package main

import (
	"context"
	"flag"
	"fmt"
	"log"
	"path/filepath"

	corev1 "k8s.io/api/core/v1"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/watch"
	"k8s.io/client-go/kubernetes"
	"k8s.io/client-go/tools/clientcmd"
	"k8s.io/client-go/util/homedir"
)

func main() {
	var kubeconfig string

	flag.StringVar(&kubeconfig, "kubeconfig", filepath.Join(homedir.HomeDir(), ".kube", "config"), "(optional) absolute path to the kubeconfig file")
	flag.Parse()
	// use the current context in kubeconfig
	config, err := clientcmd.BuildConfigFromFlags("", kubeconfig)
	if err != nil {
		log.Fatal(err)
	}

	ctx := context.Background()
	// 创建 clientset
	clientset, err := kubernetes.NewForConfig(config)
	if err != nil {
		log.Fatal(err)
	}
	// 使用 clientsent 监听 kube-system 下 Pod 对象
	list, err := clientset.CoreV1().Pods("kube-system").
		Watch(ctx, metav1.ListOptions{Watch: true})
	if err != nil {
		log.Fatal(err)
	}
	for event := range list.ResultChan() {
		pod := event.Object.(*corev1.Pod)
		switch event.Type {
		case watch.Added:
			fmt.Printf("Pod %s added\n", pod.Name)
			// todo: reconcile logic goes here
		case watch.Modified:
			fmt.Printf("Pod %s modified\n", pod.Name)
			// todo: reconcile logic goes here
		case watch.Deleted:
			fmt.Printf("Pod %s deleted\n", pod.Name)
			// todo: reconcile logic goes here
		}
	}
}