class AWS::EC2::PermissionCollection

def add(*users)
  modify(:add, *users)
end

def describe_call
  "describe_#{resource_name}_attribute"
end

def describe_params
  Hash[[["#{resource_name}_id".to_sym, @resource.send(:__resource_id__)],
        [:attribute, permissions_attribute]]]
end

def each(&block)
  resp = client.send(describe_call, describe_params)
  resp.send(inflected_permissions_attribute).each do |permission|
    if permission.respond_to?(:user_id)
      user_id = permission.user_id
      yield(user_id)
    end
  end
end

def empty?
  size == 0
end

def inflected_permissions_attribute
  Core::Inflection.ruby_name(permissions_attribute).to_sym
end

def initialize(resource, opts = {})
  @resource = resource
  super(opts)
end

def modify(action, *users)
  return if users.empty?
  opts = modify_params(Hash[[[action,
                              users.map do |user_id|
                                { :user_id => user_id }
                              end]]])
  client.send(modify_call, opts)
  nil
end

def modify_call
  "modify_#{resource_name}_attribute"
end

def modify_params(modifications)
  Hash[[["#{resource_name}_id".to_sym, @resource.send(:__resource_id__)],
        [inflected_permissions_attribute, modifications]]]
end

def permissions_attribute
  @resource.__permissions_attribute__
end

def private?
  !public?
end

def public= value
  params = value ? 
    { :add => [{ :group => "all" }] } :
    { :remove => [{ :group => "all" }] }
  client.send(modify_call, modify_params(params))
  nil
end

def public?
  resp = client.send(describe_call, describe_params)
  resp.send(inflected_permissions_attribute).any? do |permission|
    permission.respond_to?(:group) and permission.group == "all"
  end
end

def remove(*users)
  modify(:remove, *users)
end

def reset
  client.send(reset_call, reset_params)
end

def reset_call
  "reset_#{resource_name}_attribute"
end

def resource_name
  @resource.send(:inflected_name)
end

def size
  inject(0) { |sum, i| sum + 1 }
end