name: PR Preview

on:
  pull_request:
    types: [opened, reopened, synchronize, closed, ready_for_review]
    paths:
      - 'content/**'
      - 'layouts/**'
      - 'assets/**'
      - 'data/**'
      - 'api-docs/**'
      - 'openapi/**'

permissions:
  contents: write
  pull-requests: write
  statuses: write

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

jobs:
  # Skip draft PRs entirely
  check-draft:
    runs-on: ubuntu-latest
    outputs:
      should-run: ${{ steps.check.outputs.should-run }}
    steps:
      - id: check
        run: |
          if [[ "${{ github.event.pull_request.draft }}" == "true" ]]; then
            echo "should-run=false" >> $GITHUB_OUTPUT
            echo "Skipping draft PR"
          else
            echo "should-run=true" >> $GITHUB_OUTPUT
          fi

  # Notify fork PRs that preview is not available
  fork-notice:
    needs: check-draft
    if: |
      needs.check-draft.outputs.should-run == 'true' &&
      github.event.action != 'closed' &&
      github.event.pull_request.head.repo.full_name != github.repository
    runs-on: ubuntu-latest
    steps:
      - name: Post fork notice comment
        uses: actions/github-script@v7
        with:
          script: |
            const { data: comments } = await github.rest.issues.listComments({
              owner: context.repo.owner,
              repo: context.repo.repo,
              issue_number: context.issue.number
            });

            const marker = '<!-- pr-preview-fork-notice -->';
            const existing = comments.find(c => c.body.includes(marker));

            if (!existing) {
              await github.rest.issues.createComment({
                owner: context.repo.owner,
                repo: context.repo.repo,
                issue_number: context.issue.number,
                body: `${marker}\n## 📝 PR Preview Not Available\n\nPR previews are not available for pull requests from forks due to GitHub Actions security restrictions.\n\nTo preview your changes locally, run:\n\`\`\`bash\nnpx hugo server\n\`\`\`\n\nOnce merged, your changes will be visible on the production site.`
              });
            }

  # Build and deploy preview
  preview:
    needs: check-draft
    # Skip fork PRs - GITHUB_TOKEN doesn't have write access to push to gh-pages
    if: |
      needs.check-draft.outputs.should-run == 'true' &&
      github.event.action != 'closed' &&
      github.event.pull_request.head.repo.full_name == github.repository
    runs-on: ubuntu-latest
    steps:
      - name: Checkout
        uses: actions/checkout@v4
        with:
          fetch-depth: 0

      - name: Setup Node.js
        uses: actions/setup-node@v4
        with:
          node-version: '20'
          cache: 'yarn'

      - name: Install dependencies
        run: yarn install --frozen-lockfile

      - name: Set preview status (pending)
        uses: actions/github-script@v7
        with:
          script: |
            await github.rest.repos.createCommitStatus({
              owner: context.repo.owner,
              repo: context.repo.repo,
              sha: context.sha,
              state: 'pending',
              context: 'preview/deploy',
              description: 'Building preview...',
            });

      - name: Detect preview pages
        id: detect
        env:
          PR_BODY: ${{ github.event.pull_request.body }}
          BASE_REF: origin/${{ github.base_ref }}
        run: |
          if ! node .github/scripts/detect-preview-pages.js; then
            echo "::warning::detect-preview-pages.js failed — skipping preview."
            echo "pages-to-deploy=[]" >> "$GITHUB_OUTPUT"
            echo "has-api-doc-changes=false" >> "$GITHUB_OUTPUT"
            echo "has-layout-changes=false" >> "$GITHUB_OUTPUT"
            echo "needs-author-input=false" >> "$GITHUB_OUTPUT"
            echo "change-summary=Detection failed (possible merge conflicts)" >> "$GITHUB_OUTPUT"
          fi

      - name: Post pending comment (needs input)
        if: steps.detect.outputs.needs-author-input == 'true'
        uses: actions/github-script@v7
        with:
          script: |
            const { upsertPreviewComment } = await import('${{ github.workspace }}/.github/scripts/preview-comment.js');
            await upsertPreviewComment(github, context, {
              status: 'pending',
              needsInput: true,
              prNumber: context.issue.number
            });

      - name: Skip if no pages to deploy
        if: steps.detect.outputs.pages-to-deploy == '[]'
        run: |
          echo "No pages to deploy - skipping preview"
          echo "Reason: ${{ steps.detect.outputs.skip-reason || steps.detect.outputs.change-summary }}"

      - name: Build API documentation scripts
        if: steps.detect.outputs.has-api-doc-changes == 'true' && steps.detect.outputs.pages-to-deploy != '[]'
        run: yarn build:api-docs:scripts

      - name: Build API docs
        if: steps.detect.outputs.has-api-doc-changes == 'true' && steps.detect.outputs.pages-to-deploy != '[]'
        run: yarn run build:api-docs

      - name: Build Hugo site
        if: steps.detect.outputs.pages-to-deploy != '[]'
        id: build
        env:
          # Set baseURL for GitHub Pages preview subdirectory
          PREVIEW_BASE_URL: https://influxdata.github.io/docs-v2/pr-preview/pr-${{ github.event.number }}/
        run: |
          START_TIME=$(date +%s)
          # Use pr-preview environment for path offset config
          npx hugo --minify --baseURL "$PREVIEW_BASE_URL" -e pr-preview
          END_TIME=$(date +%s)
          DURATION=$((END_TIME - START_TIME))
          echo "build-time=${DURATION}s" >> $GITHUB_OUTPUT

      - name: Prepare preview files
        if: steps.detect.outputs.pages-to-deploy != '[]'
        run: |
          node .github/scripts/prepare-preview-files.js \
            '${{ steps.detect.outputs.pages-to-deploy }}' \
            public \
            preview-staging

      - name: Deploy preview
        if: steps.detect.outputs.pages-to-deploy != '[]'
        id: deploy-preview
        continue-on-error: true
        uses: rossjrw/pr-preview-action@v1.4.8
        with:
          source-dir: ./preview-staging
          preview-branch: gh-pages
          umbrella-dir: pr-preview
          action: deploy

      - name: Validate preview deployment
        if: steps.detect.outputs.pages-to-deploy != '[]'
        id: validate-deploy
        run: |
          DEPLOY_OUTCOME="${{ steps.deploy-preview.outcome }}"
          DEPLOY_URL="${{ steps.deploy-preview.outputs.deployment-url }}"

          if [ -z "$DEPLOY_URL" ]; then
            echo "Deployment step did not produce a preview URL. Failing preview job."
            exit 1
          fi

          if [ "$DEPLOY_OUTCOME" != "success" ]; then
            echo "Deployment reported outcome: $DEPLOY_OUTCOME"
            echo "Preview URL exists; treating as transient post-deploy comment error."
          fi

          echo "status=ok" >> "$GITHUB_OUTPUT"

      - name: Set preview status (success)
        if: steps.validate-deploy.outputs.status == 'ok'
        uses: actions/github-script@v7
        with:
          script: |
            const previewUrl = `https://influxdata.github.io/docs-v2/pr-preview/pr-${context.issue.number}/`;
            await github.rest.repos.createCommitStatus({
              owner: context.repo.owner,
              repo: context.repo.repo,
              sha: context.sha,
              state: 'success',
              context: 'preview/deploy',
              description: 'Preview deployed',
              target_url: previewUrl,
            });

      - name: Set preview status (skipped/failed)
        if: >-
          always() &&
          steps.detect.outcome == 'success' &&
          (steps.validate-deploy.outputs.status != 'ok' ||
           steps.detect.outputs.pages-to-deploy == '[]')
        uses: actions/github-script@v7
        with:
          script: |
            const description =
              '${{ steps.detect.outputs.pages-to-deploy }}' === '[]'
                ? 'No pages to preview'
                : 'Preview deployment failed';
            await github.rest.repos.createCommitStatus({
              owner: context.repo.owner,
              repo: context.repo.repo,
              sha: context.sha,
              state: 'failure',
              context: 'preview/deploy',
              description,
            });

      - name: Post success comment
        if: steps.detect.outputs.pages-to-deploy != '[]' && steps.validate-deploy.outputs.status == 'ok'
        uses: actions/github-script@v7
        with:
          script: |
            const { upsertPreviewComment } = await import('${{ github.workspace }}/.github/scripts/preview-comment.js');
            const pages = JSON.parse('${{ steps.detect.outputs.pages-to-deploy }}');
            const previewUrl = `https://influxdata.github.io/docs-v2/pr-preview/pr-${{ github.event.number }}/`;
            await upsertPreviewComment(github, context, {
              status: 'success',
              previewUrl,
              pages,
              buildTime: '${{ steps.build.outputs.build-time }}',
              prNumber: context.issue.number
            });

      - name: Post skipped comment
        if: steps.detect.outputs.pages-to-deploy == '[]' && steps.detect.outputs.needs-author-input != 'true'
        uses: actions/github-script@v7
        with:
          script: |
            const { upsertPreviewComment } = await import('${{ github.workspace }}/.github/scripts/preview-comment.js');
            await upsertPreviewComment(github, context, {
              status: 'skipped',
              skipReason: '${{ steps.detect.outputs.change-summary }}',
              prNumber: context.issue.number
            });

  # Cleanup on PR close
  cleanup:
    if: github.event.action == 'closed'
    runs-on: ubuntu-latest
    steps:
      - name: Checkout gh-pages
        uses: actions/checkout@v4
        with:
          ref: gh-pages

      - name: Remove preview directory
        run: |
          PREVIEW_DIR="pr-preview/pr-${{ github.event.number }}"
          if [ -d "$PREVIEW_DIR" ]; then
            rm -rf "$PREVIEW_DIR"
            git config user.name "github-actions[bot]"
            git config user.email "github-actions[bot]@users.noreply.github.com"
            git add -A
            git commit -m "Clean up preview for PR #${{ github.event.number }}" || echo "Nothing to commit"
            git push
            echo "Cleaned up $PREVIEW_DIR"
          else
            echo "No preview directory found for PR #${{ github.event.number }}"
          fi

      - name: Checkout scripts for comment deletion
        uses: actions/checkout@v4
        with:
          path: scripts-checkout

      - name: Delete preview comment
        uses: actions/github-script@v7
        with:
          script: |
            const { deletePreviewComment } = await import('${{ github.workspace }}/scripts-checkout/.github/scripts/preview-comment.js');
            await deletePreviewComment(github, context);