name: Cleanup merged branches

on:
  schedule:
    - cron: "0 3 * * *"   # täglich um 03:00 UTC
  workflow_dispatch:

permissions:
  contents: write
  pull-requests: read

jobs:
  cleanup:
    runs-on: ubuntu-latest

    steps:
      - name: Delete merged branches older than 7 days
        env:
          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        run: |
          set -euo pipefail

          CUTOFF_DATE=$(date -u -d "7 days ago" +%s)

          echo "Cutoff timestamp: $CUTOFF_DATE"

          gh pr list \
            --state merged \
            --base main \
            --json number,mergedAt,headRefName \
            --limit 500 |
          jq -r '.[] | "\(.mergedAt) \(.headRefName)"' |
          while read -r mergedAt branch; do
            # Schutz
            case "$branch" in
              main|master|develop)
                echo "Skipping protected branch: $branch"
                continue
                ;;
            esac

            MERGED_TS=$(date -d "$mergedAt" +%s)

            if [ "$MERGED_TS" -lt "$CUTOFF_DATE" ]; then
              echo "Deleting branch: $branch (merged at $mergedAt)"
              gh api \
                -X DELETE \
                repos/${{ github.repository }}/git/refs/heads/$branch \
                || echo "Branch $branch already deleted"
            else
              echo "Keeping branch: $branch (recent merge)"
            fi
          done