/*
Copyright 2016 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 app implements a server that runs a set of active
// components.  This includes cluster controller

package app

import (
	"fmt"
	"net"
	"net/http"
	"net/http/pprof"
	"strconv"

	federationclientset "k8s.io/kubernetes/federation/client/clientset_generated/federation_release_1_3"
	"k8s.io/kubernetes/federation/cmd/federation-controller-manager/app/options"
	"k8s.io/kubernetes/federation/pkg/dnsprovider"
	clustercontroller "k8s.io/kubernetes/federation/pkg/federation-controller/cluster"
	servicecontroller "k8s.io/kubernetes/federation/pkg/federation-controller/service"
	"k8s.io/kubernetes/federation/pkg/federation-controller/util"
	"k8s.io/kubernetes/pkg/client/restclient"
	"k8s.io/kubernetes/pkg/client/unversioned/clientcmd"
	"k8s.io/kubernetes/pkg/healthz"
	"k8s.io/kubernetes/pkg/util/configz"
	"k8s.io/kubernetes/pkg/util/wait"
	"k8s.io/kubernetes/pkg/version"

	"github.com/golang/glog"
	"github.com/prometheus/client_golang/prometheus"
	"github.com/spf13/cobra"
	"github.com/spf13/pflag"
)

const (
	// TODO(madhusudancs): Consider making this configurable via a flag.
	// "federation-apiserver-kubeconfig" is a reserved secret name which
	// stores the kubeconfig for federation-apiserver.
	KubeconfigSecretName = "federation-apiserver-kubeconfig"
	// "federation-apiserver-secret" was the old name we used to store
	// Federation API server kubeconfig secret. Unfortunately, this name
	// is very close to "federation-apiserver-secrets" and causes a lot
	// of confusion, particularly while debugging. So deprecating it in
	// favor of the new name but giving people time to migrate.
	// TODO(madhusudancs): this name is deprecated in 1.4 and should be
	// removed in 1.5. Remove it in 1.5.
	DeprecatedKubeconfigSecretName = "federation-apiserver-secret"
)

// NewControllerManagerCommand creates a *cobra.Command object with default parameters
func NewControllerManagerCommand() *cobra.Command {
	s := options.NewCMServer()
	s.AddFlags(pflag.CommandLine)
	cmd := &cobra.Command{
		Use: "federation-controller-manager",
		Long: `The federation controller manager is a daemon that embeds
the core control loops shipped with federation. In applications of robotics and
automation, a control loop is a non-terminating loop that regulates the state of
the system. In federation, a controller is a control loop that watches the shared
state of the federation cluster through the apiserver and makes changes attempting
to move the current state towards the desired state. Examples of controllers that
ship with federation today is the cluster controller.`,
		Run: func(cmd *cobra.Command, args []string) {
		},
	}

	return cmd
}

// Run runs the CMServer.  This should never exit.
func Run(s *options.CMServer) error {
	glog.Infof("%+v", version.Get())
	if c, err := configz.New("componentconfig"); err == nil {
		c.Set(s.ControllerManagerConfiguration)
	} else {
		glog.Errorf("unable to register configz: %s", err)
	}
	// Create the config to talk to federation-apiserver.
	kubeconfigGetter := util.KubeconfigGetterForSecret(KubeconfigSecretName)
	restClientCfg, err := clientcmd.BuildConfigFromKubeconfigGetter(s.Master, kubeconfigGetter)
	if err != nil || restClientCfg == nil {
		// Retry with the deprecated name in 1.4.
		// TODO(madhusudancs): Remove this in 1.5.
		var depErr error
		kubeconfigGetter := util.KubeconfigGetterForSecret(DeprecatedKubeconfigSecretName)
		restClientCfg, depErr = clientcmd.BuildConfigFromKubeconfigGetter(s.Master, kubeconfigGetter)
		if depErr != nil {
			return fmt.Errorf("failed to find the secret containing Federation API server kubeconfig, tried the secret name %s and the deprecated name %s: %v, %v", KubeconfigSecretName, DeprecatedKubeconfigSecretName, err, depErr)
		}
	}

	// Override restClientCfg qps/burst settings from flags
	restClientCfg.QPS = s.APIServerQPS
	restClientCfg.Burst = s.APIServerBurst

	go func() {
		mux := http.NewServeMux()
		healthz.InstallHandler(mux)
		if s.EnableProfiling {
			mux.HandleFunc("/debug/pprof/", pprof.Index)
			mux.HandleFunc("/debug/pprof/profile", pprof.Profile)
			mux.HandleFunc("/debug/pprof/symbol", pprof.Symbol)
		}
		mux.Handle("/metrics", prometheus.Handler())

		server := &http.Server{
			Addr:    net.JoinHostPort(s.Address, strconv.Itoa(s.Port)),
			Handler: mux,
		}
		glog.Fatal(server.ListenAndServe())
	}()

	run := func() {
		err := StartControllers(s, restClientCfg)
		glog.Fatalf("error running controllers: %v", err)
		panic("unreachable")
	}
	run()
	panic("unreachable")
}

func StartControllers(s *options.CMServer, restClientCfg *restclient.Config) error {
	ccClientset := federationclientset.NewForConfigOrDie(restclient.AddUserAgent(restClientCfg, "cluster-controller"))
	go clustercontroller.NewclusterController(ccClientset, s.ClusterMonitorPeriod.Duration).Run()
	dns, err := dnsprovider.InitDnsProvider(s.DnsProvider, s.DnsConfigFile)
	if err != nil {
		glog.Fatalf("Cloud provider could not be initialized: %v", err)
	}
	scClientset := federationclientset.NewForConfigOrDie(restclient.AddUserAgent(restClientCfg, servicecontroller.UserAgentName))
	servicecontroller := servicecontroller.New(scClientset, dns, s.FederationName, s.ZoneName)
	if err := servicecontroller.Run(s.ConcurrentServiceSyncs, wait.NeverStop); err != nil {
		glog.Errorf("Failed to start service controller: %v", err)
	}
	select {}
}