name: Builder Image

# Builds the nanokvm-builder image (riscv64 musl toolchain, Go, and a MaixCDK
# checkout patched with support/sg2002/additional) and publishes it to GHCR so
# the release workflow does not have to rebuild the SDK on every tag.
#
# The image is deliberately not rebuilt on every push: it only carries the
# toolchain. Release builds re-sync support/sg2002/additional into MaixCDK and
# recompile from the checked-out source, so a slightly stale image is harmless.

on:
  workflow_dispatch:
  push:
    branches:
      - main
    paths:
      - docker/**
      - .github/workflows/builder-image.yml

concurrency:
  group: builder-image
  cancel-in-progress: false

jobs:
  build:
    name: Build and publish nanokvm-builder
    runs-on: ubuntu-latest
    timeout-minutes: 240
    permissions:
      contents: read
      packages: write

    steps:
      - name: Checkout
        uses: actions/checkout@v4

      - name: Free up disk space
        run: |
          echo "Before:"
          df -h /
          sudo rm -rf /usr/share/dotnet /usr/local/lib/android /opt/ghc \
                      /usr/local/share/boost /usr/local/share/powershell
          sudo docker image prune -af
          echo "After:"
          df -h /

      - name: Resolve image reference
        id: image
        env:
          OWNER: ${{ github.repository_owner }}
        run: |
          # GHCR only accepts lowercase repository paths.
          owner=$(echo "$OWNER" | tr '[:upper:]' '[:lower:]')
          echo "ref=ghcr.io/$owner/nanokvm-builder" >> "$GITHUB_OUTPUT"

      # Logging in before the build means a credential or registry problem fails
      # in seconds instead of after a full SDK build.
      - name: Log in to GHCR
        env:
          GHCR_USER: ${{ github.actor }}
          GHCR_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        run: |
          ok=0
          for attempt in 1 2 3; do
            if printf '%s' "$GHCR_TOKEN" \
                 | docker login ghcr.io -u "$GHCR_USER" --password-stdin; then
              ok=1
              break
            fi
            echo "login attempt $attempt failed, retrying in 15s"
            sleep 15
          done
          if [ "$ok" -ne 1 ]; then
            echo "::error::could not log in to ghcr.io after 3 attempts"
            exit 1
          fi

      - name: Build image
        run: |
          # The Dockerfile chowns MaixCDK to DOCKER_UID/DOCKER_GID and the
          # entrypoint gosu's to the caller's ids, so bake in the ids the
          # release job will actually run as. Otherwise the SDK tree belongs to
          # 1000 and syncing components into it fails with permission denied.
          docker build \
            --build-arg DOCKER_UID="$(id -u)" \
            --build-arg DOCKER_GID="$(id -g)" \
            --tag "${{ steps.image.outputs.ref }}:latest" \
            --tag "${{ steps.image.outputs.ref }}:${{ github.sha }}" \
            --file docker/Dockerfile \
            .

      - name: Verify toolchain
        run: |
          docker run --rm -i "${{ steps.image.outputs.ref }}:latest" go version
          docker run --rm -i "${{ steps.image.outputs.ref }}:latest" \
            riscv64-unknown-linux-musl-gcc --version | head -1
          docker run --rm -i "${{ steps.image.outputs.ref }}:latest" patchelf --version

      - name: Push image
        env:
          IMAGE_REF: ${{ steps.image.outputs.ref }}
          SHA: ${{ github.sha }}
        run: |
          # ghcr.io occasionally times out; a retry is cheaper than rebuilding.
          # Push the immutable sha tag first so a failure there cannot leave
          # :latest — which release.yml pulls — already moved.
          for tag in "$SHA" latest; do
            ok=0
            for attempt in 1 2 3; do
              if docker push "$IMAGE_REF:$tag"; then
                ok=1
                break
              fi
              echo "push of $tag attempt $attempt failed, retrying in 15s"
              sleep 15
            done
            if [ "$ok" -ne 1 ]; then
              echo "::error::could not push $IMAGE_REF:$tag after 3 attempts"
              exit 1
            fi
          done

      - name: Summary
        run: |
          {
            echo "### Builder image published"
            echo
            echo '```'
            echo "${{ steps.image.outputs.ref }}:latest"
            echo "${{ steps.image.outputs.ref }}:${{ github.sha }}"
            echo '```'
          } >> "$GITHUB_STEP_SUMMARY"