from app import db
from datetime import datetime, date


class AutoSerialize(object):
    'Mixin for retrieving public fields of model in json-compatible format'
    __public__ = None

    def get_public(self, exclude=(), extra=()):
        "Returns model's PUBLIC data for jsonify"
        data = {}
        keys = self._sa_instance_state.attrs.items()
        public = self.__public__ + extra if self.__public__ else extra
        for k, field in keys:
            if public and k not in public: continue
            if k in exclude: continue
            value = self._serialize(field.value)
            if value:
                data[k] = value

        return data

    @classmethod
    def _serialize(cls, value, follow_fk=False):
        if type(value) in (datetime, date):
            ret = value.isoformat()
        elif hasattr(value, '__iter__'):
            ret = []
            for v in value:
                ret.append(cls._serialize(v))
        elif AutoSerialize in value.__class__.__bases__:
            ret = value.get_public()
        else:
            ret = value

        return ret


class Gas(db.Model, AutoSerialize):
    """
    Create a gas table
    """

    __table_args__ = {'extend_existing': True}
    __tablename__ = 'gas'
    __public__ = ('price', 'volume', 'milage', 'date',
                  'wintertyre', 'car', 'id')

    id = db.Column(db.Integer, primary_key=True)
    price = db.Column(db.Integer)
    volume = db.Column(db.Integer)
    milage = db.Column(db.Integer)
    date = db.Column(db.DateTime, default=datetime.utcnow)
    winterTyre = db.Column(db.Boolean)
    car_id = db.Column(db.Integer, db.ForeignKey('car.id'))

    def __ref__(self):
        return '<Gas :{}>'.format(self.id)


class Car(db.Model, AutoSerialize):
    """
    Create a table of cars
    """

    __tablename__ = 'car'
    __public__ = ('name', 'id')

    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(50))
    cars = db.relationship('Gas', backref='car',
                            lazy='dynamic')

    def __ref__(self):
        return '<Gas :{}>'.format(self.id)