# Copyright 2018 The Fuchsia Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

# Write an image manfiest at `gn gen` time.
#
# Parameters
#
#   outputs (required)
#     [list of two files] The first output is JSON, the second sh variables.
#
#   images (required)
#     [list of scopes] See below.
#
# Each scope in $images contains:
#
#   default (optional)
#     [bool] Include image in the default group (default: true).
#     It is preferred that very large images that are rarely used are not
#     in the default group.  Absence of a value is equivalent to true.
#
#   deps (required)
#     [list of labels] Target that generates the image file.
#     If `sources` is not specified, this must be an action in this file,
#     and that action must produce a valid ZBI as the first declared output.
#
#   installer (optional)
#     [string] Put this image into the installer image under this name.
#
#   public (optional)
#     [list of strings] Each is "IMAGE_{NAME}_{TYPE}" where `TYPE` can be:
#     `SPARSE` (sparse FVM), `RAW` (block image for any FS), `ZBI`
#     (bootable zircon image), `RAM` (ramdisk without kernel--obsolete),
#     `VBOOT` (ZBI in a vboot container).  "IMAGE_{NAME}_{TYPE}={FILE}"
#     will be written out (with `FILE` relative to `root_build_dir`), to be
#     consumed by //scripts and various tools to find the relevant images.
#
#   json (optional)
#     [scope] Content for images.json; `path` is added automatically.
#     Other fields should match TODO(mcgrathr): some JSON schema.
#     Standard fields not properly documented in a schema yet:
#       path (required)
#         [file] Path relative to $root_build_dir where the image is found.
#         Also serves as the Ninja command-line target argument to build it.
#       name (required)
#         [string] A simple identifier for the image.
#       type (required)
#         [string] Type of image: "zbi", "blk", "kernel", "vboot"
#       bootserver_pave (optional)
#         [string] The command-line switch to `bootserver` that should
#         precede this file's name.  The presence of this field implies
#         that this image is needed for paving via Zedboot.  The value ""
#         means this image is the primary ZBI, which is not preceded by a
#         switch on the `bootserver` command line.
#       bootserver_netboot (optional)
#         [string] The command-line switch to `bootserver` that should
#         precede this file's name.  The presence of this field implies
#         that this image is needed for netbooting via Zedboot.  The value ""
#         means this image is the primary ZBI, which is not preceded by a
#         switch on the `bootserver` command line.
#       archive (optional; default: false)
#         [boolean] This image should be included in a build archive.
#         Implied by the presence of `bootserver`.
#
#   sdk (optional)
#     [string] Put this image into the SDK under this name.
#
#   sources (optional)
#     [list of files] The image file.
#
#   updater (optional)
#     [string] Put this image into the update manifest under this name.
#
template("write_images_manifest") {
  not_needed([ "target_name" ])  # Seriously.
  images_json = []
  image_paths = []
  foreach(image, invoker.images) {
    image_sources = []
    if (defined(image.sources)) {
      image_sources += image.sources
    } else {
      foreach(label, image.deps) {
        image_sources += get_target_outputs(label)
      }
    }
    image_file = rebase_path(image_sources[0], root_build_dir)

    if (defined(image.json)) {
      images_json += [
        {
          forward_variables_from(image.json, "*")
          path = image_file
        },
      ]
    }

    if (defined(image.public)) {
      foreach(name, image.public) {
        image_paths += [ "${name}=${image_file}" ]
      }
    }
  }

  outputs = invoker.outputs
  assert(outputs == [
           outputs[0],
           outputs[1],
         ])
  write_file(outputs[0], images_json, "json")
  write_file(outputs[1], image_paths)
}