name: build-image
description: >-
  Build a kas project in a persistent directory and expose the flashable
  images. The workspace is synced into the build dir instead of built in
  place, because checkout cleans ignored files (build/, extern/) and bitbake
  reuse depends on sstate-cache surviving between runs.
inputs:
  project:
    description: kas configuration file, relative to the repository
    required: false
    default: .config.yaml
  machine:
    description: Machine the images are deployed for
    required: false
    default: raspberrypi4-64
  image-prefix:
    description: Artifact filename prefix in the deploy dir
    required: false
    default: rpilinux-image
  skip-build:
    description: Set to true to only collect images from an existing build dir
    required: false
    default: "false"
outputs:
  build-dir:
    description: Persistent project directory on the runner
    value: ${{ steps.locate.outputs.build-dir }}
  image-dir:
    description: Deploy dir bitbake wrote to
    value: ${{ steps.locate.outputs.image-dir }}
  images:
    description: Newline separated artifact filenames
    value: ${{ steps.collect.outputs.images }}
runs:
  using: composite
  steps:
    - name: Sync workspace into persistent build dir
      if: ${{ inputs.skip-build != 'true' }}
      shell: bash
      run: |
        set -euo pipefail
        SRC="$(pwd)"
        DST="${YOCTO_HOME:-$HOME/yocto-build}/$(basename "$GITHUB_REPOSITORY")"
        # checkout deletes ignored files, so the build tree must live elsewhere
        if [ "$SRC" = "$DST" ]; then
          echo "::error::workspace == build dir ($SRC); point YOCTO_HOME somewhere else"
          exit 1
        fi
        echo "syncing $SRC -> $DST"
        mkdir -p "$DST"
        # .git stays (kas requires a repo); extern/ + build/ only exist in DST,
        # so --delete cannot reach them
        rsync -a --delete --exclude /build/ --exclude /extern/ ./ "$DST/"

    - name: kas build
      if: ${{ inputs.skip-build != 'true' }}
      shell: bash
      run: |
        set -euo pipefail
        cd "${YOCTO_HOME:-$HOME/yocto-build}/$(basename "$GITHUB_REPOSITORY")"
        git config --global --add safe.directory "$PWD" || true
        "${YOCTO_HOME:-$HOME/yocto-build}/venv/bin/kas" build

    - name: Locate deploy dir
      id: locate
      shell: bash
      run: |
        set -euo pipefail
        BUILD_DIR="${YOCTO_HOME:-$HOME/yocto-build}/$(basename "$GITHUB_REPOSITORY")"
        IMAGE_DIR="$(find "$BUILD_DIR/build" -type d -path "*/tmp/deploy/images/${{ inputs.machine }}" | head -1)"
        if [ -z "$IMAGE_DIR" ]; then
          echo "::error::no deploy dir for ${{ inputs.machine }} under $BUILD_DIR/build"
          exit 1
        fi
        echo "build-dir=$BUILD_DIR" >> "$GITHUB_OUTPUT"
        echo "image-dir=$IMAGE_DIR" >> "$GITHUB_OUTPUT"

    - name: Collect artifacts
      id: collect
      shell: bash
      run: |
        set -euo pipefail
        IMAGE_DIR="${{ steps.locate.outputs.image-dir }}"
        shopt -s nullglob
        # only the timestamped names: the short ones are hardlinks to the same
        # inode and would upload every image twice
        FILES=("${IMAGE_DIR}/${{ inputs.image-prefix }}."*.rootfs-[0-9]*.wic.* \
               "${IMAGE_DIR}/${{ inputs.image-prefix }}-*.rootfs-[0-9]*.wic.*")
        if [ "${#FILES[@]}" -eq 0 ]; then
          echo "::error::no flashable .wic image for ${{ inputs.machine }} in $IMAGE_DIR"
          exit 1
        fi
        mkdir -p dist
        cp -v "${FILES[@]}" dist/
        ( cd dist && sha256sum * > SHA256SUMS )
        ls -lh dist
        printf 'images=%s\n' "$(ls dist | tr '\n' ' ')" >> "$GITHUB_OUTPUT"

    - name: Summarise
      shell: bash
      run: |
        set -euo pipefail
        SUMMARY="${GITHUB_STEP_SUMMARY:-}"
        [ -n "$SUMMARY" ] || exit 0
        {
          echo "## ${{ inputs.image-prefix }} for ${{ inputs.machine }}"
          echo
          echo "| artifact | sha256 |"
          echo "| --- | --- |"
          ( cd dist && while read -r sum file; do
              [ "$file" = SHA256SUMS ] || echo "| \`$file\` | \`${sum:0:16}\` |"
            done < SHA256SUMS )
          echo
          echo "Flash with \`bzcat <image> | sudo dd of=/dev/sdX bs=4M status=progress\`."
          echo
          echo "Incremental build tree: \`${{ steps.locate.outputs.build-dir }}\`"
        } >> "$SUMMARY"