pr_labeller.yml

name: PR Labeller

on:
  pull_request:
    types: [opened, edited]

jobs:
  label-pr:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4.2.2

      - name: Update PR labels
        uses: actions/github-script@v7.0.1
        with:
          script: |
            const prBody = context.payload.pull_request.body;
            const shouldHaveLabels = new Set();

            const labelMappings = {
              'Bug fix': 'Bug',
              'New feature': 'Feature',
              'UI/UX improvement': 'UI/UX',
              'Weather data processing': 'Data Processing',
              'Optimisation': 'Optimisation',
              'Security': 'Security',
              'Documentation update': 'Documentation',
              'Chore': 'Chore'
            };
           
            // Determine which labels should be present
            for (const [text, label] of Object.entries(labelMappings)) {
              if (prBody && prBody.includes(`- [x] ${text}`)) {
                shouldHaveLabels.add(label);
              }
            }
        
            // Get current labels
            const currentLabels = await github.rest.issues.listLabelsOnIssue({
              owner: context.repo.owner,
              repo: context.repo.repo,
              issue_number: context.payload.pull_request.number,
            });
            
            const currentLabelNames = new Set(currentLabels.data.map(l => l.name));
            const allMappedLabels = new Set(Object.values(labelMappings));
            
            // Remove labels that shouldn't be there
            const labelsToRemove = [...currentLabelNames].filter(label => 
              allMappedLabels.has(label) && !shouldHaveLabels.has(label)
            );
            
            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
              });
            }
            
            // Add missing labels
            const labelsToAdd = [...shouldHaveLabels].filter(label => 
              !currentLabelNames.has(label)
            );
            
            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
              });
            }