name: Area labels

on:
  schedule:
    - cron: '30 * * * *'
  workflow_dispatch:

permissions: {}

jobs:
  label:
    runs-on: ubuntu-latest
    permissions:
      contents: read
      pull-requests: write
    steps:
      - uses: actions/cache/restore@v6
        with:
          path: ${{ runner.temp }}/area-state.json
          key: area-labels-${{ github.run_id }}
          restore-keys: area-labels-
      - id: prs
        env:
          GH_TOKEN: ${{ github.token }}
        run: |
          state=$RUNNER_TEMP/area-state.json
          [ -s "$state" ] || echo '{}' > "$state"
          config=$(gh api "repos/$GITHUB_REPOSITORY/contents/.github/labeler.yml" --jq .sha)
          gh pr list -R "$GITHUB_REPOSITORY" --base "${{ github.event.repository.default_branch }}" -L 1000 --json number,headRefOid \
            --jq "map({key: (.number | tostring), value: (.headRefOid + \"-$config\")}) | from_entries" > "$RUNNER_TEMP/area-open.json"
          jq -r --slurpfile old "$state" 'to_entries[] | select($old[0][.key] != .value) | .key' "$RUNNER_TEMP/area-open.json" | head -n 40 > "$RUNNER_TEMP/area-todo"
          jq -c --slurpfile open "$RUNNER_TEMP/area-open.json" --rawfile todo "$RUNNER_TEMP/area-todo" \
            'with_entries(select(.key | in($open[0]))) + ($open[0] | with_entries(select(.key | IN($todo | split("\n")[]))))' "$state" > "$RUNNER_TEMP/area-next.json"
          {
            echo 'numbers<<EOF'
            cat "$RUNNER_TEMP/area-todo"
            echo EOF
          } >> "$GITHUB_OUTPUT"
      - if: steps.prs.outputs.numbers != ''
        uses: actions/labeler@v7
        with:
          pr-number: ${{ steps.prs.outputs.numbers }}
      - run: mv "$RUNNER_TEMP/area-next.json" "$RUNNER_TEMP/area-state.json"
      - uses: actions/cache/save@v6
        with:
          path: ${{ runner.temp }}/area-state.json
          key: area-labels-${{ github.run_id }}