odinpastuh

####### models.py

from django.db import models
from django.utils.translations import ugettext_lazy as _
# adds created and updated to the model. Highly recommend to add it EVERY model
from django_extensions.db.models import TimeStampedModel


class DecimalCoinField(DecimalField):
    """
    Coin field taking step of 0.1
    """

    def widget_attrs(self, widget):
        attrs = super().widget_attrs(widget)
        attrs.update({
            'step': 1,
            'min': 0
        })
        return attrs


class CoinField(models.DecimalField):
    """
    Custom field to DRY on

    models.DecimalField(max_digits=64, decimal_places=8)
    """

    description = _('Coins field')

    def __init__(self, *args, **kwargs):
        kwargs['max_digits'] = 64
        kwargs['decimal_places'] = 8
        super().__init__(*args, **kwargs)

    def formfield(self, **kwargs):
        return super().formfield(**{
            'max_digits': self.max_digits,
            'decimal_places': self.decimal_places,
            'form_class': DecimalCoinField,
            **kwargs,
        })


class Algorithm(TimeStampedModel):
    # only ID is enough
    def __str__(self):
        return f'{self.instuctions.all()}'
    
    
class Instruction(TimeStampedModel):

    GTE = 1
    GT = 2
    LTE = 3
    LT = 4
    SOME_OTHER_ACTION = 5
    ACTION_CHOICES = (
        (GTE, _('≥')),
        (GT, _('>')),
        (LTE, _('≤')),
        (LT, _('<')),
        (SOME_OTHER_ACTION, _('Some other action')),
    )
    action = models.SmallPositiveIntegerField(choices=ACTION_CHOICES)
    amount = CoinField(_('Amount'))
    algo = models.ForeignKey(Algorithm, related_name='instructions')
    
    class Meta:
        # that is ASC ordering by `created` field
        ordering = ['created']


#### admins.py

from django.contrib import admin
from .models import Algorithm
from .models import Instruction


class InstructionInline(admin.TabularInline):
    model = Instruction
    fields = '__all__'
    
    
@admin.register(Algorithm)
class AlgorithmAdmin(admin.ModelAdmin):
    # ...
    inlines = [
        InstructionInline,
    ]