package eventmgr

import (
	"admin/lib/xlog"
	"encoding/json"
	"runtime"
)

type Msg struct {
	Event   string
	Payload []byte
}

type subscriber struct {
	name    string
	topic   string
	handler func(*Msg)
}

type Mgr struct {
	subscribers []*subscriber
	broker      chan *Msg
}

func NewMgr() *Mgr {
	mgr := &Mgr{
		subscribers: make([]*subscriber, 0),
		broker:      make(chan *Msg, 1024),
	}
	mgr.start()
	return mgr
}

func (m *Mgr) start() {
	for i := 0; i < runtime.NumCPU(); i++ {
		go func() {
			for {
				select {
				case msg := <-m.broker:
					for _, sub := range m.subscribers {
						if sub.topic == msg.Event {
							sub.handler(msg)
						}
					}
				}
			}
		}()
	}
}

func (m *Mgr) Subscribe(name string, topic string, handler func(*Msg)) {
	m.subscribers = append(m.subscribers, &subscriber{name: name, topic: topic, handler: handler})
}

func (m *Mgr) Publish(event string, payload any) {
	payloadBin, err := json.Marshal(payload)
	if err != nil {
		panic(err)
	}
	msg := &Msg{Event: event, Payload: payloadBin}
	select {
	case m.broker <- msg:
	default:
		xlog.Errorf("publish event:%v broker is full", event)
	}
}