name: Deploy the documentation

on:
  push:
    branches:
      - develop
      - release-v*

  workflow_dispatch:

jobs:
  pages:
    name: GitHub Pages
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v2

      - name: Setup mdbook
        uses: peaceiris/actions-mdbook@v1
        with:
          mdbook-version: '0.4.8'

      - name: Build the documentation
        # mdbook will only create an index.html if we're including docs/README.md in SUMMARY.md.
        # However, we're using docs/README.md for other purposes and need to pick a new page
        # as the default. Let's opt for the welcome page instead.
        run: |
          mdbook build
          cp book/welcome_and_overview.html book/index.html

      # Deploy to the latest documentation directories
      - name: Deploy latest documentation
        uses: peaceiris/actions-gh-pages@v3
        with:
          github_token: ${{ secrets.GITHUB_TOKEN }}
          keep_files: true
          publish_dir: ./book
          destination_dir: ./latest

      - name: Get the current Synapse version
        id: vars
        run: echo ::set-output name=synapse-version::`python3 -c 'import synapse; print(synapse.__version__)'`

      # Deploy to the version-specific directory
      - name: Deploy release-specific documentation
        # We only carry out this step if we're running on a release branch, and the current Synapse version
        # does not have "rc" in the name.
        # The result is that only full releases are deployed, but can be updated if the release branch gets
        # retroactive fixes.
        if: ${{ startsWith( github.ref, 'refs/heads/release-v' ) && !contains( steps.vars.outputs.synapse-version, 'rc') }}
        uses: peaceiris/actions-gh-pages@v3
        with:
          github_token: ${{ secrets.GITHUB_TOKEN }}
          keep_files: true
          publish_dir: ./book
          destination_dir: ./v${{ steps.vars.outputs.synapse-version }}