pr-comment.yml

name: PR Spec Preview Comment

on:
  workflow_run:
    workflows: ["Check Specs"]
    types: [completed]

permissions:
  actions: read
  pull-requests: write

jobs:
  comment:
    name: Post spec preview
    runs-on: ubuntu-latest
    if: >
      github.event.workflow_run.event == 'pull_request' &&
      github.event.workflow_run.conclusion == 'success'
    steps:
      - name: Download PR metadata
        uses: dawidd6/action-download-artifact@bf251b5aa9c2f7eeb574a96ee720e24f801b7c11 # v6
        with:
          github_token: ${{ secrets.GITHUB_TOKEN }}
          run_id: ${{ github.event.workflow_run.id }}
          name: pr-metadata

      - name: Read PR number
        id: pr
        run: echo "number=$(cat pr-number.txt)" >> "$GITHUB_OUTPUT"

      - name: Download spec artifacts
        uses: dawidd6/action-download-artifact@bf251b5aa9c2f7eeb574a96ee720e24f801b7c11 # v6
        with:
          github_token: ${{ secrets.GITHUB_TOKEN }}
          run_id: ${{ github.event.workflow_run.id }}
          name_is_regexp: true
          name: pr-${{ steps.pr.outputs.number }}-.*
          path: /tmp/pr-artifacts
        continue-on-error: true

      - name: Comment on PR
        uses: actions/github-script@f28e40c7f34bde8b3046d885e986cb6290c5673b # v7
        with:
          script: |
            const fs = require('fs');
            const path = require('path');
            const prNumber = parseInt('${{ steps.pr.outputs.number }}');
            const runUrl = `https://github.com/${context.repo.owner}/${context.repo.repo}/actions/runs/${{ github.event.workflow_run.id }}`;

            // Find spec artifacts
            const specsDir = fs.readdirSync('/tmp/pr-artifacts').find(d => d.includes('specs'));
            const diffsDir = fs.readdirSync('/tmp/pr-artifacts').find(d => d.includes('diffs'));

            let table = '| Spec | Changed |\n|------|--------|\n';

            if (specsDir) {
              const specsPath = path.join('/tmp/pr-artifacts', specsDir);
              const htmlFiles = fs.readdirSync(specsPath)
                .filter(f => f.startsWith('draft-') && f.endsWith('.html'))
                .sort();

              for (const file of htmlFiles) {
                const name = file.replace('.html', '');
                let changed = '-';
                if (diffsDir) {
                  const diffFile = path.join('/tmp/pr-artifacts', diffsDir, `${name}-diff.txt`);
                  if (fs.existsSync(diffFile)) {
                    const content = fs.readFileSync(diffFile, 'utf8');
                    if (content.trim() && !content.includes('New spec')) {
                      changed = 'Yes';
                    }
                  }
                }
                table += `| \`${name}\` | ${changed} |\n`;
              }
            }

            const body = `<!-- ietf-spec-preview -->
            ## Spec Preview

            ${table}

            **[Download spec artifacts](${runUrl}#artifacts)** (HTML, TXT, XML, PDF)
            `;

            const { data: comments } = await github.rest.issues.listComments({
              owner: context.repo.owner,
              repo: context.repo.repo,
              issue_number: prNumber,
            });

            const existingComment = comments.find(c => c.body.includes('<!-- ietf-spec-preview -->'));

            if (existingComment) {
              await github.rest.issues.updateComment({
                owner: context.repo.owner,
                repo: context.repo.repo,
                comment_id: existingComment.id,
                body: body
              });
            } else {
              await github.rest.issues.createComment({
                owner: context.repo.owner,
                repo: context.repo.repo,
                issue_number: prNumber,
                body: body
              });
            }