name: screenshot-changelog

# Discord trigger B: when a push to main changes committed baseline PNGs, post an
# old | new+boxes | heatmap triptych per changed baseline (ADDED image / REMOVED
# title too). No build, no GPU — it only diffs two git revisions of PNGs that are
# already CI-rendered, 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/baseline-screenshots/**.png'

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 baseline 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 }}
        run: npm run screenshots:changelog