package service

import (
	"context"
	"fmt"
	"github.com/grandcat/zeroconf"
	"time"
	"work_cation/cfg"
	"work_cation/models"
)

type zeroconfService struct {
	server *zeroconf.Server
}

var Zeroconf = &zeroconfService{}

// Register 注册被发现服务
func (s *zeroconfService) Register(user *models.Users) error {
	if s.server != nil {
		return nil // already registered
	}
	server, err := zeroconf.Register(cfg.T.ZeroconfKey, "_http._tcp",
		"local.", cfg.T.ZeroconfPort, models.UserTOnlineList(user), nil)
	if err != nil {
		return err
	}
	s.server = server
	return nil
}

func (s *zeroconfService) Close() {
	if s.server != nil {
		s.server.Shutdown()
		s.server = nil
	}
}

// FindService 查找被发现服务
func (s *zeroconfService) FindService() (chan *models.Online, error) {
	resolver, err := zeroconf.NewResolver(nil)
	if err != nil {
		return nil, err
	}
	allEntries := make(chan *zeroconf.ServiceEntry)
	useEntries := make(chan *models.Online)

	go func(results <-chan *zeroconf.ServiceEntry) {
		for entry := range results {
			if entry.ServiceInstanceName() == fmt.Sprintf("%s._http._tcp.local.", cfg.T.ZeroconfKey) {
				//fmt.Printf("发现服务: %s \nIP:%s:%d \nInfo: %v\n", entry.ServiceInstanceName(), entry.AddrIPv4, entry.Port, entry.Text)
				online, err := models.NewOnline(entry)
				if err != nil {
					continue
				}
				useEntries <- online
			}
		}
	}(allEntries)
	ctx, cancel := context.WithCancel(context.Background())
	err = resolver.Browse(ctx, "_http._tcp", "local.", allEntries)
	if err != nil {
		cancel()
		return nil, err
	}
	time.AfterFunc(10*time.Second, cancel)
	return useEntries, nil
}