pr-workflow.yml

name: PR workflow

on:
  pull_request:
    types: [opened, synchronize]

jobs:
  pr-automation:
    runs-on: ubuntu-latest

    steps:
      - name: Get changed files
        id: files
        uses: tj-actions/changed-files@v44

      - name: Assign, label, and request reviewers
        uses: actions/github-script@v7
        with:
          script: |
            const owner = context.repo.owner;
            const repo = context.repo.repo;
            const prNumber = context.payload.pull_request.number;
            const author = context.payload.pull_request.user.login;

            const changedFiles = "${{ steps.files.outputs.all_changed_files }}".split(" ");

            // CONFIGURATION
            const rules = {
              frontend: {
                path: "frontend/",
                label: "frontend",
                reviewers: ["MaddieWright"]
              },
              backend: {
                path: "backend/",
                label: "backend",
                reviewers: ["HeisSteve"]
              },
               infra: {
                path: ".github/",
                label: "infra",
                reviewers: ["HeisSteve", "MaddieWright"]
             }
            };

            const labelsToAdd = new Set();
            const reviewersToAdd = new Set();

            // Determine applicable rules
            for (const file of changedFiles) {
              for (const rule of Object.values(rules)) {
                if (file.startsWith(rule.path)) {
                  labelsToAdd.add(rule.label);
                  rule.reviewers.forEach(r => reviewersToAdd.add(r));
                }
              }
            }

            // Assign PR author
            await github.rest.issues.addAssignees({
              owner,
              repo,
              issue_number: prNumber,
              assignees: [author]
            });

            // Get existing labels
            const existingLabels = await github.rest.issues.listLabelsOnIssue({
              owner,
              repo,
              issue_number: prNumber
            });

            const managedLabels = Object.values(rules).map(r => r.label);
            const existingManagedLabels = existingLabels.data
              .map(l => l.name)
              .filter(l => managedLabels.includes(l));

            // Remove labels that no longer apply
            for (const label of existingManagedLabels) {
              if (!labelsToAdd.has(label)) {
                await github.rest.issues.removeLabel({
                  owner,
                  repo,
                  issue_number: prNumber,
                  name: label
                });
              }
            }

            // Add labels
            if (labelsToAdd.size > 0) {
              await github.rest.issues.addLabels({
                owner,
                repo,
                issue_number: prNumber,
                labels: [...labelsToAdd]
              });
            }

            // Remove PR author from reviewers if present
            reviewersToAdd.delete(author);

            // Request reviewers
            if (reviewersToAdd.size > 0) {
              await github.rest.pulls.requestReviewers({
                owner,
                repo,
                pull_number: prNumber,
                reviewers: [...reviewersToAdd]
              });
            }