class ActiveRecord::Associations::Builder::CollectionAssociation

def build
  show_deprecation_warnings
  wrap_block_extension
  reflection = super
  CALLBACKS.each { |callback_name| define_callback(callback_name) }
  reflection
end

def define_callback(callback_name)
  full_callback_name = "#{callback_name}_for_#{name}"
  # TODO : why do i need method_defined? I think its because of the inheritance chain
  model.class_attribute full_callback_name.to_sym unless model.method_defined?(full_callback_name)
  model.send("#{full_callback_name}=", Array(options[callback_name.to_sym]))
end

def define_readers
  super
  mixin.class_eval <<-CODE, __FILE__, __LINE__ + 1
    def #{name.to_s.singularize}_ids
      association(:#{name}).ids_reader
    end
  CODE
end

def define_writers
  super
  mixin.class_eval <<-CODE, __FILE__, __LINE__ + 1
    def #{name.to_s.singularize}_ids=(ids)
      association(:#{name}).ids_writer(ids)
    end
  CODE
end

def extension_module_name
  @extension_module_name ||= "#{model.name.demodulize}#{name.to_s.camelize}AssociationExtension"
end

def initialize(*args, &extension)
  super(*args)
  @block_extension = extension
end

def show_deprecation_warnings
  [:finder_sql, :counter_sql].each do |name|
    if options.include? name
      ActiveSupport::Deprecation.warn("The :#{name} association option is deprecated. Please find an alternative (such as using scopes).")
    end
  end
end

def valid_options
  super + [:table_name, :finder_sql, :counter_sql, :before_add,
           :after_add, :before_remove, :after_remove, :extend]
end

def wrap_block_extension
  if block_extension
    @extension_module = mod = Module.new(&block_extension)
    silence_warnings do
      model.parent.const_set(extension_module_name, mod)
    end
    prev_scope = @scope
    if prev_scope
      @scope = proc { |owner| instance_exec(owner, &prev_scope).extending(mod) }
    else
      @scope = proc { extending(mod) }
    end
  end
end

def writable?
  true
end