src/main/java/com/university/chat/Client/ServerListener.java

@@ -1,18 +1,38 @@
 package com.university.chat.Client;
 
+import com.university.chat.Common.ChatMessage;
+import com.university.chat.Common.FileMessage;
+
+import java.io.ObjectInputStream;
+
 public class ServerListener implements Runnable{
     // TODO: store the ObjectInputStream from the user socket
     //          (this should be the same input stream the
     //           chatClient created when connecting)
+    private ObjectInputStream inputStream;
+
+    public ServerListener(ObjectInputStream inputStream) {
+        this.inputStream = inputStream;
+    }
 
     @Override
     public void run() {
         try {
-            // TODO: In an infinite loop read objects from the server
+            // In an infinite loop read objects from the server
             //   - if it's a ChatMessage  -> print "<sender>: <content>"
             //   - if it's a FileMessage  -> print that a file was received
             //                               (filename + sender), it's already
             //                               saved to disk by the server.
+            while (true) {
+                Object object = inputStream.readObject();
+
+                if(object instanceof ChatMessage) {
+                    System.out.println(((ChatMessage) object).getSender() + ": " + ((ChatMessage) object).getContent());
+                }
+                else if(object instanceof FileMessage) {
+                    System.out.println("File received: " + ((FileMessage) object).getFilename() + " from " + ((FileMessage) object).getSender());
+                }
+            }
         } catch (Exception e){
             System.out.println("Disconnected from server" );
         }

src/main/java/com/university/chat/Client/chatClient.java

@@ -1,8 +1,19 @@
 package com.university.chat.Client;
 
+import com.university.chat.Common.ChatMessage;
+import com.university.chat.Common.FileMessage;
+import com.university.chat.Common.MessageType;
+
+import java.io.*;
+import java.net.*;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.Scanner;
+
 public class chatClient {
-    public static void main() {
+    public static void main() throws IOException {
-        // TODO: Connecting to the server
+        // Connecting to the server
         //  1. Create a socket and connect to the server
         //  2. Create an ObjectOutputStream (out) and ObjectInputStream (in)
         //      from the socket's streams — output FIRST, then input.
@@ -10,9 +21,25 @@ public class chatClient {
         //  3. Start a new Thread running a ServerListener(in) so incoming
         //      messages are handled concurrently.
 
+        Socket socket = new Socket("127.0.0.1", 5000);
+        ObjectOutputStream out = new ObjectOutputStream(socket.getOutputStream());
+        ObjectInputStream in = new ObjectInputStream(socket.getInputStream());
+
+        Scanner input = new Scanner(System.in);
+        System.out.println("Enter your username: ");
+        String username = input.nextLine();
+
+        ChatMessage chatMessage = new ChatMessage(MessageType.LOGIN, username, null, "");
+        out.writeObject(chatMessage);
+        out.flush();
+
+        Thread thread = new Thread(new ServerListener(in));
+        thread.start();
+
+
         while (true){
             try {
-                // TODO: Program loop — read a line from the console and act on it:
+                //Program loop — read a line from the console and act on it:
                 //   - "/msg <user> <text>"        -> build & send a PRIVATE_MESSAGE
                 //   - "/users"                    -> build & send a USER_LIST request
                 //   - "/sendfile <user> <path>"   -> read the file into a byte[]
@@ -21,6 +48,38 @@ public class chatClient {
                 //                                     and send it as a FileMessage
                 //   - anything else               -> send a PUBLIC_MESSAGE
                 //   Remember to flush() the output stream after writeObject().
+
+                String line = input.nextLine();
+                if(line.equals("/users")) {
+                    chatMessage = new ChatMessage(MessageType.USER_LIST, username, null, null);
+                    out.writeObject(chatMessage);
+                    out.flush();
+                }
+                else if(line.startsWith("/msg")) {
+                    String[] parts = line.split(" ", 3);
+                    chatMessage = new ChatMessage(MessageType.PRIVATE_MESSAGE,
+                            username, parts[1], parts[2]);
+                    out.writeObject(chatMessage);
+                    out.flush();
+                }
+                else if(line.startsWith("/sendfile")) {
+                    String[] parts = line.split(" ", 3);
+                    String receiver = parts[1];
+                    String path = parts[2];
+
+                    Path filePath = Paths.get(path);
+                    byte[] data = Files.readAllBytes(filePath);
+                    FileMessage fileMessage = new FileMessage(username, receiver, filePath.getFileName().toString(), data);
+
+                    out.writeObject(fileMessage);
+                    out.flush();
+                }
+                else {
+                    chatMessage = new ChatMessage(MessageType.PUBLIC_MESSAGE, username, null, line);
+                    out.writeObject(chatMessage);
+                    out.flush();
+                }
+
             } catch (Exception e){
                 System.out.println("command failed: " + e.getMessage());
             }

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

@@ -1,15 +1,28 @@
 package com.university.chat.Server;
 
+import java.io.IOException;
+import java.net.*;
+
 public class ChatServer {
-    // TODO: declare a single shared UserManager instance (static final)
+    // declare a single shared UserManager instance (static final)
     //         This MUST be shared by all ClientSession threads so that
     //         broadcasting and private messaging work correctly.
 
-    public static void main(String[] args) {
+    static final UserManager userManager = new UserManager();
-        // TODO: Create a ServerSocket
 
-        // TODO: In an infinite loop:
+    public static void main(String[] args) throws IOException {
+        // Create a ServerSocket
+        ServerSocket serverSocket = new ServerSocket(5000);
+
+        // In an infinite loop:
         //  accept an incoming client connection
         //  make a new thread running ClientSession for each user.
+        while (true) {
+            Socket socket = serverSocket.accept();
+            System.out.println("New client accepted");
+            ClientSession clientSession = new ClientSession(socket, userManager);
+            Thread thread = new Thread(clientSession);
+            thread.start();
+        }
     }
 }

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

@@ -2,25 +2,35 @@ package com.university.chat.Server;
 
 import com.university.chat.Common.ChatMessage;
 import com.university.chat.Common.FileMessage;
+import com.university.chat.Common.MessageType;
 
-import java.io.IOException;
+import java.io.*;
 import java.net.Socket;
 import java.nio.file.Files;
 
 public class ClientSession implements Runnable {
 
     private String username;
+    UserManager userManager = null;
+    Socket socket = null;
+    ObjectOutputStream outputStream = null;
+    ObjectInputStream inputStream = null;
 
-    public ClientSession(Socket socket, UserManager userManager) {
+    public ClientSession(Socket socket, UserManager userManager) throws IOException {
-        // TODO : Create an ObjectOutputStream from socket.getOutputStream()
+        // Create an ObjectOutputStream from socket.getOutputStream()
         //         and an ObjectInputStream from socket.getInputStream().
+        this.userManager = userManager;
+        this.socket = socket;
+        outputStream = new ObjectOutputStream(socket.getOutputStream());
+        outputStream.flush();
+        inputStream = new ObjectInputStream(socket.getInputStream());
     }
 
     @Override
     public void run() {
         try {
 
-            // TODO: Welcome the user (login step)
+            //  Welcome the user (login step)
             //  1. Read the first object sent by the client.
             //  2. Check it's a ChatMessage with type LOGIN.
             //  3. Extract the username.
@@ -29,17 +39,50 @@ public class ClientSession implements Runnable {
             //  6. Otherwise, create the user's folders with FileManager.createUserFolders(...)
             //      and send back LOGIN_SUCCESS.
 
-            // TODO: Main message loop
+            Object object = inputStream.readObject();
+
+            if(object instanceof ChatMessage) {
+                ChatMessage chatMessage = (ChatMessage) object;
+
+                if(chatMessage.getType().equals(MessageType.LOGIN)) {
+                    username = chatMessage.getSender();
+
+                    if (userManager.addUser(username, this)) {
+                        FileManager.createUserFolders(username);
+                        ChatMessage response = new ChatMessage(MessageType.LOGIN_SUCCESS, "Server", username, "Login successfully");
+                        outputStream.writeObject(response);
+                        outputStream.flush();
+                    }
+                    else {
+                        ChatMessage response = new ChatMessage(MessageType.LOGIN_FAILED, "Server", username, "Username already exists");
+                        outputStream.writeObject(response);
+                        outputStream.flush();
+                        socket.close();
+                    }
+                }
+            }
+
+            // Main message loop
             //   In a loop, call in.readObject(), you can separate messages by their type:
             //     - if it's a ChatMessage      -> call handleChatMessage(msg)
             //     - if it's a FileMessage      -> call handleFileMessage(fileMsg)
             //   Keep looping until the connection is closed (an exception will be thrown).
 
+            while (!socket.isClosed()) {
+                object = inputStream.readObject();
+
+                if(object instanceof ChatMessage)
+                    handleChatMessage((ChatMessage) object);
+                else if(object instanceof FileMessage)
+                    handleFileMessage((FileMessage) object);
+            }
+
         } catch (Exception e) {
             System.out.println("Disconnected: " + username);
         } finally {
-            // TODO: Remove the user from UserManager so they no longer
+            // Remove the user from UserManager so they no longer
             //        receive broadcasts or appear in users list
+           if(!socket.isClosed()) userManager.removeUser(username);
         }
     }
 
@@ -47,13 +90,22 @@ 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.
+                // Broadcast this message to every connected client.
+                for (ClientSession clientSession : userManager.getAllSessions()) {
+                    clientSession.outputStream.writeObject(msg);
+                    clientSession.outputStream.flush();
+                }
             }
             case PRIVATE_MESSAGE -> {
-                // TODO: Forward this message to the receiver user.
+                // Forward this message to the receiver user.
+                userManager.getUser(msg.getReceiver()).outputStream.writeObject(msg);
+                userManager.getUser(msg.getReceiver()).outputStream.flush();
             }
             case USER_LIST -> {
-                // TODO: Reply to the requester with the list of online users.
+                // Reply to the requester with the list of online users.
+                ChatMessage chatMessage = new ChatMessage(MessageType.USER_LIST, "UserManager", username, userManager.listUsers());
+                outputStream.writeObject(chatMessage);
+                outputStream.flush();
             }
         }
     }
@@ -66,6 +118,9 @@ 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.
+        // Forward the received file-message to the destination user.
+        ClientSession recieverSession = userManager.getUser(fileMsg.getReceiver());
+        recieverSession.outputStream.writeObject(fileMsg);
+        recieverSession.outputStream.flush();
     }
 }