name: screenshot-changelog

# Discord trigger B: when a push to main changes the screenshot manifest (the
# committed pin of every R2-stored baseline), post an old | new+boxes | heatmap
# triptych per changed baseline (ADDED image / REMOVED title too). No build, no
# GPU — it diffs two git revisions of the manifest and fetches the PNG bytes
# from the R2 CAS bucket (immutable objects, so the old rev's hashes always
# resolve), so it runs in ~30s. Complements the re-render drift gate in
# wasm-build.yml (which catches un-blessed renders); this is the human-facing
# feed of intentional baseline updates as they land.

on:
  push:
    branches: [main]
    paths:
      - 'tests/screenshot-manifest.json'

concurrency:
  group: screenshot-changelog-${{ github.ref }}
  cancel-in-progress: false

jobs:
  changelog:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
        with:
          # HEAD^ is needed to diff the tip commit's manifest changes. (A push of
          # multiple commits reports only the tip commit's baseline diff — fine for
          # a changelog; baseline refreshes are single commits in practice.)
          fetch-depth: 2
      - uses: actions/setup-node@v4
        with:
          node-version: 20
      - name: Install screenshot tooling deps
        working-directory: tests
        run: npm ci
      - name: Post baseline changelog to Discord
        working-directory: tests
        env:
          DISCORD_WEBHOOK_URL: ${{ secrets.DISCORD_WEBHOOK_URL }}
          CI_SCREENSHOTS_S3_ENDPOINT: ${{ vars.CI_SCREENSHOTS_S3_ENDPOINT }}
          CI_SCREENSHOTS_S3_ACCESS_KEY_ID: ${{ secrets.CI_SCREENSHOTS_S3_ACCESS_KEY_ID }}
          CI_SCREENSHOTS_S3_SECRET_ACCESS_KEY: ${{ secrets.CI_SCREENSHOTS_S3_SECRET_ACCESS_KEY }}
        run: npm run screenshots:changelog