name: Formatting

on:
  pull_request:
    paths:
      - 'src/**'
      - 'include/**'
      - '.clang-format'
      - '.clang-format-ignore'
      - '.github/workflows/formatting.yml'
      - 'Makefile'

jobs:
  format-check-changed:
    name: clang-format on changed files
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
        with:
          fetch-depth: 0  # need history for `git diff origin/main...HEAD`

      - name: Install clang-format
        run: |
          sudo apt-get update
          sudo apt-get install -y clang-format

      - name: Check formatting on changed files
        run: |
          git fetch origin main --depth=50 || true
          BASE=$(git merge-base HEAD origin/main 2>/dev/null \
              || git rev-parse HEAD~1)
          echo "Comparing against $BASE"
          BASE="$BASE" make format-changed

  # Whole-tree check kept informational while the existing tree is
  # being progressively brought into compliance.  Promote to a hard
  # gate when a one-shot reformat commit lands and `make format-check`
  # comes back clean.
  format-check-tree:
    name: clang-format full tree (informational)
    runs-on: ubuntu-latest
    continue-on-error: true
    steps:
      - uses: actions/checkout@v4

      - name: Install clang-format
        run: |
          sudo apt-get update
          sudo apt-get install -y clang-format

      - name: Run make format-check
        run: |
          make format-check || {
              echo "::warning::Tree-wide formatting check failed."
              echo "Run 'make format' locally to see the diff."
              exit 1
          }