name: Publish Docker image

# Builds the production image and publishes it to GitHub Container Registry
# (GHCR) on every version tag. amd64 and arm64 are built on native runners,
# then stitched into one multi-arch manifest — no QEMU emulation.

on:
  push:
    tags:
      - 'v*.*.*'
  workflow_dispatch:

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

jobs:
  build:
    name: Build (${{ matrix.platform }})
    runs-on: ${{ matrix.runner }}
    strategy:
      fail-fast: false
      matrix:
        include:
          - platform: linux/amd64
            runner: ubuntu-latest
          - platform: linux/arm64
            runner: ubuntu-24.04-arm
    permissions:
      contents: read
      packages: write
    steps:
      - name: Prepare platform slug
        run: echo "PLATFORM_PAIR=${platform//\//-}" >> "$GITHUB_ENV"
        env:
          platform: ${{ matrix.platform }}

      - name: Checkout
        uses: actions/checkout@v7

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

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

      - name: Log in to GHCR
        uses: docker/login-action@v3
        with:
          registry: ${{ env.REGISTRY }}
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

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

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

      - name: Upload digest
        uses: actions/upload-artifact@v7
        with:
          name: digests-${{ env.PLATFORM_PAIR }}
          path: ${{ runner.temp }}/digests/*
          if-no-files-found: error
          retention-days: 1

  merge:
    name: Merge multi-arch manifest
    runs-on: ubuntu-latest
    needs: [build]
    permissions:
      contents: read
      packages: write
    steps:
      - name: Download digests
        uses: actions/download-artifact@v7
        with:
          path: ${{ runner.temp }}/digests
          pattern: digests-*
          merge-multiple: true

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

      - name: Docker metadata (tags)
        id: meta
        uses: docker/metadata-action@v5
        with:
          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
          tags: |
            type=semver,pattern={{version}}
            type=semver,pattern={{major}}.{{minor}}
            type=semver,pattern={{major}}
            type=raw,value=latest

      - name: Log in to GHCR
        uses: docker/login-action@v3
        with:
          registry: ${{ env.REGISTRY }}
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

      - name: Create and push manifest list
        working-directory: ${{ runner.temp }}/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 published image
        run: docker buildx imagetools inspect ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:${{ steps.meta.outputs.version }}