package registry

import (
	"context"
	"encoding/json"
	"log"
	"memobus_relay_server/config" // 替换为你的模块名
	"memobus_relay_server/storage"
	"time"
)

// InstanceInfo 定义了要注册到 Redis 的实例信息
type InstanceInfo struct {
	InstanceID       string `json:"instanceId"`
	PublicAppAddr    string `json:"publicAppAddr"`
	PublicDeviceAddr string `json:"publicDeviceAddr"`
	// 还可以增加负载信息
	ConnectedDevices int       `json:"connectedDevices"`
	LastHeartbeat    time.Time `json:"lastHeartbeat"`
}

func StartHeartbeat(getDeviceCount func() int) {
	if storage.RedisClient == nil {
		log.Println("Registry heartbeat is disabled because Redis is not enabled.")
		return
	}

	interval := time.Duration(config.Cfg.Redis.HeartbeatIntervalSeconds) * time.Second
	ticker := time.NewTicker(interval)

	updateHeartbeat := func() {
		info := InstanceInfo{
			InstanceID:       config.Cfg.Server.InstanceID,
			PublicAppAddr:    config.Cfg.Server.PublicAppAddr,
			PublicDeviceAddr: config.Cfg.Server.PublicDeviceAddr,
			ConnectedDevices: getDeviceCount(),
			LastHeartbeat:    time.Now(),
		}
		jsonData, _ := json.Marshal(info)

		key := config.Cfg.Redis.InstanceRegistryKey
		instanceID := config.Cfg.Server.InstanceID

		if err := storage.RedisClient.HSet(context.Background(), key, instanceID, jsonData).Err(); err != nil {
			log.Printf("ERROR: Failed to send heartbeat to Redis: %v", err)
		} else {
			log.Printf("Heartbeat sent. Connected devices: %d", info.ConnectedDevices)
		}
	}

	go func() {
		updateHeartbeat() // 立即执行一次
		for range ticker.C {
			updateHeartbeat()
		}
	}()
}

func Unregister() {
	if storage.RedisClient == nil {
		return
	}
	log.Println("Unregistering instance from Redis...")
	key := config.Cfg.Redis.InstanceRegistryKey
	instanceID := config.Cfg.Server.InstanceID
	if err := storage.RedisClient.HDel(context.Background(), key, instanceID).Err(); err != nil {
		// 如果注销失败，打印一个错误日志
		log.Printf("ERROR: Failed to unregister instance '%s' from Redis: %v", instanceID, err)
	} else {
		// 只有在确认没有错误后，才打印成功日志
		log.Println("Successfully unregistered.")
	}
}