case Code.ensure_loaded(Jason) do
  {:module, _} ->
    defmodule AbsintheUtils.Scalars.JSON do
      @moduledoc """
      The JSON scalar type allows arbitrary JSON values to be passed in and out.
      Requires `{ :jason, ">= 1.1" }` package: https://github.com/michalmuskala/jason

      Based in the
      [recipes on Absinthe's wiki](https://github.com/absinthe-graphql/absinthe/wiki/Scalar-Recipes)

      Note that even if you use `non_null(:json)` a string of null value (`"null"`) is still accepted.

      **Usage:**

      Import the type in your schema `import_types(AbsintheUtils.Scalars.JSON)` and you will be able
      to use the `:json` type.
      """
      use Absinthe.Schema.Notation

      scalar :json, name: "JSON" do
        description("""
        The `JSON` scalar type represents arbitrary JSON string data, represented as UTF-8
        character sequences. The JSON type is most often used to represent a free-form
        human-readable json string.
        """)

        serialize(&encode/1)
        parse(&decode/1)
      end

      @spec decode(Absinthe.Blueprint.Input.String.t()) :: {:ok, term()} | :error
      @spec decode(Absinthe.Blueprint.Input.Null.t()) :: {:ok, nil}
      defp decode(%Absinthe.Blueprint.Input.String{value: value}) do
        case Jason.decode(value) do
          {:ok, result} -> {:ok, result}
          _ -> :error
        end
      end

      defp decode(%Absinthe.Blueprint.Input.Null{}) do
        {:ok, nil}
      end

      defp decode(_), do: :error

      defp encode(value) do
        case Jason.encode(value) do
          {:ok, _} ->
            value

          {:error, _} ->
            raise Absinthe.SerializationError,
                  "Could not serialize term #{inspect(value)} as type UUID."
        end
      end
    end

  _ ->
    nil
end