name: Docker

on:
  push:
    branches:
      - main
    paths-ignore:
      - web/**
      - doc/**

  pull_request:
    branches:
      - main
    paths-ignore:
      - web/**
      - doc/**

    # Publish `v1.2.3` tags as releases.
    tags:
      - v*

concurrency:
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: true

env:
  IMAGE_NAME: conky
  DOCKERHUB_ACCOUNT: brndnmtthws
  DOCKER_BUILDKIT: 1

jobs:
  docker-buildx:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout
        uses: actions/checkout@v4
      - name: Set up QEMU
        uses: docker/setup-qemu-action@v3
      - name: Set up Docker Buildx
        id: buildx
        uses: docker/setup-buildx-action@v3
      - name: Log into Dockerhub registry
        run: echo "${{ secrets.DOCKERHUB_TOKEN }}" | docker login -u $DOCKERHUB_ACCOUNT --password-stdin
      - name: Build and push Docker image
        env:
          RELEASE: "${{ startsWith(github.ref, 'refs/tags/') && 'ON' || 'OFF' }}"
        run: |
          set -ex

          DOCKERHUB_IMAGE_ID=$DOCKERHUB_ACCOUNT/$IMAGE_NAME

          # Change all uppercase to lowercase
          DOCKERHUB_IMAGE_ID=$(echo $DOCKERHUB_IMAGE_ID | tr '[A-Z]' '[a-z]')

          image_tags=()

          # Strip git ref prefix from version
          VERSION_TAG=$(echo "${{ github.ref }}" | sed -e 's,.*/\(.*\),\1,')

          # Strip "v" prefix from tag name
          [[ "${{ github.ref }}" == "refs/tags/"* ]] && VERSION_TAG=$(echo $VERSION_TAG | sed -e 's/^v//')

          image_tags+=("--tag" "$DOCKERHUB_IMAGE_ID:$VERSION_TAG")

          # tag as latest on releases
          [[ "$RELEASE" == "ON" ]] && image_tags+=("--tag" "$DOCKERHUB_IMAGE_ID:latest")

          # Only build amd64 on PRs, build all platforms on main. The arm builds
          # take far too long.
          image_platforms="--platform linux/amd64"
          push_image=""
          cache_tag="pr-cache"

          # Only push on main
          [[ "${{ github.ref }}" == "refs/head/main" ]] \
            && push_image="--push" \
            && image_platforms="--platform linux/arm/v7,linux/arm64/v8,linux/amd64" \
            && cache_tag="main-cache"

          docker buildx build \
            ${push_image} \
            ${image_platforms} \
            --cache-from=type=registry,ref=$DOCKERHUB_ACCOUNT/$IMAGE_NAME:$cache_tag \
            --cache-to=type=registry,ref=$DOCKERHUB_ACCOUNT/$IMAGE_NAME:$cache_tag,mode=max \
            "${image_tags[@]}" \
            .