gemini-cli/.github/workflows/pr-size-labeler.yml

name: 'PR Size Labeler'

on:
  pull_request_target:
    types: ['opened', 'synchronize', 'reopened']
  workflow_dispatch:
    inputs:
      pr_number:
        description: 'PR number to label manually (for workflow_dispatch)'
        required: false
        type: 'string'

permissions:
  pull-requests: 'write'
  issues: 'write'

jobs:
  size-label:
    runs-on: 'ubuntu-latest'
    steps:
      - name: 'Run size labeler'
        env:
          GH_TOKEN: '${{ secrets.GITHUB_TOKEN }}'
          GH_REPO: '${{ github.repository }}'
        run: |
          # Determine the target PR number
          if [ -n "${{ github.event.pull_request.number }}" ]; then
            PR_NUMBER="${{ github.event.pull_request.number }}"
          elif [ -n "${{ github.event.inputs.pr_number }}" ]; then
            PR_NUMBER="${{ github.event.inputs.pr_number }}"
          else
            echo "❌ Error: No PR number provided."
            exit 1
          fi

          echo "Checking PR #$PR_NUMBER..."

          # 1. Ensure standard premium size labels exist in the repository (self-healing)
          # size/XS: Light green (#7ee081)
          # size/S: Yellow-green (#a6d49f)
          # size/M: Amber/Yellow (#f7d070)
          # size/L: Orange (#f48c06)
          # size/XL: Red (#dc2f02)
          gh label create "size/XS" --color "7ee081" --description "XS: <10 lines changed" 2>/dev/null || true
          gh label create "size/S"  --color "a6d49f" --description "S: 10-49 lines changed" 2>/dev/null || true
          gh label create "size/M"  --color "f7d070" --description "M: 50-249 lines changed" 2>/dev/null || true
          gh label create "size/L"  --color "f48c06" --description "L: 250-999 lines changed" 2>/dev/null || true
          gh label create "size/XL" --color "dc2f02" --description "XL: >=1000 lines changed" 2>/dev/null || true

          # 2. Fetch PR details in a single efficient API call
          PR_DATA=$(gh pr view "$PR_NUMBER" --json additions,deletions,changedFiles,labels)
          if [ -z "$PR_DATA" ]; then
            echo "❌ Error: Could not fetch PR details."
            exit 1
          fi

          ADDITIONS=$(echo "$PR_DATA" | jq '.additions')
          DELETIONS=$(echo "$PR_DATA" | jq '.deletions')
          CHANGED_FILES=$(echo "$PR_DATA" | jq '.changedFiles')
          TOTAL=$((ADDITIONS + DELETIONS))

          echo "PR additions: $ADDITIONS, deletions: $DELETIONS, total changes: $TOTAL, files: $CHANGED_FILES"

          # 3. Calculate new size label
          if [ $TOTAL -lt 10 ]; then
            SIZE="size/XS"
          elif [ $TOTAL -lt 50 ]; then
            SIZE="size/S"
          elif [ $TOTAL -lt 250 ]; then
            SIZE="size/M"
          elif [ $TOTAL -lt 1000 ]; then
            SIZE="size/L"
          else
            SIZE="size/XL"
          fi

          # 4. Check existing labels and update only if necessary
          EXISTING_LABELS=$(echo "$PR_DATA" | jq -r '.labels[].name' 2>/dev/null || echo "")

          LABELS_TO_REMOVE=()
          for L in size/XS size/S size/M size/L size/XL; do
            if echo "$EXISTING_LABELS" | grep -Fq "$L" && [ "$L" != "$SIZE" ]; then
              LABELS_TO_REMOVE+=("--remove-label" "$L")
            fi
          done

          LABEL_TO_ADD=()
          if ! echo "$EXISTING_LABELS" | grep -Fq "$SIZE"; then
            LABEL_TO_ADD+=("--add-label" "$SIZE")
          fi

          # Perform a single, highly atomic edit call if changes are needed
          if [ ${#LABELS_TO_REMOVE[@]} -gt 0 ] || [ ${#LABEL_TO_ADD[@]} -gt 0 ]; then
            echo "Updating labels: removing ${LABELS_TO_REMOVE[*]}, adding $SIZE"
            gh pr edit "$PR_NUMBER" "${LABELS_TO_REMOVE[@]}" "${LABEL_TO_ADD[@]}"
          else
            echo "✅ PR #$PR_NUMBER already has the correct size label ($SIZE)."
          fi

          # 5. Premium, anti-spam comment logic (updates previous comment to keep thread clean)
          COMMENT="📊 PR Size: **$SIZE**
          - Lines changed: **$TOTAL**
          - Additions: +$ADDITIONS
          - Deletions: -$DELETIONS
          - Files changed: $CHANGED_FILES"

          # Find any existing size labeler comment by the github-actions bot
          echo "Searching for existing size comment..."
          COMMENT_ID=$(gh api "repos/${{ github.repository }}/issues/$PR_NUMBER/comments" \
            --jq '.[] | select(.user.login == "github-actions[bot]" and (.body | startswith("📊 PR Size:"))) | .id' | head -n 1)

          if [ -n "$COMMENT_ID" ]; then
            echo "Updating existing comment (ID: $COMMENT_ID)..."
            gh api "repos/${{ github.repository }}/issues/comments/$COMMENT_ID" -X PATCH -f body="$COMMENT" > /dev/null
          else
            echo "Creating new comment..."
            gh pr comment "$PR_NUMBER" --body "$COMMENT" > /dev/null
          fi

          echo "🎉 PR size labeling completed successfully."