absinthe_utils

if Application.get_env(:absinthe_utils, :compile_json_scalar, true) do
  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 on 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
end