defmodule Dust.Entry do
  @moduledoc "A single cached entry with metadata."

  @type t :: %__MODULE__{
          path: String.t(),
          value: term(),
          type: String.t(),
          revision: integer(),
          synced_at: integer() | nil
        }

  defstruct [:path, :value, :type, :revision, :synced_at]

  @doc """
  Builds an entry. `:synced_at` is optional and defaults to `nil` — it is
  the local wall-clock (unix epoch ms) when this mirror last wrote the
  row, populated for leaf reads and left `nil` for subtree-assembled
  entries.
  """
  @spec new(keyword()) :: t()
  def new(opts) do
    %__MODULE__{
      path: Keyword.fetch!(opts, :path),
      value: Keyword.fetch!(opts, :value),
      type: Keyword.fetch!(opts, :type),
      revision: Keyword.fetch!(opts, :revision),
      synced_at: Keyword.get(opts, :synced_at)
    }
  end
end