/*
Copyright 2017 ZTE, Inc. and others.

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 main

import (
	"log"
	"sync"

	kapi "k8s.io/kubernetes/pkg/api"
)

type KubeBookKeeper interface {
	AddService(*kapi.Service)
	RemoveService(*kapi.Service)
	UpdateService(*kapi.Service)
	AddPod(*kapi.Pod)
	RemovePod(*kapi.Pod)
	UpdatePod(*kapi.Pod)
}

type ClientBookKeeper struct {
	sync.Mutex
	KubeBookKeeper
	services map[string]*kapi.Service
	pods     map[string]*kapi.Pod
	msbQueue chan<- MSBWork
}

func newClientBookKeeper() *ClientBookKeeper {
	return &ClientBookKeeper{
		services: make(map[string]*kapi.Service),
		pods:     make(map[string]*kapi.Pod),
	}
}

func (client *ClientBookKeeper) AddService(svc *kapi.Service) {
	client.Lock()
	defer client.Unlock()
	if _, ok := svc.ObjectMeta.Annotations[serviceKey]; !ok {
		log.Println("Not the target, skip this ADD notification for service:", svc.Name)
		return
	}

	if _, ok := client.services[svc.Name]; ok {
		log.Printf("service:%s already exist. skip this ADD notification.", svc.Name)
		return
	}

	if kapi.IsServiceIPSet(svc) {
		if svc.Spec.Type == kapi.ServiceTypeClusterIP || svc.Spec.Type == kapi.ServiceTypeNodePort {
			log.Printf("Adding %s service:%s", svc.Spec.Type, svc.Name)
			client.msbQueue <- MSBWork{
				Action:      MSBWorkAddService,
				ServiceInfo: svc.ObjectMeta.Annotations[serviceKey],
				IPAddress:   svc.Spec.ClusterIP,
			}
		} else if svc.Spec.Type == kapi.ServiceTypeLoadBalancer {
			log.Println("Adding LoadBalancerIP service:", svc.Name)
			client.msbQueue <- MSBWork{
				Action:      MSBWorkAddService,
				ServiceInfo: svc.ObjectMeta.Annotations[serviceKey],
				IPAddress:   svc.Spec.LoadBalancerIP,
			}
		} else {
			log.Printf("Service Type:%s for Service:%s is not supported", svc.Spec.Type, svc.Name)
			return
		}
		client.services[svc.Name] = svc
		log.Println("Queued Service to be added: ", svc.Name)
	} else {
		// if ClusterIP is not set, do not create a DNS records
		log.Printf("Skipping dns record for headless service: %s\n", svc.Name)
	}
}

func (client *ClientBookKeeper) RemoveService(svc *kapi.Service) {
	client.Lock()
	defer client.Unlock()
	if _, ok := svc.ObjectMeta.Annotations[serviceKey]; !ok {
		log.Println("Not the target, skip this Remove notification for service:", svc.Name)
		return
	}

	if _, ok := client.services[svc.Name]; !ok {
		log.Printf("Service:%s not exist. skip this REMOVE notification.", svc.Name)
		return
	}

	if svc.Spec.Type == kapi.ServiceTypeClusterIP || svc.Spec.Type == kapi.ServiceTypeNodePort {
		log.Printf("Removing %s service:%s", svc.Spec.Type, svc.Name)
		//Perform All DNS Removes
		client.msbQueue <- MSBWork{
			Action:      MSBWorkRemoveService,
			ServiceInfo: svc.ObjectMeta.Annotations[serviceKey],
			IPAddress:   svc.Spec.ClusterIP,
		}
	} else if svc.Spec.Type == kapi.ServiceTypeLoadBalancer {
		log.Println("Removing LoadBalancerIP service:", svc.Name)
		client.msbQueue <- MSBWork{
			Action:      MSBWorkRemoveService,
			ServiceInfo: svc.ObjectMeta.Annotations[serviceKey],
			IPAddress:   svc.Spec.LoadBalancerIP,
		}
	} else {
		log.Printf("Service Type:%s for Service:%s is not supported", svc.Spec.Type, svc.Name)
		return
	}
	delete(client.services, svc.Name)
	log.Println("Queued Service to be removed: ", svc.Name)
}

func (client *ClientBookKeeper) UpdateService(svc *kapi.Service) {
	if _, ok := svc.ObjectMeta.Annotations[serviceKey]; !ok {
		log.Println("Not the target, skip this Update notification for service:", svc.Name)
		return
	}

	client.RemoveService(svc)
	client.AddService(svc)
}

func (client *ClientBookKeeper) AddPod(pod *kapi.Pod) {
	client.Lock()
	defer client.Unlock()
	if _, ok := pod.Annotations[serviceKey]; !ok {
		log.Println("Not the target, skip this ADD notification for pod:", pod.Name)
		return
	}

	if _, ok := client.pods[pod.Name]; ok {
		log.Printf("Pod:%s already exist. skip this ADD notification.", pod.Name)
		return
	}

	//newly added Pod
	if pod.Name == "" || pod.Status.PodIP == "" {
		log.Printf("Pod:%s has neither name nor pod ip. skip this ADD notification.", pod.Name)
		addMap[pod.Name] = pod
		return
	}

	//Perform All DNS Adds
	client.msbQueue <- MSBWork{
		Action:      MSBWorkAddPod,
		ServiceInfo: pod.Annotations[serviceKey],
		IPAddress:   pod.Status.PodIP,
	}
	client.pods[pod.Name] = pod
	log.Println("Queued Pod to be added: ", pod.Name)
}

func (client *ClientBookKeeper) RemovePod(pod *kapi.Pod) {
	client.Lock()
	defer client.Unlock()
	if _, ok := pod.Annotations[serviceKey]; !ok {
		log.Println("Not the target, skip this Remove notification for pod:", pod.Name)
		return
	}

	if _, ok := client.pods[pod.Name]; !ok {
		log.Printf("Pod:%s not exist. skip this REMOVE notification.", pod.Name)
		return
	}
	//Perform All DNS Removes
	client.msbQueue <- MSBWork{
		Action:      MSBWorkRemovePod,
		ServiceInfo: pod.Annotations[serviceKey],
		IPAddress:   pod.Status.PodIP,
	}
	delete(client.pods, pod.Name)
	log.Println("Queued Pod to be removed: ", pod.Name)
}

func (client *ClientBookKeeper) UpdatePod(pod *kapi.Pod) {
	if _, ok := pod.Annotations[serviceKey]; !ok {
		log.Println("Not the target, skip this Update notification for pod:", pod.Name)
		return
	}

	client.RemovePod(pod)
	client.AddPod(pod)
}