name: Docker Release

# Triggered when a GitHub Release is published.
# Builds a multi-platform Docker image and pushes it to GitHub Container Registry (GHCR).
#
# Image: ghcr.io/hkuds/deeptutor
# Tags:
#   - Version tag stripped of 'v' prefix (e.g. release v1.2.3 → image tag 1.2.3)
#   - latest (always points to the most recently published release)
#
# Platforms: linux/amd64, linux/arm64

on:
  release:
    types: [published]

permissions:
  contents: read
  packages: write

jobs:
  build-and-push:
    name: Build and Push Multi-Platform Docker Image
    runs-on: ubuntu-latest

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

      # Required for linux/arm64 cross-compilation on GitHub-hosted ubuntu runners
      - name: Set up QEMU
        uses: docker/setup-qemu-action@v3

      # Enable BuildKit with multi-platform build support
      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v3

      - name: Log in to GitHub Container Registry
        uses: docker/login-action@v3
        with:
          registry: ghcr.io
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

      # Extract tags from the release:
      #   type=semver strips the leading 'v' (v1.2.3 → 1.2.3)
      #   type=raw adds a 'latest' tag on every published release
      - name: Extract Docker metadata
        id: meta
        uses: docker/metadata-action@v5
        with:
          images: ghcr.io/hkuds/deeptutor
          tags: |
            type=semver,pattern={{version}}
            type=raw,value=latest

      - name: Build and push
        uses: docker/build-push-action@v6
        with:
          context: .
          file: ./Dockerfile
          target: production
          platforms: linux/amd64,linux/arm64
          push: true
          tags: ${{ steps.meta.outputs.tags }}
          labels: ${{ steps.meta.outputs.labels }}
          # Use GitHub Actions cache to speed up repeated builds
          # mode=max caches all intermediate layers (frontend-builder and python-base are expensive)
          cache-from: type=gha
          cache-to: type=gha,mode=max