# -*- coding: utf-8 -*-
'''Database module, including the SQLAlchemy database object and DB-related
mixins.
'''

from .extensions import db

class CRUDMixin(object):
    """Mixin that adds convenience methods for CRUD (create, read, update, delete)
    operations.
    """
    __table_args__ = {'extend_existing': True}

    id = db.Column(db.Integer, primary_key=True)

    @classmethod
    def get_by_id(cls, id):
        if any(
            (isinstance(id, basestring) and id.isdigit(),
             isinstance(id, (int, float))),
        ):
            return cls.query.get(int(id))
        return None

    @classmethod
    def create(cls, **kwargs):
        '''Create a new record and save it the database.'''
        instance = cls(**kwargs)
        return instance.save()

    def update(self, commit=True, **kwargs):
        '''Update specific fields of a record.'''
        for attr, value in kwargs.iteritems():
            setattr(self, attr, value)
        return commit and self.save() or self

    def save(self, commit=True):
        '''Save the record.'''
        db.session.add(self)
        if commit:
            db.session.commit()
        return self

    def delete(self, commit=True):
        '''Remove the record from the database.'''
        db.session.delete(self)
        return commit and db.session.commit()