update clientSession class

src/main/java/com/university/chat/Server/ClientSession.java

@@ -84,13 +84,24 @@ public class ClientSession implements Runnable {
     private void handleChatMessage(ChatMessage msg) throws IOException {
         switch (msg.getType()) {
             case PUBLIC_MESSAGE -> {
-                // TODO: Broadcast this message to every connected client.
+
+                for (ClientSession session: userManager.getAllSessions()) {
+                    session.sendMessage(msg);
+                }
             }
             case PRIVATE_MESSAGE -> {
-                // TODO: Forward this message to the receiver user.
+
+                ClientSession receiver = userManager.getUser(msg.getSender());
+                if (receiver != null) {
+                    receiver.sendMessage(msg);
+                }
+                else {
+                    sendMessage(new ChatMessage(MessageType.PUBLIC_MESSAGE, "Server", username, "User '" + msg.getReceiver() + "' is not online."));
+                }
             }
             case USER_LIST -> {
-                // TODO: Reply to the requester with the list of online users.
+
+                sendMessage(new ChatMessage(MessageType.USER_LIST, "Server", username, userManager.listUsers()));
             }
         }
     }
@@ -103,6 +114,15 @@ public class ClientSession implements Runnable {
         Files.write(sentPath, fileMsg.getData());
         Files.write(recvPath, fileMsg.getData());
 
-        // TODO: Forward the received file-message to the destination user.
+        ClientSession receiver = userManager.getUser(fileMsg.getReceiver());
+        if (receiver != null) {
+            receiver.sendMessage(fileMsg);
+        } else {
+            sendMessage(new ChatMessage(
+                    MessageType.PUBLIC_MESSAGE,
+                    "Server", username,
+                    "User '" + fileMsg.getReceiver() + "' is not online. File saved on server."
+            ));
+        }
     }
 }