.idea/misc.xml

@@ -8,7 +8,5 @@
       </list>
     </option>
   </component>
-  <component name="ProjectRootManager" version="2" project-jdk-name="25" project-jdk-type="JavaSDK">
-    <output url="file://$PROJECT_DIR$/out" />
-  </component>
+  <component name="ProjectRootManager" version="2" project-jdk-name="21" project-jdk-type="JavaSDK" />
 </project>

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

@@ -1,20 +1,54 @@
 package com.university.chat.Client;
 
-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)
+import com.university.chat.Common.ChatMessage;
+import com.university.chat.Common.FileMessage;
+
+import java.io.ObjectInputStream;
+
+public class ServerListener implements Runnable
+{
+
+    private ObjectInputStream in;
+
+    public ServerListener(ObjectInputStream in)
+    {
+        this.in = in;
+    }
 
     @Override
-    public void run() {
-        try {
-            // TODO: 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.
-        } catch (Exception e){
-            System.out.println("Disconnected from server");
+    public void run()
+    {
+        try
+        {
+            while (true)
+            {
+                Object obj = in.readObject();
+
+                if (obj instanceof ChatMessage msg)
+                {
+                    String content = msg.getContent();
+
+                    if (content != null && !content.trim().isEmpty())
+                    {
+                        if (msg.getSender().equals("Server"))
+                        {
+                            System.out.println("[Server]: " + content);
+                        }
+                        else
+                        {
+                            System.out.println("[" + msg.getSender() + "]: " + content);
+                        }
+                    }
+                }
+                else if (obj instanceof FileMessage fileMsg)
+                {
+                    System.out.println("[File received from " + fileMsg.getSender() + "]: " + fileMsg.getFilename());
+                }
+            }
+        }
+        catch (Exception e)
+        {
+            System.out.println("Connection to server lost.");
         }
     }
-}
+}

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

@@ -1,23 +1,27 @@
 package com.university.chat.Client;
 
-public class TransferProgress {
+public class TransferProgress
+{
 
     private final long total;
     private final long startTime;
     private static final int WIDTH = 30;
 
-    public TransferProgress(long total) {
+    public TransferProgress(long total)
+    {
         this.total = total;
         this.startTime = System.currentTimeMillis();
     }
 
-    public void update(long current) {
+    public void update(long current)
+    {
 
         double percent = (double) current / total;
         int filled = (int) (percent * WIDTH);
 
         StringBuilder bar = new StringBuilder("[");
-        for (int i = 0; i < WIDTH; i++) {
+        for (int i = 0; i < WIDTH; i++)
+        {
             bar.append(i < filled ? "█" : " ");
         }
         bar.append("]");
@@ -30,7 +34,8 @@ public class TransferProgress {
                 (int) (percent * 100),
                 speed);
 
-        if (current >= total) {
+        if (current >= total)
+        {
             System.out.println();
         }
     }

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

@@ -1,29 +1,231 @@
 package com.university.chat.Client;
 
-public class chatClient {
-    public static void main() {
-        // TODO: 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.
+import com.university.chat.Common.ChatMessage;
+import com.university.chat.Common.FileMessage;
+import com.university.chat.Common.MessageType;
 
-        while (true){
-            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
-                //   - "/sendfile <user> <path>"   -> read the file into a byte[]
-                //                                     (you can use TransferProgress
-                //                                     to show progress)
-                //                                     and send it as a FileMessage
-                //   - anything else               -> send a PUBLIC_MESSAGE
-                //   Remember to flush() the output stream after writeObject().
-            } catch (Exception e){
-                System.out.println("command failed: " + e.getMessage());
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.ObjectInputStream;
+import java.io.ObjectOutputStream;
+import java.net.Socket;
+import java.util.Scanner;
+
+public class chatClient
+{
+
+    private static final String SERVER_HOST = "localhost";
+    private static final int SERVER_PORT = 5000;
+
+    public static void main(String[] args)
+    {
+
+        try
+        {
+            Socket socket = new Socket(SERVER_HOST, SERVER_PORT);
+            System.out.println("Connected to server.");
+
+
+            ObjectOutputStream out = new ObjectOutputStream(socket.getOutputStream());
+            out.flush();
+            ObjectInputStream in = new ObjectInputStream(socket.getInputStream());
+
+            System.out.print("Enter username: ");
+            Scanner scanner = new Scanner(System.in);
+            String username = scanner.nextLine();
+
+            out.writeObject(new ChatMessage(MessageType.LOGIN, username, "", ""));
+            out.flush();
+
+            Thread listenerThread = new Thread(new ServerListener(in));
+            listenerThread.start();
+
+            System.out.println("You can now chat.");
+            System.out.println("Commands:");
+            System.out.println("/msg <username> <message>");
+            System.out.println("/users");
+            System.out.println("/sendfile <username> <filepath>");
+            System.out.println("Anything else will be sent as a public message.");
+            System.out.print("> ");
+
+            while (true)
+            {
+                try
+                {
+                    String line = scanner.nextLine();
+
+                    if (line == null || line.trim().isEmpty())
+                    {
+                        System.out.print("> ");
+                        continue;
+                    }
+
+                    line = line.trim();
+
+                    if (line.startsWith("/msg "))
+                    {
+                        handlePrivateMessage(line, username, out);
+                    }
+                    else if (line.equals("/users"))
+                    {
+                        handleUserListRequest(username, out);
+                    }
+                    else if (line.startsWith("/sendfile "))
+                    {
+                        handleFileSend(line, username, out);
+                    }
+                    else
+                    {
+                        handlePublicMessage(line, username, out);
+                    }
+
+                    System.out.print("> ");
+
+                }
+                catch (Exception e)
+                {
+                    System.out.println("command failed: " + e.getMessage());
+                    System.out.print("> ");
+                }
             }
+
+        }
+        catch (Exception e)
+        {
+            System.out.println("Could not connect to server: " + e.getMessage());
         }
     }
-}
+
+    private static void handlePrivateMessage(String line, String username, ObjectOutputStream out) throws Exception {
+
+        String[] parts = line.split(" ", 3);
+
+        if (parts.length < 3)
+        {
+            System.out.println("Usage: /msg <username> <message>");
+            return;
+        }
+
+        String receiver = parts[1];
+        String messageText = parts[2];
+
+        ChatMessage privateMessage = new ChatMessage(
+                MessageType.PRIVATE_MESSAGE,
+                username,
+                messageText,
+                receiver
+        );
+
+        out.writeObject(privateMessage);
+        out.flush();
+    }
+
+    private static void handleUserListRequest(String username, ObjectOutputStream out) throws Exception
+    {
+        ChatMessage userListRequest = new ChatMessage(
+                MessageType.USER_LIST,
+                username,
+                null,
+                ""
+        );
+
+        out.writeObject(userListRequest);
+        out.flush();
+    }
+
+    private static void handlePublicMessage(String line, String username, ObjectOutputStream out) throws Exception
+    {
+        ChatMessage publicMessage = new ChatMessage(
+                MessageType.PUBLIC_MESSAGE,
+                username,
+                null,
+                line
+        );
+
+        out.writeObject(publicMessage);
+        out.flush();
+    }
+
+    private static void handleFileSend(String line, String username, ObjectOutputStream out) throws Exception
+    {
+
+        String[] parts = line.split(" ", 3);
+
+        if (parts.length < 3)
+        {
+            System.out.println("Usage: /sendfile <username> <filepath>");
+            return;
+        }
+
+        String receiver = parts[1];
+        String filePath = parts[2];
+
+        File file = new File(filePath);
+
+        if (!file.exists())
+        {
+            System.out.println("File does not exist: " + filePath);
+            return;
+        }
+
+        if (!file.isFile())
+        {
+            System.out.println("This path is not a file: " + filePath);
+            return;
+        }
+
+        long totalSize = file.length();
+
+        TransferProgress progress = new TransferProgress(totalSize);
+
+        byte[] data = new byte[(int) totalSize];
+
+        FileInputStream fis = new FileInputStream(file);
+
+        byte[] buffer = new byte[4096];
+        int bytesRead;
+        int totalRead = 0;
+
+        while ((bytesRead = fis.read(buffer)) != -1)
+        {
+
+            System.arraycopy(buffer, 0, data, totalRead, bytesRead);
+            totalRead += bytesRead;
+
+            progress.update(totalRead);
+        }
+
+        fis.close();
+
+        FileMessage fileMessage = new FileMessage(
+                username,
+                receiver,
+                file.getName(),
+                data
+        );
+
+        out.writeObject(fileMessage);
+        out.flush();
+
+        System.out.println("File sent successfully: " + file.getName());
+    }
+
+    private static byte[] readFileToByteArray(File file) throws Exception
+    {
+        byte[] data = new byte[(int) file.length()];
+
+        FileInputStream fis = new FileInputStream(file);
+
+        int totalRead = 0;
+        int bytesRead;
+
+        while (totalRead < data.length && (bytesRead = fis.read(data, totalRead, data.length - totalRead)) != -1)
+        {
+            totalRead += bytesRead;
+        }
+
+        fis.close();
+
+        return data;
+    }
+}

src/main/java/com/university/chat/Common/ChatMessage.java

@@ -2,7 +2,8 @@ package com.university.chat.Common;
 
 import java.io.Serializable;
 
-public class ChatMessage implements Serializable {
+public class ChatMessage implements Serializable
+{
 
     private static final long serialVersionUID = 1L;
 
@@ -11,7 +12,8 @@ public class ChatMessage implements Serializable {
     private String receiver;
     private String content;
 
-    public ChatMessage(MessageType type, String sender, String receiver, String content) {
+    public ChatMessage(MessageType type, String sender, String receiver, String content)
+    {
         this.type = type;
         this.sender = sender;
         this.receiver = receiver;

src/main/java/com/university/chat/Common/FileMessage.java

@@ -2,7 +2,8 @@ package com.university.chat.Common;
 
 import java.io.Serializable;
 
-public class FileMessage implements Serializable {
+public class FileMessage implements Serializable
+{
 
     private static final long SerialVersionUID = 1L;
 
@@ -11,26 +12,31 @@ public class FileMessage implements Serializable {
     private String filename;
     private byte[] data;
 
-    public FileMessage(String sender, String receiver, String filename, byte[] data) {
+    public FileMessage(String sender, String receiver, String filename, byte[] data)
+    {
         this.sender = sender;
         this.receiver = receiver;
         this.filename = filename;
         this.data = data;
     }
 
-    public String getSender() {
+    public String getSender()
+    {
         return sender;
     }
 
-    public String getReceiver() {
+    public String getReceiver()
+    {
         return receiver;
     }
 
-    public String getFilename() {
+    public String getFilename()
+    {
         return filename;
     }
 
-    public byte[] getData() {
+    public byte[] getData()
+    {
         return data;
     }
 }

src/main/java/com/university/chat/Common/MessageType.java

@@ -2,7 +2,8 @@ package com.university.chat.Common;
 
 import java.io.Serializable;
 
-public enum MessageType implements Serializable {
+public enum MessageType implements Serializable
+{
     LOGIN,
     LOGIN_SUCCESS,
     LOGIN_FAILED,

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

@@ -1,15 +1,53 @@
 package com.university.chat.Server;
 
-public class ChatServer {
+import java.net.ServerSocket;
+import java.net.Socket;
+
+public class ChatServer
+{
+    private static final UserManager userManager = new UserManager();
+
+    private static final int PORT = 5000;
     // 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.
 
-    public static void main(String[] args) {
+    public static void main(String[] args)
+    {
+
+        System.out.println("Chat server starting on port " + PORT + "...");
+
+        try (ServerSocket serverSocket = new ServerSocket(PORT))
+        {
+
+            System.out.println("Server started. Waiting for clients...");
+
+            while (true)
+            {
+
+                Socket clientSocket = serverSocket.accept();
+
+                System.out.println("New client connected: "
+                        + clientSocket.getInetAddress());
+
+                ClientSession session =
+                        new ClientSession(clientSocket, userManager);
+
+                Thread thread = new Thread(session);
+                thread.start();
+            }
+
+        }
+        catch (Exception e)
+        {
+            System.out.println("Server error: " + e.getMessage());
+            e.printStackTrace();
+        }
+    }
         // TODO: Create a ServerSocket
 
         // 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

@@ -2,70 +2,152 @@ 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.ObjectInputStream;
+import java.io.ObjectOutputStream;
 import java.io.IOException;
 import java.net.Socket;
 import java.nio.file.Files;
 
-public class ClientSession implements Runnable {
+public class ClientSession implements Runnable
+{
 
+    private final Socket socket;
+    private final UserManager userManager;
+    private ObjectOutputStream out;
+    private ObjectInputStream in;
     private String username;
 
-    public ClientSession(Socket socket, UserManager userManager) {
-        // TODO : Create an ObjectOutputStream from socket.getOutputStream()
-        //         and an ObjectInputStream from socket.getInputStream().
+    public ClientSession(Socket socket, UserManager userManager)
+    {
+        this.socket = socket;
+        this.userManager = userManager;
     }
 
     @Override
-    public void run() {
-        try {
+    public void run()
+    {
+        try
+        {
+            this.out = new ObjectOutputStream(socket.getOutputStream());
+            this.out.flush();
+            this.in = new ObjectInputStream(socket.getInputStream());
 
-            // 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.
-            //  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(...)
-            //      and send back LOGIN_SUCCESS.
+            Object obj = in.readObject();
 
-            // TODO: 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).
+            if (obj instanceof ChatMessage loginMsg && loginMsg.getType() == MessageType.LOGIN)
+            {
+                String requestedUsername = loginMsg.getSender();
+
+                if (userManager.addUser(requestedUsername, this))
+                {
+                    this.username = requestedUsername;
+                    FileManager.createUserFolders(this.username);
+
+                    send(new ChatMessage(MessageType.LOGIN_SUCCESS, "Server", "Welcome to the chat system!", ""));
+                }
+                else
+                {
+                    send(new ChatMessage(MessageType.LOGIN_FAILED, "Server", "Username already taken.", ""));
+                    socket.close();
+                    return;
+                }
+            }
+            else
+            {
+                socket.close();
+                return;
+            }
+
+            while (true)
+            {
+                Object receivedObj = in.readObject();
+
+                if (receivedObj instanceof ChatMessage msg)
+                {
+                    handleChatMessage(msg);
+                }
+                else if (receivedObj 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
         }
-    }
-
-
-    private void handleChatMessage(ChatMessage msg) throws IOException {
-        switch (msg.getType()) {
-            case PUBLIC_MESSAGE -> {
-                // TODO: Broadcast this message to every connected client.
+        catch (Exception e)
+        {
+            System.out.println("Disconnected: " + (username != null ? username : "Unknown client"));
+        }
+        finally
+        {
+            if (username != null)
+            {
+                userManager.removeUser(username);
             }
-            case PRIVATE_MESSAGE -> {
-                // TODO: Forward this message to the receiver user.
+            try
+            {
+                socket.close();
             }
-            case USER_LIST -> {
-                // TODO: Reply to the requester with the list of online users.
+            catch (IOException e)
+            {
+                System.err.println("Error closing socket: " + e.getMessage());
             }
         }
     }
 
-    private void handleFileMessage(FileMessage fileMsg) throws IOException {
-        // Storing the file
+    public void send(Object msg) throws IOException
+    {
+        if (out != null)
+        {
+            out.writeObject(msg);
+            out.flush();
+        }
+    }
+
+    private void handleChatMessage(ChatMessage msg) throws IOException
+    {
+        switch (msg.getType())
+        {
+            case PUBLIC_MESSAGE ->
+            {
+                for (ClientSession session : userManager.getAllSessions())
+                {
+                    session.send(msg);
+                }
+            }
+            case PRIVATE_MESSAGE ->
+            {
+                ClientSession receiver = userManager.getUser(msg.getReceiver());
+                if (receiver != null)
+                {
+                    receiver.send(msg);
+                }
+                else
+                {
+                    send(new ChatMessage(MessageType.PUBLIC_MESSAGE, "Server", "User not found: " + msg.getReceiver(), username));
+                }
+            }
+            case USER_LIST ->
+            {
+                String userListStr = userManager.listUsers();
+                send(new ChatMessage(MessageType.USER_LIST, "Server", userListStr, username));
+            }
+        }
+    }
+
+    private void handleFileMessage(FileMessage fileMsg) throws IOException
+    {
         var sentPath = FileManager.getSentPath(fileMsg.getSender(), fileMsg.getFilename());
         var recvPath = FileManager.getReceivedPath(fileMsg.getReceiver(), fileMsg.getFilename());
 
         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.send(fileMsg);
+        }
     }
 }