name: Master PR Title Guard

on:
  pull_request:
    branches:
      - master
    types:
      - opened
      - edited
      - synchronize
      - reopened
      - ready_for_review

permissions:
  contents: read

jobs:
  validate-title:
    name: Require semver prefix in PR title
    runs-on: ubuntu-latest
    steps:
      - name: Validate pull request title prefix
        env:
          PR_TITLE: ${{ github.event.pull_request.title }}
        run: |
          title_lower="$(echo "${PR_TITLE}" | tr '[:upper:]' '[:lower:]')"
          if [[ "${title_lower}" == major* || "${title_lower}" == minor* || "${title_lower}" == fix* || "${title_lower}" == patch* || "${title_lower}" == path* ]]; then
            echo "PR title is valid: ${PR_TITLE}"
            exit 0
          fi
          echo "Invalid PR title: '${PR_TITLE}'"
          echo "Title must start with one of: major, minor, fix, patch, or path."
          exit 1