name: Update PR title

on:
  pull_request_target:
    types: [opened, edited, reopened]

jobs:
  update-title:
    if: github.event.action != 'edited' || github.event.changes.base.ref.from != ''
    runs-on: ubuntu-latest
    permissions:
      pull-requests: write
    steps:
      - name: Update PR title
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
          PR_NUMBER: ${{ github.event.pull_request.number }}
          TARGET_BRANCH: "${{ github.base_ref }}"
          PR_TITLE: "${{ github.event.pull_request.title }}"
          REPO: "${{ github.repository }}"
        run: |
          VERSION=$(echo $TARGET_BRANCH | grep -oP '^release_\K\d+.\d+$' || true)
          NEW_TITLE=$(echo "$PR_TITLE" | sed -E "s/\[[0-9]+\.[0-9]+\] //")
          if [[ -n "$VERSION" ]]; then
            NEW_TITLE="[$VERSION] $NEW_TITLE"
          fi
          if [[ "$NEW_TITLE" != "$PR_TITLE" ]]; then
            gh pr edit $PR_NUMBER --repo "$REPO" --title "$NEW_TITLE"
          fi