/**
 * Compare k6 summary JSON against baseline thresholds.
 * Usage: node compare.mjs <summary.json>
 * Exit 1 if p95 latency degrades by > 20% from baseline.
 */
import { readFileSync } from 'fs';

const baselineThresholds = {
  http_req_duration_p95: 500,  // ms
  http_req_duration_p99: 1000, // ms
  http_req_failed_rate: 0.01,  // 1%
};

const summaryPath = process.argv[2];
if (!summaryPath) {
  console.error('Usage: node compare.mjs <k6-summary.json>');
  process.exit(1);
}

try {
  const summary = JSON.parse(readFileSync(summaryPath, 'utf8'));
  const metrics = summary.metrics || {};
  let failed = false;

  const p95 = metrics.http_req_duration?.values?.['p(95)'];
  if (p95 && p95 > baselineThresholds.http_req_duration_p95) {
    console.error(`FAIL: p95 latency ${p95.toFixed(0)}ms > baseline ${baselineThresholds.http_req_duration_p95}ms`);
    failed = true;
  }

  const p99 = metrics.http_req_duration?.values?.['p(99)'];
  if (p99 && p99 > baselineThresholds.http_req_duration_p99) {
    console.error(`FAIL: p99 latency ${p99.toFixed(0)}ms > baseline ${baselineThresholds.http_req_duration_p99}ms`);
    failed = true;
  }

  const failRate = metrics.http_req_failed?.values?.rate;
  if (failRate && failRate > baselineThresholds.http_req_failed_rate) {
    console.error(`FAIL: error rate ${(failRate * 100).toFixed(2)}% > baseline ${baselineThresholds.http_req_failed_rate * 100}%`);
    failed = true;
  }

  if (failed) {
    process.exit(1);
  }
  console.log('PASS: All performance metrics within baseline thresholds');
} catch (e) {
  console.error('Failed to parse summary:', e.message);
  process.exit(1);
}