name: Docker image

# Phase 5 / spec §15.5 — multi-arch image builds.
#
# Pushes to ghcr.io on:
#   - tag (v*.*.*)    → ghcr.io/<owner>/od:<tag> + :latest

on:
  push:
    tags: ['v*.*.*']

jobs:
  build-and-push:
    runs-on: ubuntu-latest
    permissions:
      contents: read
      packages: write
      id-token: write
    steps:
      - name: Check out repository
        uses: actions/checkout@v4

      - name: Set up QEMU
        uses: docker/setup-qemu-action@v3
        with:
          platforms: linux/amd64,linux/arm64

      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v3

      - name: Log in to GitHub Container Registry
        if: github.event_name != 'pull_request'
        uses: docker/login-action@v3
        with:
          registry: ghcr.io
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

      - name: Extract metadata
        id: meta
        uses: docker/metadata-action@v5
        with:
          images: ghcr.io/${{ github.repository_owner }}/od
          # spec §15.1 tag scheme:
          #   - main           → :edge + :sha-<short>
          #   - vX.Y.Z         → :X.Y.Z + :latest
          #   - any branch     → :branch-<name>
          tags: |
            type=ref,event=branch,suffix=-{{date 'YYYYMMDD-HHmmss' tz='UTC'}}
            type=ref,event=tag
            type=raw,value=edge,enable=${{ github.ref == 'refs/heads/main' }}
            type=raw,value=latest,enable=${{ startsWith(github.ref, 'refs/tags/v') }}
            type=sha,prefix=sha-,format=short

      - name: Build and push
        uses: docker/build-push-action@v6
        with:
          context: .
          file: deploy/Dockerfile
          # spec §15.1 — multi-arch single manifest
          platforms: linux/amd64,linux/arm64
          # PR builds smoke-test the build only; merges to main /
          # tags publish.
          push: ${{ github.event_name != 'pull_request' }}
          tags: ${{ steps.meta.outputs.tags }}
          labels: ${{ steps.meta.outputs.labels }}
          # The in-tree Dockerfile uses node:24-alpine + apk for build
          # tooling; we keep that default so the workflow doesn't drift
          # from local builds. Spec §15.1 nominates bookworm-slim as
          # the canonical base; switching is a follow-up that needs
          # the Dockerfile's apk lines re-cast for apt.
          cache-from: type=gha
          cache-to: type=gha,mode=max