Script to assign secret santas and notify them using smtp

secretsanta.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

# Import smtplib for the actual sending function
import smtplib
import getpass
from email.mime.text import MIMEText
from random import Random

# Names and mail adresses of people that a part of the Wichtel ceremony
mails = {
    "Alice": "[email protected]",
    "Bob": "[email protected]",
    "Foo": "[email protected]",
    "Bar": "[email protected]"
}
names = list(mails.keys())

# E-Mail settings
smtpaddress = "[email protected]"
smtpusername = "[email protected]"
smtpserver = "smtp.example.com"
smtpport = 465

# Shuffle the list
# Every participant is a wichtel to the next person in the shuffled list
# The last person in the list is the wichtel to the first one
oracle = Random()
wichtels = list(names)
targets = list(names)
oracle.shuffle(targets)

# Check for duplicates (wichtel who drew themselves)
swaps = list()
for (i, wichtel), target in zip(enumerate(wichtels), targets):
    if wichtel is target:
        swaps.append(i)

# Swap target for those who drew themselves
if len(swaps) is 1:  # With a random other
    i = swaps[0]
    j = (i + 1) % len(names)
    targets[i] = targets[j]
    targets[j] = wichtels[i]
else:  # With the other duplicates
    for i, s in enumerate(swaps):
        targets[s] = wichtels[swaps[(i + 1) % len(swaps)]]

# Check Wichtels, just to be sure
for wichtel, target in zip(wichtels, targets):
    assert(wichtel is not target)

# Connect to the mailserver
print("Establish connection to %s" % smtpserver)
smtp = smtplib.SMTP_SSL(smtpserver, smtpport)
smtp.login(smtpusername, getpass.getpass())
print("Established")


# Sends a mail to the wichtel saying who it's target is
def sendwichtelmail(wichtel, target):
    # Set the mail message
    msg = MIMEText('''Hallo %s,\nDieses Jahr darfst du %s etwas schenken.\n
        Grüße vom Christkind :)''' % (wichtel, target), "plain", "utf-8")

    # Set the other attributes of the mail
    msg['Subject'] = "[Geheim] Wichtel"
    msg['From'] = "Christkind <" + smtpaddress + ">"
    msg['To'] = wichtel + " <" + mails[wichtel] + ">"

    # Send the message via our own SMTP server, but don't include the
    # envelope header.
    smtp.sendmail(smtpaddress, mails[wichtel], msg.as_string())

# Actually send the mails
try:
    for (i, name), target in zip(enumerate(wichtels), targets):
        sendwichtelmail(name, target)
        print("Sent mail %d/%d" % (i + 1, len(names)))
except:
    # Close connection on error
    smtp.quit()
    raise

# Close mailserver connection
smtp.quit()
print("Connection closed")