name: Docker Publish

on:
  push:
    branches: 
      - 'master'
    tags: 
      - 'v*.*.*'

jobs:
  build:

    runs-on: ubuntu-latest

    steps:
      - name: Checkout repository
        uses: actions/checkout@v6

      # Workaround: https://github.com/docker/build-push-action/issues/461
      - name: Setup Docker buildx
        # https://github.com/docker/setup-buildx-action
        uses: docker/setup-buildx-action@v4

      # Login against Docker registry
      - name: Log into registry
        # https://github.com/docker/login-action
        uses: docker/login-action@v3
        with:
          username: ${{ secrets.DOCKERHUB_USERNAME }}
          password: ${{ secrets.DOCKERHUB_TOKEN }}

      # Extract Docker image tag from git tag. E.g. if git tag is "v0.19.1" then use 
      # Docker image tag "0.19.1". The "latest" tag reflects the most recent build on
      # master.
      - name: Extract Docker metadata
        id: meta
        # https://github.com/docker/metadata-action
        uses: docker/metadata-action@v5
        with:
          images: docker.io/${{ secrets.DOCKERHUB_USERNAME }}/scryer-prolog
          tags: |
            type=semver,pattern={{version}}
            type=raw,value=latest,enable={{is_default_branch}}
            # type=raw,value=latest,enable=${{ github.ref == format('refs/heads/{0}', 'master') }}

      # Build and push Docker image with Buildx
      - name: Build and push Docker image
        id: build-and-push
        # https://github.com/docker/build-push-action
        uses: docker/build-push-action@v6
        # v4 adds SLSA Provenance attestation which is 
        # - unsupported by AWS Lambda 
        # - limited support by Google Cloud Run 
        #   > If deploying a multi-architecture image, the manifest list must include linux/amd64.
        # see https://github.com/docker/build-push-action/releases/tag/v4.0.0
        # we might want to disable this if its a problem for someone
        with:
          context: .
          push: true
          tags: ${{ steps.meta.outputs.tags }}
          labels: ${{ steps.meta.outputs.labels }}