'''
Task Coach - Your friendly task manager
Copyright (C) 2004-2014 Task Coach developers <developers@taskcoach.org>

Task Coach is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

Task Coach is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.
'''

from taskcoachlib import persistence, operating_system
from taskcoachlib.thirdparty.ntlm import IMAPNtlmAuthHandler
from taskcoachlib.widgets.password import GetPassword
from taskcoachlib.i18n import _
import os
import stat
import re
import imaplib
import ConfigParser
import wx
import socket
import mailbox


_RX_MAILBOX_MESSAGE = re.compile(r'mailbox-message://(.*)@(.*)/(.*)#((?:-)?\d+)')
_RX_IMAP_MESSAGE = re.compile(r'imap-message://([^@]+)@([^/]+)/(.*)#(\d+)')
_RX_IMAP = re.compile(r'imap://([^@]+)@([^/]+)/fetch%3EUID%3E(?:/|\.)(.*)%3E(\d+)')
_RX_MAILBOX = re.compile(r'mailbox://([^?]+)\?number=(\d+)')


class ThunderbirdError(Exception):
    pass


class ThunderbirdCancelled(ThunderbirdError):
    pass


def unquote(s):
    """Converts %nn sequences into corresponding characters. I
    couldn't find anything in the standard library to do this, but I
    probably didn't search hard enough."""

    rx = re.compile('%([0-9a-fA-F][0-9a-fA-F])')
    mt = rx.search(s)
    while mt:
        s = s[:mt.start(1) - 1] + chr(int(mt.group(1), 16)) + s[mt.end(1):]
        mt = rx.search(s)

    return s


def loadPreferences():
    """Reads Thunderbird's prefs.js file and return a dictionary of
    configuration options."""

    config = {}

    def user_pref(key, value):
        config[key] = value

    for line in file(os.path.join(getDefaultProfileDir(), 'prefs.js'), 'r'):
        if line.startswith('user_pref('):
            # pylint: disable=W0122
            exec line in {'user_pref': user_pref, 'true': True, 'false': False}

    return config


def getThunderbirdDir():
    path = None

    if operating_system.isMac():
        path = os.path.join(os.environ['HOME'], 'Library', 'Thunderbird')
    elif os.name == 'posix':
        path = os.path.join(os.environ['HOME'], '.thunderbird')
        if not os.path.exists(path):
            path = os.path.join(os.environ['HOME'], '.mozilla-thunderbird')
    elif os.name == 'nt':
        if os.environ.has_key('APPDATA'):
            path = os.path.join(os.environ['APPDATA'], 'Thunderbird')
        elif os.environ.has_key('USERPROFILE'):
            path = os.path.join(os.environ['USERPROFILE'], 'Application Data', 'Thunderbird')
    else:
        raise EnvironmentError('Unsupported platform: %s' % os.name)

    if path is None:
        raise ThunderbirdError(_('Could not find Thunderbird data dir'))

    return path

_PORTABLECACHE = None


def getDefaultProfileDir():
    """Returns Thunderbird's default profile directory"""

    global _PORTABLECACHE  # pylint: disable=W0603

    path = getThunderbirdDir()

    # Thunderbird Portable does not have a profiles.ini file, only one
    # profile. And there's only one way to know where it
    # is... Hackish.

    if os.name == 'nt' and not os.path.exists(os.path.join(path, 'profiles.ini')):
        if _PORTABLECACHE is not None:
            return _PORTABLECACHE

        from taskcoachlib.thirdparty import wmi  # pylint: disable=W0404

        for process in wmi.WMI().Win32_Process():
            if process.ExecutablePath and process.ExecutablePath.lower().endswith('thunderbirdportable.exe'):
                _PORTABLECACHE = os.path.join(os.path.split(process.ExecutablePath)[0], 'Data', 'profile')
                break
        else:
            raise ThunderbirdError(_('Could not find Thunderbird profile.'))

        return _PORTABLECACHE

    parser = ConfigParser.RawConfigParser()
    parser.read([os.path.join(path, 'profiles.ini')])

    for section in parser.sections():
        if parser.has_option(section, 'Default') and int(parser.get(section, 'Default')):
            if int(parser.get(section, 'IsRelative')):
                return os.path.join(path, parser.get(section, 'Path'))
            return parser.get(section, 'Path')

    for section in parser.sections():
        if parser.has_option(section, 'Name') and parser.get(section, 'Name') == 'default':
            if int(parser.get(section, 'IsRelative')):
                return os.path.join(path, parser.get(section, 'Path'))
            return parser.get(section, 'Path')

    raise ThunderbirdError(_('No default section in profiles.ini'))


class ThunderbirdMailboxReader(object):
    """Extracts an e-mail from a Thunderbird file. Behaves like a
    stream object to read this e-mail."""

    def __init__(self, url):
        """url is the internal reference to the mail, as collected
        through drag-n-drop."""

        mt = _RX_MAILBOX_MESSAGE.search(url)
        if mt is None:
            raise ThunderbirdError(_('Malformed Thunderbird internal ID:\n%s. Please file a bug report.') % url)

        self.url = url

        # The url has the form
        # mailbox-message://<username>@<hostname>//<filename>#<id>. Or
        # so I hope.

        config = loadPreferences()

        self.user = unquote(mt.group(1))
        self.server = unquote(mt.group(2))
        self.path = unquote(mt.group(3)).split('/')
        self.offset = long(mt.group(4))

        for i in xrange(200):
            base = 'mail.server.server%d' % i
            if config.has_key('%s.userName' % base):
                if config['%s.userName' % base] == self.user and config['%s.hostname' % base] == self.server:
                    # First try the relative path.
                    if config.has_key('%s.directory-rel' % base):
                        path = config['%s.directory-rel' % base]
                        if path.startswith('[ProfD]'):
                            path = os.path.join(getDefaultProfileDir(), path[7:])
                        self.filename = os.path.join(path, *tuple(self.path))
                        if os.path.exists(self.filename):
                            break
                        else:
                            self.filename = os.path.join(config['%s.directory' % base], *tuple(self.path))
                            if os.path.exists(self.filename):
                                break
        else:
            raise ThunderbirdError(_('Could not find directory for ID\n%s.\nPlease file a bug report.') % url)

        self.fp = file(self.filename, 'rb')
        if self.offset >= 0:
            self.fp.seek(self.offset)
        else:
            self.fp.seek(self.offset, os.SEEK_END)

        self.done = False

    def read(self):
        """Buffer-like read() method"""

        if self.done:
            return ''

        lines = []

        # In theory, the message ends with a single dot. As always, in
        # theory, theory is like practice but in practice...

        starting = True

        for line in self.fp:
            if not starting:
                if line.startswith('From '):
                    break
            lines.append(line)
            starting = False

        self.done = True
        return ''.join(lines)

    def __iter__(self):
        class Iterator(object):
            def __init__(self, fp):
                self.fp = fp

            def __iter__(self):
                return self

            def next(self):
                line = self.fp.readline()
                if line.strip() == '.':
                    raise StopIteration
                return line

        return Iterator(self.fp)

    def saveToFile(self, fp):
        fp.write(self.read())


class ThunderbirdImapReader(object):
    def __init__(self, url):
        mt = _RX_IMAP.search(url)
        if mt is None:
            mt = _RX_IMAP_MESSAGE.search(url)
            if mt is None:
                raise ThunderbirdError(_('Unrecognized URL scheme: "%s"') % url)

        self.url = url

        self.user = unquote(mt.group(1))
        self.server = mt.group(2) 
        port = None
        if ':' in self.server:
            self.server, port = self.server.split(':')
            port = int(port)
        self.box = mt.group(3)
        self.uid = int(mt.group(4))

        config = loadPreferences()

        stype = None
        # We iterate over a maximum of 100 mailservers. You'd think that
        # mailservers would be numbered consecutively, but apparently
        # that is not always the case, so we cannot assume that because
        # serverX does not exist, serverX+1 won't either. 
        for serverIndex in range(100): 
            name = 'mail.server.server%d' % serverIndex
            if config.has_key(name + '.hostname') and \
                self.__equal_servers(config[name + '.hostname'], self.server) \
                and config[name + '.type'] == 'imap':
                if config.has_key(name + '.port'):
                    port = int(config[name + '.port'])
                if config.has_key(name + '.socketType'):
                    stype = config[name + '.socketType']
                break
        self.ssl = (stype == 3)

        if self.server in ('imap.google.com', 'imap.googlemail.com'):
            # When dragging mail from Thunderbird that uses Gmail via IMAP the
            # server reported is imap.google.com, but for a direct connection we
            # need to connect with imap.gmail.com:
            self.server = 'imap.gmail.com'
        elif config.has_key(name + '.realhostname'):
            self.server = config[name + '.realhostname']
        self.port = port or {True: 993, False: 143}[self.ssl]
        
    @staticmethod
    def __equal_servers(server1, server2):
        ''' Return whether the servers are the same. '''
        gmail_servers = ('imap.gmail.com', 'imap.google.com', 
                         'imap.googlemail.com')
        if server1 in gmail_servers and server2 in gmail_servers:
            return True
        else:
            return server1 == server2

    def _getMail(self):
        ''' Retrieve the email message from the IMAP server as specified by
            the dropped URL. '''
        imap_class = imaplib.IMAP4_SSL if self.ssl else imaplib.IMAP4
        try:
            imap = imap_class(self.server, self.port)
        except socket.gaierror, reason:
            error_message = _('Could not open an IMAP connection to '
                              '%(server)s:%(port)s\nto retrieve Thunderbird '
                              'email message:\n%(reason)s') % \
                              dict(server=self.server, port=self.port, 
                                   reason=reason)
            raise ThunderbirdError(error_message)

        password_domain = '%s:%d' % (self.server, self.port)
        pwd = GetPassword(password_domain, self.user)
        if pwd is None:
            raise ThunderbirdCancelled('User canceled')

        while True:
            try:
                if 'AUTH=CRAM-MD5' in imap.capabilities:
                    response, dummy = imap.login_cram_md5(str(self.user), 
                                                          str(pwd))
                elif 'AUTH=NTLM' in imap.capabilities:
                    domain = wx.GetTextFromUser( \
                        _('Please enter the domain for user %s') % self.user)
                    domain_username = '\\'.join([domain.upper(), 
                                                 str(self.user)])
                    response, dummy_parameters = imap.authenticate('NTLM', 
                        IMAPNtlmAuthHandler.IMAPNtlmAuthHandler( \
                            domain_username, str(pwd)))
                else:
                    response, dummy_parameters = imap.login(self.user, pwd)
            except imap.error, reason:
                response = 'KO'
                error_message, = reason.args

            if response == 'OK':
                break

            pwd = GetPassword(password_domain, self.user, reset=True)
            if pwd is None:
                raise ThunderbirdCancelled('User canceled')

        # Two possibilities for separator...

        response, dummy_parameters = imap.select(self.box)

        if response != 'OK':
            response, dummy_parameters = imap.select(self.box.replace('/', '.'))
            if response != 'OK':
                raise ThunderbirdError(_('Could not select inbox "%s"\n(%s)') \
                                       % (self.box, response))

        response, parameters = imap.uid('FETCH', str(self.uid), '(RFC822)')

        if response != 'OK':
            raise ThunderbirdError(_('No such mail: %d') % self.uid)

        return parameters[0][1]

    def saveToFile(self, fp):
        fp.write(self._getMail())


class ThunderbirdLocalMailboxReader(object):
    ''' Reads email from a local Thunderbird mailbox. '''
    def __init__(self, url):
        self.url = url
        
    def _getMail(self):
        match = _RX_MAILBOX.match(self.url)
        if match is None:
            raise ThunderbirdError(_('Unrecognized URL scheme: "%s"') % self.url)
        path = unquote(match.group(1))
        # Note that the number= part of the URL is not the message key, but
        # rather an offset in the mbox file.
        offset = int(match.group(2))
        # So we skip the first offset bytes before reading the contents:
        with file(path, 'rb') as mbox:
            mbox.seek(offset)
            contents = mbox.read(4 * 1024 * 1024)  # Assume message size <= 4MB
        # Then we get a filename for a temporary file...
        filename = persistence.get_temp_file()
        # And save the remaining contents of the original mbox file: 
        with file(filename, 'wb') as tmpmbox:
            tmpmbox.write(contents)
        # Now we can open the temporary mbox file...
        mb = mailbox.mbox(filename)
        # And the message we look for should be the first one:
        return mb.get_string(0)
        
    def saveToFile(self, fp):
        fp.write(self._getMail())
    

def getMail(id_):
    if id_.startswith('mailbox-message://'):
        reader = ThunderbirdMailboxReader(id_)
    elif id_.startswith('imap'):
        reader = ThunderbirdImapReader(id_)
    elif id_.startswith('mailbox:'):
        reader = ThunderbirdLocalMailboxReader(id_)
    else:
        raise TypeError('Not supported: %s' % id_)

    filename = persistence.get_temp_file(suffix='.eml')
    reader.saveToFile(file(filename, 'wb'))

    if os.name == 'nt':
        os.chmod(filename, stat.S_IREAD)

    return filename