"""The UserManagerToMiddleKit class."""

from MiscUtils import NoDefault
from MiscUtils.Funcs import uniqueId
from MiddleKit.Run.ObjectStore import UnknownObjectError

from UserManager import UserManager


class UserManagerToMiddleKit(UserManager):
    """UserManagerToMiddleKit stores users in a given MiddleKit object store.

    However, the manager itself does not keep any information there.
    This might change in the future.

    In your MiddleKit model, your User class should have the attributes:
    name, password and externalId; all of type string.
    The max len for external id should be at least 14.
    You can decide what you like for the others.
    Only name and password have to be required.

    Then you must edit User.py so that:
      * In addition to inheriting GenUser, it also inherits UserKit.User
      * It invokes both base class' __init__()s
      * The __init__ takes manager, name and password, and passes them on.

            from UserKit.User import User

            class User(GenUser, User):

                def __init__(self, manager=None, name=None, password=None):
                    GenUser.__init__(self)
                    User.__init__(self, manager, name, password)

    If your user class is called something other than 'User', then you must
    pass it to the store:

        from MyUser import MyUser
        userMgr = UserManagerToMiddleKit(userClass=MyUser, store=store)

    """


    ## Init ##

    def __init__(self, userClass=None, store=None, useSQL=None):
        # If no userClass was specified, try to pull 'User'
        # out of the object model.
        if userClass is None:
            userClass = store.model().klass('User', None)

        UserManager.__init__(self, userClass)

        if store is None:
            from MiddleKit.Run.ObjectStore import ObjectStore
            store = ObjectStore
        assert store, 'No MiddleKit store.'
        self._store = store

        # If the user didn't say whether or not to useSQL, then
        # we'll check if this looks like a SQLObjectStore. If so,
        # then using SQL server side queries will speed up our
        # operation:
        if useSQL is None:
            useSQL = getattr(self._store, 'executeSQL') is not None
        self._useSQL = useSQL

        # _saveNewUsers: if true, then we do a store.saveChanges()
        # whenever a new user is added. This helps with the
        # integrity of accessors like users().
        # @@ 2001-02-18 ce: But perhaps that's a problem because
        # manager is not a MiddleKit object...
        self._saveNewUsers = True


    ## MiddleKit specifics ##

    def loadUser(self, serialNum, default=NoDefault):
        try:
            user = self._store.fetchObject(self._userClass, serialNum, default)
        except UnknownObjectError:
            raise KeyError(serialNum)
        if user is default:
            return default
        else:
            self._cachedUsers.append(user)
            self._cachedUsersBySerialNum[serialNum] = user
            return user


    ## UserManager customizations ##

    def setUserClass(self, userClass):
        """Overridden to verify that our userClass is really a MiddleObject."""
        from MiddleKit.Run.MiddleObject import MiddleObject
        assert issubclass(userClass, MiddleObject)
        UserManager.setUserClass(self, userClass)


    ## UserManager concrete methods ##

    def addUser(self, user):
        if user.externalId() is None:
            user.setExternalId(uniqueId(user))
        self._store.addObject(user)
        if self._saveNewUsers:
            self._store.saveChanges()
        UserManager.addUser(self, user)

    def userForSerialNum(self, id, default=NoDefault):
        user = self._cachedUsersBySerialNum.get(id)
        if user is not None:
            return user
        return self.loadUser(id, default)

    def userForExternalId(self, externalId, default=NoDefault):
        for user in self._cachedUsers:
            if user.externalId() == externalId:
                return user
        if self._useSQL:
            users = self._store.fetchObjectsOfClass(self._userClass,
                clauses='where externalId=%r' % externalId)
            if users:
                assert len(users) == 1
                return users[0]
        else:
            for user in self.users():
                if user.externalId() == externalId:
                    return user
        if default is NoDefault:
            raise KeyError(externalId)
        else:
            return default

    def userForName(self, name, default=NoDefault):
        for user in self._cachedUsers:
            if user.name() == name:
                return user
        if self._useSQL:
            users = self._store.fetchObjectsOfClass(
                self._userClass, clauses='where name=%r' % name)
            if users:
                assert len(users) == 1
                return users[0]
        else:
            for user in self.users():
                if user.name() == name:
                    return user
        if default is NoDefault:
            raise KeyError(name)
        else:
            return default

    def users(self):
        return self._store.fetchObjectsOfClass(self._userClass)

    def activeUsers(self):
        # @@ 2001-02-17 ce: this ultimately does a fetch every time,
        # which sucks if we already have the user in memory.
        # This is really an MK issue regarding caching of objects
        # and perhaps a SQL database issue as well.
        return [user for user in self.users() if user.isActive()]

    def inactiveUsers(self):
        return [user for user in self.users() if not user.isActive()]