name: "Pull Request Labeler"
on:
  pull_request_target:
    types: [opened, synchronize]
# Do not execute arbitrary code on this workflow.
# See warnings at https://docs.github.com/en/actions/reference/workflows-and-actions/events-that-trigger-workflows#pull_request_target

jobs:
  labeler:
    permissions:
      contents: read
      pull-requests: write
    runs-on: ubuntu-24.04-arm
    steps:
    - name: Auto-label PR
      uses: actions/github-script@v9
      with:
        script: |
          const branch = context.payload.pull_request.head.ref;
          const labels = new Set();

          // enhancement: branch contains feat
          if (/feat/i.test(branch)) labels.add('enhancement');

          // bugfix: branch starts with fix or bug
          if (/^(fix|bug)/i.test(branch)) labels.add('bugfix');

          // refactor: branch starts with refactor
          if (/^refactor/i.test(branch)) labels.add('refactor');

          // repo: branch contains repo or ci
          if (/repo|ci/i.test(branch)) {
            labels.add('repo');
          } else {
            // Also label 'repo' if .github files were changed (needs one API call)
            try {
              const files = await github.paginate(
                github.rest.pulls.listFiles,
                { owner: context.repo.owner, repo: context.repo.repo, pull_number: context.payload.pull_request.number, per_page: 100 },
                (res) => res.data.map(f => f.filename)
              );
              if (files.some(f => f.startsWith('.github/'))) labels.add('repo');
            } catch (e) {
              core.warning(`Could not list PR files (rate limited?): ${e.message}`);
            }
          }

          if (labels.size > 0) {
            const labelArray = [...labels];
            core.info(`Applying labels: ${labelArray.join(', ')}`);
            try {
              await github.rest.issues.addLabels({
                owner: context.repo.owner,
                repo: context.repo.repo,
                issue_number: context.payload.pull_request.number,
                labels: labelArray,
              });
            } catch (e) {
              core.warning(`Could not apply labels (rate limited?): ${e.message}`);
            }
          } else {
            core.info('No labels matched for this PR.');
          }