/*
Copyright 2015 The Kubernetes Authors.

Licensed 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 proxy

import (
	"fmt"

	"k8s.io/api/core/v1"
	"k8s.io/apimachinery/pkg/types"
	"k8s.io/kubernetes/pkg/proxy/config"
)

// ProxyProvider is the interface provided by proxier implementations.
type ProxyProvider interface {
	config.EndpointsHandler
	config.ServiceHandler

	// Sync immediately synchronizes the ProxyProvider's current state to proxy rules.
	Sync()
	// SyncLoop runs periodic work.
	// This is expected to run as a goroutine or as the main loop of the app.
	// It does not return.
	SyncLoop()
}

// ServicePortName carries a namespace + name + portname.  This is the unique
// identifier for a load-balanced service.
type ServicePortName struct {
	types.NamespacedName
	Port string
}

func (spn ServicePortName) String() string {
	return fmt.Sprintf("%s:%s", spn.NamespacedName.String(), spn.Port)
}

// ServicePort is an interface which abstracts information about a service.
type ServicePort interface {
	// String returns service string.  An example format can be: `IP:Port/Protocol`.
	String() string
	// ClusterIPString returns service cluster IP in string format.
	ClusterIPString() string
	// ExternalIPStrings returns service ExternalIPs as a string array.
	ExternalIPStrings() []string
	// LoadBalancerIPStrings returns service LoadBalancerIPs as a string array.
	LoadBalancerIPStrings() []string
	// GetProtocol returns service protocol.
	GetProtocol() v1.Protocol
	// GetHealthCheckNodePort returns service health check node port if present.  If return 0, it means not present.
	GetHealthCheckNodePort() int
	// GetNodePort returns a service Node port if present. If return 0, it means not present.
	GetNodePort() int
}

// Endpoint in an interface which abstracts information about an endpoint.
// TODO: Rename functions to be consistent with ServicePort.
type Endpoint interface {
	// String returns endpoint string.  An example format can be: `IP:Port`.
	// We take the returned value as ServiceEndpoint.Endpoint.
	String() string
	// GetIsLocal returns true if the endpoint is running in same host as kube-proxy, otherwise returns false.
	GetIsLocal() bool
	// IP returns IP part of the endpoint.
	IP() string
	// Port returns the Port part of the endpoint.
	Port() (int, error)
	// Equal checks if two endpoints are equal.
	Equal(Endpoint) bool
}

// ServiceEndpoint is used to identify a service and one of its endpoint pair.
type ServiceEndpoint struct {
	Endpoint        string
	ServicePortName ServicePortName
}
