name: Frontend diagnostics (comment)

on:
  workflow_run:
    workflows:
      - Frontend diagnostics (inspect)
    types:
      - completed

permissions:
  actions: read
  contents: read
  issues: write
  pull-requests: write

jobs:
  comment:
    name: Comment frontend diagnostics report
    if: github.event.workflow_run.event == 'pull_request' && github.event.workflow_run.conclusion == 'success'
    runs-on: ubuntu-latest
    concurrency:
      group: frontend-diagnostics-report-${{ github.event.workflow_run.id }}
      cancel-in-progress: true
    steps:
      - name: Download frontend diagnostics report
        uses: actions/download-artifact@v8
        with:
          name: frontend-diagnostics
          path: ${{ runner.temp }}/frontend-diagnostics
          github-token: ${{ github.token }}
          repository: ${{ github.repository }}
          run-id: ${{ github.event.workflow_run.id }}

      - name: Resolve current pull request
        id: resolve-pr
        uses: actions/github-script@v9
        env:
          PR_NUMBER_FILE: ${{ runner.temp }}/frontend-diagnostics/pr-number.txt
        with:
          script: |
            const fs = require('fs/promises');
            const { owner, repo } = context.repo;
            const workflowRun = context.payload.workflow_run;
            const pullRequestNumberText = (await fs.readFile(process.env.PR_NUMBER_FILE, 'utf8')).trim();
            if (!/^[1-9]\d*$/.test(pullRequestNumberText)) {
              throw new Error('Invalid pull request number in frontend diagnostics artifact.');
            }

            const pullRequestNumber = Number(pullRequestNumberText);
            if (!Number.isSafeInteger(pullRequestNumber)) {
              throw new Error('Pull request number in frontend diagnostics artifact is not a safe integer.');
            }

            const { data: currentPullRequest } = await github.rest.pulls.get({
              owner,
              repo,
              pull_number: pullRequestNumber,
            });

            if (currentPullRequest.state !== 'open' || currentPullRequest.head.sha !== workflowRun.head_sha) {
              core.notice(`Skipping stale frontend diagnostics report for pull request #${pullRequestNumber}.`);
              core.setOutput('is-current', 'false');
              return;
            }

            core.setOutput('is-current', 'true');
            core.setOutput('pr-number', String(pullRequestNumber));

      - name: Comment on pull request
        if: steps.resolve-pr.outputs.is-current == 'true'
        uses: thollander/actions-comment-pull-request@v3
        with:
          pr-number: ${{ steps.resolve-pr.outputs.pr-number }}
          comment-tag: frontend-diagnostics
          file-path: ${{ runner.temp }}/frontend-diagnostics/frontend-diagnostics.md