add viewing user profile.

src/main/java/org/to/telegramfinalproject/Server/ClientHandler.java

@@ -1707,8 +1707,20 @@ public class ClientHandler implements Runnable {
 //                        break;
 //                    }
 //
+                    case "get_user_profile": {
+                        // Get the current user's user_id
+                        String user_id = this.currentUser.getUser_id();
 
+                        // Get the profile JSON from SidebarService
+                        JSONObject data = SidebarService.getUserProfile(user_id);
 
+                        if (data == null) {
+                            response = new ResponseModel("error", "Failed to retrieve user profile.");
+                        } else {
+                            response = new ResponseModel("success", "User profile retrieved successfully.", data);
+                        }
+                        break;
+                    }
 
                     default:
                         response = new ResponseModel("error", "Unknown action: " + action);

src/main/java/org/to/telegramfinalproject/Server/SidebarService.java

@@ -0,0 +1,57 @@
+package org.to.telegramfinalproject.Server;
+
+import org.json.JSONObject;
+import org.to.telegramfinalproject.Database.userDatabase;
+import org.to.telegramfinalproject.Models.User;
+
+public class SidebarService {
+    private static userDatabase userDB = new userDatabase();
+
+    // Returns current user's profile data (name, bio, status, etc.)
+    public static JSONObject getUserProfile(String userId) {
+        User user = userDB.findByUserId(userId);
+
+        if (user == null) {
+            return null;
+        }
+
+        JSONObject profile = new JSONObject();
+        profile.put("user_id", user.getUser_id());
+        profile.put("profile_name", user.getProfile_name());
+        profile.put("bio", user.getBio() != null ? user.getBio() : "");
+        profile.put("status", "ONLINE");
+        profile.put("profile_picture_url", user.getImage_url());
+
+        return profile;
+    }
+
+    // Updates one or more profile fields for the user
+    public static JSONObject updateUserProfile(String userId, JSONObject updateData) {
+        return null;
+    }
+
+    // Changes the user's profile picture
+    public static JSONObject changeProfilePicture(String userId, byte[] imageData) {
+        return null;
+    }
+
+    // Changes user-id
+    public static JSONObject updateUserId(String userId, String newUserId) {
+        return null;
+    }
+
+    // (Optional) Changes username
+    public static JSONObject updateUserName(String userId, String newUserName) {
+        return null;
+    }
+
+    // Changes user's profile name
+    public static JSONObject updateProfileName(String userId, String newProfileName) {
+        return null;
+    }
+
+    // Changes or sets the user's date of birth
+    public static JSONObject updateDateOfBirth(String userId, String newDateOfBirth) {
+        return null;
+    }
+}