name: bake-plugin-previews

# Post-merge + nightly bake of the home gallery's plugin previews.
#
# Role after the pipeline rework (specs/change/20260618-plugin-preview-bake-
# pipeline/spec.md): this workflow is the trusted UPLOADER + manifest review PR
# writer + nightly BACKSTOP.
#   - Pull requests validate the bake without secrets in
#     bake-plugin-previews-pr.yml.
#   - Manifest refreshes that need R2 credentials or a write-capable token happen
#     here after merge, from trusted main code.
#   - Fork contributions follow the same post-merge path.
#   - Nightly re-runs catch transient bake failures and BAKE_VERSION bumps.
# When it does need to land a manifest, it opens ONE rolling review PR (it cannot
# push to protected main directly). Until a plugin is baked the gallery falls
# back to its live example.html iframe, so there is no gap.

on:
  push:
    branches: [main]
    paths:
      - 'plugins/_official/**'
      - 'scripts/bake-plugin-previews.mjs'
  schedule:
    - cron: '0 18 * * *' # nightly self-healing full sweep
  workflow_dispatch: {}

permissions:
  contents: write # push the rolling manifest branch
  pull-requests: write # open the review PR (gh pr create needs this; unset perms default to none)

concurrency:
  group: bake-plugin-previews
  cancel-in-progress: false

jobs:
  bake:
    name: Bake plugin previews
    runs-on: ubuntu-24.04
    timeout-minutes: 90
    steps:
      - name: Checkout
        uses: actions/checkout@v6.0.2
        with:
          # Do NOT persist the default GITHUB_TOKEN as a github.com credential.
          # The rolling manifest branch is force-pushed below with the release-bot
          # App token (`x-access-token:${APP_TOKEN}`) precisely so the resulting PR
          # sync is attributed to app/open-design-release-bot and its CI runs
          # automatically (a github-actions[bot]-attributed pull_request run is held
          # as `action_required` — GitHub's bot-recursion gate — which starves
          # bake-plugin-previews-automerge.yml, since that reactor only approves +
          # enqueues on `workflow_run.conclusion == 'success'`). When checkout
          # persists the GITHUB_TOKEN it installs an `http.https://github.com/.extraheader`
          # Authorization header that overrides the inline App token on push, so the
          # force-push authenticates as github-actions[bot] and the rolling PR's CI
          # never runs without a manual "Approve and run". Nothing between here and
          # the push needs the persisted credential (setup-workspace only touches the
          # pnpm store; render/upload uses R2 creds; gh + push use the App token), so
          # dropping it is safe and keeps the App token the sole push credential.
          persist-credentials: false

      - name: Setup workspace
        uses: ./.github/actions/setup-workspace

      - name: Render previews + publish clips to R2 (main only)
        uses: ./.github/actions/bake-previews
        with:
          upload: ${{ github.ref == 'refs/heads/main' }}
          r2-access-key-id: ${{ secrets.CLOUDFLARE_R2_REPOSITORY_ASSETS_AK }}
          r2-secret-access-key: ${{ secrets.CLOUDFLARE_R2_REPOSITORY_ASSETS_SK }}
          r2-bucket: ${{ secrets.CLOUDFLARE_R2_REPOSITORY_ASSETS_BUCKET }}
          r2-endpoint: ${{ secrets.CLOUDFLARE_R2_REPOSITORY_ASSETS_URL }}

      - name: Mint release-bot token for the rolling manifest PR
        if: ${{ github.ref == 'refs/heads/main' }}
        id: app
        # A GITHUB_TOKEN-authored push/PR does NOT trigger workflows, so a manifest
        # PR opened with it never runs `Validate workspace` — main's required check
        # — and can never clear the merge queue (even manually). Author the rolling
        # branch + PR with the release-bot App instead: its push DOES start CI, and
        # its distinct identity (app/open-design-release-bot) lets a different bot
        # (github-actions[bot]) approve it in bake-plugin-previews-automerge.yml.
        # Minted here (not at job start) because an App token lives ~1h and the
        # bake render+upload above can run long.
        uses: actions/create-github-app-token@v2
        with:
          app-id: ${{ secrets.RELEASE_BOT_APP_ID }}
          private-key: ${{ secrets.RELEASE_BOT_PRIVATE_KEY }}

      - name: Open or update the rolling manifest PR for review
        if: ${{ github.ref == 'refs/heads/main' }} # branch debug runs skip publishing
        # The clips are already on R2; the manifest is version-pinned (it ships
        # with the build), so it must land on main through a reviewed PR rather
        # than a direct push to protected main.
        #
        # Two guards keep this quiet and tidy (spec slice 1):
        #   1. Open a PR only when a `previews` entry actually changed. The
        #      manifest's `generatedAt` timestamp moves every run, so the old
        #      whole-file `git diff` opened a noise PR every time (e.g. #4261).
        #      scripts/plugin-previews-diff.mjs compares only the `previews`
        #      subtree.
        #   2. Use ONE rolling branch (`chore/plugin-previews`) and force-update
        #      the existing open PR in place, instead of stacking a fresh
        #      `chore/plugin-previews-<run_id>` branch + PR per run (which built
        #      the backlog this rework removes).
        #
        # Authored by the release-bot App (token minted above) so the manifest
        # commit triggers CI; bake-plugin-previews-automerge.yml then approves +
        # enqueues it once `Validate workspace` is green.
        env:
          GH_TOKEN: ${{ steps.app.outputs.token }}
          APP_TOKEN: ${{ steps.app.outputs.token }}
          REPO: ${{ github.repository }}
        run: |
          OLD=data/plugin-previews/manifest.json
          NEW=.tmp/plugin-previews/manifest.json
          # Capture on its own line so `set -e` surfaces a helper error (the diff
          # script exits 2 on bad args / unreadable manifest) instead of command
          # substitution swallowing it into the test and silently skipping the PR.
          diff_result="$(node scripts/plugin-previews-diff.mjs "$OLD" "$NEW")"
          case "$diff_result" in
            changed) ;;
            unchanged) echo "previews unchanged (only generatedAt moved) — nothing to review"; exit 0 ;;
            *) echo "unexpected diff result: '$diff_result'" >&2; exit 1 ;;
          esac
          cp "$NEW" "$OLD"
          BRANCH="chore/plugin-previews"
          # Rebuild the rolling branch as `<rendered HEAD> + one manifest commit`. The commit is a
          # plain local commit (its committer identity is NOT a trust signal — the auto-merge
          # reactor instead requires the PR diff to touch ONLY manifest.json, which a forged
          # committer cannot defeat). Parent on the checked-out HEAD — the exact revision $NEW was
          # rendered against — NOT live main: the bake can run ~90min while main advances, and
          # basing it on live main would publish a manifest from an older render on top of newer
          # commits. The reactor's base-freshness gate skips a behind PR so the next bake re-renders
          # on the newer tip.
          git config user.name "open-design-bot"
          git config user.email "bot@open-design.ai"
          git checkout -B "$BRANCH"
          git add "$OLD"
          git commit -m "chore(plugin-previews): refresh baked preview manifest"
          # Push with the App token (not the checkout's GITHUB_TOKEN, whose pushes do not start CI)
          # so the rolling PR runs `Validate workspace` and can clear the merge queue.
          git push --force \
            "https://x-access-token:${APP_TOKEN}@github.com/${REPO}.git" "$BRANCH"
          # Reuse the existing open PR (the force-push already refreshed it); only
          # create one if none is open.
          if [ "$(gh pr view "$BRANCH" --json state --jq '.state' 2>/dev/null)" = "OPEN" ]; then
            echo "rolling PR already open for $BRANCH — force-push refreshed it in place"
          else
            gh pr create --base main --head "$BRANCH" \
              --title "chore(plugin-previews): refresh baked preview manifest" \
              --reviewer lefarcen \
              --body "Automated by the bake-plugin-previews workflow: preview clips were re-rendered and uploaded to R2; this updates data/plugin-previews/manifest.json to match (the clips live on R2 and are not committed). This is a single **rolling** PR — each bake force-updates it in place rather than stacking a new PR per run. @lefarcen please review and merge."
          fi