name: Generate UML

# Trigger whenever the domain model or the generator script itself changes.
# "workflow_dispatch" lets you re-run it manually from the GitHub UI.
on:
  push:
    paths:
      - "src/netdiag/domain/models.py"
      - "scripts/generate_uml.py"
  workflow_dispatch:

# The job needs write access so it can push the generated files back.
permissions:
  contents: write

jobs:
  generate-uml:
    runs-on: ubuntu-latest

    steps:
      # ── 1. check out the repository ────────────────────────────────────────
      - uses: actions/checkout@v4

      # ── 2. set up Python (stdlib only – no pip packages needed) ────────────
      - uses: actions/setup-python@v5
        with:
          python-version: "3.11"

      # ── 3. generate UML/UML.d2 from models.py ──────────────────────────────
      - name: Generate D2 source
        run: python scripts/generate_uml.py src/netdiag/domain/models.py UML/UML.d2

      # ── 4. install the D2 CLI ───────────────────────────────────────────────
      #
      # The official install script detects the platform and drops the binary
      # into one of several locations depending on how the shell is invoked.
      # We add all common candidates to GITHUB_PATH so the next step finds it
      # regardless of where the script chose to install.
      #
      # Pin a specific version to keep renders reproducible.
      # Bump this when you want to adopt a newer D2 release.
      - name: Install D2
        env:
          D2_VERSION: "0.7.1"
        run: |
          curl -fsSL \
            "https://github.com/terrastruct/d2/releases/download/v${D2_VERSION}/d2-v${D2_VERSION}-linux-amd64.tar.gz" \
            | tar -xz -C /tmp
          sudo install -m 0755 \
            "/tmp/d2-v${D2_VERSION}-linux-amd64/bin/d2" \
            /usr/local/bin/d2
          d2 --version

      # ── 5. render SVG ───────────────────────────────────────────────────────
      - name: Render UML/UML.svg
        run: d2 UML/UML.d2 UML/UML.svg

      # ── 6. commit generated files back to the repo ─────────────────────────
      #
      # stefanzweifel/git-auto-commit-action is a thin wrapper around
      # "git add / git commit / git push". It silently skips the commit when
      # nothing has changed, so re-running the workflow is always safe.
      #
      # The "[skip ci]" suffix prevents this commit from re-triggering CI
      # (GitHub Actions honors this convention natively).
      - name: Commit generated UML files
        uses: stefanzweifel/git-auto-commit-action@v5
        with:
          commit_message: "chore: auto-generate UML diagrams [skip ci]"
          file_pattern: "UML/UML.d2 UML/UML.svg"