comment.yml

# ------------------------------------------------------------
# Moonfin Plugin - PR Comment Workflow
# ------------------------------------------------------------
#
# Triggered by: workflow_run (after the Build workflow completes)
#
# Security:
#   This workflow runs in the context of the base repo and has
#   write access to PRs. It NEVER checks out or executes code
#   from the PR - it only reads the build-results artifact
#   uploaded by the (read-only) build workflow.
# ------------------------------------------------------------

name: PR Comment

on:
  workflow_run:
    workflows: [Build]
    types: [completed]

permissions:
  pull-requests: write
  actions: read

jobs:
  comment:
    name: Post Build Results
    runs-on: ubuntu-latest
    if: >-
      github.event.workflow_run.event == 'pull_request' &&
      (github.event.workflow_run.conclusion == 'success' ||
       github.event.workflow_run.conclusion == 'failure')

    steps:
      - name: Download build results
        uses: actions/download-artifact@v4
        with:
          name: build-results
          path: build-results
          run-id: ${{ github.event.workflow_run.id }}
          github-token: ${{ secrets.GITHUB_TOKEN }}

      - name: Post PR comment
        uses: actions/github-script@v7
        with:
          script: |
            const fs = require('fs');

            // Read outcomes metadata
            const outcomes = JSON.parse(fs.readFileSync('build-results/outcomes.json', 'utf8'));
            const prNumber = outcomes.pr_number;
            const sha = outcomes.sha;

            const marker = '<!-- moonfin-build-result -->';
            const runUrl = `${context.serverUrl}/${context.repo.owner}/${context.repo.repo}/actions/runs/${context.payload.workflow_run.id}`;

            const steps = {
              'Backend Build':    outcomes.backend_build,
            };
            const failed  = Object.entries(steps).filter(([, v]) => v !== 'success');
            const success = failed.length === 0;

            const lines = [marker];

            if (success) {
              lines.push(
                '## Build Successful',
                '',
                'The plugin compiled successfully against **.NET 8** / **Jellyfin 10.10.0**.',
              );
            } else {
              lines.push(
                '## Build Failed',
                '',
                `The following step(s) failed: **${failed.map(([k]) => k).join('**, **')}**`,
              );

              // Append collapsible log for each failed step
              const logFiles = {
                'Backend Build':    'backend-build.log',
              };

              for (const [name] of failed) {
                const logPath = `build-results/${logFiles[name]}`;
                let log = '';
                try {
                  const full = fs.readFileSync(logPath, 'utf8');
                  const logLines = full.split('\n');
                  log = logLines.slice(-50).join('\n');
                } catch { log = '_Log file not available._'; }

                lines.push(
                  '',
                  `<details><summary>${name} log (last 50 lines)</summary>`,
                  '',
                  '```',
                  log,
                  '```',
                  '',
                  '</details>',
                );
              }
            }

            lines.push(
              '',
              `| Property | Value |`,
              `|---|---|`,
              `| **Commit** | \`${sha.substring(0, 7)}\` |`,
              `| **Workflow** | [Build #${context.payload.workflow_run.run_number}](${runUrl}) |`,
            );

            const body = lines.join('\n');

            // Find existing comment to update
            const { data: comments } = await github.rest.issues.listComments({
              owner: context.repo.owner,
              repo: context.repo.repo,
              issue_number: prNumber,
            });

            const existing = comments.find(c => c.body?.includes(marker));

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