name: release

# Publishes ghcr.io/<owner>/muse. The package inherits this repo's visibility
# on first publish, so it lands PRIVATE — pulling it needs a token with
# read:packages (see README, "Pulling on a server").
on:
  push:
    branches: [main]
    tags: ["v*"]
    # Docs-only edits shouldn't burn a build or move :latest.
    paths-ignore:
      - "**.md"
      - ".gitignore"
  workflow_dispatch:

concurrency:
  # A newer push makes an in-flight build pointless.
  group: release-${{ github.ref }}
  cancel-in-progress: true

jobs:
  build:
    runs-on: ubuntu-latest
    permissions:
      contents: read
      packages: write        # required to push to GHCR

    steps:
      - uses: actions/checkout@v4

      - name: Sanity-check the API before publishing
        run: |
          python3 -m pip install --quiet -r requirements.txt
          python3 -c "import app; print('app imports OK')"

      # Typechecks and compiles the UI. The Docker build runs this too, but
      # doing it up front fails in ~40s instead of after the whole image is
      # assembled, and surfaces TS errors as their own step in the log.
      - uses: actions/setup-node@v4
        with:
          node-version: "22"
          cache: npm
          cache-dependency-path: web/package-lock.json

      - name: Build the UI
        working-directory: web
        run: |
          npm ci
          npm run build

      # Registers binfmt handlers so buildx can produce a linux/arm64 image on
      # an amd64 runner. REQUIRED by the multi-arch build below — without it
      # buildx fails outright ("exec format error"), it does not silently fall
      # back to amd64 only.
      - uses: docker/setup-qemu-action@v3
        with:
          platforms: arm64

      - uses: docker/setup-buildx-action@v3

      - name: Log in to GHCR
        uses: docker/login-action@v3
        with:
          registry: ghcr.io
          username: ${{ github.actor }}
          # Automatically provided; no PAT needed for pushing from CI.
          password: ${{ secrets.GITHUB_TOKEN }}

      - name: Tags and labels
        id: meta
        uses: docker/metadata-action@v5
        with:
          images: ghcr.io/${{ github.repository }}
          tags: |
            type=raw,value=latest,enable={{is_default_branch}}
            type=sha,format=short
            type=semver,pattern={{version}}
            type=semver,pattern={{major}}.{{minor}}

      - name: Build and push
        uses: docker/build-push-action@v6
        with:
          context: .
          # amd64 AND arm64.
          #
          # This was amd64-only, and that was the right call while the only
          # host running muse was one x86_64 box — arm64 meant paying QEMU for
          # an image nobody would pull. That changed when muse became the
          # front door of a public project: Raspberry Pis, arm64 NASes and
          # Ampere VPSes are a large share of self-hosters, and every other
          # image in that stack already publishes both. muse would have been
          # the single thing making it un-runnable on a Pi.
          #
          # The old comment's cost estimate no longer applies either: the
          # expensive stage (the Next.js build) is pinned to $BUILDPLATFORM in
          # the Dockerfile, so it runs natively once instead of being emulated
          # per platform. What is emulated is a pip install of prebuilt
          # wheels.
          platforms: linux/amd64,linux/arm64
          push: true
          tags: ${{ steps.meta.outputs.tags }}
          labels: ${{ steps.meta.outputs.labels }}
          cache-from: type=gha
          cache-to: type=gha,mode=max

      - name: Summary
        run: |
          echo "### Published" >> $GITHUB_STEP_SUMMARY
          echo '```' >> $GITHUB_STEP_SUMMARY
          echo "${{ steps.meta.outputs.tags }}" >> $GITHUB_STEP_SUMMARY
          echo '```' >> $GITHUB_STEP_SUMMARY