import socket
import sys

def scanner(target, port):
    #Banner Time
    print("-" * 50)
    print("Scanning: "+target)
    print("Port Number: "+port)
    print("-" * 50)

    try:
        s=socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        socket.setdefaulttimeout(1)
        result = s.connect_ex((target, port))
        if result == 0:
            print("Port {port} is open.")
        s.close()
    except KeyboardInterrupt:
        print("Closing Program")
        sys.exit()

def main():
    f=0
    while f==0:
        try:
            if sys.argv == 3:
                target = socket.gethostbyname(sys.argv[1])
                port = sys.arg[2]
            else:
                print("Error Incorrect Syntax.\n Expected portscan.py <ip> <portnumber>")
            
            while i != 1:
                if port not in range(1,65535):
                    port = input("Please enter a valid port:\n")
                else:
                    i = 1
            
            scanner(target, port)
            f=1
        except KeyboardInterrupt:
            print("Closing Program")
            sys.exit()

        except socket.gaierror:
            target = input("Please enter a valid IP or Hostname:\n")