package main;

import java.net.*;
import java.util.Scanner;

public class sender {
	public static void main(String args[]) {
		Scanner in = new Scanner(System.in);

		System.out.println("Enter Host:");
		String host = in.nextLine();

		System.out.println("Enter Start Port:");
		int startPort = in.nextInt();

		System.out.println("Enter Amount Of Ports To Scan:");
		int range = in.nextInt();

		System.out.println("Enter Timeout in millisec");
		int timeout = in.nextInt();
		
		in.close();
		
		portCheck(host,startPort,range,timeout); // Start PortCheck with users input
	}

	private static boolean portCheck(String ip, int start, int end, int timeout) {
		boolean single = false;
		int closed = 0;
		int open = 0;

		if(end == 0){
			single = true; // Allow user to scan for only one port
		}else{
			end = start+end;
		}

		for(int i=start; i<=end; i++){
			try {
				Socket socket = new Socket();
				socket.connect(new InetSocketAddress(ip, i), timeout);
				socket.close();
				open++; // count open connections
				
				if(open%5 == 0){//Only display 5 each row
					System.out.println(i + " ");
				}else{
					System.out.print(i + " ");
				}
			} catch (Exception ex) {
				closed++;
				if(single){
					System.out.println(i + " is closed");
				}
			}	
		}
		if(closed == end-start+1){
			System.out.println("");
			System.out.println("Port " +start+ " to " +end+ " Is closed");
		}else{
			System.out.println("");
			System.out.println(open+ " Ports are open in the range from "+start+ " to " +end);
			System.out.println(closed+ " are closed");
		}
		return true;
	}
	
}