name: Build and publish Docker image

# Builds SaraView's image (Dockerfile at the repo root) and pushes it to
# GitHub Container Registry (ghcr.io) so it can be pulled directly on
# ZimaOS instead of building locally every time.
#
# Runs on every push to main (tagged "latest" + the short commit SHA) and
# on version tags like v1.0.0 (tagged with that version). Also runnable
# by hand from the Actions tab ("workflow_dispatch").
#
# One manual, one-time step after this first runs: GHCR packages built via
# a workflow's built-in token default to PRIVATE, even on a public repo.
# Go to your GitHub profile -> Packages -> saraview -> Package settings ->
# Change visibility -> Public, or ZimaOS won't be able to pull it without
# a login.

on:
  push:
    branches: ["main"]
    tags: ["v*.*.*"]
  workflow_dispatch:

permissions:
  contents: read
  packages: write

jobs:
  build-and-push:
    runs-on: ubuntu-latest
    steps:
      - name: Check out repository
        uses: actions/checkout@v4

      - name: Compute lowercase image name
        # GHCR requires an all-lowercase image path even though GitHub
        # usernames/repos themselves are case-insensitive (e.g. SRHTNIN
        # becomes srhtnin here).
        run: echo "IMAGE=ghcr.io/$(echo '${{ github.repository }}' | tr '[:upper:]' '[:lower:]')" >> "$GITHUB_ENV"

      - name: Log in to GitHub Container Registry
        uses: docker/login-action@v3
        with:
          registry: ghcr.io
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

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

      - name: Compute tags
        id: meta
        uses: docker/metadata-action@v5
        with:
          images: ${{ env.IMAGE }}
          tags: |
            type=raw,value=latest,enable={{is_default_branch}}
            type=semver,pattern={{version}}
            type=sha,prefix=,format=short

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