#  based on https://blog.oddbit.com/post/2020-09-25-building-multi-architecture-im/
---
# Interlisp workflow to build Docker Image that support multiple architectures
name: 'Build Medley Docker image'

# Run this workflow on push to master
on:
  push:
    branches:
      - master

# Jobs that compose this workflow
jobs:
  # Job to build the docker image
  docker:
    runs-on: ubuntu-latest
    steps:
      # Checkout the branch
      - name: Checkout
        uses: actions/checkout@v2

      # Setup needed environment variables
      - name: Prepare
        id: prep
        run: |
          DOCKER_IMAGE=interlisp/${GITHUB_REPOSITORY#*/}
          VERSION=latest
          SHORTREF=${GITHUB_SHA::8}

          # If this is git tag, use the tag name as a docker tag
          if [[ $GITHUB_REF == refs/tags/* ]]; then
            VERSION=${GITHUB_REF#refs/tags/v}
          fi
          TAGS="${DOCKER_IMAGE}:${VERSION},${DOCKER_IMAGE}:${SHORTREF}"

          # If the VERSION looks like a version number, assume that
          # this is the most recent version of the image and also
          # tag it 'latest'.
          if [[ $VERSION =~ ^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}$ ]]; then
            TAGS="$TAGS,${DOCKER_IMAGE}:latest"
          fi

          # Set output parameters.
          echo ::set-output name=tags::${TAGS}
          echo ::set-output name=docker_image::${DOCKER_IMAGE}
          echo ::set-output name=build_time::$(date -u +'%Y-%m-%dT%H:%M:%SZ')

      # Setup Docker Machine Emulation environment
      - name: Set up QEMU
        uses: docker/setup-qemu-action@master
        with:
          platforms: all

      # Setup Docker Buildx function
      - name: Set up Docker Buildx
        id: buildx
        uses: docker/setup-buildx-action@master

      # Login to DockerHub - required to store the image
      - name: Login to DockerHub
        if: github.event_name != 'pull_request'
        uses: docker/login-action@v1
        with:
          username: ${{ secrets.DOCKER_USERNAME }}
          password: ${{ secrets.DOCKER_PASSWORD }}

      # Start the Docker Build using the Dockerfilein the repository
      - name: Build
        uses: docker/build-push-action@v2
        with:
          builder: ${{ steps.buildx.outputs.name }}
          context: .
          file: ./Dockerfile
          # Platforms
          #  linux/amd64 -- Standard x86_64
          #  linux/arm64 -- Apple M1
          #  linux/arm/v7 -- Raspberry pi
          platforms: linux/amd64,linux/arm64,linux/arm/v7
          # Push the created image
          push: true
          # tags to assign to the Docker image
          tags: ${{ steps.prep.outputs.tags }}