# coding: utf-8
"""
:mod:`imaputils` --- Extra IMAPv4 utilities
-------------------------------------------
"""
import imaplib, ssl, email
import re
from functools import wraps
from imapclient.response_parser import parse_fetch_response
from modoboa.lib import parameters
from modoboa.lib.connections import *
from modoboa.lib.webutils import static_url
from exceptions import ImapError

#imaplib.Debug = 4

class capability(object):
    """
    Simple decorator to check if the server presents the required
    capability. If not, a fallback method is called instead.

    :param name: the capability name (upper case)
    :param fallback_method: a method's name
    """
    def __init__(self, name, fallback_method):
        self.name = name
        self.fallback_method = fallback_method

    def __call__(self, method):
        @wraps(method)
        def wrapped_func(cls, *args, **kwargs):
            if self.name in cls.m.capabilities:
                return method(cls, *args, **kwargs)
            return getattr(cls, self.fallback_method)(*args, **kwargs)

        return wrapped_func


class IMAPconnector(object):
    __metaclass__ = ConnectionsManager

    list_base_pattern = r'\((?P<flags>.*?)\) "(?P<delimiter>.*)" "(?P<name>[^"]*)"'
    list_response_pattern = re.compile(list_base_pattern)
    listextended_response_pattern = \
        re.compile(list_base_pattern + r'\s*(?P<childinfo>.*)')
    unseen_pattern = re.compile(r'[^\(]+\(UNSEEN (\d+)\)')

    def __init__(self, user=None, password=None):
        self.criterions = []
        self.address = parameters.get_admin("IMAP_SERVER")
        self.port = int(parameters.get_admin("IMAP_PORT"))
        status, msg = self.login(user, password)
        if not status:
            raise Exception(msg)

    def _cmd(self, name, *args):
        """IMAP command wrapper

        To simplify errors handling, this wrapper calls the
        appropriate method (``uid`` or FIXME) and then check the
        return code. If an error has occured, an ``ImapError``
        exception is raised.

        For specific commands commands (FETCH, ...), the result is
        parsed using the IMAPclient module before being returned.

        :param name: the command's name
        :return: the command's result
        """
        if name in ['FETCH', 'SORT', 'STORE', 'COPY']:
            try:
                typ, data = self.m.uid(name, *args)
            except imaplib.IMAP4.error, e:
                raise ImapError(e)
            if typ == "NO":
                raise ImapError(data)
            if name == 'FETCH':
                return parse_fetch_response(data)
            return data

        try:
            typ, data = self.m._simple_command(name, *args)
        except imaplib.IMAP4.error, e:
            raise ImapError(e)
        if typ == "NO":
            raise ImapError(data)
        if not name in self.m.untagged_responses:
            return None
        return self.m.untagged_responses.pop(name)

    def __find_content_in_bodystruct(self, bodystruct, mtype, stype, prefix=""):
        """Retrieve the number (index) of a specific part

        This part number will generally be used inside a FETCH request
        to specify a ``BODY.PEEK`` section.

        :param bodystruct: a BODYSTRUCTURE list
        :param mtype: the MIME main type (like text)
        :param stype: the MIME sub type (like plain)
        :param prefix: the prefix that will be added to the current part number
        :return: a tuple (index (None on error), encoding (string), size (int))
        """
        if type(bodystruct[0]) in [list, tuple]:
            cpt = 1
            for part in bodystruct[0]:
                nprefix = "%s" % cpt if prefix == "" else "%s.%d" % (prefix, cpt)
                index, encoding, size = \
                    self.__find_content_in_bodystruct(bodystruct[0], mtype, stype, nprefix)
                if index:
                    return (index, encoding, size)
                cpt += 1

        if bodystruct[0] == mtype and bodystruct[1] == stype:
            return ("1" if not len(prefix) else prefix, bodystruct[5], int(bodystruct[6]))
        return (None, None, 0)

    def refresh(self, user, password):
        """Check if current connection needs a refresh

        Is it really secure?
        """
        if self.m is not None:
            try:
                self.m.select()
                return
            except imaplib.IMAP4.error, error:
                print error          
        print self.login(user, password)


    def login(self, user, passwd):
        try:
            secured = parameters.get_admin("IMAP_SECURED")
            if secured == "yes":
                self.m = imaplib.IMAP4_SSL(self.address, self.port)
            else:
                self.m = imaplib.IMAP4(self.address, self.port)
        except (socket.error, imaplib.IMAP4.error, ssl.SSLError), error:
            return False, _("Connection to IMAP server failed, check your configuration")
        try:
            self.m.login(user, passwd)
        except (imaplib.IMAP4.error, ssl.SSLError), error:
            return False, _("Authentication failed, check your configuration")
        return True, None

    def logout(self):
        try:
            self.m.select()
        except imaplib.IMAP4.error:
            pass
        self.m.logout()
        del self.m
        self.m = None

    def messages_count(self, **kwargs):
        """An enhanced version of messages_count

        With IMAP, to know how many messages a mailbox contains, we
        have to make a request to the server. To avoid requests
        multiplications, we sort messages in the same time. This will
        be usefull for other methods.

        :param order: sorting order
        :param folder: mailbox to scan
        """
        if "order" in kwargs.keys() and kwargs["order"]:
            sign = kwargs["order"][:1]
            criterion = kwargs["order"][1:].upper()
            if sign == '-':
                criterion = "REVERSE %s" % criterion
        else:
            criterion = "REVERSE DATE"
        folder = kwargs.has_key("folder") and kwargs["folder"] or None
        self.select_mailbox(folder, False)
        data = self._cmd("SORT", "(%s)" % criterion, "UTF-8", "(NOT DELETED)",
                         *self.criterions)
        self.messages = data[0].split()
        self.getquota(folder)
        return len(self.messages)

    def select_mailbox(self, name, readonly=True):
        """Issue a SELECT/EXAMINE command to the server

        The given name is first 'imap-utf7' encoded.
        
        :param name: mailbox's name
        :param readonly: 
        """
        name = name.encode("imap4-utf-7")
        if readonly:
            self._cmd("EXAMINE", name)
        else:
            self._cmd("SELECT", name)

    def unseen_messages(self, mailbox):
        """Return the number of unseen messages

        :param mailbox: the mailbox's name
        :return: an integer
        """
        # self.select_mailbox(mailbox)
        # data = self._cmd("SEARCH", "UTF-8", "(NOT DELETED UNSEEN)")
        # return len(data[0].split())
        data = self._cmd("STATUS", mailbox.encode("imap4-utf-7"), "(UNSEEN)")
        m = self.unseen_pattern.match(data[0])
        if m is None:
            return 0
        return int(m.group(1))

    def _encodefolder(self, folder):
        if not folder:
            return "INBOX"
        return folder.encode("imap4-utf-7")

    def _parse_folder_name(self, descr, prefix, delimiter, parts):
        if not len(parts):
            return False
        path = "%s%s%s" % (prefix, delimiter, parts[0])
        sdescr = None
        for d in descr:
            if d["path"] == path:
                sdescr = d
                break
        if sdescr is None:
            sdescr = {"name" : parts[0], "path" : path, "sub" : []}
            descr += [sdescr]            
        if self._parse_folder_name(sdescr["sub"], path, delimiter, parts[1:]):
            sdescr["class"] = "subfolders"
        return True

    def _listfolders_simple(self, topmailbox='INBOX', md_mailboxes=[]):
        (status, data) = self.m.list()
        result = []
        for mb in data:
            flags, delimiter, name = self.list_response_pattern.match(mb).groups()
            name = name.strip('"').decode("imap4-utf-7")
            if re.search("\%s" % delimiter, name):
                parts = name.split(".")
                if not descr.has_key("path"):
                    descr["path"] = parts[0]
                    descr["sub"] = []
                if self._parse_folder_name(descr["sub"], parts[0], delimiter, 
                                           parts[1:]):
                    descr["class"] = "subfolders"
                continue
            present = False
            descr = {"name" : name}
            for mdf in md_mailboxes:
                if mdf["name"] == name:
                    present = True
                    break
            if not present:
                result += [descr]
        from operator import itemgetter
        return sorted(result, key=itemgetter("name"))

    @capability('LIST-EXTENDED', '_listfolders_simple')
    def _listfolders(self, topmailbox='', md_mailboxes=[]):
        pattern = ("%s.%%" % topmailbox.encode("imap4-utf-7")) if len(topmailbox) else "%"
        resp = self._cmd("LSUB", "", pattern, "RETURN", "(CHILDREN)")
        result = []
        for mb in resp:
            flags, delimiter, name, childinfo = \
                self.listextended_response_pattern.match(mb).groups()
            flags = flags.split(' ')
            name = name.decode("imap4-utf-7")
            present = False
            for mdm in md_mailboxes:
                if mdm["name"] == name:
                    present = True
                    break
            if present:
                continue
            descr = dict(name=name)
            if r'\HasChildren' in flags:
                descr["path"] = name
                descr["sub"] = []
                descr["class"] = "subfolders"
            result += [descr]
        from operator import itemgetter
        return sorted(result, key=itemgetter("name"))

    def getfolders(self, user, topmailbox='', unseen_messages=True):
        if len(topmailbox):
            md_mailboxes = []
        else:
            md_mailboxes = [{"name" : "INBOX", "class" : "inbox"},
                            {"name" : parameters.get_user(user, "DRAFTS_FOLDER"), 
                             "class" : "drafts"},
                            {"name" : 'Junk'},
                            {"name" : parameters.get_user(user, "SENT_FOLDER")},
                            {"name" : parameters.get_user(user, "TRASH_FOLDER"),
                             "class" : "trash"}]
        md_mailboxes += self._listfolders(topmailbox, md_mailboxes)
        if unseen_messages:
            for fd in md_mailboxes:
                key = fd.has_key("path") and "path" or "name"
                count = self.unseen_messages(fd[key])
                if count == 0:
                    continue
                fd["unseen"] = count
        return md_mailboxes

    def _add_flag(self, mbox, msgset, flag):
        """Add flag(s) to a messages set

        :param mbox: the mailbox containing the messages
        :param msgset: messages set (uid)
        :param flag: the flag to add
        """
        self.select_mailbox(mbox, False)
        self._cmd("STORE", msgset, "+FLAGS", flag)

    def mark_messages_unread(self, mbox, msgset):
        """Mark a set of messages as unread

        :param mbox: the mailbox containing the messages
        :param msgset: messages set (uid)
        """
        self.select_mailbox(mbox, False)
        self._cmd("STORE", msgset, "-FLAGS", r'(\Seen)')

    def mark_messages_read(self, mbox, msgset):
        """Mark a set of messages as unread

        :param mbox: the mailbox containing the messages
        :param msgset: messages set (uid)
        """
        self._add_flag(mbox, msgset, r'(\Seen)')

    def msgforwarded(self, folder, imapid):
        self._add_flag(folder, imapid, '($Forwarded)')

    def msg_answered(self, folder, imapid):
        self._add_flag(folder, imapid, r'(\Answered)')

    def move(self, msgset, oldmailbox, newmailbox):
        """Move messages between mailboxes

        """
        self.select_mailbox(oldmailbox, False)
        self._cmd("COPY", msgset, newmailbox.encode("imap4-utf-7"))
        self._cmd("STORE", msgset, "+FLAGS", r'(\Deleted)')

    def push_mail(self, folder, msg):
        now = imaplib.Time2Internaldate(time.time())
        self.m.append(self._encodefolder(folder), r'(\Seen)', now, str(msg))

    def empty(self, mbox):
        self.select_mailbox(mbox, False)
        resp = self._cmd("SEARCH", "ALL")
        print resp
        
        # for num in data[0].split():
        #     self.m.store(num, "+FLAGS", r'(\Deleted)')
        # self.m.expunge()

    def compact(self, mbox):
        """Compact a specific mailbox

        Issue an EXPUNGE command for the specified mailbox.
        
        :param mbox: the mailbox's name
        """
        self.select_mailbox(mbox, False)
        self._cmd("EXPUNGE")

    def create_folder(self, name, parent=None):
        if parent is not None:
            name = "%s.%s" % (parent, name)
        typ, data = self.m.create(self._encodefolder(name))
        if typ == "NO":
            raise WebmailError(data[0])
        return True

    def rename_folder(self, oldname, newname):
        typ, data = self.m.rename(self._encodefolder(oldname),
                                  self._encodefolder(newname))
        if typ == "NO":
            raise WebmailError(data[0], ajax=True)
        return True

    def delete_folder(self, name):
        typ, data = self.m.delete(self._encodefolder(name))
        if typ == "NO":
            raise WebmailError(data[0])
        return True

    def getquota(self, folder):
        if not "QUOTA" in self.m.capabilities:
            self.quota_limit = self.quota_actual = None
            return

        status, data = self.m.getquotaroot(self._encodefolder(folder))
        if status == "OK":
            quotadef = data[1][0]
            m = re.match("[^\s]+ \(STORAGE (\d+) (\d+)\)", quotadef)
            if not m:
                print "Problem while parsing quota def"
                return
            self.quota_limit = int(m.group(2))
            self.quota_actual = int(m.group(1))

    def fetchpart(self, uid, folder, part):
        self.m.select(self._encodefolder(folder), True)
        typ, data = self.m.fetch(uid, "(BODY[%(p)s.MIME] BODY[%(p)s])" \
                                     % {"p" : part})
        if typ != "OK":
            return None
        msg = email.message_from_string(data[0][1] + data[1][1])
        return msg

    def fetch(self, start, stop=None, mbox=None, **kwargs):
        """Retrieve information about messages from the server

        Issue a FETCH command to retrieve information about one or
        more messages (such as headers) from the server.

        :param start: index of the first message
        :param stop: index of the last message (optionnal)
        :param mbox: the mailbox that contains the messages
        """
        self.select_mailbox(mbox, False)
        if start and stop:
            submessages = self.messages[start - 1:stop]
            range = ",".join(submessages)
        else:
            submessages = [start]
            range = start
        query = '(FLAGS BODY.PEEK[HEADER.FIELDS (DATE FROM TO CC SUBJECT)])'
        data = self._cmd("FETCH", range, query)
        result = []
        for uid in submessages:
            msg = email.message_from_string(data[int(uid)]['BODY[HEADER.FIELDS (DATE FROM TO CC SUBJECT)]'])
            msg['imapid'] = uid
            if not r'\Seen' in data[int(uid)]['FLAGS']:
                msg['class'] = 'unseen'
            if r'\Answered' in data[int(uid)]['FLAGS']:
                msg['img_flags'] = static_url('pics/answered.png')
            result += [msg]
        return result

    def fetchmail(self, mbox, mailid, fmt="plain"):
        """Retrieve information about a specific message

        Issue a FETCH command to retrieve a message's content from the
        server. In order to not overload the server, we first retrieve
        the BODYSTRUCTURE of the message. Then, according to the
        result and to the user's preferences, we retrieve the
        appropriate content (plain, html, etc.).

        :param mbox: the mailbox containing the message
        :param mailid: the message's unique id
        :param fmt: the desired content's format
        """
        self.select_mailbox(mbox, False)
        data = self._cmd("FETCH", mailid, "(BODYSTRUCTURE BODY.PEEK[HEADER.FIELDS (DATE FROM TO CC SUBJECT)])")
        content = data[int(mailid)]['BODY[HEADER.FIELDS (DATE FROM TO CC SUBJECT)]']

        fallback_fmt = "html" if fmt == "plain" else "plain"
        (pnum, encoding, size) = (None, None, 0)
        for f in [fmt, fallback_fmt]:
            pnum, encoding, size = \
                self.__find_content_in_bodystruct(data[int(mailid)]['BODYSTRUCTURE'],
                                                  "text", f)
            if pnum is not None and size:
                break
        if pnum is None:
            return None

        data = self._cmd("FETCH", mailid, "(BODY.PEEK[%s])" % pnum)

        data = data[int(mailid)]['BODY[%s]' % pnum]        
        if encoding == "base64":
            import base64
            content += base64.b64decode(data)
        elif encoding == "quoted-printable":
            import quopri
            content += quopri.decodestring(data)
        else:
            content += data

        return email.message_from_string(content)

def get_imapconnector(request):
    imapc = IMAPconnector(user=request.user.username, 
                          password=request.session["password"])
    return imapc