complete client-side classes

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

@@ -1,18 +1,66 @@
 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
+    //  store the ObjectInputStream from the user socket
     //          (this should be the same input stream the
     //           chatClient created when connecting)
+    private final ObjectInputStream in;
 
+    public ServerListener(ObjectInputStream in)
+    {
+        this.in = in;
+    }
     @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 obj = in.readObject();
+                if (obj instanceof ChatMessage)
+                {
+                    ChatMessage msg = (ChatMessage) obj;
+                    String sender = msg.getSender();
+                    String content = msg.getContent();
+                    switch (msg.getType())
+                    {
+                        case PUBLIC_MESSAGE -> {
+                            System.out.println("[Public] "+sender+": "+content);
+                        }
+                        case PRIVATE_MESSAGE -> {
+                            if ("Server".equals(sender))
+                            {
+                                System.out.println("[Server] "+content);
+                            } else
+                            {
+                                System.out.println("[Private] "+sender+": "+content);
+                            }
+                        }
+                        case USER_LIST -> {
+                            System.out.println("Online users: "+content);
+                        }
+                        case LOGIN_SUCCESS -> {
+                            System.out.println("[Server] "+content);
+                        }
+                        default -> {
+                            System.out.println(sender+": "+content);
+                        }
+                    }
+                } else if (obj instanceof FileMessage)
+                {
+                    FileMessage file = (FileMessage) obj;
+                    System.out.println("Received file "+file.getFilename()+" from "+ file.getSender());
+                }
+            }
         } catch (Exception e){
             System.out.println("Disconnected from server");
         }

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

@@ -1,18 +1,81 @@
 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.ObjectInputStream;
+import java.io.ObjectOutputStream;
+import java.net.Socket;
+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() {
-        // 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.
         //  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.
+        //  3. Start a new Thread running a ServerListener(in) so incoming messages are handled concurrently.
 
-        while (true){
+        Socket socket = null;
+        ObjectOutputStream out = null;
+        ObjectInputStream in = null;
+        Scanner scanner = null;
+        String username = null;
+
+        try
+        {
+            socket = new Socket("localhost", 12345);
+            out = new ObjectOutputStream(socket.getOutputStream());
+            out.flush();
+            in = new ObjectInputStream(socket.getInputStream());
+            scanner = new Scanner(System.in);
+
+            System.out.println("Enter your username: ");
+            username = scanner.nextLine().trim();
+            if (username.isEmpty())
+            {
+                System.out.println("Username cannot be empty!");
+                return;
+            }
+
+            ChatMessage loginMsg = new ChatMessage(MessageType.LOGIN, username, null, username);
+            out.writeObject(loginMsg);
+            out.flush();
+
+            Object response = in.readObject();
+            if (response instanceof ChatMessage)
+            {
+                ChatMessage loginRespose = (ChatMessage) response;
+                if (loginRespose.getType() == MessageType.LOGIN_FAILED)
+                {
+                    System.out.println("Login failed: "+loginRespose.getContent());
+                    return;
+                } else if (loginRespose.getType() == MessageType.LOGIN_SUCCESS)
+                {
+                    System.out.println("Login successful: "+loginRespose.getContent());
+                }
+            }
+
+            ServerListener serverListener = new ServerListener(in);
+            Thread listener = new Thread(serverListener);
+            listener.setDaemon(true);
+            listener.start();
+
+        } catch (Exception e)
+        {
+            System.out.println(e.getMessage());
+            return;
+        }
+
+        boolean running = true;
+        while (running){
             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[]
@@ -21,9 +84,81 @@ public class chatClient {
                 //                                     and send it as a FileMessage
                 //   - anything else               -> send a PUBLIC_MESSAGE
                 //   Remember to flush() the output stream after writeObject().
+
+                System.out.println("> ");
+                String line = scanner.nextLine();
+                if (line == null) continue;
+                line = line.trim();
+                if (line.isEmpty()) continue;
+
+                if (line.equals("/exit")) {
+                    System.out.println("Goodbye!");
+                    running = false;
+                    break;
+                }
+                if (line.startsWith("/msg"))
+                {
+                    String[] parts = line.split(" ", 3);
+                    if (parts.length < 3)
+                    {
+                        System.out.println("Usage: /msg <username> <message>");
+                        continue;
+                    }
+
+                    String receiver = parts[1];
+                    String content = parts[2];
+                    ChatMessage msg = new ChatMessage(MessageType.PRIVATE_MESSAGE, username, receiver, content);
+                    out.writeObject(msg);
+                    out.flush();
+                } else if (line.startsWith("/sendfile"))
+                {
+                    String[] parts = line.split(" ", 3);
+                    if (parts.length < 3)
+                    {
+                        System.out.println("Usage: /sendfile <username> <filepath>");
+                        continue;
+                    }
+                    String receiver = parts[1];
+                    String filepath =parts[2];
+                    Path path = Paths.get(filepath);
+                    if(!Files.exists(path) || Files.isDirectory(path))
+                    {
+                        System.out.println("File not found or is a directory.");
+                        continue;
+                    }
+                    byte[] data = Files.readAllBytes(path);
+                    String filename = path.getFileName().toString();
+                    FileMessage fileMsg = new FileMessage(username, receiver, filename, data);
+                    out.writeObject(fileMsg);
+                    out.flush();
+                    System.out.println("File sent: "+filename+" to "+receiver);
+                } else if (line.equals("/users")) {
+                    ChatMessage msg = new ChatMessage(MessageType.USER_LIST, username, null, "");
+                    out.writeObject(msg);
+                    out.flush();
+                } else
+                {
+                    ChatMessage msg = new ChatMessage(MessageType.PUBLIC_MESSAGE, username, null, line);
+                    out.writeObject(msg);
+                    out.flush();
+                }
+
             } catch (Exception e){
                 System.out.println("command failed: " + e.getMessage());
+                running = false;
+                break;
             }
         }
+
+        try
+        {
+            if (scanner != null) scanner.close();
+            if (out != null) out.close();
+            if (in != null) in.close();
+            if (socket != null) socket.close();
+        } catch (Exception e)
+        {
+            System.out.println(e.getMessage());
+        }
     }
 }

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

@@ -1,15 +1,34 @@
 package com.university.chat.Server;
 
+import java.io.IOException;
+import java.net.ServerSocket;
+import java.net.Socket;
+
 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();
 
     public static void main(String[] args) {
-        // TODO: Create a ServerSocket
 
-        // TODO: In an infinite loop:
-        //  accept an incoming client connection
-        //  make a new thread running ClientSession for each user.
+        final int port = 12345;
+        System.out.println("chat server starting on port "+port);
+        try (ServerSocket serverSocket = new ServerSocket(port)) {
+            System.out.println("server is listening...");
+
+            while (true)
+            {
+                Socket clientSocket = serverSocket.accept();
+                System.out.println("new client connected from "+clientSocket.getInetAddress());
+
+                ClientSession session = new ClientSession(clientSocket, userManager);
+                Thread clientThread = new Thread(session);
+                clientThread.start();
+            }
+        } catch (IOException e)
+        {
+            System.err.println(e.getMessage());
+            e.printStackTrace();
+        }
+
     }
 }

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

@@ -2,44 +2,119 @@ 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.ObjectInputStream;
+import java.io.ObjectOutputStream;
 import java.net.Socket;
 import java.nio.file.Files;
 
 public class ClientSession implements Runnable {
 
     private String username;
+    private final Socket socket;
+    private final UserManager userManager;
+    private ObjectInputStream in;
+    private ObjectOutputStream out;
+
 
     public ClientSession(Socket socket, UserManager userManager) {
-        // TODO : Create an ObjectOutputStream from socket.getOutputStream()
-        //         and an ObjectInputStream from socket.getInputStream().
+        this.socket = socket;
+        this.userManager = userManager;
+        try
+        {
+            out = new ObjectOutputStream(socket.getOutputStream());
+            out.flush();
+            in = new ObjectInputStream(socket.getInputStream());
+        } catch (IOException e)
+        {
+            e.printStackTrace();
+        }
     }
 
     @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.
+            Object obj = in.readObject();
+
             //  2. Check it's a ChatMessage with type LOGIN.
+            if (!(obj instanceof ChatMessage))
+            {
+                socket.close();
+                return;
+            }
+            ChatMessage loginMsg = (ChatMessage) obj;
+            if (loginMsg.getType() != MessageType.LOGIN)
+            {
+                out.writeObject(new ChatMessage(MessageType.LOGIN_FAILED, "Server", null, "Invalid login request"));
+                out.flush();
+                socket.close();
+                return;
+            }
+
             //  3. Extract the username.
+            String requestedUser = loginMsg.getContent();
+
             //  4. Try to register the user via userManager.addUser(...).
+            boolean success = userManager.addUser(requestedUser, this);
+
             //  5. If the username is taken, send back LOGIN_FAILED and close the socket.
+            if (!success)
+            {
+                out.writeObject(new ChatMessage(MessageType.LOGIN_FAILED, "Server", null, "Username is already taken"));
+                out.flush();
+                socket.close();
+                return;
+            }
+
             //  6. Otherwise, create the user's folders with FileManager.createUserFolders(...)
             //      and send back LOGIN_SUCCESS.
+            this.username = requestedUser;
+            FileManager.createUserFolders(username);
+            out.writeObject(new ChatMessage(MessageType.LOGIN_SUCCESS, "Server", null, "Welcome "+username));
+            out.flush();
+            System.out.println("User logged in: "+username);
 
-            // TODO: Main message loop
+            //  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 (true)
+            {
+                Object received = in.readObject();
+                if (received instanceof ChatMessage)
+                {
+                    handleChatMessage((ChatMessage) received);
+                } else if (received instanceof FileMessage)
+                {
+                    handleFileMessage((FileMessage) received);
+                }
+            }
 
         } 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 (username != null)
+            {
+                userManager.removeUser(username);
+                System.out.println("User removed: "+username);
+            }
+            try
+            {
+                if (socket != null && !socket.isClosed())
+                {
+                    socket.close();
+                }
+            } catch (IOException e)
+            {
+                e.printStackTrace();
+            }
         }
     }
 
@@ -47,13 +122,36 @@ 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 session : userManager.getAllSessions())
+                {
+                    if (session != this)
+                    {
+                        session.out.writeObject(msg);
+                        session.out.flush();
+                    }
+                }
             }
             case PRIVATE_MESSAGE -> {
-                // TODO: Forward this message to the receiver user.
+                //  Forward this message to the receiver user.
+                String receiver = msg.getReceiver();
+                ClientSession target = userManager.getUser(receiver);
+                if (target != null)
+                {
+                    target.out.writeObject(msg);
+                    target.out.flush();
+                } else {
+                    out.writeObject(new ChatMessage(MessageType.PRIVATE_MESSAGE, "Server", null,
+                            "User " + receiver + " is not online."));
+                    out.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.
+                String list = userManager.listUsers();
+                ChatMessage listMsg = new ChatMessage(MessageType.USER_LIST, "Server", null, list);
+                out.writeObject(listMsg);
+                out.flush();
             }
         }
     }
@@ -66,6 +164,16 @@ 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 receiver = userManager.getUser(fileMsg.getReceiver());
+        if (receiver != null)
+        {
+            receiver.out.writeObject(fileMsg);
+            receiver.out.flush();
+        } else
+        {
+            out.writeObject(new ChatMessage(MessageType.PRIVATE_MESSAGE, "Server", null, "Cannot send file; user "+fileMsg.getReceiver()+" is offline"));
+            out.flush();
+        }
     }
 }