class DeepPreloader::PolymorphicSpec

def self.parse(data)
  if data.is_a?(Hash)
    specs = data.each_with_object({}) do |(k, v), h|
      h[k.to_s] = DeepPreloader::Spec.parse(v)
    end
    self.new(specs)
  else
    raise ArgumentError.new("Invalid polymorphic spec: '#{data.inspect}' is not a hash")
  end
end

def ==(other)
  self.class == other.class && self.specs_by_type == other.specs_by_type
end

def for_type(clazz)
  specs_by_type[clazz.name]
end

def hash
  [self.class, self.specs_by_type].hash
end

def initialize(specs_by_type = {})
  @specs_by_type = specs_by_type
end

def inspect
  "PolySpec#{specs_by_type.inspect}"
end

def merge!(other)
  case other
  when nil
    return
  when DeepPreloader::PolymorphicSpec
    other.specs_by_type.each do |k, v|
      if specs_by_type[k]
        specs_by_type[k].merge!(v)
      else
        specs_by_type[k] = v
      end
    end
  else
    raise ArgumentError.new("Cannot merge #{other.class.name} into #{self.inspect}")
  end
  self
end

def polymorphic?
  true
end