name: PR title

on:
  pull_request:
    types: [opened, edited, reopened, synchronize]

permissions: {}

jobs:
  check-format:
    name: Check format
    runs-on: ubuntu-latest
    steps:
      - name: Validate title
        env:
          PR_TITLE: ${{ github.event.pull_request.title }}
        run: |
          pattern='^(\[[^][]+\])+ +[^[:space:]].*$'
          if [[ "$PR_TITLE" =~ $pattern ]]; then
            exit 0
          fi

          echo "::error::PR title must start with one or more [Tag] prefixes, followed by a space and a description."
          exit 1