# -*- coding: utf-8 -*-
# account.py
# Copyright (C) 2013 LEAP
#
# This program 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.
#
# This program 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/>.
"""
Soledad Backed Account.
"""
import copy
import time

from twisted.mail import imap4
from zope.interface import implements

from leap.common.check import leap_assert, leap_assert_type
from leap.mail.imap.index import IndexedDB
from leap.mail.imap.fields import WithMsgFields
from leap.mail.imap.parser import MBoxParser
from leap.mail.imap.mailbox import SoledadMailbox
from leap.soledad.client import Soledad


#######################################
# Soledad Account
#######################################


def _unicode_as_str(text):
    """
    Return some representation of C{text} as a str.

    This is here mainly because Twisted's exception methods are not able to
    print unicode text.

    :param text: The text to convert.
    :type text: unicode

    :return: A representation of C{text} as str.
    :rtype: str
    """
    # XXX is there a better str representation for unicode?
    return repr(text)


class SoledadBackedAccount(WithMsgFields, IndexedDB, MBoxParser):
    """
    An implementation of IAccount and INamespacePresenteer
    that is backed by Soledad Encrypted Documents.
    """

    implements(imap4.IAccount, imap4.INamespacePresenter)

    _soledad = None
    selected = None

    def __init__(self, account_name, soledad=None):
        """
        Creates a SoledadAccountIndex that keeps track of the mailboxes
        and subscriptions handled by this account.

        :param acct_name: The name of the account (user id).
        :type acct_name: str

        :param soledad: a Soledad instance.
        :param soledad: Soledad
        """
        leap_assert(soledad, "Need a soledad instance to initialize")
        leap_assert_type(soledad, Soledad)

        # XXX SHOULD assert too that the name matches the user/uuid with which
        # soledad has been initialized.

        self._account_name = self._parse_mailbox_name(account_name)
        self._soledad = soledad

        self.initialize_db()

        # every user should have the right to an inbox folder
        # at least, so let's make one!

        if not self.mailboxes:
            self.addMailbox(self.INBOX_NAME)

    def _get_empty_mailbox(self):
        """
        Returns an empty mailbox.

        :rtype: dict
        """
        return copy.deepcopy(self.EMPTY_MBOX)

    def _get_mailbox_by_name(self, name):
        """
        Return an mbox document by name.

        :param name: the name of the mailbox
        :type name: str

        :rtype: SoledadDocument
        """
        doc = self._soledad.get_from_index(
            self.TYPE_MBOX_IDX, self.MBOX_KEY,
            self._parse_mailbox_name(name))
        return doc[0] if doc else None

    @property
    def mailboxes(self):
        """
        A list of the current mailboxes for this account.
        """
        return [doc.content[self.MBOX_KEY]
                for doc in self._soledad.get_from_index(
                    self.TYPE_IDX, self.MBOX_KEY)]

    @property
    def subscriptions(self):
        """
        A list of the current subscriptions for this account.
        """
        return [doc.content[self.MBOX_KEY]
                for doc in self._soledad.get_from_index(
                    self.TYPE_SUBS_IDX, self.MBOX_KEY, '1')]

    def getMailbox(self, name):
        """
        Returns a Mailbox with that name, without selecting it.

        :param name: name of the mailbox
        :type name: str

        :returns: a a SoledadMailbox instance
        :rtype: SoledadMailbox
        """
        name = self._parse_mailbox_name(name)

        if name not in self.mailboxes:
            raise imap4.MailboxException("No such mailbox: %s" %
                                         _unicode_as_str(name))

        return SoledadMailbox(name, soledad=self._soledad)

    ##
    ## IAccount
    ##

    def addMailbox(self, name, creation_ts=None):
        """
        Add a mailbox to the account.

        :param name: the name of the mailbox
        :type name: str

        :param creation_ts: an optional creation timestamp to be used as
                            mailbox id. A timestamp will be used if no
                            one is provided.
        :type creation_ts: int

        :returns: True if successful
        :rtype: bool
        """
        name = self._parse_mailbox_name(name)

        if name in self.mailboxes:
            raise imap4.MailboxCollision, _unicode_as_str(name)

        if not creation_ts:
            # by default, we pass an int value
            # taken from the current time
            # we make sure to take enough decimals to get a unique
            # mailbox-uidvalidity.
            creation_ts = int(time.time() * 10E2)

        mbox = self._get_empty_mailbox()
        mbox[self.MBOX_KEY] = name
        mbox[self.CREATED_KEY] = creation_ts

        doc = self._soledad.create_doc(mbox)
        return bool(doc)

    def create(self, pathspec):
        """
        Create a new mailbox from the given hierarchical name.

        :param pathspec: The full hierarchical name of a new mailbox to create.
                         If any of the inferior hierarchical names to this one
                         do not exist, they are created as well.
        :type pathspec: str

        :return: A true value if the creation succeeds.
        :rtype: bool

        :raise MailboxException: Raised if this mailbox cannot be added.
        """
        # TODO raise MailboxException
        paths = filter(
            None,
            self._parse_mailbox_name(pathspec).split('/'))
        for accum in range(1, len(paths)):
            try:
                self.addMailbox('/'.join(paths[:accum]))
            except imap4.MailboxCollision:
                pass
        try:
            self.addMailbox('/'.join(paths))
        except imap4.MailboxCollision:
            if not pathspec.endswith('/'):
                return False
        return True

    def select(self, name, readwrite=1):
        """
        Selects a mailbox.

        :param name: the mailbox to select
        :type name: str

        :param readwrite: 1 for readwrite permissions.
        :type readwrite: int

        :rtype: bool
        """
        name = self._parse_mailbox_name(name)

        if name not in self.mailboxes:
            return None

        self.selected = name

        return SoledadMailbox(
            name, rw=readwrite,
            soledad=self._soledad)

    def delete(self, name, force=False):
        """
        Deletes a mailbox.

        Right now it does not purge the messages, but just removes the mailbox
        name from the mailboxes list!!!

        :param name: the mailbox to be deleted
        :type name: str

        :param force: if True, it will not check for noselect flag or inferior
                      names. use with care.
        :type force: bool
        """
        name = self._parse_mailbox_name(name)

        if not name in self.mailboxes:
            raise imap4.MailboxException("No such mailbox: %s" %
                                         _unicode_as_str(name))

        mbox = self.getMailbox(name)

        if force is False:
            # See if this box is flagged \Noselect
            # XXX use mbox.flags instead?
            if self.NOSELECT_FLAG in mbox.getFlags():
                # Check for hierarchically inferior mailboxes with this one
                # as part of their root.
                for others in self.mailboxes:
                    if others != name and others.startswith(name):
                        raise imap4.MailboxException, (
                            "Hierarchically inferior mailboxes "
                            "exist and \\Noselect is set")
        mbox.destroy()

        # XXX FIXME --- not honoring the inferior names...

        # if there are no hierarchically inferior names, we will
        # delete it from our ken.
        #if self._inferiorNames(name) > 1:
            # ??! -- can this be rite?
            #self._index.removeMailbox(name)

    def rename(self, oldname, newname):
        """
        Renames a mailbox.

        :param oldname: old name of the mailbox
        :type oldname: str

        :param newname: new name of the mailbox
        :type newname: str
        """
        oldname = self._parse_mailbox_name(oldname)
        newname = self._parse_mailbox_name(newname)

        if oldname not in self.mailboxes:
            raise imap4.NoSuchMailbox, _unicode_as_str(oldname)

        inferiors = self._inferiorNames(oldname)
        inferiors = [(o, o.replace(oldname, newname, 1)) for o in inferiors]

        for (old, new) in inferiors:
            if new in self.mailboxes:
                raise imap4.MailboxCollision, _unicode_as_str(new)

        for (old, new) in inferiors:
            mbox = self._get_mailbox_by_name(old)
            mbox.content[self.MBOX_KEY] = new
            self._soledad.put_doc(mbox)

        # XXX ---- FIXME!!!! ------------------------------------
        # until here we just renamed the index...
        # We have to rename also the occurrence of this
        # mailbox on ALL the messages that are contained in it!!!
        # ... we maybe could use a reference to the doc_id
        # in each msg, instead of the "mbox" field in msgs
        # -------------------------------------------------------

    def _inferiorNames(self, name):
        """
        Return hierarchically inferior mailboxes.

        :param name: name of the mailbox
        :rtype: list
        """
        # XXX use wildcard query instead
        inferiors = []
        for infname in self.mailboxes:
            if infname.startswith(name):
                inferiors.append(infname)
        return inferiors

    def isSubscribed(self, name):
        """
        Returns True if user is subscribed to this mailbox.

        :param name: the mailbox to be checked.
        :type name: str

        :rtype: bool
        """
        mbox = self._get_mailbox_by_name(name)
        return mbox.content.get('subscribed', False)

    def _set_subscription(self, name, value):
        """
        Sets the subscription value for a given mailbox

        :param name: the mailbox
        :type name: str

        :param value: the boolean value
        :type value: bool
        """
        # maybe we should store subscriptions in another
        # document...
        if not name in self.mailboxes:
            self.addMailbox(name)
        mbox = self._get_mailbox_by_name(name)

        if mbox:
            mbox.content[self.SUBSCRIBED_KEY] = value
            self._soledad.put_doc(mbox)

    def subscribe(self, name):
        """
        Subscribe to this mailbox

        :param name: name of the mailbox
        :type name: str
        """
        name = self._parse_mailbox_name(name)
        if name not in self.subscriptions:
            self._set_subscription(name, True)

    def unsubscribe(self, name):
        """
        Unsubscribe from this mailbox

        :param name: name of the mailbox
        :type name: str
        """
        name = self._parse_mailbox_name(name)
        if name not in self.subscriptions:
            raise imap4.MailboxException, \
                "Not currently subscribed to %s" % _unicode_as_str(name)
        self._set_subscription(name, False)

    def listMailboxes(self, ref, wildcard):
        """
        List the mailboxes.

        from rfc 3501:
        returns a subset of names from the complete set
        of all names available to the client.  Zero or more untagged LIST
        replies are returned, containing the name attributes, hierarchy
        delimiter, and name.

        :param ref: reference name
        :type ref: str

        :param wildcard: mailbox name with possible wildcards
        :type wildcard: str
        """
        # XXX use wildcard in index query
        ref = self._inferiorNames(
            self._parse_mailbox_name(ref))
        wildcard = imap4.wildcardToRegexp(wildcard, '/')
        return [(i, self.getMailbox(i)) for i in ref if wildcard.match(i)]

    ##
    ## INamespacePresenter
    ##

    def getPersonalNamespaces(self):
        return [["", "/"]]

    def getSharedNamespaces(self):
        return None

    def getOtherNamespaces(self):
        return None

    # extra, for convenience

    def deleteAllMessages(self, iknowhatiamdoing=False):
        """
        Deletes all messages from all mailboxes.
        Danger! high voltage!

        :param iknowhatiamdoing: confirmation parameter, needs to be True
                                 to proceed.
        """
        if iknowhatiamdoing is True:
            for mbox in self.mailboxes:
                self.delete(mbox, force=True)

    def __repr__(self):
        """
        Representation string for this object.
        """
        return "<SoledadBackedAccount (%s)>" % self._account_name