package discovery

import (
	"context"
	"google.golang.org/grpc/resolver"
)

type Registry interface {
	// Registry server instance
	Registry(ctx context.Context, server Server) (err error)
}

type GrpcResolver interface {
	DialUrl(serviceName string) string
	// Resolver get grpc dial resolver
	Resolver() (builder resolver.Builder, err error)
}

type Resolver interface {
	// ResolveAll get service all instance
	ResolveAll(ctx context.Context, serviceName string) (servers []Server, err error)
	// Watch when service instance change, send current all instances to channel
	Watch(ctx context.Context, serviceName string) (ch chan []Server, err error)
}

type Discovery interface {
	Registry
	Resolver
	GrpcResolver
}

// Server registry format
type Server struct {
	Name  string            `json:"name"`
	Addr  string            `json:"addr"`  // 地址
	Attrs map[string]string `json:"attrs"` // attributes
}