implement all TODOs without UI

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

@@ -1,10 +1,16 @@
 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 in;
+    public ServerListener(ObjectInputStream objectInputStream){this.in = objectInputStream;}
     @Override
     public void run() {
         try {
@@ -13,6 +19,21 @@ public class ServerListener implements Runnable{
             //   - 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 obj = in.readObject();
+                if(obj instanceof ChatMessage msg)
+                {
+                    System.out.println("<" + msg.getSender() + ">: " + msg.getContent());
+                }
+                else
+                {
+                    FileMessage fileMsg = (FileMessage) obj;
+                    System.out.println("a file was received");
+                    System.out.println("<" + fileMsg.getSender() + ">: " + fileMsg.getFilename());
+                    System.out.println("it's already saved to disk by the server.");
+                }
+            }
         } catch (Exception e){
             System.out.println("Disconnected from server");
         }

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

@@ -1,7 +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 com.university.chat.Server.FileManager;
+
+import javax.naming.ldap.SortKey;
+import java.awt.*;
+import java.io.*;
+import java.net.Socket;
+import java.nio.file.Files;
+import java.util.Scanner;
+
 public class chatClient {
-    public static void main() {
+    public static void main(String[] args) throws IOException {
         // TODO: Connecting to the server
         //  1. Create a socket and connect to the server
         //  2. Create an ObjectOutputStream (out) and ObjectInputStream (in)
@@ -9,9 +21,22 @@ public class chatClient {
         //  2. Get the username, and send a LOGIN ChatMessage with that username
         //  3. Start a new Thread running a ServerListener(in) so incoming
         //      messages are handled concurrently.
-
+        Socket socket = new Socket("localhost", 12345);
+        ObjectOutputStream out = new ObjectOutputStream(socket.getOutputStream());
+        out.flush();
+        ObjectInputStream in = new ObjectInputStream(socket.getInputStream());
+        System.out.print("Enter your username: ");
+        Scanner in2 = new Scanner(System.in);
+        String username = in2.nextLine();
+        ChatMessage logIn = new ChatMessage(MessageType.LOGIN, username, "server", "logIn");
+        out.writeObject(logIn);
+        out.flush();
+        ServerListener serverListener = new ServerListener(in);
+        Thread thread = new Thread(serverListener);
+        thread.start();
         while (true){
-            try {
+            try
+            {
                 // TODO: 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
@@ -21,6 +46,47 @@ 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 = in2.nextLine();
+                ChatMessage msg = null;
+                if(line.equalsIgnoreCase("/users"))
+                {
+                    msg = new ChatMessage(MessageType.USER_LIST, username, "server", "user list");
+                    out.writeObject(msg);
+                    out.flush();
+                }
+                else if(line.startsWith("/msg "))
+                {
+                    String[] parts = line.split(" ", 3);
+                    String receiver = parts[1];
+                    String messageText = parts[2];
+                    msg = new ChatMessage(MessageType.PRIVATE_MESSAGE, username, receiver, messageText);
+                    out.writeObject(msg);
+                    out.flush();
+                }
+                else if(line.startsWith("/sendfile "))
+                {
+                    String[] parts = line.split(" ", 3);
+                    String receiver = parts[1];
+                    String path = parts[2];
+                    File file = new File(path);
+                    byte[] fileData = Files.readAllBytes(file.toPath());
+                    long totalBytes = fileData.length;
+                    TransferProgress transferProgress = new TransferProgress(totalBytes);
+                    transferProgress.update(0);
+                    String fileName = file.getName();
+                    FileMessage fileMsg = new FileMessage(username, receiver, fileName, fileData);
+                    transferProgress.update(totalBytes/2);
+                    out.writeObject(fileMsg);
+                    out.flush();
+                    transferProgress.update(totalBytes);
+                }
+                else
+                {
+                    msg = new ChatMessage(MessageType.PUBLIC_MESSAGE, username, "all", line);
+                    out.writeObject(msg);
+                    out.flush();
+                }
+
             } catch (Exception e){
                 System.out.println("command failed: " + e.getMessage());
             }

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

@@ -1,15 +1,36 @@
 package com.university.chat.Server;
 
+import java.io.IOException;
+import java.net.ServerSocket;
+import java.net.Socket;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+
 public class ChatServer {
     // TODO: declare a single shared UserManager instance (static final)
     //         This MUST be shared by all ClientSession threads so that
     //         broadcasting and private messaging work correctly.
+    private static final UserManager userManager = new UserManager();
+    private static final int port = 12345;
+    private static final ExecutorService threadPool = Executors.newCachedThreadPool();
 
-    public static void main(String[] args) {
+    public static void main(String[] args)  {
         // TODO: Create a ServerSocket
-
+        ServerSocket serverSocket = null;
+        try {
+            serverSocket = new ServerSocket(port);
+            while (true)
+            {
+                Socket clientSocket = serverSocket.accept();
+                ClientSession clientSession = new ClientSession(clientSocket, userManager);
+                threadPool.execute(clientSession);
+            }
+        } catch (IOException e) {
+            System.err.println("Server error: " + e.getMessage());
+        }
         // TODO: In an infinite loop:
         //  accept an incoming client connection
         //  make a new thread running ClientSession for each user.
+
     }
 }

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

@@ -2,28 +2,66 @@ 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.ObjectInput;
+import java.io.ObjectInputStream;
+import java.io.ObjectOutputStream;
 import java.net.Socket;
 import java.nio.file.Files;
+import java.util.Objects;
 
 public class ClientSession implements Runnable {
 
     private String username;
+    private final Socket socket;
+    private final UserManager userManager;
+    private final ObjectOutputStream out;
+    private final ObjectInputStream in;
 
-    public ClientSession(Socket socket, UserManager userManager) {
+    public ClientSession(Socket socket, UserManager userManager) throws IOException {
         // TODO : Create an ObjectOutputStream from socket.getOutputStream()
         //         and an ObjectInputStream from socket.getInputStream().
+        this.socket = socket;
+        this.userManager = userManager;
+        this.out = new ObjectOutputStream(socket.getOutputStream());
+        this.out.flush();
+        this.in = new ObjectInputStream(socket.getInputStream());
     }
 
     @Override
     public void run() {
-        try {
-
+        try
+        {
             // TODO: 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.
+            Object obj = in.readObject();
+
+            if(obj instanceof ChatMessage)
+            {
+                ChatMessage msg = (ChatMessage) obj;
+                if(msg.getType() == MessageType.LOGIN)
+                {
+                    username = msg.getSender();
+                    if(userManager.addUser(username, this))
+                    {
+                        FileManager.createUserFolders(username);
+                        out.writeObject(new ChatMessage(MessageType.LOGIN_SUCCESS, "server", username, "LOGIN_SUCCESS"));
+                        System.out.println("Welcome " + username);
+                        out.flush();
+                    }
+                    else
+                    {
+                        out.writeObject(new ChatMessage(MessageType.LOGIN_FAILED, "server", username, "LOGIN_FAILED"));
+                        out.flush();
+                        socket.close();
+                        return;
+                    }
+                }
+            }
             //  4. Try to register the user via userManager.addUser(...).
             //  5. If the username is taken, send back LOGIN_FAILED and close the socket.
             //  6. Otherwise, create the user's folders with FileManager.createUserFolders(...)
@@ -34,12 +72,25 @@ public class ClientSession implements Runnable {
             //     - 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 (true)
+            {
+                Object obj2 = in.readObject();
+                if(obj2 instanceof ChatMessage msg)
+                {
+                    handleChatMessage(msg);
+                }
+                else if(obj2 instanceof FileMessage fileMsg)
+                {
+                    handleFileMessage(fileMsg);
+                }
+            }
         } catch (Exception e) {
             System.out.println("Disconnected: " + username);
         } finally {
             // TODO: Remove the user from UserManager so they no longer
             //        receive broadcasts or appear in users list
+            userManager.removeUser(username);
+            try { socket.close(); } catch (IOException ignored) {}
         }
     }
 
@@ -48,13 +99,36 @@ public class ClientSession implements Runnable {
         switch (msg.getType()) {
             case PUBLIC_MESSAGE -> {
                 // TODO: Broadcast this message to every connected client.
+                for (ClientSession client: userManager.getAllSessions())
+                {
+                    if(!Objects.equals(client.username, username))
+                    {
+                        client.out.writeObject(msg);
+                        client.out.flush();
+                    }
+                }
+                break;
             }
             case PRIVATE_MESSAGE -> {
                 // TODO: Forward this message to the receiver user.
+                ClientSession receiverSession = userManager.getUser(msg.getReceiver());
+                if (receiverSession != null) {
+                    receiverSession.out.writeObject(msg);
+                    receiverSession.out.flush();
+                }
+                break;
             }
             case USER_LIST -> {
                 // TODO: Reply to the requester with the list of online users.
+                ClientSession senderSession = userManager.getUser(msg.getSender());
+                if (senderSession != null) {
+                    ChatMessage listReply = new ChatMessage(MessageType.USER_LIST, "server", username, userManager.listUsers());
+                    senderSession.out.writeObject(listReply);
+                    senderSession.out.flush();
+                }
+                break;
             }
+
         }
     }
 
@@ -67,5 +141,11 @@ public class ClientSession implements Runnable {
         Files.write(recvPath, fileMsg.getData());
 
         // TODO: Forward the received file-message to the destination user.
+        ClientSession receiverSession = userManager.getUser(fileMsg.getReceiver());
+        if (receiverSession != null)
+        {
+            receiverSession.out.writeObject(fileMsg);
+            receiverSession.out.flush();
+        }
     }
 }