module ActiveRecord::Reflection

def add_aggregate_reflection(ar, name, reflection)
  ar.aggregate_reflections = ar.aggregate_reflections.merge(-name.to_s => reflection)
end

def add_reflection(ar, name, reflection)
  ar.clear_reflections_cache
  name = -name.to_s
  ar._reflections = ar._reflections.except(name).merge!(name => reflection)
end

def create(macro, name, scope, options, ar)
  reflection = reflection_class_for(macro).new(name, scope, options, ar)
  options[:through] ? ThroughReflection.new(reflection) : reflection
end

def reflection_class_for(macro)
  case macro
  when :composed_of
    AggregateReflection
  when :has_many
    HasManyReflection
  when :has_one
    HasOneReflection
  when :belongs_to
    BelongsToReflection
  else
    raise "Unsupported Macro: #{macro}"
  end
end