name: bench-advisory

# SDD-120 §6 / SRS-218 — advisory-only realtime-audio bench workflow.
# Runs the criterion bench harness on PR + tag events, compares the
# current results against the SAD-089 baseline JSON resolved at the
# merge-base, and renders a markdown report posted (or updated) as a
# single sticky PR comment. The job status is ALWAYS success — this
# workflow never fails a check on regression (SRS-218 clause 4).

on:
  pull_request:
    types: [opened, synchronize, reopened]
  push:
    tags: ["**"]

permissions:
  pull-requests: write
  contents: read

jobs:
  bench-advisory:
    name: bench-advisory
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
        with:
          fetch-depth: 0
      - name: System deps (cpal / Opus / SDL2)
        run: |
          sudo apt-get update
          sudo apt-get install -y \
            libasound2-dev libpulse-dev pkg-config \
            libdbus-1-dev \
            libsdl2-dev \
            libopus-dev
      - uses: dtolnay/rust-toolchain@stable
      - uses: Swatinem/rust-cache@v2
      - name: Run benchmarks
        run: |
          if ! cargo bench -p chanora_audio \
            --bench realtime_capture \
            --bench opus_codec \
            --bench resampler; then
            echo "::warning::Benchmark harness failed; continuing advisory workflow per SRS-218 clause 4"
          fi
      - name: Emit current baseline JSON
        run: cargo run --example emit_baseline -p chanora_audio
      - name: Resolve merge-base baseline
        run: |
          DEFAULT_BRANCH="${{ github.event.repository.default_branch }}"
          if [ "${{ github.event_name }}" = "pull_request" ]; then
            BASE_SHA="${{ github.event.pull_request.base.sha }}"
            MERGE_BASE=$(git merge-base "$BASE_SHA" HEAD || true)
          else
            MERGE_BASE=$(git merge-base "origin/${DEFAULT_BRANCH}" HEAD || true)
          fi
          if [ -n "$MERGE_BASE" ] && git show "${MERGE_BASE}:crates/chanora_audio/benches/baselines/x86_64-unknown-linux-gnu.json" > baseline.json 2>/dev/null; then
            echo "BASELINE_FOUND=1" >> "$GITHUB_ENV"
          else
            echo "BASELINE_FOUND=0" >> "$GITHUB_ENV"
            echo "{}" > baseline.json
          fi
      - name: Compare against baseline
        run: |
          cargo run --example compare_baseline -p chanora_audio -- \
            --current current.json \
            --baseline baseline.json \
            --output report.md
      - name: Post PR comment
        if: github.event_name == 'pull_request'
        uses: actions/github-script@v7
        with:
          script: |
            const fs = require('fs');
            const body = fs.readFileSync('report.md', 'utf8');
            const marker = '<!-- chanora-bench-advisory -->';
            const { data: comments } = await github.rest.issues.listComments({
              owner: context.repo.owner,
              repo: context.repo.repo,
              issue_number: context.issue.number,
            });
            const existing = comments.find(c => c.body && c.body.startsWith(marker));
            if (existing) {
              await github.rest.issues.updateComment({
                owner: context.repo.owner,
                repo: context.repo.repo,
                comment_id: existing.id,
                body,
              });
            } else {
              await github.rest.issues.createComment({
                owner: context.repo.owner,
                repo: context.repo.repo,
                issue_number: context.issue.number,
                body,
              });
            }
      - name: Upload report artifact (push events)
        if: github.event_name == 'push'
        uses: actions/upload-artifact@v4
        with:
          name: bench-report
          path: report.md
