name: Clean up per-branch caches

on:
  pull_request:
    types:
      - closed
  workflow_dispatch:

jobs:
  cleanup:
    runs-on: ubuntu-latest

    permissions:
      actions: write
      contents: read

    steps:
      - name: Checkout
        uses: actions/checkout@v6

      - name: Cleanup
        run: |
          gh extension install actions/gh-actions-cache

          BRANCH=refs/pull/${{ github.event.pull_request.number }}/merge

          echo "Fetching list of cache keys"
          keys=$(gh actions-cache list -R $GITHUB_REPOSITORY -B $BRANCH -L 100 | cut -f 1)

          set +e
          echo "Deleting caches..."
          for key in $keys ; do
            gh actions-cache delete $key -R $GITHUB_REPOSITORY -B $BRANCH --confirm
          done
          echo "Done"
        env:
          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
