package ws

import (
	"sync"

	"github.com/wonli/aqi/logger"
)

type PubSub struct {
	Topics        *sync.Map      //Topics map[string]*Topic //主题名称和Top对应map
	TopicMsgQueue chan *TopicMsg //主题消息队列
}

func NewPubSub() *PubSub {
	return &PubSub{
		Topics:        new(sync.Map),
		TopicMsgQueue: make(chan *TopicMsg, 128),
	}
}

func (a *PubSub) initTopic(topicId string) *Topic {
	//主题不存在时先创建主题
	topic, ok := a.Topics.Load(topicId)
	if !ok {
		t := &Topic{
			Id:          topicId,
			PubSub:      a,
			SubUsers:    sync.Map{},
			SubHandlers: sync.Map{},
		}

		a.Topics.Store(topicId, t)
		return t
	}

	return topic.(*Topic)
}

// Pub 发布主题
func (a *PubSub) Pub(topicId string, data any) {
	msg := Action{
		Action: "subscriber",
		Data: H{
			"topicId": topicId,
			"message": data,
		},
	}

	//主题不存在时先创建主题
	a.initTopic(topicId)
	a.TopicMsgQueue <- &TopicMsg{
		Ori:     data,
		TopicId: topicId,
		Msg:     msg.Encode(),
	}
}

// Sub 订阅主题
func (a *PubSub) Sub(topicId string, user *User) {
	a.initTopic(topicId).AddSubUser(user)
}

// SubFunc 以函数方式订阅
func (a *PubSub) SubFunc(topicId string, f func(msg *TopicMsg)) {
	a.initTopic(topicId).AddSubHandle(f)
}

func (a *PubSub) Start() {
	for {
		select {
		case msg, ok := <-a.TopicMsgQueue:
			if !ok {
				logger.SugarLog.Info("从订阅主题队列取数据失败")
				continue
			}

			t, hasTopic := a.Topics.Load(msg.TopicId)
			if !hasTopic {
				logger.SugarLog.Info("未发布订阅主题收到消息")
				continue
			}

			//订阅消息的函数处理
			t.(*Topic).ApplyFunc(msg)

			//订阅消息的用户处理
			t.(*Topic).SendToSubUser(msg.Msg)
		}
	}
}