/*
Copyright 2014 The Kubernetes Authors All rights reserved.

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 cluster

import (
	"net"
	"strings"

	federation_v1alpha1 "k8s.io/kubernetes/federation/apis/federation/v1alpha1"
	"k8s.io/kubernetes/pkg/api/unversioned"
	"k8s.io/kubernetes/pkg/api/v1"
	"k8s.io/kubernetes/pkg/client/restclient"
	"k8s.io/kubernetes/pkg/client/typed/discovery"
	"k8s.io/kubernetes/pkg/client/unversioned/clientcmd"
	utilnet "k8s.io/kubernetes/pkg/util/net"
)

const (
	UserAgentName = "Cluster-Controller"
	KubeAPIQPS    = 20.0
	KubeAPIBurst  = 30
)

type ClusterClient struct {
	discoveryClient *discovery.DiscoveryClient
}

func NewClusterClientSet(c *federation_v1alpha1.Cluster) (*ClusterClient, error) {
	var serverAddress string
	hostIP, err := utilnet.ChooseHostInterface()
	if err != nil {
		return nil, err
	}

	for _, item := range c.Spec.ServerAddressByClientCIDRs {
		_, cidrnet, err := net.ParseCIDR(item.ClientCIDR)
		if err != nil {
			return nil, err
		}
		myaddr := net.ParseIP(hostIP.String())
		if cidrnet.Contains(myaddr) == true {
			serverAddress = item.ServerAddress
			break
		}
	}
	var clusterClientSet = ClusterClient{}
	if serverAddress != "" {
		clusterConfig, err := clientcmd.BuildConfigFromFlags(serverAddress, "")
		if err != nil {
			return nil, err
		}
		clusterConfig.QPS = KubeAPIQPS
		clusterConfig.Burst = KubeAPIBurst
		clusterClientSet.discoveryClient = discovery.NewDiscoveryClientForConfigOrDie((restclient.AddUserAgent(clusterConfig, UserAgentName)))
		if clusterClientSet.discoveryClient == nil {
			return nil, nil
		}
	}
	return &clusterClientSet, err
}

// GetClusterHealthStatus gets the kubernetes cluster health status by requesting "/healthz"
func (self *ClusterClient) GetClusterHealthStatus() *federation_v1alpha1.ClusterStatus {
	clusterStatus := federation_v1alpha1.ClusterStatus{}
	currentTime := unversioned.Now()
	newClusterReadyCondition := federation_v1alpha1.ClusterCondition{
		Type:               federation_v1alpha1.ClusterReady,
		Status:             v1.ConditionTrue,
		Reason:             "ClusterReady",
		Message:            "/healthz responded with ok",
		LastProbeTime:      currentTime,
		LastTransitionTime: currentTime,
	}
	newClusterNotReadyCondition := federation_v1alpha1.ClusterCondition{
		Type:               federation_v1alpha1.ClusterReady,
		Status:             v1.ConditionFalse,
		Reason:             "ClusterNotReady",
		Message:            "/healthz responded without ok",
		LastProbeTime:      currentTime,
		LastTransitionTime: currentTime,
	}
	newNodeOfflineCondition := federation_v1alpha1.ClusterCondition{
		Type:               federation_v1alpha1.ClusterOffline,
		Status:             v1.ConditionTrue,
		Reason:             "ClusterNotReachable",
		Message:            "cluster is not reachable",
		LastProbeTime:      currentTime,
		LastTransitionTime: currentTime,
	}
	newNodeNotOfflineCondition := federation_v1alpha1.ClusterCondition{
		Type:               federation_v1alpha1.ClusterOffline,
		Status:             v1.ConditionFalse,
		Reason:             "ClusterReachable",
		Message:            "cluster is reachable",
		LastProbeTime:      currentTime,
		LastTransitionTime: currentTime,
	}
	body, err := self.discoveryClient.Get().AbsPath("/healthz").Do().Raw()
	if err != nil {
		clusterStatus.Conditions = append(clusterStatus.Conditions, newNodeOfflineCondition)
	} else {
		if !strings.EqualFold(string(body), "ok") {
			clusterStatus.Conditions = append(clusterStatus.Conditions, newClusterNotReadyCondition, newNodeNotOfflineCondition)
		} else {
			clusterStatus.Conditions = append(clusterStatus.Conditions, newClusterReadyCondition)
		}
	}
	return &clusterStatus
}