#!/usr/bin/env python

import imaplib
import smtplib
import datetime
from email.parser import BytesParser
from email.message import EmailMessage
from email.policy import default

from dateutil import parser

def process_mailbox(M):
    rv, data = M.search(None, 'UNSEEN')
    if rv != 'OK':
        print('Failed to search for UNSEEN messages')
        return [], -1

    mails = []
    n_failures = 0
    for num in data[0].split():
        rv, data = M.fetch(num, '(RFC822)')
        if rv != 'OK':
            print('Error fetching message from server: {}'.format(num))
            n_failures += 1

        msg = BytesParser(policy=default).parsebytes(data[0][1])
        mails.append({
            'date': msg['Date'],
            'subject': msg['Subject']
        })

    return mails, n_failures

mailboxes = ['Notifications/NPPC/Updates', 'Notifications/NPPC/Uptime', 'Notifications/NPPC/Icinga']
credential_file = './account'

creds = None
with open(credential_file) as f:
    creds = f.readlines()

creds = [line.rstrip('\n') for line in creds]

M = imaplib.IMAP4_SSL(creds[2])

try:
    M.login(creds[0], creds[1]) 
except imaplib.IMAP4.error:
    print('Login Failed')
    exit(1)

all_messages = {}

for box in mailboxes:
    rv, data = M.select(box)
    if rv != 'OK':
        print('Failed to open {}'.format(box)) 
        exit(1)


    all_messages[box] = process_mailbox(M)

email_content = [] 
for box, messages in all_messages.items():

    ms = sorted(messages[0], 
                key=lambda m: parser.parse(m['date']))

    content = '{} failures to fetch messages in {}\n'.format(messages[1], box)
    ms = ["{}: {}".format(m['date'], m['subject'])
          for m in ms]
    content += '\n'.join(ms)
    email_content.append(content)

email_content = '\n\n'.join(email_content)

summary = EmailMessage()
summary.set_content(email_content)
summary['Subject'] = datetime.datetime.now().strftime('Summary of emails on %c')
summary['From'] = 'maf54@aber.ac.uk'
summary['To'] = 'maf54@aber.ac.uk'

s = smtplib.SMTP('smtphost.aber.ac.uk')
s.sendmail('maf54@aber.ac.uk', 'maf54@aber.ac.uk', summary.as_string())
s.quit()

M.close()
M.logout()