name: Docker Image CI

on:
  push:
    branches: [ master ]
  pull_request:
    branches: [ master ]

jobs:

  build:
    runs-on: ubuntu-latest
    env:
      DH_REGISTRY: docker.io
      GH_REGISTRY: ghcr.io
      IMAGE_NAME: ${{ github.repository }}
      REPOSITORY: ${{ github.event.repository.name }}
      DOCKER_USERNAME: ${{ secrets.DOCKER_USERNAME }}
    permissions:
      contents: read
      packages: write

    steps:
    - name: Checkout repository
      uses: actions/checkout@v2

    - name: Provide default tag username
      if: ${{ env.DOCKER_USERNAME == '' }}
      run: |
          echo "DOCKER_USERNAME=remote" >> $GITHUB_ENV

    - name: Build the Docker image
      run: docker build . --file Dockerfile --tag "$DOCKER_USERNAME/$REPOSITORY:latest"

    - name: Log in to Docker Hub
      uses: docker/login-action@v1
      if: github.ref == 'refs/heads/master' && github.event_name == 'push'
      with:
        registry: ${{ env.DH_REGISTRY }}
        username: ${{ env.DOCKER_USERNAME }}
        password: ${{ secrets.DOCKER_PASSWORD }}

    - name: Push to Docker Hub
      if: github.ref == 'refs/heads/master' && github.event_name == 'push'
      run: docker push "$DOCKER_USERNAME/$REPOSITORY:latest"
    
    - name: Log in to the Container registry
      uses: docker/login-action@v1
      with:
        registry: ${{ env.GH_REGISTRY }}
        username: ${{ github.actor }}
        password: ${{ secrets.GITHUB_TOKEN }}
    
    - name: Extract metadata (tags, labels) for Docker
      id: meta
      uses: docker/metadata-action@v3
      with:
        images: ${{ env.GH_REGISTRY }}/${{ env.IMAGE_NAME }}

    - name: Push to GitHub
      uses: docker/build-push-action@v2
      if: github.event_name == 'push'
      with:
        context: .
        push: true
        tags: ${{ steps.meta.outputs.tags }}
        labels: ${{ steps.meta.outputs.labels }}