From 6e4113a45ce0710bae1ffd6e660fcdfab5097fe6 Mon Sep 17 00:00:00 2001
From: vaporvee <yannik@vaporvee.com>
Date: Wed, 17 Apr 2024 18:14:17 +0200
Subject: [PATCH] improved udp server

---
 server/main.go | 32 ++++++++++++++++++++++++++------
 1 file changed, 26 insertions(+), 6 deletions(-)

diff --git a/server/main.go b/server/main.go
index eb110ea..3d08098 100644
--- a/server/main.go
+++ b/server/main.go
@@ -8,6 +8,7 @@ import (
 	"io"
 	"net"
 	"os"
+	"time"
 
 	"github.com/joho/godotenv"
 )
@@ -54,7 +55,8 @@ func main() {
 	fmt.Println("Server running on " + port)
 
 	buf := make([]byte, 1024)
-	clients := make(map[string]string) // Map to keep track of clients and their session IDs
+	clients := make(map[string]string)           // Map to keep track of clients and their session IDs
+	clientLastSeen := make(map[string]time.Time) // Map to track the last seen time of each client
 
 	for {
 		n, addr, err := conn.ReadFromUDP(buf)
@@ -73,34 +75,51 @@ func main() {
 		// Use the client's IP and port as the key to uniquely identify the connection
 		key := addr.String()
 
+		// Update the last seen time for the client
+		clientLastSeen[key] = time.Now()
+
 		// Check if the client's connection already has a session ID
 		if _, ok := clients[key]; !ok {
 			// The client is new, generate a session ID
 			sessionID := generateSessionID()
 			clients[key] = sessionID
 			// Send the session ID back to the client
-			responsePayload := Payload{SessionID: sessionID}
+			responsePayload := Payload{Type: "init_success", SessionID: sessionID}
 			response, _ := json.Marshal(responsePayload)
 			conn.WriteToUDP(response, addr)
 		}
 
 		switch payload.Type {
 		case "init":
-			fmt.Printf("Received initiation generated SessionID: %s", clients[key])
+			fmt.Printf("Received initiation generated SessionID: %s\n", clients[key])
 		case "move":
 			fmt.Printf("Received move message from Session ID: %s : X=%d, Y=%d\n", clients[key], payload.Direction.X, payload.Direction.Y)
 			// Handle movement logic here
+		case "disconnect":
+			// Disconnect the client
+			delete(clients, key)
+			delete(clientLastSeen, key)
+			fmt.Printf("Client %s disconnected\n", clients[key])
 		case "message":
 			fmt.Printf("Received message from Session ID: %s : %s\n", clients[key], payload.Message)
 			broadcastMessage(conn, clients, payload.Message)
 		default:
 			fmt.Printf("Received unknown message type Session ID: %s\n", clients[key])
 		}
+
+		// Check for disconnected clients and reset their session ID
+		for clientKey, lastSeen := range clientLastSeen {
+			if time.Since(lastSeen) > 5*time.Minute { // 5 minutes timeout
+				delete(clients, clientKey)
+				delete(clientLastSeen, clientKey)
+				fmt.Printf("Client %s disconnected and session ID reset\n", clients[clientKey])
+			}
+		}
 	}
 }
 
 func broadcastMessage(conn *net.UDPConn, clients map[string]string, message string) {
-	for clientKey := range clients {
+	for clientKey, sessionID := range clients {
 		// Parse the clientKey to get the *net.UDPAddr
 		clientAddr, err := net.ResolveUDPAddr("udp", clientKey)
 		if err != nil {
@@ -108,8 +127,9 @@ func broadcastMessage(conn *net.UDPConn, clients map[string]string, message stri
 			continue
 		}
 		payload := Payload{
-			Type:    "message",
-			Message: message,
+			Type:      "message",
+			Message:   message,
+			SessionID: sessionID,
 		}
 		response, _ := json.Marshal(payload)
 		conn.WriteToUDP(response, clientAddr)