From 4f1a17dea1f9a273841ec01cae2f102252f96589 Mon Sep 17 00:00:00 2001
From: Yi-Ting Shih <ytshih@it.cs.nycu.edu.tw>
Date: Thu, 16 Oct 2025 08:09:19 +0800
Subject: [PATCH] Fix: fuck udp

---
 cmd.go          |  1 -
 stages/lobby.go |  7 +------
 test.go         | 38 --------------------------------------
 utils/udp.go    | 37 ++++++++++++++++++++++++++-----------
 4 files changed, 27 insertions(+), 56 deletions(-)
 delete mode 100644 test.go

diff --git a/cmd.go b/cmd.go
index c2a8aaa..f95b04c 100644
--- a/cmd.go
+++ b/cmd.go
@@ -26,5 +26,4 @@ func init() {
 
 	RootCmd.AddCommand(authCmd)
 	RootCmd.AddCommand(playerCmd)
-	RootCmd.AddCommand(testCmd)
 }
diff --git a/stages/lobby.go b/stages/lobby.go
index 1304ada..ae42f18 100644
--- a/stages/lobby.go
+++ b/stages/lobby.go
@@ -116,12 +116,7 @@ type clientScanMsg time.Time
 
 func (m *LobbyModel) clientScan() tea.Cmd {
 	return tea.Tick(REFRESH_TIME, func(t time.Time) tea.Msg {
-		m.endpoints = []string{}
-		for _, endpoint := range viper.GetStringSlice("udp-endpoints") {
-			if err := utils.Ping(endpoint); err == nil {
-				m.endpoints = append(m.endpoints, endpoint)
-			}
-		}
+		m.endpoints, m.err = utils.Ping(viper.GetStringSlice("udp-endpoints"))
 		return clientScanMsg(t)
 	})
 }
diff --git a/test.go b/test.go
deleted file mode 100644
index 54df20c..0000000
--- a/test.go
+++ /dev/null
@@ -1,38 +0,0 @@
-package main
-
-import (
-	"gitea.konchin.com/ytshih/inp2025/utils"
-	"github.com/spf13/cobra"
-)
-
-var testCmd = &cobra.Command{
-	Use: "test",
-}
-
-var testServerCmd = &cobra.Command{
-	Use: "server",
-	Run: func(cmd *cobra.Command, args []string) {
-		dataCh := make(chan string)
-		_, shutdown, err := utils.ListenUDPData(18787, dataCh)
-		if err != nil {
-			panic(err)
-		}
-		defer shutdown()
-		<-dataCh
-	},
-}
-
-var testClientCmd = &cobra.Command{
-	Use: "client",
-	Run: func(cmd *cobra.Command, args []string) {
-		err := utils.Ping("localhost:18787")
-		if err != nil {
-			panic(err)
-		}
-	},
-}
-
-func init() {
-	testCmd.AddCommand(testServerCmd)
-	testCmd.AddCommand(testClientCmd)
-}
diff --git a/utils/udp.go b/utils/udp.go
index e33b37a..214577a 100644
--- a/utils/udp.go
+++ b/utils/udp.go
@@ -3,6 +3,7 @@ package utils
 import (
 	"fmt"
 	"net"
+	"time"
 
 	"gitea.konchin.com/ytshih/inp2025/types"
 	"github.com/vmihailenco/msgpack/v5"
@@ -11,6 +12,8 @@ import (
 const (
 	BUFFER_SIZE  int = 1024
 	MAGIC_NUMBER int = 114514
+
+	LISTEN_TIMEOUT = 200 * time.Millisecond
 )
 
 type UDPReqType int
@@ -36,24 +39,36 @@ func ListenUDPData(
 	return ListenUDP(port, dataCh, nil)
 }
 
-func Ping(endpoint string) error {
+func Ping(endpoints []string) ([]string, error) {
 	pingCh := make(chan string)
 	local, shutdown, err := ListenUDP(0, nil, pingCh)
 	if err != nil {
-		return err
+		return []string{}, err
 	}
 	defer shutdown()
 
-	err = SendRawPayload(endpoint, UDPPayload{
-		MagicNumber: MAGIC_NUMBER,
-		Endpoint:    local,
-		Type:        UDPReqTypePingRequest,
-	})
-	if err != nil {
-		return err
+	for _, endpoint := range endpoints {
+		SendRawPayload(endpoint, UDPPayload{
+			MagicNumber: MAGIC_NUMBER,
+			Endpoint:    local,
+			Type:        UDPReqTypePingRequest,
+		})
+	}
+
+	doneCh := make(chan struct{})
+	go func() {
+		time.Sleep(LISTEN_TIMEOUT)
+		doneCh <- struct{}{}
+	}()
+	ret := []string{}
+	for {
+		select {
+		case <-doneCh:
+			return ret, nil
+		case endpoint := <-pingCh:
+			ret = append(ret, endpoint)
+		}
 	}
-	<-pingCh
-	return nil
 }
 
 func ListenUDP(