name: Build & Push DEV to GHCR

on:
  pull_request:
    branches: [ dev ]
  push:
    branches: [ dev ]

permissions:
  contents: read
  packages: write

jobs:
  docker:
    runs-on: ubuntu-latest

    env:
      # PRs: single-arch build (faster). Push to dev: multi-arch.
      PLATFORMS: ${{ github.event_name == 'pull_request' && 'linux/amd64' || 'linux/amd64,linux/arm64' }}

    steps:
      - name: Checkout
        uses: actions/checkout@v4

      - name: Compute DEV tags
        run: |
          SHA7="${GITHUB_SHA::7}"
          echo "SHA7=$SHA7" >> $GITHUB_ENV
          echo "DEV_TAGS=ghcr.io/${GITHUB_REPOSITORY}:dev,ghcr.io/${GITHUB_REPOSITORY}:dev-${SHA7}" >> $GITHUB_ENV
          echo "Computed DEV_TAGS=${{ env.DEV_TAGS }}"

      - name: Set up QEMU
        if: ${{ env.PLATFORMS == 'linux/amd64,linux/arm64' }}
        uses: docker/setup-qemu-action@v3

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

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

      - name: Build & (maybe) push
        uses: docker/build-push-action@v5
        with:
          context: .
          file: ./Dockerfile
          platforms: ${{ env.PLATFORMS }}
          push: ${{ github.event_name != 'pull_request' }}
          tags: ${{ env.DEV_TAGS }}
          build-args: |
            VERSION=dev-${{ env.SHA7 }}
          cache-from: type=gha
          cache-to: type=gha,mode=max
          provenance: false