package main

import (
	"context"
	"encoding/json"
	"fmt"
	"log"
	"os"
	"os/signal"
	"syscall"
	"time"

	"go.etcd.io/etcd/v3/clientv3"
)

var endPoints = []string{
	"192.168.0.11:2379",
	//  "192.168.0.12:2379",
	//   "192.168.0.13:2379",
}

var wait = 3 * time.Second

func main() {
	log.Println("test etcd")
	cli, err := clientv3.New(clientv3.Config{
		Endpoints:   endPoints,
		DialTimeout: 5 * time.Second,
	})

	if err != nil {
		// handle error
		log.Fatalln("etcd connection error: ", err)
	}

	defer cli.Close()

	// 设置超时
	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
	_, err = cli.Put(ctx, "name", "Jaye")
	defer cancel()
	if err != nil {
		log.Println("cli.Put", err.Error())
	}

	// 取值
	ctx, cancel = context.WithTimeout(context.Background(), 5*time.Second)
	res, err := cli.Get(ctx, "/test/ok")
	if err != nil {
		log.Println("cli.Get", err.Error())
	}

	for k, v := range res.Kvs {
		fmt.Println("查询结果", k, string(v.Key), string(v.Value))
	}

	// watch
	// for {
	// 	rch := cli.Watch(context.Background(), "home")
	// 	for resp := range rch {
	// 		for k, v := range resp.Events {
	// 			fmt.Println(k, v.Type, string(v.Kv.Key), string(v.Kv.Value))
	// 		}
	// 	}
	// }

	watchConfig(cli, "config_key", &appConfig)

	//平滑重启
	ch := make(chan os.Signal, 1)
	// We'll accept graceful shutdowns when quit via SIGINT (Ctrl+C)
	// recivie signal to exit main goroutine
	// window signal
	signal.Notify(ch, syscall.SIGINT, syscall.SIGTERM, os.Interrupt, syscall.SIGHUP)

	// linux signal if you use linux on production,please use this code.
	// signal.Notify(ch, syscall.SIGINT, syscall.SIGTERM, syscall.SIGUSR2, os.Interrupt, syscall.SIGHUP)

	// Block until we receive our signal.
	sig := <-ch

	log.Println("exit signal: ", sig.String())
	// Create a deadline to wait for.
	ctx, cancel = context.WithTimeout(context.Background(), wait)
	defer cancel()

	<-ctx.Done()

	log.Println("shutting down")
}

// AppConfig 应用config
type AppConfig struct {
	AppID   string `json:"app_id"`
	AppName string `json:"app_name`
}

var appConfig AppConfig

// watchConfig 监听配置变化
func watchConfig(clt *clientv3.Client, key string, ss interface{}) {
	watchCh := clt.Watch(context.TODO(), key)
	go func() {
		for res := range watchCh {
			value := res.Events[0].Kv.Value
			if err := json.Unmarshal(value, ss); err != nil {
				fmt.Println("now", time.Now(), "watchConfig err", err)
				continue
			}
			fmt.Println("now", time.Now(), "watchConfig", ss)
		}
	}()
}