name: Build RPi image

# Yocto (kas) build of rpilinux-image for raspberrypi4-64.
#
# Runner requirements (see chat/notes):
#   - matches the instance runner's "ubuntu-latest" label (bare label = job
#     runs on the runner's machine, i.e. a host job). Yocto needs ~250GB
#     persistent disk, so the runner must actually be a machine (or a
#     container with a big persistent volume), not a throwaway sandbox.
#   - ~250GB free in $HOME, plus the poky host dependencies + node
#   - runner.timeout >= 8h for the first build (runner default is 3h)
#
# Upgrade path: register a dedicated runner with label "yocto:host" and
# change runs-on below to "yocto".

on:
  push:
    branches: [main]
  workflow_dispatch:

# Never run two builds at once on the same (single) runner.
concurrency:
  group: yocto-rpi-build
  cancel-in-progress: false

permissions:
  contents: read

jobs:
  build:
    runs-on: ubuntu-latest
    timeout-minutes: 600
    steps:
      - uses: builtin:checkout

      - name: Probe environment and host dependencies
        run: |
          echo "=== runner environment ==="
          uname -a
          [ -r /etc/os-release ] && . /etc/os-release && echo "$PRETTY_NAME"
          echo "HOME=$HOME  nproc=$(nproc)"
          df -h "$HOME" | tail -1
          free -h 2>/dev/null | sed -n 2p || true
          command -v docker >/dev/null && docker info --format 'docker: {{.ServerVersion}}' 2>/dev/null || echo "no docker daemon"
          echo "=== dependency check ==="
          set -e
          missing=""
          for t in git python3 curl wget rsync gawk xz diffstat chrpath node npm; do
            command -v "$t" >/dev/null 2>&1 || missing="$missing $t"
          done
          if [ -n "$missing" ]; then
            echo "::error::Missing host tools:$missing"
            echo "Install on the runner host, e.g.:"
            echo '  sudo apt-get install -y --no-install-recommends build-essential \
                  bison chrpath curl diffstat file gawk git libpython3-dev libssl-dev \
                  make python3 python3-venv python3-pip python3-dev rsync swig unzip \
                  wget xz-utils zstd bzip2 nodejs npm'
            exit 1
          fi

      - name: Set up kas (persistent venv)
        run: |
          set -e
          export YOCTO_HOME="$HOME/yocto-ci"
          mkdir -p "$YOCTO_HOME"
          [ -d "$YOCTO_HOME/venv" ] || python3 -m venv "$YOCTO_HOME/venv"
          "$YOCTO_HOME/venv/bin/pip" -q install -U kas
          "$YOCTO_HOME/venv/bin/kas" --version

      - name: Sync to persistent project dir and build
        run: |
          set -euo pipefail
          export YOCTO_HOME="$HOME/yocto-ci"
          # Persistent project dir: keeps extern/ (layer clones) and build/
          # (sstate + tmp) between runs -> incremental builds after the first.
          rsync -a --delete \
            --exclude .git --exclude extern --exclude build \
            ./ "$YOCTO_HOME/yocto_rpi/"
          cd "$YOCTO_HOME/yocto_rpi"
          git config --global --add safe.directory "$YOCTO_HOME/yocto_rpi" || true
          "$YOCTO_HOME/venv/bin/kas" build

      - name: Collect images
        run: |
          set -euo pipefail
          export YOCTO_HOME="$HOME/yocto-ci"
          cd "$YOCTO_HOME/yocto_rpi"
          IMG_DIR="build/*/tmp/deploy/images/raspberrypi4-64"
          ls -lh $IMG_DIR
          mkdir -p "$GITEA_WORKSPACE/dist"
          cp $IMG_DIR/* "$GITEA_WORKSPACE/dist/"
          {
            echo "## RPi4 image built"
            echo
            echo "- commit: ${GITEA_SHA}"
            echo "- images also on the runner host at: \`$YOCTO_HOME/yocto_rpi/$IMG_DIR\`"
          } >> "$GITEA_STEP_SUMMARY"

      - name: Upload images
        uses: actions/upload-artifact@v4
        with:
          name: rpilinux-image-rpi4
          path: dist/
          retention-days: 14