defmodule Livebook.Runtime.NoopRuntime do
  @moduledoc false

  # A runtime that doesn't do any actual evaluation,
  # thus not requiring any underlying resources.

  defstruct [:started]

  def new() do
    %__MODULE__{started: false}
  end

  defimpl Livebook.Runtime do
    def describe(_runtime) do
      [{"Type", "Noop"}]
    end

    def connect(runtime), do: {:ok, %{runtime | started: true}}
    def connected?(runtime), do: runtime.started
    def take_ownership(_, _), do: make_ref()
    def disconnect(runtime), do: {:ok, %{runtime | started: false}}
    def duplicate(_), do: Livebook.Runtime.NoopRuntime.new()

    def evaluate_code(_, _, _, _, _ \\ []), do: :ok
    def forget_evaluation(_, _), do: :ok
    def drop_container(_, _), do: :ok
    def handle_intellisense(_, _, _, _), do: make_ref()

    def read_file(_, _), do: raise("not implemented")
    def start_smart_cell(_, _, _, _, _), do: :ok
    def set_smart_cell_parent_locators(_, _, _), do: :ok
    def stop_smart_cell(_, _), do: :ok

    def fixed_dependencies?(_), do: false

    def add_dependencies(_runtime, code, dependencies) do
      Livebook.Runtime.Dependencies.add_dependencies(code, dependencies)
    end

    def search_packages(_, _, _), do: make_ref()

    def put_system_envs(_, _), do: :ok
    def delete_system_envs(_, _), do: :ok
  end
end