neovim-flake/.github/workflows/docs-preview.yml

name: Build and Preview Manual

on:
  workflow_dispatch:
  pull_request:
    types: [opened, synchronize, reopened, closed]
    paths:
      - ".github/workflows/docs-preview.yml"
      - "modules/**"
      - "docs/**"

# Defining permissions here passes it to all workflows.
# https://docs.github.com/en/actions/writing-workflows/choosing-what-your-workflow-does/controlling-permissions-for-github_token
permissions:
  contents: write
  pull-requests: write
  issues: write

concurrency:
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: true

jobs:
  build-preview:
    runs-on: ubuntu-latest
    steps:
      - name: Install Nix
        uses: DeterminateSystems/nix-installer-action@main
      - uses: DeterminateSystems/magic-nix-cache-action@main

      - name: Checkout
        uses: actions/checkout@v4

      - name: Set default git branch (to reduce log spam)
        run: git config --global init.defaultBranch main

      - name: Build documentation packages
        run: nix build .#docs-html --print-build-logs

      - name: Deploy to GitHub Pages preview
        run: |
          PR_NUMBER=${{ github.event.pull_request.number }}
          BRANCH_NAME="gh-pages"
          PREVIEW_DIR="docs-preview-${PR_NUMBER}"

          # Clone the gh-pages branch and move to the preview subdirectory
          git clone --single-branch --branch $BRANCH_NAME https://github.com/${{ github.repository }} gh-pages
          cd gh-pages

          mkdir -p $PREVIEW_DIR

          # Copy the build files to the preview subdirectory
          cp -rvf ../result/share/doc/nvf/* ./$PREVIEW_DIR

          # Configure git to use the GitHub Actions token for authentication
          git config --global user.name "GitHub Actions"
          git config --global user.email "actions@github.com"

          # Set the GitHub token for authentication
          git remote set-url origin https://x-access-token:${{ secrets.GITHUB_TOKEN }}@github.com/${{ github.repository }}

          # Add and commit the changes
          git add --all
          git commit -m "Deploy PR #${PR_NUMBER} preview" || echo "No changes to commit"
          git push --force origin $BRANCH_NAME          

  comment-url:
    needs: build-preview
    runs-on: ubuntu-latest
    steps:
      - name: Prepare Environment
        id: prelude
        run: |
          PR_NUMBER=${{ github.event.pull_request.number }}
          URL="https://${{ github.repository_owner }}.github.io/nvf/docs-preview-${PR_NUMBER}/"

          # Propagate non-interpolatable environment vars
          echo "URL=$URL" >> "$GITHUB_OUTPUT"
          echo "REV=$GITHUB_SHA" >> "$GITHUB_OUTPUT"
          echo "ACTOR=$GITHUB_ACTOR" >> "$GITHUB_OUTPUT"
          echo "REF=$GITHUB_HEAD_REF" >> "$GITHUB_OUTPUT"
          echo "RUNS=$GITHUB_RUN_NUMBER" >> "$GITHUB_OUTPUT"

          echo "Live Preview URL: $URL"
          echo "Rev: $GITHUB_SHA"
          echo "Actor: $GITHUB_ACTOR"
          echo "Ref: "$GITHUB_HEAD_REF"
          echo "Reruns: "$GITHUB_RUN_NUMBER"

          echo "### :rocket: Live Preview Deployed " >> "$GITHUB_STEP_SUMMARY"
          echo "Preview can be found at ${URL}" >> "$GITHUB_STEP_SUMMARY"          

      - name: Find Comment
        uses: peter-evans/find-comment@v3
        id: fc
        with:
          comment-author: "github-actions[bot]"
          issue-number: ${{ github.event.pull_request.number }}
          body-includes: "Live preview deployed"

      - name: Post live preview comment
        uses: peter-evans/create-or-update-comment@v4
        env:
          COMMENT_ID: ${{ steps.fc.outputs.comment-id }}
          URL: ${{ steps.prelude.outputs.URL }}
          GITHUB_SHA: ${{ steps.prelude.outputs.REV }}
          ACTOR: ${{ steps.prelude.outputs.ACTOR }}
          REF: ${{ steps.prelude.outputs.REF }}
          RUNS: ${{ steps.prelude.outputs.RUNS }}
        with:
          comment-id: ${{ env.COMMENT_ID }}
          issue-number: ${{ github.event.pull_request.number }} # issue number also applies to pull requests
          edit-mode: replace # replace previous body
          body: |
            ### :rocket: Live preview deployed from ${{ env.GITHUB_SHA }}

            View it [here](${{ env.URL }}):

            <details>
              <summary><strong>Debug Information</strong></summary>
              <p>Triggered by: ${{ env.ACTOR }}</p>
              <p><code>HEAD</code> at: ${{ env.REF }}</p>
              <p>Reruns: ${{ env.RUNS }}</p>
            </details>            

  cleanup:
    if: ${{ github.event.pull_request.merged == true || github.event.pull_request.state == 'closed' }}
    runs-on: ubuntu-latest
    steps:
      - name: Checkout repository
        uses: actions/checkout@v4

      - name: Delete preview for closed/merged PR
        run: |
          PR_NUMBER=${{ github.event.pull_request.number }}
          BRANCH_NAME="gh-pages"
          PREVIEW_DIR="docs-preview-${PR_NUMBER}"

          # Clone the gh-pages branch
          git clone --single-branch --branch $BRANCH_NAME https://github.com/${{ github.repository }} gh-pages
          cd gh-pages

          # Check if the preview directory exists, and delete it if it does
          if [ -d "$PREVIEW_DIR" ]; then
            echo "Deleting preview directory $PREVIEW_DIR"
            rm -rf $PREVIEW_DIR
          else
            echo "Preview directory $PREVIEW_DIR does not exist. Skipping deletion."
          fi

          # Configure git to use the GitHub Actions token for authentication
          git config --global user.name "GitHub Actions"
          git config --global user.email "actions@github.com"

          # Set the GitHub token for authentication
          git remote set-url origin https://x-access-token:${{ secrets.GITHUB_TOKEN }}@github.com/${{ github.repository }}

          # Add and commit the changes (only if there's something to delete)
          git add .
          git diff --quiet || git commit -m "Remove preview for PR #${PR_NUMBER}"
          git push origin $BRANCH_NAME          

  cleanup-comment:
    needs: cleanup
    runs-on: ubuntu-latest
    steps:
      - name: Post cleanup verification
        uses: peter-evans/create-or-update-comment@v4
        with:
          issue-number: ${{ github.event.pull_request.number }}
          body: |
            ✅ Preview has been deleted successfully!