name: Build and publish container images

on:
  push: { branches: [ main ] }

permissions:
  packages: write

jobs:
  build:
    if: ${{ startsWith(github.event.head_commit.message, 'feat:') || startsWith(github.event.head_commit.message, 'fix:') }}
    runs-on: ubuntu-20.04
    outputs:
      commit: ${{ steps.metadata.outputs.commit }}
    strategy:
      matrix:
        architecture: [ amd64, arm64v8 ]
        include: 
          - architecture: amd64
            platform: linux/amd64
          - architecture: arm64v8
            platform: linux/arm64
    steps:
      - name: Checkout code
        uses: actions/checkout@v4

      - name: Obtain project metadata 
        id: metadata
        run: echo "commit=$(git rev-parse --short HEAD)" >> $GITHUB_OUTPUT

      - name: Setup Docker Buildx
        uses: docker/setup-buildx-action@v3
  
      - name: Setup QEMU
        uses: docker/setup-qemu-action@v3

      - name: Login to GitHub Container Registry
        uses: docker/login-action@v3
        with:
          registry: ghcr.io
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

      - name: Generate image metadata
        uses: docker/metadata-action@v5
        id: image-metadata
        with:
          images: ghcr.io/${{ github.repository }}
          tags: |
            type=raw,value=${{ matrix.architecture }}-${{ steps.metadata.outputs.commit }},enable={{is_default_branch}}
            type=raw,value=${{ matrix.architecture }},enable={{is_default_branch}}

      - name: Build and push platform specific images
        uses: docker/build-push-action@v6
        with:
          push: true
          cache-from: type=gha
          cache-to: type=gha,mode=max
          platforms: ${{ matrix.platform }}
          tags: ${{ steps.image-metadata.outputs.tags }}
          build-args: |
            BUILDKIT_CONTEXT_KEEP_GIT_DIR=true

  merge:
    runs-on: ubuntu-20.04
    needs: [ build ]
    env:
      IMAGE: ghcr.io/${{ github.repository }}
      COMMIT: ${{ needs.build.outputs.commit }}
    steps:
      - name: Checkout code
        uses: actions/checkout@v4

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

      - name: Generate manifest for multi-arch images from source manifests
        run: |
          docker buildx imagetools create \
            --tag ${IMAGE}:${COMMIT} ${IMAGE}:{amd64,arm64v8}-${COMMIT}
          docker buildx imagetools create \
            --tag ${IMAGE}:latest ${IMAGE}:{amd64,arm64v8}