deploy-preview.yaml

name: deploy-preview
on:
  workflow_run:
    workflows:
      - build-book
    types:
      - requested
      - completed

jobs:
  deploy:
    runs-on: ubuntu-latest
    defaults:
      run:
        shell: bash -l {0}
    steps:
      - uses: actions/checkout@v4
      - name: Fetch Repo Name
        id: repo-name
        run: echo "::set-output name=value::$(echo '${{ github.repository }}' | awk -F '/' '{print $2}')"  # just the repo name, not owner

      - name: Set message value
        run: |
          echo "comment_message=👋 Thanks for opening this PR! The book will be automatically built with [GitHub Actions](https://github.com/features/actions). To see the status of your deployment, click below." >> $GITHUB_ENV

      - name: Find Pull Request
        uses: actions/github-script@v7
        id: find-pull-request
        with:
          script: |
            let pullRequestNumber = ''
            let pullRequestHeadSHA = ''
            core.info('Finding pull request...')
            const pullRequests = await github.rest.pulls.list({owner: context.repo.owner, repo: context.repo.repo})
            for (let pullRequest of pullRequests.data) {
              if(pullRequest.head.sha === context.payload.workflow_run.head_commit.id) {
                  pullRequestHeadSHA = pullRequest.head.sha
                  pullRequestNumber = pullRequest.number
                  break
              }
            }
            core.setOutput('number', pullRequestNumber)
            core.setOutput('sha', pullRequestHeadSHA)
            if(pullRequestNumber === '') {
              core.info(
                 `No pull request associated with git commit SHA: ${context.payload.workflow_run.head_commit.id}`
              )
            }
            else{
              core.info(`Found pull request ${pullRequestNumber}, with head sha: ${pullRequestHeadSHA}`)
            }

      - name: Find preview comment
        uses: peter-evans/find-comment@v3
        if: steps.find-pull-request.outputs.number != ''
        id: fc
        with:
          issue-number: '${{ steps.find-pull-request.outputs.number }}'
          comment-author: 'github-actions[bot]'
          body-includes: '${{ env.comment_message }}'

      - name: Create preview comment
        if: |
          github.event.workflow_run.conclusion != 'success'
          && steps.find-pull-request.outputs.number != ''
          && steps.fc.outputs.comment-id == ''
        uses: peter-evans/create-or-update-comment@v4
        with:
          issue-number: ${{ steps.find-pull-request.outputs.number }}
          body: |
            ${{ env.comment_message }}
            🔍 Git commit SHA: ${{ steps.find-pull-request.outputs.sha }}
            ✅ Deployment Preview URL: In Progress

      - name: Update preview comment
        if: |
          github.event.workflow_run.conclusion != 'success'
          && steps.find-pull-request.outputs.number != ''
          && steps.fc.outputs.comment-id != ''
        uses: peter-evans/create-or-update-comment@v4
        with:
          comment-id: ${{ steps.fc.outputs.comment-id }}
          edit-mode: replace
          body: |
            ${{ env.comment_message }}
            🔍 Git commit SHA: ${{ steps.find-pull-request.outputs.sha }}
            ✅ Deployment Preview URL: In Progress

      - name: Download Artifact Book
        if: |
          github.event.workflow_run.conclusion == 'success'
          && steps.find-pull-request.outputs.number != ''
          && steps.fc.outputs.comment-id != ''
        uses: dawidd6/action-download-artifact@v3.1.4
        with:
          github_token: ${{ secrets.GITHUB_TOKEN }}
          workflow: build-book.yaml
          run_id: ${{ github.event.workflow_run.id }}
          name: book-zip-${{ steps.find-pull-request.outputs.number }}

      - name: Unzip the book
        if: |
          github.event.workflow_run.conclusion == 'success'
          && steps.find-pull-request.outputs.number != ''
          && steps.fc.outputs.comment-id != ''
        run: |
          rm -rf _build/html
          unzip book.zip
          rm -f book.zip

      # Push the book's HTML to github-pages
      # This will be published at /_preview/PRnumber/ relative to the main site
      - name: Deploy to GitHub pages
        id: deploy
        if: |
          github.event.workflow_run.conclusion == 'success'
          && steps.find-pull-request.outputs.number != ''
          && steps.fc.outputs.comment-id != ''
        uses: peaceiris/actions-gh-pages@v3.9.3
        with:
          github_token: ${{ secrets.GITHUB_TOKEN }}
          publish_dir: _build/html
          enable_jekyll: false
          destination_dir: _preview/${{ steps.find-pull-request.outputs.number }}

      - name: Finalize preview comment
        if: |
          github.event.workflow_run.conclusion == 'success'
          && steps.find-pull-request.outputs.number != ''
          && steps.fc.outputs.comment-id != ''
          && steps.deploy.conclusion == 'success'
        uses: peter-evans/create-or-update-comment@v4
        with:
          comment-id: ${{ steps.fc.outputs.comment-id }}
          edit-mode: replace
          body: |
            ${{ env.comment_message }}
            🔍 Git commit SHA: ${{ steps.find-pull-request.outputs.sha }}
            ✅ Deployment Preview URL: https://${{ github.repository_owner }}.github.io/${{ steps.repo-name.outputs.value }}/_preview/${{ steps.find-pull-request.outputs.number }}