class Lumberjack::Formatter::StructuredFormatter

def call(obj)
  call_with_references(obj, Set.new)
end

def call_with_references(obj, references)
  if obj.is_a?(Hash)
    with_object_reference(obj, references) do
      hash = {}
      obj.each do |name, value|
        value = call_with_references(value, references)
        hash[name.to_s] = value unless value.is_a?(RecusiveReferenceError)
      end
      hash
    end
  elsif obj.is_a?(Enumerable) && obj.respond_to?(:size) && obj.size != Float::INFINITY
    with_object_reference(obj, references) do
      array = []
      obj.each do |value|
        value = call_with_references(value, references)
        array << value unless value.is_a?(RecusiveReferenceError)
      end
      array
    end
  elsif @formatter
    @formatter.format(obj)
  else
    obj
  end
end

def initialize(formatter = nil)
  @formatter = formatter
end

def with_object_reference(obj, references)
  if obj.is_a?(Enumerable)
    return RecusiveReferenceError.new if references.include?(obj.object_id)
    references << obj.object_id
    begin
      yield
    ensure
      references.delete(obj.object_id)
    end
  else
    yield
  end
end