class AWS::EC2::InternetGateway

def attach vpc
  client_opts = {}
  client_opts[:internet_gateway_id] = internet_gateway_id
  client_opts[:vpc_id] = vpc_id_option(vpc)
  client.attach_internet_gateway(client_opts)
  nil
end

def attachments
  attachment_set.map {|details| Attachment.new(self, details) }
end

def delete
  client_opts = {}
  client_opts[:internet_gateway_id] = internet_gateway_id
  client.delete_internet_gateway(client_opts)
  nil
end

def detach vpc
  client_opts = {}
  client_opts[:internet_gateway_id] = internet_gateway_id
  client_opts[:vpc_id] = vpc_id_option(vpc)
  client.detach_internet_gateway(client_opts)
  nil
end

def exists?
  begin
    get_resource
    true
  rescue Errors::InvalidInternetGatewayID::NotFound
    false
  end
end

def initialize internet_gateway_id, options = {}
  @internet_gateway_id = internet_gateway_id
  super
end

def vpc
  if attachment = attachments.first
    attachment.vpc
  end
end

def vpc= vpc
  if attachment = attachments.first
    attachment.delete
  end
  attach(vpc) if vpc
end

def vpc_id_option vpc
  vpc.is_a?(VPC) ? vpc.vpc_id : vpc
end