name: Docker

on:
  push:
    tags:
      - 'v*'
  workflow_dispatch:
    inputs:
      tag:
        description: 'Image tag (e.g., latest, v0.1.0)'
        required: false
        default: 'latest'

env:
  REGISTRY: ghcr.io
  IMAGE_NAME: ${{ github.repository }}

jobs:
  build:
    strategy:
      fail-fast: false
      matrix:
        include:
          - platform: linux/amd64
            runner: ubuntu-latest
          - platform: linux/arm64
            runner: ubuntu-24.04-arm
    runs-on: ${{ matrix.runner }}
    permissions:
      contents: read
      packages: write
    outputs:
      # Pass digest info to merge job
      digest-amd64: ${{ steps.build.outputs.digest }}
      digest-arm64: ${{ steps.build.outputs.digest }}

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

      - 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: ${{ env.REGISTRY }}
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

      - name: Extract metadata
        id: meta
        uses: docker/metadata-action@v5
        with:
          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}

      - name: Build and push by digest
        id: build
        uses: docker/build-push-action@v6
        with:
          context: .
          platforms: ${{ matrix.platform }}
          labels: ${{ steps.meta.outputs.labels }}
          outputs: type=image,name=${{ env.REGISTRY }}/${{ env.IMAGE_NAME }},push-by-digest=true,name-canonical=true,push=true
          cache-from: type=gha,scope=${{ matrix.platform }}
          cache-to: type=gha,scope=${{ matrix.platform }},mode=max

      - name: Export digest
        run: |
          mkdir -p /tmp/digests
          digest="${{ steps.build.outputs.digest }}"
          touch "/tmp/digests/${digest#sha256:}"

      - name: Upload digest
        uses: actions/upload-artifact@v4
        with:
          name: digests-${{ matrix.platform == 'linux/amd64' && 'amd64' || 'arm64' }}
          path: /tmp/digests/*
          if-no-files-found: error
          retention-days: 1

  merge:
    runs-on: ubuntu-latest
    needs: build
    permissions:
      contents: read
      packages: write

    steps:
      - name: Download digests
        uses: actions/download-artifact@v4
        with:
          path: /tmp/digests
          pattern: digests-*
          merge-multiple: true

      - 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: ${{ env.REGISTRY }}
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

      - name: Extract metadata
        id: meta
        uses: docker/metadata-action@v5
        with:
          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
          tags: |
            # For tags: v1.2.3 -> latest, 1, 1.2, 1.2.3
            type=semver,pattern={{version}}
            type=semver,pattern={{major}}.{{minor}}
            type=semver,pattern={{major}}
            type=raw,value=latest,enable={{is_default_branch}}
            # For manual dispatch
            type=raw,value=${{ github.event.inputs.tag }},enable=${{ github.event_name == 'workflow_dispatch' }}

      - name: Create manifest list and push
        working-directory: /tmp/digests
        run: |
          docker buildx imagetools create $(jq -cr '.tags | map("-t " + .) | join(" ")' <<< "$DOCKER_METADATA_OUTPUT_JSON") \
            $(printf '${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}@sha256:%s ' *)

      - name: Inspect image
        run: |
          docker buildx imagetools inspect ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:${{ steps.meta.outputs.version }}

      - name: Generate build summary
        run: |
          {
            echo "## Docker Image Published"
            echo ""
            echo "**Registry**: \`${{ env.REGISTRY }}\`"
            echo ""
            echo "**Tags**:"
            echo '${{ steps.meta.outputs.tags }}' | while read -r tag; do
              echo "- \`$tag\`"
            done
            echo ""
            echo "**Platforms**: linux/amd64, linux/arm64"
            echo ""
            echo "### Pull Command"
            echo '```bash'
            echo "docker pull ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:latest"
            echo '```'
          } >> $GITHUB_STEP_SUMMARY
