#!/usr/bin/python2

import smtplib
from time import strftime,ctime
from sys import argv
import hashlib


def parse_file_to_send(filename):

    try:
        data = file(filename).read()
    except IOError:
        print 'Error in reading file %s' % filename
        return None

    try:
        head,body = data.split('\n\n',1)
    except:
        print 'Malformed email: unable to split head and body'
        return None

    parameters = {}
    for headline in head.split('\n'):
        try:
            field,value = headline.split(':',1)
        except:
            print 'Malformed header line: %s' % headline
            return None
        if value.strip() != '':
            parameters[field] = value.strip()

    parameters['Message'] = body
    print 'File OK'
    return parameters


def extract_addresses(address_string):

    rtn = []
    fields = address_string.split(', ')
    while fields:

        addr = fields.pop(0)
        while fields and (1 == addr.count('"') % 2):
            addr += ', ' + fields.pop(0)
        if addr:
            rtn.append(addr)

    return rtn


def send_message( dict_of_fields, Debug=False ):
# We expect a dictionary, keys include:
#   From
#   To       Comma separated list
#   Subject
#   Message
# Optional
#   CC       Comma separated list
#   BCC      Comma separated list
# We insert the date

    required_fields = [ 'From', 'To', 'Subject' ]
    for f in required_fields:
        if f not in dict_of_fields:
            return 'Require "%s" field' % f

    if 'Message' not in dict_of_fields:
        return 'Require "%s" field' % 'Message'

    possible_fields = [ 'CC', 'BCC', 'MIME-Version'   , 'Content-Type', \
                        'Content-Transfer-Encoding'   , 'Reply-To',     \
                        'Return-Path', 'Mail-Reply-To', 'Message-ID',   \
                        ]

    msg_id_hdr = 'Message-ID'
    if msg_id_hdr not in dict_of_fields:
        msg_id = '<'
        msg_id += strftime('%Y%m%d%H%M%S_')
        msg_id += hashlib.md5(dict_of_fields['Message'].encode('utf-8')).hexdigest()[:8]
        msg_id += '@solipsys.co.uk'
        msg_id += '>'
        dict_of_fields[ msg_id_hdr ] = msg_id

    for f in possible_fields:
        if f not in dict_of_fields:
            dict_of_fields[f] = ''

    to_addrs = extract_addresses( dict_of_fields['To'] )
    to_addrs += extract_addresses( dict_of_fields['CC'] )
    to_addrs += extract_addresses( dict_of_fields['BCC'] )

    message = ''
    for f in required_fields:
        message += '%s: %s\n' % (f,dict_of_fields[f])
    for f in possible_fields:
        if f in dict_of_fields and dict_of_fields[f] != '' and f!='BCC':
            message += '%s: %s\n' % (f,dict_of_fields[f])
    message += strftime('Date: %a, %d %b %Y %H:%M:%S %z\n')

    message += '\n'
    message += dict_of_fields['Message']

    server_host_name = 'EMAIL_HOST'
    username = 'USERNAME'
    password = 'PASSWORD'

    print 'Sending message'

    server = smtplib.SMTP(server_host_name,587)
    server.set_debuglevel(0)
    server.ehlo()
    server.starttls()
    server.ehlo()
    server.login(username, password)
    server.sendmail(dict_of_fields['From'], to_addrs, message)
    server.quit()

    return 'OK'


if __name__=='__main__':

    Debug = True
    Debug = False

    files_sent = False
    for file_to_send in argv[1:]:
        parameters = parse_file_to_send(file_to_send)
        if parameters:
            print send_message(parameters,Debug)
            files_sent = True

    if not files_sent:
        parameters = {
            'Reply-To': 'test_reply@solipsys.co.uk',
            'From'    : 'test_from@solipsys.co.uk',
            'To'      : 'test_to@solipsys.co.uk',
            'Subject' : 'Test Subject',
            'CC'      : 'test_cc@solipsys.co.uk',
            'BCC'     : 'text_bcc@solipsys.co.uk',
            'Message' : '',
            }
        parameters['Message'] = '''
> 'Reply-To': 'test_reply@solipsys.co.uk',
> 'From'    : 'test_from@solipsys.co.uk',
> 'To'      : 'test_to@solipsys.co.uk',
> 'Subject' : 'Test Subject',
> 'CC'      : 'test_cc@solipsys.co.uk',
> 'BCC'     : 'text_bcc@solipsys.co.uk',
'''

        print send_message(parameters,Debug)