package stat

import (
	"container/list"
	"fmt"
	"github.com/TransX/log"
	"sync"
)

type TunnelStatusManager struct {
	mux        sync.Mutex
	tunnelList *list.List
	regChan    chan interface{}
	unregChan  chan interface{}
}

func NewTunnelStatusManager() *TunnelStatusManager {
	t := new(TunnelStatusManager)
	t.regChan = make(chan interface{})
	t.unregChan = make(chan interface{})
	t.tunnelList = new(list.List)
	go t.chanListener()
	return t
}

func (this *TunnelStatusManager) GetRegChan() chan interface{} {
	return this.regChan
}

func (this *TunnelStatusManager) GetUnregChan() chan interface{} {
	return this.unregChan
}

func (this *TunnelStatusManager) register(t interface{}) {
	this.mux.Lock()
	defer this.mux.Unlock()
	this.tunnelList.PushBack(t)
}

func (this *TunnelStatusManager) unregister(t interface{}) {
	this.mux.Lock()
	defer this.mux.Unlock()
	l := this.tunnelList
	// log.Debug("%d tunnels before remove.", this.tunnelList.Len())
	nl := new(list.List)
	for e := l.Front(); e != nil; e = e.Next() {
		if e.Value != t {
			nl.PushBack(e.Value)
		}

	}
	this.tunnelList = nl
	// log.Debug("%d tunnels after remove.", this.tunnelList.Len())

}

func (this *TunnelStatusManager) chanListener() {
	for {
		select {
		case r := <-this.regChan:
			this.register(r)
			log.Debug(this.QueryStatString())
		case ur := <-this.unregChan:
			this.unregister(ur)
		}
	}
}

func (this *TunnelStatusManager) QueryStatString() string {
	this.mux.Lock()
	defer this.mux.Unlock()
	return fmt.Sprintf("There %d tunnels running.\n", this.tunnelList.Len())
}