From f14b18142f6e6989e5119fccdc3033fa1d07def3 Mon Sep 17 00:00:00 2001
From: Robert <Robert@TryingToScale.com>
Date: Sat, 8 Feb 2025 21:41:49 -0500
Subject: [PATCH] @USER tagged private messages

---
 chat_server.go | 46 ++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 42 insertions(+), 4 deletions(-)

diff --git a/chat_server.go b/chat_server.go
index 0047b2b..7fbea18 100644
--- a/chat_server.go
+++ b/chat_server.go
@@ -10,7 +10,7 @@ import (
 	"net"
 	"sync"
 	"time"
-
+	"strings"
 	"gopkg.in/yaml.v2"
 	"os"
 	"github.com/yang3yen/xxtea-go/xxtea"
@@ -93,6 +93,16 @@ func (um *UserManagerTCP) GetUserListTCP() string {
 	}
 	return userList
 }
+func (um *UserManagerTCP) UserMatchTCP(user string, encrypted []byte, sender net.Conn) {
+	um.mutex.Lock()
+	defer um.mutex.Unlock()
+	for clientCon, client := range um.clients {
+		if user == client.username {
+			clientCon.Write(encrypted)
+		}
+	}
+}
+
 func (um *UserManagerUDP) GetUserListUDP() string {
 	um.mutex.Lock()
 	defer um.mutex.Unlock()
@@ -253,6 +263,20 @@ func sayServer(text string) ([]byte, error) {
 	return encrypted, nil
 }
 
+func parseInput(input string) (username string, message string) {
+	// Check if the input starts with '@'
+	if strings.HasPrefix(input, "@") {
+		// Trim the '@' and split by spaces
+		parts := strings.SplitN(input[1:], " ", 2)
+		username = parts[0]
+		if len(parts) > 1 {
+			message = parts[1]
+			return username, message
+		}
+	}
+	return "", ""
+}
+
 func handleTCPClient(conn net.Conn) {
 	defer conn.Close()
 
@@ -296,9 +320,14 @@ func handleTCPClient(conn net.Conn) {
 			// Handle the 'users' command
 			userList := userManagerTCP.GetUserListTCP()
 			sayTCP(conn, "User's Online: "+userList)
-		} else {
-			// Broadcast the message to all other clients
-			broadcastTCP(decrypted, conn)
+		} else {			
+			privateUser, text := parseInput(message)
+			if privateUser != "" && text != "" {
+				privateTCP(privateUser, decrypted, conn)
+			} else {
+				// Broadcast the message to all other clients
+				broadcastTCP(decrypted, conn)
+			}
 		}
 	}
 
@@ -382,6 +411,15 @@ func startUDPServer() error {
 	}
 }
 
+func privateTCP(user string, data []byte, sender net.Conn) {
+	encrypted, err := encryptor.Encrypt(data)
+	if err != nil {
+		fmt.Printf("Encryption error: %v\n", err)
+		return
+	}
+	userManagerTCP.UserMatchTCP(user, encrypted, sender)
+}
+
 func broadcastTCP(data []byte, sender net.Conn) {
 	encrypted, err := encryptor.Encrypt(data)
 	if err != nil {