name: Pi image

# Builds a ready-to-flash Raspberry Pi OS Lite image with Ashvale Station
# preinstalled, and attaches it to a GitHub Release.
#
# Built in CI rather than on a laptop on purpose. The artifact is something
# other people flash onto their own hardware, so it should be reproducible from
# a public log by anyone who wants to check what went into it, rather than
# appearing from a machine only I can see.

on:
  workflow_dispatch:
    inputs:
      publish:
        description: "Attach the image to a release"
        type: boolean
        default: false
  push:
    tags:
      - "v*"

permissions:
  contents: write

jobs:
  build:
    runs-on: ubuntu-latest
    timeout-minutes: 180

    steps:
      - name: Check out Ashvale
        uses: actions/checkout@v4
        with:
          path: ashvale

      # pi-gen needs about 10 GB and a stock runner does not have it spare.
      - name: Reclaim disk space
        run: |
          sudo rm -rf /usr/share/dotnet /usr/local/lib/android /opt/ghc \
                      /usr/local/share/boost "$AGENT_TOOLSDIRECTORY"
          df -h / | tail -1

      - name: Install build dependencies
        run: |
          sudo apt-get update
          # Taken from pi-gen's own `depends` file at the pinned commit rather
          # than guessed. My first attempt installed qemu-user-static, and
          # pi-gen wants qemu-user-binfmt: it checks for the binfmt handler, not
          # the emulator binary, and failed in under a second.
          sudo apt-get install -y --no-install-recommends \
            quilt parted coreutils qemu-user-binfmt debootstrap zerofree zip \
            dosfstools e2fsprogs libcap2-bin libarchive-tools grep rsync \
            xz-utils curl xxd file git kmod bc gpg pigz arch-test
          # Prove the handler is actually registered before spending an hour.
          test -f /proc/sys/fs/binfmt_misc/qemu-aarch64 \
            || sudo systemctl restart systemd-binfmt || true
          ls /proc/sys/fs/binfmt_misc/ | head

      # Pinned to a commit, not a branch. An image other people flash should not
      # change because an upstream branch moved between builds.
      - name: Check out pi-gen
        uses: actions/checkout@v4
        with:
          repository: RPi-Distro/pi-gen
          ref: ca8aeed0ae300c2a89f55ce9617d5f96a27e99e5   # arm64 branch, pinned
          path: pi-gen
          fetch-depth: 1

      - name: Assemble the custom stage
        run: |
          cp ashvale/deploy/pi-image/config pi-gen/config
          cp -r ashvale/deploy/pi-image/stage-ashvale pi-gen/stage-ashvale
          # Lite only: everything from stage3 up is the desktop.
          touch pi-gen/stage3/SKIP pi-gen/stage4/SKIP pi-gen/stage5/SKIP
          touch pi-gen/stage4/SKIP_IMAGES pi-gen/stage5/SKIP_IMAGES
          # stage2 stops exporting so ours is the only image produced.
          rm -f pi-gen/stage2/EXPORT_IMAGE
          echo "ASHVALE_SRC=${GITHUB_WORKSPACE}/ashvale" >> pi-gen/config
          echo "--- config ---" && cat pi-gen/config

      - name: Build
        working-directory: pi-gen
        run: sudo -E ./build.sh

      - name: Collect artifact
        id: artifact
        run: |
          IMG=$(find pi-gen/deploy -name '*.img.xz' | head -1)
          test -n "$IMG" || { echo "no image produced"; ls -R pi-gen/deploy; exit 1; }
          mkdir -p out && mv "$IMG" out/
          cd out
          NAME=$(basename *.img.xz)
          sha256sum "$NAME" > "$NAME.sha256"
          echo "name=$NAME" >> "$GITHUB_OUTPUT"
          ls -lh
          # A release asset is capped at 2 GB; Lite compresses to well under that,
          # but fail loudly here rather than at upload time.
          SIZE=$(stat -c%s "$NAME")
          echo "compressed size: $((SIZE/1024/1024)) MiB"
          test "$SIZE" -lt 2000000000 || { echo "image exceeds the 2 GB release limit"; exit 1; }

      - name: Upload as a workflow artifact
        uses: actions/upload-artifact@v4
        with:
          name: ashvale-pi-image
          path: out/*
          retention-days: 14

      - name: Attach to release
        if: startsWith(github.ref, 'refs/tags/') || inputs.publish
        env:
          GH_TOKEN: ${{ github.token }}
        run: |
          TAG="${GITHUB_REF_NAME}"
          gh release view "$TAG" --repo "$GITHUB_REPOSITORY" >/dev/null 2>&1 \
            || gh release create "$TAG" --repo "$GITHUB_REPOSITORY" \
                 --title "$TAG" --notes "Ashvale Station image for Raspberry Pi."
          gh release upload "$TAG" out/* --repo "$GITHUB_REPOSITORY" --clobber