"""Database classes and models."""
from pypistats.extensions import db

Column = db.Column
basestring = (str, bytes)


class CRUDMixin(object):
    """Mixin that adds convenience methods for CRUD operations."""

    @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.items():
            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()


class Model(CRUDMixin, db.Model):
    """Base model class that includes CRUD convenience methods."""

    __abstract__ = True


class SurrogatePK(object):
    """A mixin that adds a surrogate integer "primary key" column.

    Adds a surrogate integer "primary key" column named ``id`` to any
    declarative-mapped class.
    """

    __table_args__ = {"extend_existing": True}

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

    @classmethod
    def get_by_id(cls, record_id):
        """Get record by ID."""
        if any((isinstance(record_id, basestring) and record_id.isdigit(), isinstance(record_id, (int, float)))):
            return cls.query.get(int(record_id))
        return None