124 lines
4.6 KiB
Python
Executable file
124 lines
4.6 KiB
Python
Executable file
import datetime
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import uuid
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from django.db import models
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from django.db import transaction
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from django.db.models import F
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from django.utils.translation import gettext_lazy as _
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from model_utils.choices import Choices
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from rest_framework.exceptions import APIException, ValidationError
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from apps.users.models import User
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class TransactionManager(models.Manager):
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def create_transaction(self,
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amount,
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payee: User,
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payer: User = None,
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delay=0,
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detail_id=None,
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application_client_id=None,
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state=None):
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if not (isinstance(payer, User) or payer is None):
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raise ValidationError('payer type not valid')
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if not isinstance(payee, User):
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raise ValidationError('payee type not valid')
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if not amount > 0:
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raise ValidationError('amount should be greater than zero')
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if not delay >= 0:
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raise ValidationError('delay should be greater than equal zero')
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transaction = self.model(payer=payer,
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payee=payee,
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amount=amount,
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delay=delay,
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detail_id=detail_id,
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application_client_id=application_client_id
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)
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if state:
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transaction.state = state
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transaction.save()
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return transaction
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class Transaction(models.Model):
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STATE_CHOICES = Choices(
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(1, 'created', 'created'),
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(2, 'delayed', 'delayed'),
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(3, 'pending', 'pending'),
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(4, 'failed', 'failed'),
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(5, 'done', 'done'),
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)
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uuid = models.UUIDField(primary_key=True, editable=False, default=uuid.uuid4, unique=True, db_index=True) # reserve_code
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amount = models.IntegerField(_('amount'), blank=False)
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delay = models.IntegerField(default=0, blank=True) # number of days for delayed payments
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payer = models.ForeignKey(User, on_delete=models.PROTECT, related_name='payments', blank=True, null=True)
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payee = models.ForeignKey(User, on_delete=models.PROTECT, related_name='receipts')
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state = models.IntegerField(choices=STATE_CHOICES, default=STATE_CHOICES.created)
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create = models.DateTimeField(_('create'), blank=True, null=True, auto_now=True)
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last_update = models.DateTimeField(_('last update'), blank=True, null=True, auto_now=True)
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application_client_id = models.CharField(max_length=100, db_index=True, null=True)
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detail_id = models.IntegerField(null=True, blank=True) # or better detail url or res number
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objects = TransactionManager()
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# class Meta:
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# unique_together = ('application_client_id', 'detail_id',)
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def pay(self, payer=None):
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if not self.payer and not payer:
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raise APIException('payer identification error')
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if self.payer and payer and not self.payer == payer:
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raise APIException('payer identification error')
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if not self.payer:
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self.payer = payer
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with transaction.atomic():
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# TODO: check bundry conditions
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self.last_update = datetime.datetime.now()
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if not self.state == self.STATE_CHOICES.created:
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raise APIException('this transaction is not ready to pay')
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if self.payer.balance < self.amount:
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raise APIException('not enough balance')
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self.payer.balance = F('balance') - self.amount
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self.payer.save(update_fields=['balance'])
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self.payer.refresh_from_db()
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if self.payer.balance < 0:
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raise APIException('not enough balance')
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if self.delay:
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self.state = self.STATE_CHOICES.delayed
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self.save()
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else:
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self.payee.balance = F('balance') + self.amount
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self.payee.save(update_fields=['balance'])
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self.state = self.STATE_CHOICES.done
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self.save()
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self.save()
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return self
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def receipt(self):
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with transaction.atomic():
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self.last_update = datetime.datetime.now()
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# TODO: check bundry conditions
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if not self.state == self.STATE_CHOICES.delayed:
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raise APIException('this transaction is not delayed')
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self.payee.balance = F('balance') + self.amount
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self.state = self.STATE_CHOICES.done
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self.payee.save()
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self.save()
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def __str__(self):
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return f"{self.payer} -> {self.payee} ({self.uuid}): {self.amount}"
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