# -*- coding: utf-8 -*-
# Copyright (c) 2010 Mark Sandstrom
# Copyright (c) 2011-2013 Raphaël Barrois
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.


from __future__ import unicode_literals


"""factory_boy extensions for use with the Django framework."""


from . import base


class DjangoModelFactory(base.Factory):
    """Factory for Django models.

    This makes sure that the 'sequence' field of created objects is a new id.

    Possible improvement: define a new 'attribute' type, AutoField, which would
    handle those for non-numerical primary keys.
    """

    ABSTRACT_FACTORY = True
    FACTORY_DJANGO_GET_OR_CREATE = ()

    @classmethod
    def _get_manager(cls, target_class):
        try:
            return target_class._default_manager   # pylint: disable=W0212
        except AttributeError:
            return target_class.objects

    @classmethod
    def _setup_next_sequence(cls):
        """Compute the next available PK, based on the 'pk' database field."""

        model = cls._associated_class  # pylint: disable=E1101
        manager = cls._get_manager(model)

        try:
            return 1 + manager.values_list('pk', flat=True
                ).order_by('-pk')[0]
        except (IndexError, TypeError):
            # IndexError: No instance exist yet
            # TypeError: pk isn't an integer type
            return 1

    @classmethod
    def _get_or_create(cls, target_class, *args, **kwargs):
        """Create an instance of the model through objects.get_or_create."""
        manager = cls._get_manager(target_class)

        assert 'defaults' not in cls.FACTORY_DJANGO_GET_OR_CREATE, (
            "'defaults' is a reserved keyword for get_or_create "
            "(in %s.FACTORY_DJANGO_GET_OR_CREATE=%r)"
            % (cls, cls.FACTORY_DJANGO_GET_OR_CREATE))

        key_fields = {}
        for field in cls.FACTORY_DJANGO_GET_OR_CREATE:
            key_fields[field] = kwargs.pop(field)
        key_fields['defaults'] = kwargs

        obj, _created = manager.get_or_create(*args, **key_fields)
        return obj

    @classmethod
    def _create(cls, target_class, *args, **kwargs):
        """Create an instance of the model, and save it to the database."""
        manager = cls._get_manager(target_class)

        if cls.FACTORY_DJANGO_GET_OR_CREATE:
            return cls._get_or_create(target_class, *args, **kwargs)

        return manager.create(*args, **kwargs)

    @classmethod
    def _after_postgeneration(cls, obj, create, results=None):
        """Save again the instance if creating and at least one hook ran."""
        if create and results:
            # Some post-generation hooks ran, and may have modified us.
            obj.save()