name: PR Title Sync

on:
  pull_request:
    types: [opened, synchronize, edited]
    paths:
      - 'VERSION'

concurrency:
  group: pr-title-sync-${{ github.event.pull_request.number }}
  cancel-in-progress: true

jobs:
  sync:
    name: Sync PR title to VERSION
    runs-on: ubuntu-latest
    permissions:
      contents: read
      pull-requests: write
    if: github.actor != 'github-actions[bot]'
    steps:
      - name: Checkout PR head
        uses: actions/checkout@v4
        with:
          fetch-depth: 1
          ref: ${{ github.event.pull_request.head.sha }}

      - name: Rewrite PR title to match VERSION
        env:
          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
          PR_NUM: ${{ github.event.pull_request.number }}
          OLD_TITLE: ${{ github.event.pull_request.title }}
        run: |
          set -euo pipefail
          chmod +x ./bin/gstack-pr-title-rewrite.sh
          VERSION=$(cat VERSION | tr -d '[:space:]')
          NEW_TITLE=$(./bin/gstack-pr-title-rewrite.sh "$VERSION" "$OLD_TITLE")
          if [ "$NEW_TITLE" = "$OLD_TITLE" ]; then
            echo "Title already correct; no change."
            exit 0
          fi
          echo "Rewriting: $OLD_TITLE -> $NEW_TITLE"
          gh pr edit "$PR_NUM" --title "$NEW_TITLE"