name: Build and publish container

on:
  push:
    branches: [main]
    tags: ["v*"]
  pull_request:
    branches: [main]

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

      - name: Determine registry host
        run: echo "REGISTRY=${GITHUB_SERVER_URL#*://}" >> "$GITHUB_ENV"

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

      # Uses a Personal Access Token with package read/write scope, stored as
      # the PACKAGES_TOKEN secret. The auto-provided GITEA_TOKEN does not carry
      # container-registry write permission on most Gitea instances.
      - name: Log in to the Gitea container registry
        if: github.event_name != 'pull_request'
        uses: docker/login-action@v3
        with:
          registry: ${{ env.REGISTRY }}
          username: ${{ github.repository_owner }}
          password: ${{ secrets.PACKAGES_TOKEN }}

      - name: Extract image metadata
        id: meta
        uses: docker/metadata-action@v5
        with:
          images: ${{ env.REGISTRY }}/${{ github.repository }}
          # Semantic version tags are produced from pushed v* git tags.
          # `latest` follows the newest non-prerelease release via latest=auto.
          # Branch and SHA tags are kept for traceability of non-release builds.
          tags: |
            type=semver,pattern={{version}}
            type=semver,pattern={{major}}.{{minor}}
            type=semver,pattern={{major}}
            type=ref,event=branch
            type=ref,event=pr
            type=sha
          flavor: |
            latest=auto

      - name: Build and push
        uses: docker/build-push-action@v6
        with:
          context: .
          push: ${{ github.event_name != 'pull_request' }}
          tags: ${{ steps.meta.outputs.tags }}
          labels: ${{ steps.meta.outputs.labels }}