#!/usr/bin/env python3

from email.message import EmailMessage
import sys

if sys.argv[1] == "--help" or sys.argv[1] == "-h" or sys.argv[1] == "":
    print("""
This is just a hacked together python script from stackoverflow that can be used to add a proper
MIME header for file attachments to a mail. Pipe the outpit to sendmail -oi -t to send.

usage:
mail-script "from@email.com" "to@email.com" "subject" /file/to/append < /body/of/mail | sendmail -oi -t
""")
    exit(0)

msg = EmailMessage()
msg['From'] = sys.argv[1]
msg['To'] = sys.argv[2]
msg['Subject'] = sys.argv[3]
# Don't mess with the preamble, the documentation is wrong to suggest you do

msg.set_content(''.join([line for line in sys.stdin]))

with open(sys.argv[4], 'r') as attachment:
    #msg.add_attachment(attachment.read(), maintype='text', subtype='plain')
    asStr = attachment.read()
    asBytes = asStr.encode('utf-8')
    msg.add_attachment(asBytes, maintype='application', subtype='octet-stream', filename="appendix.txt")

    print(msg.as_string())