name: publish-image

on:
  push:
    tags:
      - "v*.*.*"

  workflow_run:
    workflows: ["Stable Tag"]   # MUST match stable-tag.yml -> name: Stable Tag
    types: [completed]

jobs:
  build-and-push:
    if: |
      (github.event_name == 'push') ||
      (github.event_name == 'workflow_run' && github.event.workflow_run.conclusion == 'success')

    runs-on: ubuntu-latest
    permissions:
      contents: read
      packages: write

    steps:
      - name: Checkout
        uses: actions/checkout@v4
        with:
          # push: checks out the tag ref
          # workflow_run: checks out the exact commit that the Stable Tag workflow ran on
          ref: ${{ github.event_name == 'workflow_run' && github.event.workflow_run.head_sha || github.ref }}

      - name: Set up QEMU
        uses: docker/setup-qemu-action@v3

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

      - name: Login to GHCR
        uses: docker/login-action@v3
        with:
          registry: ghcr.io
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

      - name: Compute tags
        id: meta
        shell: bash
        run: |
          set -euo pipefail
          IMAGE="ghcr.io/${{ github.repository }}"

          if [ "${{ github.event_name }}" = "push" ]; then
            TAG="${{ github.ref_name }}"     # e.g. v1.1.0
            echo "tags=$IMAGE:$TAG,$IMAGE:latest" >> "$GITHUB_OUTPUT"
          else
            echo "tags=$IMAGE:stable" >> "$GITHUB_OUTPUT"
          fi

      - name: Build and push
        uses: docker/build-push-action@v6
        with:
          context: .
          file: ./Dockerfile
          push: true
          platforms: linux/amd64,linux/arm64
          tags: ${{ steps.meta.outputs.tags }}
          cache-from: type=gha
          cache-to: type=gha,mode=max