name: Check PR body for changelog convention

on:
  merge_group:
  pull_request:
    types: [opened, synchronize, reopened, edited, labeled, converted_to_draft, ready_for_review]

jobs:
  check-pr-body:
    runs-on: ubuntu-latest
    steps:
      - name: Check PR body
        if: github.event_name == 'pull_request'
        uses: actions/github-script@v7
        with:
          script: |
            const { title, body, labels, draft } = context.payload.pull_request;
            if (!draft && /^(feat|fix):/.test(title) && !labels.some(label => label.name == "changelog-no")) {
              if (!labels.some(label => label.name.startsWith("changelog-"))) {
                core.setFailed('feat/fix PR must have a `changelog-*` label');
              }
              if (!/^This PR [^<]/.test(body)) {
                core.setFailed('feat/fix PR must have changelog summary starting with "This PR ..." as first line.');
              }
            }