main.yml

# This is a basic workflow to help you get started with Actions

name: CI

# Controls when the workflow will run
on:
  # Triggers the workflow on push or pull request events but only for the master branch
  push:
    branches: [ master ]
  pull_request:
    branches: [ master ]

  # Allows you to run this workflow manually from the Actions tab
  workflow_dispatch:
jobs:
  build_css:
    runs-on: ubuntu-latest

    steps:
      - name: Checkout source Git branch
        uses: actions/checkout@v2
        with:
            ref: master
            fetch-depth: 10
            submodules: true

      - name: Make destination directory for compiled CSS
        run: mkdir -vp /tmp/css

      - name: Compile CSS from SCSS files
        uses: gha-utilities/sass-build@v0.4.8
        with:
          source: style.sass
          destination: /tmp/css/style.css

      - name: Checkout destination Git branch
        uses: actions/checkout@v2
        with:
            ref: gh-pages
            fetch-depth: 1

      - name: Reset gh-pages branch to master
        run: |
          git reset --hard origin/master
          git config --local user.email 'action@github.com'
          git config --local user.name 'GitHub Action'
          
      - name: Push changes
        uses: ad-m/github-push-action@master
        with:
          github_token: ${{ secrets.GITHUB_TOKEN }}
          branch: gh-pages
          force: true

      - name: Move compiled CSS to path within pr-pages branch
        run: mv /tmp/css/style.css style.css

      - name: Add and Commit changes to gh-pages branch
        run: |
          git config --local user.email 'action@github.com'
          git config --local user.name 'GitHub Action'
          cat >.gitignore<<EOF
          *.css
          *.css.map
          !style.css
          EOF
          git add .
          git commit -m 'Updates compiled CSS files'

      - name: Push changes
        uses: ad-m/github-push-action@master
        with:
          github_token: ${{ secrets.GITHUB_TOKEN }}
          branch: gh-pages