name: Docs preview

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

permissions: {}

concurrency:
  group: docs-preview-${{ github.event.pull_request.number }}
  cancel-in-progress: true

env:
  FERN_PUBLISHED_BRANCH: docs-website

jobs:
  build-and-deploy:
    if: github.actor != 'dependabot[bot]'
    runs-on: ubuntu-latest
    permissions:
      contents: read
      issues: write
      pull-requests: write
    steps:
      - name: Checkout repository
        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6

      - name: Install uv
        uses: astral-sh/setup-uv@08807647e7069bb48b6ef5acd8ec9567f424441b # v8.1.0
        with:
          version: "0.9.5"

      - name: Set up Python
        run: uv python install 3.11

      - name: Install docs dependencies
        run: uv sync --all-packages --group docs --group notebooks

      - name: Create preview notebooks
        run: |
          mkdir -p docs/notebooks
          cp docs/notebook_source/_README.md docs/notebooks/README.md
          cp docs/notebook_source/_pyproject.toml docs/notebooks/pyproject.toml

          for src in docs/notebook_source/*.py; do
            name=$(basename "$src" .py)
            .venv/bin/jupytext --to ipynb --output "docs/notebooks/${name}.ipynb" "$src"
          done

      - name: Build docs
        run: .venv/bin/mkdocs build

      - name: Verify published Fern archive exists
        run: |
          if ! git ls-remote --exit-code --heads origin "$FERN_PUBLISHED_BRANCH" >/dev/null 2>&1; then
            echo "::error::$FERN_PUBLISHED_BRANCH does not exist. Publish a Fern release snapshot first."
            exit 1
          fi

      - name: Checkout published Fern archive
        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
        with:
          fetch-depth: 0
          path: published-fern-preview
          ref: ${{ env.FERN_PUBLISHED_BRANCH }}

      - name: Prepare Fern preview source
        env:
          FERN_PREVIEW_ROOT: ${{ runner.temp }}/fern-preview
        run: |
          rm -rf "$FERN_PREVIEW_ROOT"
          mv published-fern-preview "$FERN_PREVIEW_ROOT"
          python3 fern/scripts/fern-published-branch.py sync-source \
            --source-root "$GITHUB_WORKSPACE" \
            --published-root "$FERN_PREVIEW_ROOT"

      - name: Check Fern docs
        id: fern-check
        continue-on-error: true
        env:
          FERN_PREVIEW_ROOT: ${{ runner.temp }}/fern-preview
        run: |
          cd "$FERN_PREVIEW_ROOT"
          make check-fern-docs \
            DOCS_PYTHON="$GITHUB_WORKSPACE/.venv/bin/python" \
            DOCS_JUPYTEXT="$GITHUB_WORKSPACE/.venv/bin/jupytext"

      - name: Skip hosted previews for fork PRs
        if: github.event.pull_request.head.repo.full_name != github.repository
        run: echo "::notice::Skipping hosted docs previews because this PR comes from a fork."

      - name: Deploy Fern preview
        if: github.event.pull_request.head.repo.full_name == github.repository && steps.fern-check.outcome == 'success'
        id: fern-preview
        continue-on-error: true
        env:
          FERN_TOKEN: ${{ secrets.DOCS_FERN_TOKEN }}
          PR_NUMBER: ${{ github.event.pull_request.number }}
          FERN_PREVIEW_ROOT: ${{ runner.temp }}/fern-preview
        run: |
          if [ -z "$FERN_TOKEN" ]; then
            echo "::error::DOCS_FERN_TOKEN secret is required to publish Fern preview docs."
            exit 1
          fi

          cd "$FERN_PREVIEW_ROOT/fern"
          fern_version=$(jq -r .version fern.config.json)
          if [[ ! "$fern_version" =~ ^[0-9]+[.][0-9]+[.][0-9]+([-.][0-9A-Za-z]+)*$ ]]; then
            echo "::error::Invalid Fern version in fern.config.json: $fern_version"
            exit 1
          fi

          log_file="$RUNNER_TEMP/fern-preview.log"

          set -o pipefail
          npx -y "fern-api@$fern_version" generate --docs --preview --id "pr-$PR_NUMBER" --force --no-prompt 2>&1 | tee "$log_file"

          echo "url=https://nvidia-preview-pr-$PR_NUMBER.docs.buildwithfern.com/nemo/datadesigner" >> "$GITHUB_OUTPUT"

      - name: Deploy to Cloudflare Pages
        if: github.event.pull_request.head.repo.full_name == github.repository
        id: deploy
        continue-on-error: true
        uses: cloudflare/wrangler-action@ebbaa1584979971c8614a24965b4405ff95890e0 # v4.0.0
        with:
          apiToken: ${{ secrets.CLOUDFLARE_API_TOKEN }}
          accountId: ${{ secrets.CLOUDFLARE_ACCOUNT_ID }}
          command: pages deploy site/ --project-name=dd-docs-preview --branch=pr-${{ github.event.pull_request.number }}

      - name: Find existing comment
        if: github.event.pull_request.head.repo.full_name == github.repository
        uses: peter-evans/find-comment@b30e6a3c0ed37e7c023ccd3f1db5c6c0b0c23aad # v4
        id: find-comment
        with:
          issue-number: ${{ github.event.pull_request.number }}
          comment-author: "github-actions[bot]"
          body-includes: "<!-- docs-preview -->"

      - name: Post or update PR comment
        if: github.event.pull_request.head.repo.full_name == github.repository
        uses: peter-evans/create-or-update-comment@e8674b075228eee787fea43ef493e45ece1004c9 # v5
        with:
          comment-id: ${{ steps.find-comment.outputs.comment-id }}
          issue-number: ${{ github.event.pull_request.number }}
          edit-mode: replace
          body: |
            <!-- docs-preview -->
            **MkDocs preview:** ${{ steps.deploy.outcome == 'success' && steps.deploy.outputs.deployment-url || 'MkDocs preview failed; see workflow logs.' }}

            **Fern preview:** ${{ steps.fern-preview.outcome == 'success' && steps.fern-preview.outputs.url || 'Fern preview failed or skipped; see workflow logs.' }}

            > Fern previews include the `docs-website` version archive with PR changes synced into latest. Notebook tutorials are rendered without execution outputs in previews.

      - name: Fail if Fern docs check failed
        if: steps.fern-check.outcome == 'failure'
        run: exit 1