Generate comprehensive report
    const report = generateBenchmarkReport(metrics, validation);

    // Step 4: Save benchmark report
    const reportPath = 'performance-benchmark.json';
    fs.writeFileSync(reportPath, JSON.stringify(report, null, 2));

    // Step 5: Display results
    displayResults(validation);

    console.log('\n📊 Performance Benchmarks Summary:');
    console.log('==================================');
    console.log(`Cache Write Throughput: ${metrics.application.cache?.writeThroughput?.toLocaleString() || 'N/A'} ops/sec`);
    console.log(`Cache Read Throughput: ${metrics.application.cache?.readThroughput?.toLocaleString() || 'N/A'} ops/sec`);
    console.log(`Mixed Workload Throughput: ${metrics.application.cache?.mixedThroughput?.toLocaleString() || 'N/A'} ops/sec`);
    console.log(`Response Time P95: ${metrics.application.cache?.latencyP95 || 'N/A'}ms`);
    console.log('');
    console.log(`✅ Benchmark report saved to: ${reportPath}`);

    if (report.recommendations.length > 0) {
      console.log('\n💡 Performance Recommendations:');
      console.log('===============================');
      report.recommendations.forEach((rec, index) => {
        console.log(`${index + 1}. ${rec.metric} (${rec.priority} Priority)`);
        rec.recommendations.forEach(r => console.log(`   - ${r}`));
        console.log('');
      });
    }

    console.log('🎉 Performance benchmarking complete!');

    // Exit with appropriate code
    process.exit(validation.overall === 'PASS' ? 0 : 1);

  } catch (error) {
    console.error('❌ Error during performance benchmarking:', error.message);
    process.exit(1);
  }
}

if (require.main === module) {
  main();
}
