74 lines
2.4 KiB
Python
74 lines
2.4 KiB
Python
from django.db import transaction
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from django.db.models import Sum
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from rest_framework.exceptions import APIException
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from apps.product import models as product_models
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class QuotaDistributionService:
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"""
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Service layer to manage multiple quota distributions as one unified entity.
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Used for organization-based views and POS operations.
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"""
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def __init__(self, quota, organization):
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self.quota = quota
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self.organization = organization
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self.distribution = product_models.QuotaDistribution.objects.filter(
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quota=quota,
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assigned_organization=organization,
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warehouse_entry__gt=0
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).first()
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@property
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def total_weight():
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return self.distribution.aggregate(
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total=Sum('weight')
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)['total'] or 0
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@property
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def remaining_weight():
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return self.distribution.aggregate(
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total=Sum('remaining_weight')
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)['total'] or 0
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def to_representation(self): # noqa
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return {
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'quota_id': self.quota.id,
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'quota_identity': self.quota.quota_id,
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'product': self.quota.product.name,
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'total_weight': self.total_weight,
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'remaining_weight': self.remaining_weight,
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'distribution_ids': self.distribution_ids,
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}
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@transaction.atomic
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def consume(self, amount): # noqa
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"""
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Consume 'amount' of weight across all distributions in order.
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Automatically splits usage if needed.
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"""
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if amount > self.remaining_weight:
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raise APIException('Not enough weight to consume')
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remaining_to_consume = amount
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for dist in self.distribution.select_for_update():
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if remaining_to_consume <= 0:
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break
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available = dist.remaining_weight
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if available <= 0:
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continue
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consume_amount = min(available, remaining_to_consume)
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dist.remaining_weight -= consume_amount
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dist.save(update_fields=["remaining_weight"])
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remaining_to_consume -= consume_amount
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if remaining_to_consume > 0:
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raise APIException('Not enough weight to consume')
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return True
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