#!/usr/bin/env python3
# sendmail.py - A mail-sending abstraction library
# Author: Simon Volpert <simon@simonvolpert.com>
# This program is free software, released under the Apache License, Version 2.0. See the LICENSE file for more information

import subprocess
import sys
import smtplib
import threading
from email.mime.text import MIMEText

email_from = 'nobody <noreply@localhost.localdomain>'

def send(config, to, subject, text_body, headers={}, callback=None):
	use_smtp = True
	success = True
	# Select email backend
	for setting in ['server', 'login', 'passwd']:
		if setting not in config or config[setting] == '':
			use_smtp = False
	if 'email_from' not in config.keys() or config['email_from'] == '':
		config['email_from'] = email_from
	# Create email message
	message = MIMEText(text_body)
	message['From'] = config['email_from']
	message['To'] = to
	message['Subject'] = subject
	message['Auto-Submitted'] = 'auto-generated'
	for header in headers.keys():
		message[header] = headers[header]
	# Send the message
	if use_smtp:
		try:
			server = smtplib.SMTP(config['server'])
			server.login(config['login'], config['passwd'])
			server.sendmail(message['From'], message['To'], message.as_string())
			server.quit()
		except KeyboardInterrupt:
			sys.exit()
		except:
			print('SMTP failed: %s' % sys.exc_info()[1])
			success = False
	else:
		try:
			server = subprocess.Popen(['/usr/sbin/sendmail','-i', message['To']], stdin=subprocess.PIPE, stderr=subprocess.PIPE)
			server.communicate(bytes(message.as_string(), 'UTF-8'))
		except:
			print('Sendmail failed: %s' % sys.exc_info()[1])
			success = False
	if callback is not None:
		callback(success)
	return success


def background_send(config, to, subject, text_body, headers={}, callback=None):
	subthread = threading.Thread(target=send, args=(config, to, subject, text_body, headers, callback), daemon=True)
	subthread.start()