name: Change PR target if base branch is master

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

jobs:
  change-pr-target:
    runs-on: ubuntu-latest
    steps:
      - name: Set target environment variable
        run: |
          if [[ "${GITHUB_HEAD_REF}" == fe* || "${GITHUB_HEAD_REF}" == FE* ]]; then
            echo "target=frontend" >> $GITHUB_ENV
          elif [[ "${GITHUB_HEAD_REF}" == be* || "${GITHUB_HEAD_REF}" == BE* ]]; then
            echo "target=backend" >> $GITHUB_ENV
          fi

      - name: Change base branch for PR
        if: env.target == 'frontend' || env.target == 'backend'
        run: gh pr edit ${{ github.event.pull_request.number }} --base ${{ env.target }} --repo ${{ github.repository }}
        env:
          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}