benchmark.yml

name: Performance Benchmarks

on:
  pull_request:
    paths:
      - 'internal/adapter/**'
      - 'scripts/ci-benchmark-check.sh'
      - 'scripts/perf-regressor.go'
      - '.github/workflows/benchmark.yml'
  push:
    branches:
      - main
    paths:
      - 'internal/adapter/**'
  workflow_dispatch:

jobs:
  benchmark:
    name: Run Performance Benchmarks
    runs-on: macos-latest  # Use macOS for consistency with CI environment
    timeout-minutes: 20

    steps:
      - name: Checkout code
        uses: actions/checkout@v4
        with:
          fetch-depth: 0  # Fetch full history for baseline comparison

      - name: Set up Go
        uses: actions/setup-go@v4
        with:
          go-version: '1.23'
          cache: true

      - name: Create baseline directory
        run: mkdir -p .benchmarks

      - name: Download baseline from main
        if: github.event_name == 'pull_request'
        run: |
          # Fetch baseline from main branch
          git fetch origin main:main
          git show main:.benchmarks/baseline.json > .benchmarks/baseline-main.json 2>/dev/null || {
            echo "⚠️  Baseline not found on main branch, skipping regression check"
            echo "To create baseline: scripts/benchmark-baseline.sh"
            exit 0
          }
          mv .benchmarks/baseline-main.json .benchmarks/baseline.json
        continue-on-error: true

      - name: Run benchmark regression check
        if: github.event_name == 'pull_request'
        run: |
          chmod +x scripts/ci-benchmark-check.sh
          REGRESSION_THRESHOLD=10 scripts/ci-benchmark-check.sh
        continue-on-error: true
        env:
          CI_COMMIT_SHA: ${{ github.sha }}

      - name: Create baseline (main branch)
        if: github.event_name == 'push' && github.ref == 'refs/heads/main'
        run: |
          chmod +x scripts/benchmark-baseline.sh
          scripts/benchmark-baseline.sh
          # The baseline file is created as .benchmarks/baseline-<commit>.json

      - name: Upload benchmark results
        if: always()
        uses: actions/upload-artifact@v3
        with:
          name: benchmark-reports
          path: .benchmarks/
          retention-days: 30

      - name: Comment PR with results
        if: github.event_name == 'pull_request' && always()
        uses: actions/github-script@v7
        with:
          script: |
            const fs = require('fs');
            const path = require('path');

            // Look for regression report
            const reportFiles = fs.readdirSync('.benchmarks')
              .filter(f => f.startsWith('regression-report'));

            if (reportFiles.length === 0) {
              console.log('No regression report found');
              return;
            }

            const reportFile = path.join('.benchmarks', reportFiles[0]);
            const report = JSON.parse(fs.readFileSync(reportFile, 'utf8'));

            let comment = '## 📊 Performance Benchmark Results\n\n';

            if (report.passed_threshold) {
              comment += '✅ **All benchmarks passed!** No performance regressions detected.\n\n';
              comment += `- Total benchmarks checked: ${report.total_benchmarks}\n`;
            } else {
              comment += '❌ **Performance regression detected**\n\n';
              comment += `- Regressions: ${report.regression_count}/${report.total_benchmarks}\n`;
              comment += '\n### Regressions\n\n';

              for (const reg of report.regressions) {
                comment += `- **${reg.benchmark}**: ${reg.degradation_percent}% slower\n`;
                comment += `  - Threshold: ${reg.threshold_ms}ms\n`;
                comment += `  - Actual: ${reg.actual_ms}ms\n`;
              }
            }

            if (report.warnings && report.warnings.length > 0) {
              comment += '\n### Warnings\n\n';
              for (const warning of report.warnings) {
                comment += `- ⚠️  ${warning}\n`;
              }
            }

            comment += '\n**Regression threshold**: 10%\n';
            comment += `**Report**: [Download](https://github.com/${{ github.repository }}/actions/runs/${{ github.run_id }})`;

            github.rest.issues.createComment({
              issue_number: context.issue.number,
              owner: context.repo.owner,
              repo: context.repo.repo,
              body: comment
            });

  benchmark-summary:
    name: Benchmark Summary
    needs: benchmark
    runs-on: ubuntu-latest
    if: always()

    steps:
      - name: Check benchmark status
        run: |
          if [ "${{ needs.benchmark.result }}" == "failure" ]; then
            echo "⚠️  Benchmark check completed with issues"
          else
            echo "✅ Benchmark check passed"
          fi