/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package registry

import (
	gxsort "github.com/dubbogo/gost/sort"
)

// ServiceInstance is the model class of an instance of a service, which is used for service registration and discovery.
type ServiceInstance interface {

	// GetId will return this instance's id. It should be unique.
	GetId() string

	// GetServiceName will return the serviceName
	GetServiceName() string

	// GetHost will return the hostname
	GetHost() string

	// GetPort will return the port.
	GetPort() int

	// IsEnable will return the enable status of this instance
	IsEnable() bool

	// IsHealthy will return the value represent the instance whether healthy or not
	IsHealthy() bool

	// GetMetadata will return the metadata
	GetMetadata() map[string]string
}

// DefaultServiceInstance the default implementation of ServiceInstance
// or change the ServiceInstance to be struct???
type DefaultServiceInstance struct {
	Id          string
	ServiceName string
	Host        string
	Port        int
	Enable      bool
	Healthy     bool
	Metadata    map[string]string
}

// GetId will return this instance's id. It should be unique.
func (d *DefaultServiceInstance) GetId() string {
	return d.Id
}

// GetServiceName will return the serviceName
func (d *DefaultServiceInstance) GetServiceName() string {
	return d.ServiceName
}

// GetHost will return the hostname
func (d *DefaultServiceInstance) GetHost() string {
	return d.Host
}

// GetPort will return the port.
func (d *DefaultServiceInstance) GetPort() int {
	return d.Port
}

// IsEnable will return the enable status of this instance
func (d *DefaultServiceInstance) IsEnable() bool {
	return d.Enable
}

// IsHealthy will return the value represent the instance whether healthy or not
func (d *DefaultServiceInstance) IsHealthy() bool {
	return d.Healthy
}

// GetMetadata will return the metadata, it will never return nil
func (d *DefaultServiceInstance) GetMetadata() map[string]string {
	if d.Metadata == nil {
		d.Metadata = make(map[string]string, 0)
	}
	return d.Metadata
}

// ServiceInstanceCustomizer is an extension point which allow user using custom logic to modify instance
// Be careful of priority. Usually you should use number between [100, 9000]
// other number will be thought as system reserve number
type ServiceInstanceCustomizer interface {
	gxsort.Prioritizer

	Customize(instance ServiceInstance)
}