from django.db import models


class Station(models.Model):
    name = models.CharField(max_length=24)


class TransportNode(models.Model):
    start_point = models.ForeignKey(
        Station, related_name='station_start_point')
    end_point = models.ForeignKey(Station, related_name='station_end_point')
    # some meta fields e.g. price_coefficient, time and others
    price = models.DecimalField(max_digits=6, decimal_places=2)
    weight = models.FloatField()


class Route(models.Model):
    name = models.CharField(max_length=24)
    transport_nodes = models.ManyToManyField(TransportNode)


class Train(models.Model):
    name = models.CharField(max_length=24)
    route = models.ForeignKey(Route)
    price_coefficient = models.FloatField()


class PlaceType(models.Model):
    name = models.CharField(max_length=24)
    price_coefficient = models.FloatField()


class Place(models.Model):
    train = models.ForeignKey(Train)
    place_type = models.ForeignKey(PlaceType)


class Transaction(models.Model):
    user = models.ForeignKey('User')
    total_price = models.DecimalField(max_digits=6, decimal_places=2)


class Ticket(models.Model):
    place = models.ForeignKey(Place)
    user = models.ForeignKey('User')
    transaction = models.ForeignKey(Transaction)


class Balance(models.Model):
    user = models.ForeignKey('User')
    balance = models.DecimalField(max_digits=6, decimal_places=2)