name: Build & deploy documentation

on:
  push:
    branches:
      - main
  pull_request:

jobs:
  deploy:
    runs-on: ubuntu-20.04
    concurrency:
      group: ${{ github.workflow }}-${{ github.ref }}

    steps:
      - uses: actions/checkout@v2

      - name: Setup Python
        uses: actions/setup-python@v2
        with:
          python-version: '3.8'

      - name: Upgrade pip
        run: |
          # install pip=>20.1 to use "pip cache dir"
          python3 -m pip install --upgrade pip

      - name: Get pip cache dir
        id: pip-cache
        run: echo "::set-output name=dir::$(pip cache dir)"

      - name: Cache dependencies
        uses: actions/cache@v2
        with:
          path: ${{ steps.pip-cache.outputs.dir }}
          key: ${{ runner.os }}-pip-${{ hashFiles('**/requirements.txt') }}
          restore-keys: |
            ${{ runner.os }}-pip-

      - name: Build docs

        run: |
          cd docs
          pip install --progress-bar off -r requirements.txt
          make help
          make html

      - name: Deploy
        uses: peaceiris/actions-gh-pages@v3
        with:
          github_token: ${{ secrets.GITHUB_TOKEN }}
          publish_dir: docs/build/html
        if: github.event_name != 'pull_request'