name: CI
on:
  push:
    branches-ignore: [main]

jobs:
  full-gate:
    runs-on: docker-host
    steps:
      - uses: actions/checkout@v4.2.2
        with:
          fetch-depth: 0 # the merge-base below needs history; checkout defaults to depth 1
      - name: Detect a docs-only branch
        id: scope
        run: |
          git fetch --no-tags --quiet origin +refs/heads/main:refs/remotes/origin/main
          base=$(git merge-base refs/remotes/origin/main HEAD) \
            || { echo 'No merge-base with main - running the gate'; echo 'docs_only=false' >> "$GITHUB_OUTPUT"; exit 0; }
          changed=$(git diff --name-only "$base" HEAD)
          printf '%s\n' "$changed"
          # Skip only when there IS a diff and every path is *.md. An empty diff, an unreadable
          # range, anything else - fall through to the gate.
          if [ -n "$changed" ] && ! printf '%s\n' "$changed" | grep -qvE '\.md$'; then
            echo 'docs_only=true' >> "$GITHUB_OUTPUT"
          else
            echo 'docs_only=false' >> "$GITHUB_OUTPUT"
          fi
      - name: Full gate
        if: steps.scope.outputs.docs_only != 'true'
        run: bash ci.sh
      # Never gated on docs_only: release.yml re-tags this exact image, and ff-only merges make
      # every branch head a main commit - a main commit without an image is an unreleasable one.
      - name: Push app image tagged with the commit hash
        env:
          IMAGE: gitea.larvit.se/${{ github.repository }}:${{ github.sha }}
          REGISTRY_TOKEN: ${{ secrets.DOCKER_REGISTRY_TOKEN }}
          REGISTRY_USER: ${{ vars.DOCKER_REGISTRY_USER }}
        run: |
          printf '%s' "$REGISTRY_TOKEN" | docker login gitea.larvit.se -u "$REGISTRY_USER" --password-stdin
          docker build -t "$IMAGE" .
          docker push "$IMAGE"
      - name: Log out of the registry
        if: always()
        run: docker logout gitea.larvit.se