defmodule OpenRtbEcto.V2.BidRequest.Native do
  @moduledoc """
  This object represents a native type impression. Native ad units are intended to blend seamlessly
  into the surrounding content (e.g., a sponsored Twitter or Facebook post). As such, the response
  must be well-structured to afford the publisher fine-grained control over rendering.

  The Native Subcommittee has developed a companion specification to OpenRTB called the Dynamic
  Native Ads API. It defines the request parameters and response markup structure of native ad
  units. This object provides the means of transporting request parameters as an opaque string so
  that the specific parameters can evolve separately under the auspices of the Dynamic Native Ads
  API. Similarly, the ad markup served will be structured according to that specification.

  The presence of a Native as a subordinate of the Imp object indicates that this impression is
  offered as a native type impression. At the publisher’s discretion, that same impression may also
  be offered as banner, video, and/or audio by also including as Imp subordinates objects of those
  types. However, any given bid for the impression must conform to one of the offered types.
  """

  use Ecto.Schema
  import Ecto.Changeset
  alias OpenRtbEcto.V2.Native

  @type t :: %__MODULE__{}

  @primary_key false
  embedded_schema do
    field(:request)
    embeds_one(:request_native, Native.Request)
    field(:ver)
    field(:api, {:array, :integer})
    field(:battr, {:array, :integer})
    field(:ext, :map, default: %{})
  end

  def changeset(native, attrs \\ %{}) do
    native
    |> cast(attrs, [:request, :ver, :api, :battr, :ext])
    |> validate_required(:request)
    |> validate_subset(:api, 1..6)
    |> validate_subset(:battr, 1..17)
    |> cast_embed(:request_native)
  end
end