# Links:
#   [1] https://gist.github.com/robulouski/7441883
#   [2] https://yuji.wordpress.com/2011/06/22/python-imaplib-imap-example-with-gmail/
#   [3] http://www.faqs.org/rfcs/rfc3501.html
#
# Если возникает ошибка:
#   imaplib.error: b'[ALERT] Please log in via your web browser:
# https://support.google.com/mail/accounts/answer/78754 (Failure)'
#
# То для ее решения выполняем следующие действия:
#   1. On your computer, open Gmail.
#   2. In the top right, click Settings Settings.
#   3. Click Settings.
#   4. Click the Forwarding and POP/IMAP tab.
#   5. In the "IMAP Access" section, select Enable IMAP.
#   6. Click Save Changes.
#
# Потом заходим сюда https://myaccount.google.com/lesssecureapps и
# переключаем ползунок на ON.
#
# Собственно, делаем все то, что написано по ссылке (
# https://support.google.com/mail/accounts/answer/78754).
import email
from imaplib import IMAP4, IMAP4_SSL


class MailDumper:

  def __init__(self, imap_host, imap_user, imap_pass, imap_port=None,
               imap_ssl=False):
    self.imap_host = imap_host
    self.imap_user = imap_user
    self.imap_pass = imap_pass
    self.imap_port = imap_port
    self.imap_ssl = imap_ssl
    self.connect()
    self.login()

  def connect(self):
    imap_cls = IMAP4_SSL if self.imap_ssl else IMAP4
    if self.imap_port is not None:
      self.client = imap_cls(self.imap_host, self.imap_port)
    else:
      self.client = imap_cls(self.imap_host)

  def login(self):
    self.client.login(self.imap_user, self.imap_pass)

  def logout(self):
    self.client.logout()

  # ...

  def get_folders(self):
    typ, data = self.client.list()
    assert(typ == 'OK')
    return data

  # ...

  def dump(self, mailbox):
    typ, data = self.client.select(mailbox, True)
    assert(typ == 'OK')
    # 'data' is count of messages in mailbox ('EXISTS' response).
    # Это точно не количество!
    print(data)
    # typ, data = self.client.search(None, 'ALL')
    # assert (typ == 'OK')
    # message_ids = data[0].split()
    # print(message_ids)
    typ, data = self.client.uid('search', None, 'ALL')
    assert(typ == 'OK')
    email_uids = data[0].split()
    # Тут нужно создавать треды и сохранять письма
    for email_uid in email_uids:
      typ, data = self.client.uid('fetch', email_uid, '(RFC822)')
      message = email.message_from_bytes(data[0][1])
      print('Subject:', message['subject'])
      print('From:', message['from'])
      for part in message.walk():
        print(part.get_content_type())
        if part.get_content_maintype() == 'text':
          # print(part.get_content_subtype())
          charset = part.get_content_charset('iso-8859-1')
          data = part.get_payload(decode=True)
          print(data.decode(charset))
        else:
          print('[Skipped]')
      print('-' * 40)


if __name__ == '__main__':
  # Gmail requires use SSL
  dumper = MailDumper('imap.gmail.com', 'sergey.m@upsafe.com', 'wri15hp0fx',
                      imap_ssl=True)
  print('Existing Folders:', dumper.get_folders())
  dumper.dump('inbox')
  dumper.logout()