name: labels
# The automation LABELS.md promises. Two halves:
#   scope     — path-derived scope:* labels on PRs (actions/labeler)
#   reconcile — the state:* machine + the stale sweep (.github/scripts/labels-reconcile.sh)
#
# pull_request_target, not pull_request: every PR here arrives from a fork,
# where pull_request (and pull_request_review) run with a READ-ONLY token and
# cannot label anything. _target is safe in this workflow because no PR code
# is ever checked out or executed — labeler reads changed paths via the API,
# and reconcile checks out the BASE branch only. Keep it that way.
#
# Review-submitted transitions (bots finishing a round) ride the cron: there
# is no pull_request_review_target, so the 15-minute tick is the wake signal —
# the same cadence the reviewer bots poll at.
on:
  schedule:
    - cron: "*/15 * * * *"
  workflow_dispatch: # also bootstraps missing labels — run once on a fresh repo
  pull_request_target:
    types: [opened, reopened, ready_for_review, converted_to_draft, synchronize]

permissions:
  contents: read
  issues: write
  pull-requests: write

concurrency:
  group: labels-${{ github.event.pull_request.number || 'cron' }}
  cancel-in-progress: false

jobs:
  scope:
    if: github.event_name == 'pull_request_target'
    runs-on: ubuntu-latest
    steps:
      - uses: actions/labeler@v5
        with:
          # additive only — a hand-applied scope must survive the machine
          sync-labels: false

  reconcile:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4 # base branch only — never the PR's code
      - name: reconcile state + stale
        env:
          GH_TOKEN: ${{ github.token }}
          REPO: ${{ github.repository }}
        run: bash .github/scripts/labels-reconcile.sh