name: Docker Build

on:
  pull_request:
    paths:
      - 'docker/**'
      - 'docker-compose.yaml'
      - '.dockerignore'
      - 'chatmaild/**'
      - 'cmdeploy/**'
      - '.github/workflows/docker-build.yaml'
  push:
    branches:
      - main
      - j4n/docker
    paths:
      - 'docker/**'
      - 'docker-compose.yaml'
      - '.dockerignore'
      - 'chatmaild/**'
      - 'cmdeploy/**'
      - '.github/workflows/docker-build.yaml'
    tags:
      - 'v*'

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

jobs:
  build:
    name: Build Docker image
    runs-on: ubuntu-latest
    permissions:
      contents: read
      packages: write
    steps:
      - uses: actions/checkout@v4

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

      - name: Login to GHCR
        if: github.event_name == 'push'
        uses: docker/login-action@v3
        with:
          registry: ${{ env.REGISTRY }}
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

      - name: Extract metadata (tags, labels)
        id: meta
        uses: docker/metadata-action@v5
        with:
          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
          tags: |
            # Tagged releases: v1.2.3 → :1.2.3, :1.2, :latest
            type=semver,pattern={{version}}
            type=semver,pattern={{major}}.{{minor}}
            # Branch pushes: j4n/docker → :j4n-docker
            type=ref,event=branch
            # Always: :sha-<hash>
            type=sha

      - name: Build and push
        uses: docker/build-push-action@v6
        with:
          context: .
          file: docker/chatmail_relay.dockerfile
          push: ${{ github.event_name == 'push' }}
          tags: ${{ steps.meta.outputs.tags }}
          labels: ${{ steps.meta.outputs.labels }}
          cache-from: type=gha
          cache-to: type=gha,mode=max
          build-args: |
            GIT_HASH=${{ github.sha }}