#!/usr/bin/env python
# -*- coding: utf-8 -*-
# Copyright (c) 2009-2011, Nicolas Clairon
# All rights reserved.
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#
#     * Redistributions of source code must retain the above copyright
#       notice, this list of conditions and the following disclaimer.
#     * Redistributions in binary form must reproduce the above copyright
#       notice, this list of conditions and the following disclaimer in the
#       documentation and/or other materials provided with the distribution.
#     * Neither the name of the University of California, Berkeley nor the
#       names of its contributors may be used to endorse or promote products
#       derived from this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND ANY
# EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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# SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

from pymongo.database import Database as PymongoDatabase
from bson.dbref import DBRef
from mongokit.document import Document
from mongokit.collection import Collection


class Database(PymongoDatabase):

    def __init__(self, *args, **kwargs):
        self._collections = {}
        super(Database, self).__init__(*args, **kwargs)

    def __getattr__(self, key):
        if key in self.connection._registered_documents:
            document = self.connection._registered_documents[key]
            return getattr(self[document.__collection__], key)
        else:
            if not key in self._collections:
                self._collections[key] = Collection(self, key)
            return self._collections[key]

    def dereference(self, dbref, model=None):
        if model is None:
            return super(Database, self).dereference(dbref)
        if not isinstance(dbref, DBRef):
            raise TypeError("first argument must be a DBRef")
        if dbref.database is not None and dbref.database != self.name:
            raise ValueError("trying to dereference a DBRef that points to "
                             "another database (%r not %r)" % (dbref.database, self._Database__name))
        if not issubclass(model, Document):
            raise TypeError("second argument must be a Document")
        return getattr(self[dbref.collection], model.__name__).one({'_id': dbref.id})