class ReeObject::ToHash

def call(obj)
  recursively_convert(obj, {}, {})
end

def convert_array(obj, acc, cache)
  obj.map { |el| recursively_convert(el, {}, cache) }
end

def convert_hash(obj, acc, cache)
  obj.each do |k, v|
    key_sym = k.to_sym
    acc[key_sym] = recursively_convert(v, {}, cache)
  end
  acc
end

def convert_object(obj, acc, cache)
  return obj if obj.is_a?(Class) || obj.is_a?(Module)
  if cache.key?(obj.object_id)
    raise RecursiveObjectErr, "Recursive object found: #{obj}"
  end
  cache[obj.object_id] = true
  obj.instance_variables.each do |var|
    key_name = var.to_s.delete("@")
    key_sym = key_name.to_sym
    key = key_sym
    value = obj.instance_variable_get(var)
    acc[key] = recursively_convert(value, {}, cache)
  end
  cache.delete(obj.object_id)
  acc
end

def recursively_convert(obj, acc, cache)
  ancestors = obj.class.ancestors
  if ancestors.intersection(BASIC_TYPES).size > 0
    obj
  elsif obj.is_a?(Array)
    convert_array(obj, acc, cache)
  elsif obj.is_a?(Hash)
    convert_hash(obj, acc, cache)
  elsif obj.respond_to?(:to_h)
    convert_hash(obj.to_h, acc, cache)
  else
    convert_object(obj, acc, cache)
  end
end