name: Update Stable Docs

on:
  release:
    types: [published]
  push:
    branches:
    - main

permissions:
  contents: write

jobs:
  update_stable_docs:
    runs-on: ubuntu-latest
    steps:
    - name: Checkout repository
      uses: actions/checkout@v3
      with:
        fetch-depth: 0  # We need all commits to find docs/ changes
    - name: Set up Git user
      run: |
        git config user.name "Automated"
        git config user.email "actions@users.noreply.github.com"
    - name: Check if stable branch exists
      run: |
        if ! git ls-remote --heads origin stable | grep stable; then
          git checkout -b stable
          git push -u origin stable
        fi
    - name: Handle Release
      if: github.event_name == 'release'
      run: |
        git fetch --all
        git checkout stable
        git reset --hard ${GITHUB_REF#refs/tags/}
        git push origin stable --force
    - name: Handle Commit to Main
      if: contains(github.event.head_commit.message, '!stable-docs')
      run: |
        git fetch origin
        git checkout -b stable origin/stable
        # Get the list of modified files in docs/ from the current commit
        FILES=$(git diff-tree --no-commit-id --name-only -r ${{ github.sha }} -- docs/)
        # Check if the list of files is non-empty
        if [[ -n "$FILES" ]]; then
          # Checkout those files to the stable branch to over-write with their contents
          for FILE in $FILES; do
            git checkout ${{ github.sha }} -- $FILE
          done
          git add docs/
          git commit -m "Doc changes from ${{ github.sha }}"
          git push origin stable
        else
          echo "No changes to docs/ in this commit."
          exit 0
        fi