from socket import *
import argparse as ap
import getpass as gp

#Get sender_email and recipient_email as arguments to the program
parser = ap.ArgumentParser(description='A test SMTP client without authentication')
parser.add_argument('-f', '--from', dest='fromMail', required=True, metavar='<sender_email>')
parser.add_argument('-t', '--to', dest='toMail', required=True, metavar='<recipient_email>')
#If using the authentication of the SMTP server, also get a valid username (optional exercise)
#parser.add_argument('-u', '--username', dest='username', required=True, metavar='<username>')

args = parser.parse_args()
fromMail = args.fromMail #Sender's email address
toMail = args.toMail #Recipient's email address
#username = args.username #SMTP username in case you are implementing the optional exercise

#If using the authentication of the SMTP server, ask for a valid password (optional exercise)
#password = gp.getpass(prompt='Password: ')

# Message to send
msg = "\r\n I love computer networks!"
endmsg = "\r\n.\r\n"

# Our mail server is smtp.stud.ntnu.no but it allows only authenticated communications. (optional exercise)
#mailserver = 'smtp.stud.ntnu.no'
# You can run a local simple SMTP server such as "Fake SMTP Server" and communicate with it without authentication.
mailserver = 'localhost'

# Create socket called clientSocket and establish a TCP connection
# (use the appropriate port) with mailserver
#Fill in start
serverName = 'mailServer'
serverPort = 2525
clientSocket = socket(AF_INET, SOCK_STREAM) #SOCK_STREAM: TCP socket, AF_INET: IPv4
clientSocket.connect((mailserver,serverPort))
#Fill in end

recv = clientSocket.recv(1024)
print (recv)
if recv[:3] != '220':
    print ('220 reply not received from server.')

# Send HELO command and print server response.
# Can use EHLO instead since HELO is obsolete, but the latter can still be used
heloCommand = 'EHLO Hey\r\n'
clientSocket.send(heloCommand.encode())

recv1 = clientSocket.recv(1024)
print (recv1)
if recv1[:3] != '250':
    print ('250 reply not received from server.')

# Send MAIL FROM command and print server response.
mailFromCommand = 'MAIL FROM: <{}> \r\n'.format(fromMail)
clientSocket.send(mailFromCommand.encode()) #Python 3

recv2 = clientSocket.recv(1024)
print('Mail from: ', recv2)
if recv2[:3] != '250':
    print ('250 reply not received from server.')

# Send RCPT TO command and print server response.
RCPTtoCommand = 'RCPT TO: <{}> \r\n'.format(toMail)
clientSocket.send(RCPTtoCommand.encode())

recv3 = clientSocket.recv(1024)
print('RCPT to: ', recv3)
if recv3[:3] != '250':
    print ('250 reply not received from server.')


# Send DATA command and print server response.
DataCommand = 'DATA \r\n'
clientSocket.send(DataCommand.encode())

recv4 = clientSocket.recv(1024)
print('Data: ', recv4)
if recv4[:3] != '250':
    print ('250 feilreply not received from server.')

# Send message data.
clientSocket.send(msg.encode())

# Message ends with a single period.
dot = '.'
clientSocket.send(dot.encode())

# Send QUIT command and get server response.
quitCommand = 'QUIT \r\n'
clientSocket.send(quitCommand.encode())
recv4 = clientSocket.recv(1024)