mirror of
https://github.com/lemeow125/Borrowing-TrackerBackend.git
synced 2024-11-17 06:19:26 +08:00
203 lines
11 KiB
Python
203 lines
11 KiB
Python
from rest_framework import serializers, exceptions
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from accounts.models import CustomUser
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from equipments.models import EquipmentInstance
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from .models import Transaction
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from breakages.models import BreakageReport
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from accounts.models import CustomUser
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from config.settings import DEBUG
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class CustomUserSerializer(serializers.ModelSerializer):
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name = serializers.CharField(source='__str__')
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class Meta:
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model = CustomUser
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fields = ['id', 'name']
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class EquipmentInstanceSerializer(serializers.ModelSerializer):
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name = serializers.CharField(source='equipment.name')
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class Meta:
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model = EquipmentInstance
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fields = ['id', 'name']
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class TransactionSerializer(serializers.HyperlinkedModelSerializer):
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borrower = serializers.SlugRelatedField(
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many=False, slug_field='id', queryset=CustomUser.objects.all(), required=True, allow_null=False)
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teacher = serializers.SlugRelatedField(
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many=False, slug_field='id', queryset=CustomUser.objects.all(), required=True, allow_null=False)
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equipments = serializers.SlugRelatedField(
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many=True, slug_field='id', queryset=EquipmentInstance.objects.all(), required=True)
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timestamp = serializers.DateTimeField(
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format="%m-%d-%Y %I:%M %p", read_only=True)
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transaction_status = serializers.ChoiceField(
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choices=Transaction.TRANSACTION_STATUS_CHOICES)
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class Meta:
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model = Transaction
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fields = ['id', 'borrower', 'teacher',
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'equipments', 'transaction_status', 'timestamp']
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read_only_fields = ['id', 'timestamp']
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def to_representation(self, instance):
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rep = super().to_representation(instance)
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rep['borrower'] = CustomUserSerializer(instance.borrower).data
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rep['teacher'] = CustomUserSerializer(instance.teacher).data
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rep['equipments'] = EquipmentInstanceSerializer(
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instance.equipments, many=True).data
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return rep
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# Do not allow deletion of transactions
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def delete(self):
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raise exceptions.ValidationError(
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"Deletion of transactions is not allowed. Please opt to cancel a transaction or finalize it")
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def create(self, validated_data):
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# Any transactions created will be associated with the one sending the POST/CREATE request
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user = self.context['request'].user
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validated_data['borrower'] = user
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# All created transactions will be labelled as Pending
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validated_data['transaction_status'] = 'Pending Approval'
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# If no teacher responsible for the borrow transaction is selected, raise an error
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if 'teacher' not in validated_data:
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raise serializers.ValidationError(
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"You have not selected a teacher responsible for your borrow transaction")
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# If no borrower responsible for the borrow transaction is selected, raise an error
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if 'borrower' not in validated_data:
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raise serializers.ValidationError(
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"No borrower assigned for this transaction!")
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# If the user in the teacher field is not actually a teacher, raise an error
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borrower = validated_data.get('borrower')
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if borrower and borrower.is_teacher or borrower.is_technician:
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raise serializers.ValidationError(
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"The borrower must be a student. Not a teacher or techician")
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# If the user in the teacher field is not actually a teacher, raise an error
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teacher = validated_data.get('teacher')
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if teacher and not teacher.is_teacher:
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raise serializers.ValidationError(
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"The assigned teacher is not a valid teacher")
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# If the user in the teacher field is not actually a teacher, raise an error
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teacher = validated_data.get('teacher')
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if teacher and not teacher.is_teacher:
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raise serializers.ValidationError(
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"The specified user is not a teacher.")
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# If there are no equipments specified, raise an error
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if 'equipments' in validated_data and validated_data['equipments'] == []:
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raise serializers.ValidationError(
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"You cannot create a transaction without any equipments selected"
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)
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# Check if any of the equipment instances are already in a non-finalized transaction
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equipments = validated_data['equipments']
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for equipment in equipments:
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existing__pending_transactions = Transaction.objects.filter(
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equipments=equipment, transaction_status__in=['Pending Approval', 'Approved', 'Borrowed', 'With Breakages: Pending Resolution', 'Returned: Pending Checking'])
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if existing__pending_transactions.exists():
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raise serializers.ValidationError(
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f"Cannot add Equipment ID:{equipment.id}. It is still part of a non-finalized transaction")
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return super().create(validated_data)
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def update(self, instance, validated_data):
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user = self.context['request'].user
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# If user is not a teacher or a technician, forbid them from changing the status of a transaction
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if not user.is_teacher and not user.is_technician and 'transaction_status' in validated_data and validated_data['transaction_status'] != instance.transaction_status:
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raise serializers.ValidationError(
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"You are not a teacher or technician. You do not have permission to change the status of transactions"
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)
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# If user is not a teacher, forbid them from changing the status of a transaction
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if not user.is_teacher and 'transaction_status' in validated_data and validated_data['transaction_status'] != instance.transaction_status:
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raise serializers.ValidationError(
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"You do not have permission to change the status of a transaction"
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)
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# Do not allow changes to equipments on created transactions
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if 'equipments' in validated_data and instance.equipments != validated_data['equipments']:
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raise serializers.ValidationError(
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"You cannot change the equipments of an already created transaction"
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)
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# For already finalized/done transactions (Rejected or Finalized ones)
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# Do not allow any changes to already finalized transactions
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if instance.transaction_status in ['Rejected', 'Finalized']:
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raise serializers.ValidationError(
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"Unable to update rejected or finalized transaction. Please create a new one"
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)
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# Check if the update involves the transaction status
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if 'transaction_status' in validated_data:
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# For Pending transactions
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# If not changing to Approved or Rejected, throw an error
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if instance.transaction_status == "Pending" and (validated_data['transaction_status'] != "Approved" or validated_data['transaction_status'] != "Rejected"):
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raise serializers.ValidationError(
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"A pending transaction can only change to Approved or Rejected"
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)
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# For Approved transactions,
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# If not changing to Borrowed or Cancelled, throw an error
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# Already approved transactions can only be moved to Borrowed or Cancelled
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if instance.transaction_status == "Approved" and (validated_data['transaction_status'] != "Borrowed" or validated_data != "Cancelled"):
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raise serializers.ValidationError(
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"An already approved transaction can only changed to Borrowed (On borrow) or Cancelled"
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)
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# For Borrowed transactions,
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# If not changing to returned, throw an error
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# Borrowed transactions that can only be changed to returned, pending checking for broken items
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if instance.transaction_status == "Borrowed" and (validated_data['transaction_status'] != "Finalized" or validated_data != "With Breakages: Pending Resolution"):
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raise serializers.ValidationError(
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"A borrowed transaction can only changed to status of Finalized or With Breakages: Pending Resolution"
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)
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# For Return: Pending Checking transactions,
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# If not changing to With Breakages: Pending Resolution or Finalized, throw an error
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# Returned transactions can only be finalized without any issues or be marked as with breakages
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if instance.transaction_status == "Returned: Pending Checking" and (validated_data['transaction_status'] != "Finalized" or validated_data != "With Breakages: Pending Resolution"):
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raise serializers.ValidationError(
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"A borrowed transaction can only changed to status of Finalized or With Breakages: Pending Resolution"
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)
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# For transactions with pending breakage resolutions,
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# Do not allow updating of status. It should be updated within its respective breakage report
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# If it has been resolved there, this field will automatically update to Finalized
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if instance.transaction_status == "With Breakages: Pending Resolution":
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raise serializers.ValidationError(
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"A transaction with pending breakage resolutions must be updated or resolved in its respective breakage report"
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)
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# If there are no issues and a transaction changes from Approved to Borrowed, label the selected equipment's statuses as Borrowed
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if instance.transaction_status == "Approved" and validated_data['transaction_status'] == "Borrowed":
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equipments = validated_data.get('equipments', [])
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for equipment in equipments:
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equipment.transaction_status = 'Borrowed'
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equipment.save()
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return super().update(validated_data)
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# If the transaction changes from Borrowed to Finalized and there are no breakages, label the selected equipment's statuses as Available again from Borrowed
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if instance.transaction_status == "Borrowed" and validated_data['transaction_status'] == "Finalized":
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equipments = validated_data.get('equipments', [])
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for equipment in equipments:
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equipment.transaction_status = 'Available'
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equipment.save()
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return super().update(validated_data)
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# If the transaction changes from Borrowed to With Breakages, we create a Breakage Report instance
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if instance.transaction_status == "Borrowed" and validated_data['transaction_status'] == "Finalized":
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BreakageReport.objects.create(
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transaction=instance,
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equipments=instance.equipments.all(),
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resolved=False
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)
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# Changing equipment status of broken items when there are breakages is handled in breakage reports
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return super().update(instance, validated_data)
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