name: ✨ Auto-label PR

on:
  pull_request_target:
    types: [opened, synchronized, reopened]

jobs:
  update-pr:
    name: Update PR
    runs-on: ubuntu-latest
    permissions:
      pull-requests: write
    steps:
      - name: Gather Info
        id: check
        uses: actions/github-script@3a2844b7e9c422d3c10d287c895573f7108da1b3 # v9.0.0
        with:
          script: |
            const { data: pr } = await github.rest.pulls.get({
              owner: context.repo.owner,
              repo: context.repo.repo,
              pull_number: context.payload.pull_request.number
            });

            // Check if PR has assignees
            const hasAssignees = pr.assignees && pr.assignees.length > 0;
            core.setOutput('has_assignees', hasAssignees);
            core.setOutput('author', pr.user.login);

            // Get list of changed files
            const { data: files } = await github.rest.pulls.listFiles({
              owner: context.repo.owner,
              repo: context.repo.repo,
              pull_number: context.payload.pull_request.number
            });

            // Find all packages that were modified
            const packagesRegex = /^packages\/([^\/]+)\//;
            const affectedPackages = new Set();

            for (const file of files) {
              const match = file.filename.match(packagesRegex);
              if (match) {
                affectedPackages.add(match[1]);
              }
            }

            const labels = Array.from(affectedPackages).map(pkg => `pkg/${pkg}`);
            core.setOutput('labels', JSON.stringify(labels));
            console.log('Detected package labels:', labels);

            // Get current labels on the PR that match pkg/* pattern
            const currentPkgLabels = pr.labels
              .map(label => label.name)
              .filter(name => name.startsWith('pkg/'));

            core.setOutput('current_pkg_labels', JSON.stringify(currentPkgLabels));
            console.log('Current pkg labels:', currentPkgLabels);

      - name: Sync Author
        if: steps.check.outputs.has_assignees == 'false'
        uses: actions/github-script@3a2844b7e9c422d3c10d287c895573f7108da1b3 # v9.0.0
        with:
          script: |
            try {
              await github.rest.issues.addAssignees({
                owner: context.repo.owner,
                repo: context.repo.repo,
                issue_number: context.payload.pull_request.number,
                assignees: ['${{ steps.check.outputs.author }}']
              });

              console.log('Assigned PR author: ${{ steps.check.outputs.author }}');
            } catch (err) {
              console.warn("Error assigning author:", err);
            }

      - name: Sync Labels
        uses: actions/github-script@3a2844b7e9c422d3c10d287c895573f7108da1b3 # v9.0.0
        with:
          script: |
            const newLabels = ${{ steps.check.outputs.labels }};
            const currentLabels = ${{ steps.check.outputs.current_pkg_labels }};

            // Find labels to add (in newLabels but not in currentLabels)
            const labelsToAdd = newLabels.filter(label => !currentLabels.includes(label));

            // Find labels to remove (in currentLabels but not in newLabels)
            const labelsToRemove = currentLabels.filter(label => !newLabels.includes(label));

            // Add new labels
            if (labelsToAdd.length > 0) {
              await github.rest.issues.addLabels({
                owner: context.repo.owner,
                repo: context.repo.repo,
                issue_number: context.payload.pull_request.number,
                labels: labelsToAdd
              });
              console.log('Added labels:', labelsToAdd);
            }

            // Remove obsolete labels
            for (const label of labelsToRemove) {
              await github.rest.issues.removeLabel({
                owner: context.repo.owner,
                repo: context.repo.repo,
                issue_number: context.payload.pull_request.number,
                name: label
              });
              console.log('Removed label:', label);
            }

            if (labelsToAdd.length === 0 && labelsToRemove.length === 0) {
              console.log('No label changes needed');
            }