HW-10-Socket-Programming/src/main/java/com/university/chat/Client/chatClient.java

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.Socket;
import java.util.Scanner;

public class chatClient {
    private static final String DEFAULT_HOST = "localhost";
    private static final int DEFAULT_PORT = 8585;
    public static void main(String[] args) {
        // TODO: Connecting to the server
        //  1. Create a socket and connect to the server
        Scanner scanner = new Scanner(System.in);
        System.out.print("Enter username: ");
        String username = scanner.nextLine().trim();
        try {
            Socket socket = new Socket(DEFAULT_HOST, DEFAULT_PORT);
        //  2. Create an ObjectOutputStream (out) and ObjectInputStream (in)
        //      from the socket's streams — output FIRST, then input.
            ObjectOutputStream out = new ObjectOutputStream(socket.getOutputStream());
            out.flush();
            ObjectInputStream in = new ObjectInputStream(socket.getInputStream());
        //  2. Get the username, and send a LOGIN ChatMessage with that username
            out.writeObject(new ChatMessage(MessageType.LOGIN, username, "SERVER", ""));
            out.flush();
            Object response = in.readObject();
            if (response instanceof ChatMessage serverMsg){
                if (serverMsg.getType() == MessageType.LOGIN_FAILED){
                    System.out.println("Login failed: " + serverMsg.getContent());
                    socket.close();
                    scanner.close();
                    return;
                }
                else if (serverMsg.getType() == MessageType.LOGIN_SUCCESS){
                    System.out.println("Login successful! " + serverMsg.getContent());
                    System.out.println("Commands: /msg <user> <text>, /users, /sendfile <user> <path>, or just type text for public chat.");
                }
            }
            //  3. Start a new Thread running a ServerListener(in) so incoming
            //      messages are handled concurrently.
            ServerListener listener = new ServerListener(in);
            Thread listenerThread = new Thread(listener);
            listenerThread.start();

        while (true){
            try {
                // TODO: Program loop — read a line from the console and act on it:
                String line = scanner.nextLine().trim();
                if (line.isEmpty()) continue;
                if (line.startsWith("/msg ")){
                //   - "/msg <user> <text>"        -> build & send a PRIVATE_MESSAGE
                    String[] parts = line.split(" ", 3);
                    if (parts.length >= 3){
                        String targetUser = parts[1];
                        String text = parts[2];
                        out.writeObject(new ChatMessage(MessageType.PRIVATE_MESSAGE, username, targetUser, text));
                        out.flush();
                    }
                    else{
                        System.out.println("Usage: /msg <user> <text>");
                    }
                }
                else if (line.equals("/users")){
                //   - "/users"                    -> build & send a USER_LIST request
                    out.writeObject(new ChatMessage(MessageType.USER_LIST, username, "SERVER", ""));
                    out.flush();
                }
                else if (line.startsWith("/sendfile ")){
                //   - "/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
                    String[] parts = line.split(" ", 3);
                    if (parts.length >= 3){
                        String targetUser = parts[1];
                        String filePath = parts[2];
                        File file = new File(filePath);
                        if (!file.exists() || !file.isFile()){
                            System.out.println("File does not exist or is not a valid file.");
                            continue;
                        }

                        long fileSize = file.length();
                        byte[] fileData = new byte[(int) fileSize];
                        // Reading file while simulating the TransferProgress bar
                        try (FileInputStream fis = new FileInputStream(file)){
                            TransferProgress progress = new TransferProgress(fileSize);
                            int bytesRead;
                            int totalBytesRead = 0;
                            byte[] buffer = new byte[4096];

                            while ((bytesRead = fis.read(buffer)) != -1){
                                System.arraycopy(buffer, 0, fileData, totalBytesRead, bytesRead);
                                totalBytesRead += bytesRead;
                                progress.update(totalBytesRead);
                            }
                        }

                        FileMessage fileMsg = new FileMessage(username, targetUser, file.getName(), fileData);
                        out.writeObject(fileMsg);
                        out.flush();
                        System.out.println("File sent to server successfully.");
                    }
                    else{
                        System.out.println("Usage: /sendfile <user> <path>");
                    }
                }
                else{
                    // - anything else -> send a PUBLIC_MESSAGE
                    out.writeObject(new ChatMessage(MessageType.PUBLIC_MESSAGE, username, "ALL", line));
                    out.flush();
                }
                //   Remember to flush() the output stream after writeObject().
            }
            catch (Exception e){
                System.out.println("command failed: " + e.getMessage());
            }
        }
    }
    catch (Exception e){
        System.out.println("Client Error: " + e.getMessage());
    }
}}