#!/usr/bin/python
import re
import StringIO
import warnings

from backwardlines import BackwardLines

class CouldntParse(Warning): pass

class Address:
    def __init__(self, addr):
        self.text = addr
        mo = re.search(r'<(.*?)>', addr) # XXX rre trucho
        if not mo:
            mo = re.match(r'\s*(?:\(.*\)\s*)?(\S+@\S+)\s*(?:\(.*\)\s*)?', addr)
        if mo:
            self.address = mo.group(1)
        else:
            warnings.warn(addr, CouldntParse, 0)
            self.address = addr

def parse_address_list(s):
    return [Address(addr) for addr in s.split(',')]

class BackwardMessage:
    def __init__(self):
        self.headers = {}
        self.continuations = []
        self.header_lines = []

    def get(self, name, default=None):
        return self.headers.get(name, default)

    def __getitem__(self, name):
        return self.headers[name]

    def parse(self, line):
        if line == '\n':
            self.header_lines = []
        elif line.startswith('From '):
            self.parse_header_lines()
        else:
            self.header_lines.append(line)

    def parse_header_lines(self):
        for line in self.header_lines:
            self.parse_header_line(line)

    def parse_header_line(self, line):
        if line[0] in ' \t':
            self.continuations.append(line)
        else:
            mo = re.match(r'(.*?):\s*(.*)', line)
            if mo:
                header_name = mo.group(1).lower()
                header_contents = mo.group(2)
                header_contents += ''.join(reversed(self.continuations))

                if header_name in ['from', 'to']:
                    header_contents = parse_address_list(header_contents)

                self.headers[header_name] = header_contents

            self.continuations = []

class BackwardReadingMailbox:
    def __init__(self, mailbox):
        self.mailbox = mailbox

    def __iter__(self):
        current_message = BackwardMessage()
        for line in BackwardLines(self.mailbox):
            current_message.parse(line)
            if line.startswith('From '):
                yield current_message
                current_message = BackwardMessage()

def recipients(mailbox):
    return set(addr.address
               for message in BackwardReadingMailbox(mailbox)
               for addr in message.get('to', []))

def rendition(number):
    return '\033[%sm' % number

def message_summary(message):
    address = message.get('from', ['nobody'])[0].address[:25]
    subject = message.get('subject', '')[:79 - len(address)]
    return '%s%s %s%s%s' % (rendition(2), address, rendition('0;31'), subject, rendition(0))

test_message = """From somebody
From: a <b@example.org>
To: c <d@example.org>
Subject: hello

hi there
you: go!
"""

test_mbox_2 = """From a
To: e <f@example.org>,
    g <h@example.org>

!
From d
To: you <you@example.org>, kragen-journal@canonical.org

"""


def test():
    sio = StringIO.StringIO(test_message)
    i = 0
    for message in BackwardReadingMailbox(sio):
        i += 1
        ok(message['subject'], 'hello')
        ok(message['from'][0].address, 'b@example.org')
        ok(message['to'][0].address, 'd@example.org')
        ok(message_summary(message), '\033[2mb@example.org \033[0;31mhello\033[0m')
    ok(i, 1)

    sio = StringIO.StringIO(test_mbox_2)
    messages = list(BackwardReadingMailbox(sio))
    ok(len(messages), 2)
    ok(messages[0]['to'][0].text, 'you <you@example.org>')
    ok([addr.address for addr in messages[1]['to']], 
       ['f@example.org', 'h@example.org'])
    ok(recipients(sio), 
       set(['you@example.org', 
            'f@example.org',
            'h@example.org',
            'kragen-journal@canonical.org',
            ]))

    ok(Address('MAILER-DAEMON@canonical.org (Mail Delivery Subsystem)').address,
       'MAILER-DAEMON@canonical.org')

def ok(a, b): assert a == b, (a, b)

test()

def main(outbox, inbox):
    important_senders = recipients(outbox)

    i = 0
    for message in BackwardReadingMailbox(inbox):
        if message['from'][0].address in important_senders:
            print_message_summary(message)
            i += 1
            if i > 20: break

if __name__ == '__main__':
    main(open('/home/kragen/mail/panacea-sent-mail'),
         open('/home/kragen/mbox'))