// Copyright 2015 The Vanadium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package discovery

// Service represents service information for service discovery.
type Service struct {
	// The universal unique identifier of a service instance.
	// If this is not specified, a random unique identifier will be assigned.
	InstanceId string
	// Optional name of the service instance.
	InstanceName string
	// The interface that the service implements.
	// E.g., 'v.io/v23/services/vtrace.Store'.
	InterfaceName string
	// The service attributes.
	// E.g., {'resolution': '1024x768'}.
	Attrs Attributes
	// The addresses (vanadium object names) that the service is served on.
	// E.g., '/host:port/a/b/c', '/ns.dev.v.io:8101/blah/blah'.
	Addrs []string
	// The service attachments.
	// E.g., {'thumbnail': binary_data }.
	//
	// WARNING: THIS FIELD IS NOT SUPPORTED YET.
	Attachments Attachments
}

// Attributes represents service attributes as a key/value pair.
//
// The key must be US-ASCII printable characters, excluding the '=' character
// and should not start with '_' character.
type Attributes map[string]string

// Attachments represents service attachments as a key/value pair. Unlike
// attributes, attachments are mostly for larger binary data and they are
// not queryable. It is recommended to put as small attachments as possible
// since it may require additional RPC calls causing delay in discovery.
//
// The key must be US-ASCII printable characters, excluding the '=' character
// and should not start with '_' character.
type Attachments map[string][]byte

// Found represents a service that is discovered by scan.
type Found struct {
	Service Service
	// TODO(jhahn): Add proximity.
}

// Lost represents a service that is lost during scan.
type Lost struct {
	InstanceId string
}

// Update represents a discovery update.
type Update union {
	Found Found
	Lost  Lost
}