name: Cloudflare Pages PR Preview — Deploy
description: >-
  Deploys a pre-built static HTML directory to Cloudflare Pages under a per-PR
  branch alias, injects noindex headers/meta tags, and posts/updates a sticky
  PR comment with the preview URLs.

inputs:
  directory:
    description: Path to the built static HTML directory (e.g. blog/public)
    required: true
  project-name:
    description: Cloudflare Pages project name (must already exist in the CF dashboard)
    required: true
  api-token:
    description: Cloudflare API token with Pages:Edit permission on the project
    required: true
  account-id:
    description: Cloudflare account ID
    required: true
  branch:
    description: Cloudflare Pages branch alias for this deployment
    required: false
    default: pr-${{ github.event.pull_request.number }}
  inject-noindex:
    description: >-
      Whether to inject X-Robots-Tag headers (via _headers file) and a
      <meta name="robots"> tag into all HTML pages to prevent search engine
      indexing of the preview. Set to 'false' to skip.
    required: false
    default: 'true'
  comment-marker:
    description: HTML comment marker used to identify and update the sticky PR comment
    required: false
    default: '<!-- cf-pages-preview -->'
  comment-title:
    description: Heading shown in the sticky PR comment
    required: false
    default: 'Preview Deployed'
  comment-mode:
    description: >-
      How to handle prior preview comments. 'sticky' (default) updates the
      existing marker comment in place. 'repost' minimizes all prior marker
      comments as OUTDATED (GitHub's native hide-comment UI) and posts a fresh
      comment at the bottom of the conversation — preserving history while
      surfacing the latest links prominently.
    required: false
    default: sticky
  github-token:
    description: GitHub token for posting/updating the PR comment
    required: false
    default: ${{ github.token }}
  pr-number:
    description: >-
      PR number to comment on. Only needed on triggers where
      context.payload.pull_request is unavailable (e.g. workflow_dispatch).
      Defaults to the event payload's PR number.
    required: false
    default: ${{ github.event.pull_request.number }}
  commit-sha:
    description: >-
      Commit SHA shown in the sticky comment. Useful when the checked-out
      ref differs from github.sha (e.g. building a pinned head SHA on
      workflow_dispatch). Defaults to github.sha.
    required: false
    default: ${{ github.sha }}

outputs:
  deployment-url:
    description: URL of the specific deployment (changes per push)
    value: ${{ steps.deploy.outputs.deployment-url }}
  alias-url:
    description: Stable branch-alias URL (same across pushes to this PR)
    value: ${{ steps.deploy.outputs.pages-deployment-alias-url }}

runs:
  using: composite
  steps:
    # Prevent preview deployments from being indexed by search engines.
    # Cloudflare Pages serves _headers as HTTP headers for matching paths.
    # X-Robots-Tag covers all content types (HTML, RSS, sitemaps, etc.)
    - name: Add noindex headers
      if: inputs.inject-noindex == 'true'
      shell: bash
      env:
        DIR: ${{ inputs.directory }}
      run: |
        cat > "${DIR}/_headers" <<'EOF'
        /*
          X-Robots-Tag: noindex, nofollow, noarchive, nosnippet
        EOF

    # Also inject a <meta> tag into every HTML page as belt-and-suspenders
    # in case the site is later served from somewhere that ignores _headers.
    - name: Inject noindex meta tag
      if: inputs.inject-noindex == 'true'
      shell: bash
      env:
        DIR: ${{ inputs.directory }}
      run: |
        find "${DIR}" -name '*.html' -print0 | \
          xargs -0 -r sed -i 's|<head>|<head><meta name="robots" content="noindex, nofollow, noarchive, nosnippet">|'

    - name: Deploy to Cloudflare Pages
      id: deploy
      uses: cloudflare/wrangler-action@v3
      with:
        apiToken: ${{ inputs.api-token }}
        accountId: ${{ inputs.account-id }}
        command: pages deploy ${{ inputs.directory }} --project-name=${{ inputs.project-name }} --branch=${{ inputs.branch }}

    - name: Comment with preview URL
      uses: actions/github-script@v8
      env:
        DEPLOY_URL: ${{ steps.deploy.outputs.deployment-url }}
        ALIAS_URL: ${{ steps.deploy.outputs.pages-deployment-alias-url }}
        COMMENT_MARKER: ${{ inputs.comment-marker }}
        COMMENT_TITLE: ${{ inputs.comment-title }}
        COMMENT_MODE: ${{ inputs.comment-mode }}
        INJECT_NOINDEX: ${{ inputs.inject-noindex }}
        PR_NUMBER: ${{ inputs.pr-number }}
        COMMIT_SHA: ${{ inputs.commit-sha }}
      with:
        github-token: ${{ inputs.github-token }}
        script: |
          const main = require(process.env.GITHUB_ACTION_PATH + '/comment.js');
          await main({ github, context, core });