package service

import (
	"encoding/json"
	"github.com/fox/fox/etcd"
	"github.com/fox/fox/ipb"
	"github.com/fox/fox/log"
	"github.com/fox/fox/nat"
	"github.com/fox/fox/processor"
	"github.com/golang/protobuf/proto"
	"github.com/nats-io/nats.go"
	"os"
	"sync"
)

const (
	updateTopic = "update.service.topic"
)

// 初始化服务所需要的参数
type InitNatsServiceParams struct {
	EtcdAddress  []string
	EtcdUsername string
	EtcdPassword string
	NatsAddress  []string
	ServiceType  string  // 本服务的服务类型
	ServiceName  string  // 本服务的服务名，唯一索引
	OnFunc       IOnFunc // 包含初始化，停止，服务的消息处理
	TypeId       int     // 与ServiceType一一对应
	Version      string
}

type NatsService struct {
	*BaseService
	nats         *nat.Nats
	registry     *etcd.Registry[etcd.ServiceNode]
	rpcProcessor *processor.Processor
	node         etcd.ServiceNode // 本服务节点信息
}

func NewNatsService(param *InitNatsServiceParams) (*NatsService, error) {
	var err error
	s := new(NatsService)
	s.BaseService = NewBaseService(param.ServiceType, param.ServiceName, param.OnFunc, s)
	if s.registry, err = etcd.NewRegistry[etcd.ServiceNode](param.EtcdAddress, param.EtcdUsername, param.EtcdPassword); err != nil {
		return nil, err
	}
	s.node = etcd.ServiceNode{
		TypeId:  param.TypeId,
		Name:    s.Name(),
		Type:    s.Type(),
		Version: param.Version,
	}
	if err = s.registry.Register(s.node); err != nil {
		return nil, err
	}
	s.registry.WatchServices()

	s.nats = nat.NewNats(param.ServiceName, param.NatsAddress...)
	if err = s.nats.Connect(); err != nil {
		s.registry.UnregisterService()
		return nil, err
	}
	// 订阅本服务名的topic
	if err = s.Subscribe(Topic(s)); err != nil {
		log.Error(err.Error())
	}
	// 订阅广播服务上线
	_ = s.subscribeUpdateService()
	s.publishUpdateService()

	// 订阅rpc回调
	_ = s.subscribeRpc()
	return s, nil
}

func (n *NatsService) publishUpdateService() {
	jsonData, _ := json.Marshal(n.node)
	_ = n.nats.Publish(updateTopic, jsonData)
}

func (n *NatsService) subscribeUpdateService() error {
	return n.SubscribeCb(updateTopic, func(m *nats.Msg) {
		var node = &etcd.ServiceNode{}
		_ = json.Unmarshal(m.Data, node)
		// 不是同类服务不处理，是自己发出来的更新，也不处理
		if node.Type != n.Type() || node.Name == n.Name() {
			return
		}
		// 有新服务上线，本服务准备退出
		if n.node.Version < node.Version {
			n.NotifyStop()
			n.WaitStop()
			log.InfoF("%v auto exit, initiating shutdown...", n.Name())
			os.Exit(0)
		}
	})
}

func (n *NatsService) subscribeRpc() error {
	return n.SubscribeCb(RpcTopic(n), func(m *nats.Msg) {
		var iMsg = &ipb.InternalMsg{}
		_ = proto.Unmarshal(m.Data, iMsg)
		_ = n.rpcProcessor.Dispatch(iMsg.RetRpcMsgId, iMsg)
	})
}

// 订阅回调
func (n *NatsService) SubscribeCb(topic string, cb func(m *nats.Msg)) error {
	return n.nats.SubscribeCb(topic, func(m *nats.Msg) {
		n.RunOnce(func() {
			cb(m)
		})
	})
}

func (n *NatsService) Subscribe(topic string) error {
	return n.nats.Subscribe(topic, n.msg)
}

// 队列订阅，队列中只会有一个消费者消费该消息
func (n *NatsService) QueueSubscribe(topic string, queue string) error {
	return n.nats.QueueSubscribe(topic, queue, n.msg)
}

func (s *NatsService) OnStop() {
	s.nats.Close()
}

func (s *NatsService) Send(topic string, msg *ipb.InternalMsg) error {
	data, _ := proto.Marshal(msg)
	return s.nats.Publish(topic, data)
}

func (s *NatsService) Call(rpcTopic string, msg *ipb.InternalMsg, cb func(msg *ipb.InternalMsg)) error {
	data, _ := proto.Marshal(ipb.MakeRpcMsg(msg.ServiceName, msg.ConnId, msg.UserId, msg.MsgId, msg.Msg))
	err := s.nats.Publish(rpcTopic, data)
	if err != nil {
		return err
	}
	s.rpcProcessor.RegisterMessage(msg.RetRpcMsgId, ipb.InternalMsg{}, cb)
	return nil
}

func (s *NatsService) ServiceEtcd() *etcd.Registry[etcd.ServiceNode] {
	return s.registry
}

// 从etcd中获取所有服务节点
func (s *NatsService) GetServiceNodes() *sync.Map {
	return s.registry.GetNodes()
}

// 查找指定的服务节点信息
func (s *NatsService) FindServiceNode(serviceName string) (etcd.ServiceNode, error) {
	return s.registry.FindNode(serviceName)
}