Improved serializer for transaction and added available equipment viewset

equipment_tracker/equipments/admin.py

@@ -6,11 +6,11 @@ from .models import Equipment, EquipmentInstance
 @admin.register(Equipment)
 class EquipmentAdmin(SimpleHistoryAdmin):
     readonly_fields = ('date_added', 'last_updated')
-    list_display = ('name', 'date_added', 'last_updated')
+    list_display = ('id', 'name', 'date_added', 'last_updated')
 
 
 @admin.register(EquipmentInstance)
 class EquipmentInstanceAdmin(SimpleHistoryAdmin):
     readonly_fields = ('date_added', 'last_updated')
-    list_display = ('equipment', 'status', 'remarks',
+    list_display = ('id', 'equipment', 'status', 'remarks',
                     'date_added', 'last_updated')

equipment_tracker/equipments/models.py

@@ -19,12 +19,13 @@ class Equipment(models.Model):
     history = HistoricalRecords()
 
     def __str__(self):
-        return f'{self.name} ID:{self.id}'
+        return f'{self.name}'
 
 
 class EquipmentInstance(models.Model):
     EQUIPMENT_INSTANCE_STATUS_CHOICES = (
         ('Available', 'Available'),
+        ('Pending', 'Pending'),
         ('Broken', 'Broken'),
         ('Borrowed', 'Borrowed'),
     )
@@ -37,7 +38,7 @@ class EquipmentInstance(models.Model):
     history = HistoricalRecords()
 
     def __str__(self):
-        return f'{self.equipment.name} ID:{self.id}'
+        return f'{self.equipment.name}'
 
 
 @receiver(post_migrate)
@@ -48,19 +49,25 @@ def create_superuser(sender, **kwargs):
                 'name': 'Pyrex Beaker',
                 'description': '',
                 'category': 'Glassware',
-                'remarks': 'First beaker of equipment tracker!'
+                'remarks': 'A beaker for storing fluids'
             },
             {
                 'name': 'Bunsen Burner',
                 'description': '',
                 'category': 'Miscellaneous',
-                'remarks': 'First bunsen burner of equipment tracker!'
+                'remarks': 'A burner for heating things'
             },
             {
                 'name': 'Microscope',
                 'description': '',
                 'category': 'Miscellaneous',
-                'remarks': 'First microscope of equipment tracker!'
+                'remarks': 'A microscope for zooming into tiny objects'
+            },
+            {
+                'name': 'Petri Dish',
+                'description': '',
+                'category': 'Glassware',
+                'remarks': 'A petri dish'
             }
         ]
 
@@ -72,6 +79,8 @@ def create_superuser(sender, **kwargs):
             )
             if (CREATED):
                 print('Created Equipment: ' + data['name'])
+                print(
+                    'Generating 3 Equipment Instances for Equipment: ' + data['name'])
                 # Generate 3 equipment instances per SKU
                 for x in range(3):
                     EQUIPMENT_INSTANCE = EquipmentInstance.objects.create(

equipment_tracker/equipments/urls.py

@@ -18,6 +18,10 @@ urlpatterns = [
          views.EquipmentLogViewSet.as_view({'get': 'list'})),
     # Last changed equipment
     path('equipments/latest', views.LastUpdatedEquipmentViewSet.as_view()),
+    # List of equipment instances that are available for borrowing (those not belonging to a non-finalized transaction)
+    path('equipment_instances/available',
+         views.AvailableEquipmentInstanceViewSet.as_view()),
+    # Logs for each equipment instance
     # Logs for all equipment instances
     path('equipment_instances/logs', views.EquipmentInstancesLogsViewSet.as_view()),
     # Logs for each equipment instance

equipment_tracker/equipments/views.py

@@ -1,9 +1,11 @@
 from rest_framework.permissions import IsAuthenticated
 from rest_framework import viewsets, generics
 from .models import Equipment, EquipmentInstance
+from django.db.models import Q
 from . import serializers
 from config.settings import DEBUG
 from accounts.permissions import IsTechnician
+from transactions.models import Transaction
 
 # -- Equipment Viewsets
 
@@ -56,6 +58,31 @@ class EquipmentInstanceViewSet(viewsets.ModelViewSet):
     serializer_class = serializers.EquipmentInstanceSerializer
     queryset = EquipmentInstance.objects.all().order_by('id')
 
+
+class AvailableEquipmentInstanceViewSet(generics.ListAPIView):
+    if (not DEBUG):
+        permission_classes = [IsAuthenticated]
+    serializer_class = serializers.EquipmentInstanceSerializer
+
+    def get_queryset(self):
+        """
+        This view should return a list of all the equipment instances
+        that are not associated with a non-finalized transaction.
+        """
+        # Get all non-finalized transactions
+        non_finalized_transactions = Transaction.objects.filter(
+            ~Q(transaction_status__in=['Finalized', 'Cancelled']))
+
+        # Get all equipment instances associated with non-finalized transactions
+        non_finalized_equipments = EquipmentInstance.objects.filter(
+            transaction__in=non_finalized_transactions)
+
+        # Get all equipment instances which are not associated with non-finalized transactions
+        queryset = EquipmentInstance.objects.exclude(
+            id__in=non_finalized_equipments.values_list('id', flat=True)).order_by('id')
+
+        return queryset
+
 # For viewing all equipment instance logs
 
 

equipment_tracker/schema.yml

@@ -766,6 +766,23 @@ paths:
       responses:
         '204':
           description: No response body
+  /api/v1/equipments/equipment_instances/available:
+    get:
+      operationId: api_v1_equipments_equipment_instances_available_list
+      tags:
+      - api
+      security:
+      - jwtAuth: []
+      - {}
+      responses:
+        '200':
+          content:
+            application/json:
+              schema:
+                type: array
+                items:
+                  $ref: '#/components/schemas/EquipmentInstance'
+          description: ''
   /api/v1/equipments/equipment_instances/latest:
     get:
       operationId: api_v1_equipments_equipment_instances_latest_list
@@ -1187,6 +1204,9 @@ components:
     CustomUser:
       type: object
       properties:
+        id:
+          type: integer
+          readOnly: true
         username:
           type: string
           readOnly: true
@@ -1213,6 +1233,7 @@ components:
       required:
       - avatar
       - first_name
+      - id
       - last_name
       - username
     Equipment:
@@ -1454,6 +1475,9 @@ components:
     PatchedCustomUser:
       type: object
       properties:
+        id:
+          type: integer
+          readOnly: true
         username:
           type: string
           readOnly: true
@@ -1545,6 +1569,10 @@ components:
           type: array
           items:
             type: integer
+        remarks:
+          type: string
+          nullable: true
+          maxLength: 512
         transaction_status:
           $ref: '#/components/schemas/TransactionStatusEnum'
         timestamp:
@@ -1587,11 +1615,13 @@ components:
     StatusEnum:
       enum:
       - Available
+      - Pending
       - Broken
       - Borrowed
       type: string
       description: |-
         * `Available` - Available
+        * `Pending` - Pending
         * `Broken` - Broken
         * `Borrowed` - Borrowed
     TokenObtainPair:
@@ -1648,6 +1678,10 @@ components:
           type: array
           items:
             type: integer
+        remarks:
+          type: string
+          nullable: true
+          maxLength: 512
         transaction_status:
           $ref: '#/components/schemas/TransactionStatusEnum'
         timestamp:

equipment_tracker/transactions/serializers.py

@@ -106,57 +106,106 @@ class TransactionSerializer(serializers.HyperlinkedModelSerializer):
                 raise serializers.ValidationError(
                     f"Cannot add Equipment ID:{equipment.id}. It is still part of a non-finalized transaction")
 
-        return super().create(validated_data)
+        # Create the transaction if there are no issues
+        transaction = super().create(validated_data)
+
+        # Get the equipments from the newly created transaction
+        equipments = transaction.equipments.all()
+
+        # Iterate through each of those equipment instances and change their status field to "Pending"
+        # This updates the status field of all equipment instances in a single query
+        EquipmentInstance.objects.filter(
+            id__in=[equipment.id for equipment in equipments]).update(status='Pending')
+
+        return transaction
 
     def update(self, instance, validated_data):
         user = self.context['request'].user
 
-        # If user is not a teacher or a technician, forbid them from changing the status of a transaction
+        # User Validation
-        if not user.is_teacher and not user.is_technician and 'transaction_status' in validated_data and validated_data['transaction_status'] != instance.transaction_status:
+
+        # If user is not a teacher or a technician (ie a student), forbid them from changing the status of a transaction
+        if not user.is_teacher and not user.is_technician and 'transaction_status' in validated_data and validated_data.get('transaction_status') != instance.transaction_status:
             raise serializers.ValidationError(
                 "You are not a teacher or technician. You do not have permission to change the status of transactions"
             )
 
-        # If user is not a teacher, forbid them from changing the status of a transaction
+        # If the user is a teacher but is not assigned to the current transaction, forbid them from changing anything in the transaction
-        if not user.is_teacher and 'transaction_status' in validated_data and validated_data['transaction_status'] != instance.transaction_status:
+        if user.is_teacher and instance.teacher != user:
             raise serializers.ValidationError(
-                "You do not have permission to change the status of a transaction"
+                "You are not the assigned teacher for this transaction"
             )
+
+        # If the user is a teacher and is updating a transaction with values other than Approved or Rejected, forbid them from doing so (Only technicians can update to other statuses)
+        if user.is_teacher and not (validated_data.get('transaction_status') == 'Rejected' or validated_data.get('transaction_status') == 'Approved'):
+            raise serializers.ValidationError(
+                "Teachers can only mark assigned transactions as Approved or Rejected. Please consult with a Technician should you wish to process this request"
+            )
+
+        # Equipment Instances Validation
         # Do not allow changes to equipments on created transactions
-        if 'equipments' in validated_data and instance.equipments != validated_data['equipments']:
+        if 'equipments' in validated_data:
             raise serializers.ValidationError(
                 "You cannot change the equipments of an already created transaction"
             )
 
-        # For already finalized/done transactions (Rejected or Finalized ones)
+        # Transaction Status Validation
-        # Do not allow any changes to already finalized transactions
-        if instance.transaction_status in ['Rejected', 'Finalized']:
-            raise serializers.ValidationError(
-                "Unable to update rejected or finalized transaction. Please create a new one"
-            )
-
         # Check if the update involves the transaction status
         if 'transaction_status' in validated_data:
 
-            # For Pending transactions
+            # For already finalized/done transactions (Rejected or Finalized ones)
+            # Do not allow any changes to already finalized transactions
+            if instance.transaction_status in ['Rejected', 'Finalized']:
+                raise serializers.ValidationError(
+                    "Unable to update rejected or finalized transaction. Please create a new one"
+                )
+
+            # For Pending Approval transactions
             # If not changing to Approved or Rejected, throw an error
-            if instance.transaction_status == "Pending" and (validated_data['transaction_status'] != "Approved" or validated_data['transaction_status'] != "Rejected"):
+            if instance.transaction_status == "Pending Approval" and not (validated_data.get('transaction_status') == "Approved" or validated_data.get('transaction_status') == "Rejected"):
                 raise serializers.ValidationError(
                     "A pending transaction can only change to Approved or Rejected"
                 )
 
+            # If a transaction goes from Pending Approval to Rejected, reset the status of related equipment instances so that they can be included in new transactions
+            if instance.transaction_status == "Pending Approval" and validated_data.get('transaction_status') == "Rejected":
+                equipments = instance.equipments.all()
+                # Iterate through each of those equipment instances and change their status field to "Available"
+                # This updates the status field of all equipment instances in a single query
+                EquipmentInstance.objects.filter(
+                    id__in=[equipment.id for equipment in equipments]).update(status='Available')
+                return super().update(instance, validated_data)
+
             # For Approved transactions,
             # If not changing to Borrowed or Cancelled, throw an error
             # Already approved transactions can only be moved to Borrowed or Cancelled
-            if instance.transaction_status == "Approved" and (validated_data['transaction_status'] != "Borrowed" or validated_data != "Cancelled"):
+            if instance.transaction_status == "Approved" and not (validated_data.get('transaction_status') == "Borrowed" or validated_data.get('transaction_status') == "Cancelled"):
                 raise serializers.ValidationError(
-                    "An already approved transaction can only changed to Borrowed (On borrow) or Cancelled"
+                    "An already approved transaction can only changed to Borrowed or Cancelled"
                 )
 
+            # If the transaction somehow gets Cancelled after being Approved, label the selected equipment's statuses as Available again
+            if instance.transaction_status == "Approved" and validated_data.get('transaction_status') == "Cancelled":
+                equipments = instance.equipments.all()
+                # Iterate through each of those equipment instances and change their status field to "Available"
+                # This updates the status field of all equipment instances in a single query
+                EquipmentInstance.objects.filter(
+                    id__in=[equipment.id for equipment in equipments]).update(status='Available')
+                return super().update(instance, validated_data)
+
+            # If there are no issues and a transaction changes from Approved to Borrowed, label the selected equipment's statuses as Borrowed
+            if instance.transaction_status == "Approved" and validated_data.get('transaction_status') == "Borrowed":
+                equipments = instance.equipments.all()
+                # Iterate through each of those equipment instances and change their status field to "Borrowed"
+                # This updates the status field of all equipment instances in a single query
+                EquipmentInstance.objects.filter(
+                    id__in=[equipment.id for equipment in equipments]).update(status='Borrowed')
+                return super().update(instance, validated_data)
+
             # For Borrowed transactions,
-            # If not changing to returned, throw an error
+            # If not changing to Returned: Pending Checking, throw an error
-            # Borrowed transactions that can only be changed to returned, pending checking for broken items
+            # Borrowed transactions that are Returned must be checked first upon returning (thus needing Returned: Pending Checking)
-            if instance.transaction_status == "Borrowed" and (validated_data['transaction_status'] != "Finalized" or validated_data != "With Breakages: Pending Resolution"):
+            if instance.transaction_status == "Borrowed" and not validated_data.get('transaction_status') == "Returned: Pending Checking":
                 raise serializers.ValidationError(
                     "A borrowed transaction can only changed to status of Finalized or With Breakages: Pending Resolution"
                 )
@@ -164,12 +213,12 @@ class TransactionSerializer(serializers.HyperlinkedModelSerializer):
             # For Return: Pending Checking transactions,
             # If not changing to With Breakages: Pending Resolution or Finalized, throw an error
             # Returned transactions can only be finalized without any issues or be marked as with breakages
-            if instance.transaction_status == "Returned: Pending Checking" and (validated_data['transaction_status'] != "Finalized" or validated_data != "With Breakages: Pending Resolution"):
+            if instance.transaction_status == "Returned: Pending Checking" and not (validated_data.get('transaction_status') == "Finalized" or validated_data.get('transaction_status') == "With Breakages: Pending Resolution"):
                 raise serializers.ValidationError(
                     "A borrowed transaction can only changed to status of Finalized or With Breakages: Pending Resolution"
                 )
 
-            # For transactions with pending breakage resolutions,
+            # For transactions with pending breakage resolutions
             # Do not allow updating of status. It should be updated within its respective breakage report
             # If it has been resolved there, this field will automatically update to Finalized
             if instance.transaction_status == "With Breakages: Pending Resolution":
@@ -177,27 +226,24 @@ class TransactionSerializer(serializers.HyperlinkedModelSerializer):
                     "A transaction with pending breakage resolutions must be updated or resolved in its respective breakage report"
                 )
 
-            # If there are no issues and a transaction changes from Approved to Borrowed, label the selected equipment's statuses as Borrowed
-            if instance.transaction_status == "Approved" and validated_data['transaction_status'] == "Borrowed":
-                equipments = validated_data.get('equipments', [])
-                for equipment in equipments:
-                    equipment.transaction_status = 'Borrowed'
-                    equipment.save()
-                return super().update(validated_data)
             # If the transaction changes from Borrowed to Finalized and there are no breakages, label the selected equipment's statuses as Available again from Borrowed
-            if instance.transaction_status == "Borrowed" and validated_data['transaction_status'] == "Finalized":
+            if instance.transaction_status == "Borrowed" and validated_data.get('transaction_status') == "Finalized":
-                equipments = validated_data.get('equipments', [])
+                equipments = instance.equipments.all()
-                for equipment in equipments:
+                # Iterate through each of those equipment instances and change their status field to "Available"
-                    equipment.transaction_status = 'Available'
+                # This updates the status field of all equipment instances in a single query
-                    equipment.save()
+                EquipmentInstance.objects.filter(
-                return super().update(validated_data)
+                    id__in=[equipment.id for equipment in equipments]).update(status='Available')
-            # If the transaction changes from Borrowed to With Breakages, we create a Breakage Report instance
+                return super().update(instance, validated_data)
-            if instance.transaction_status == "Borrowed" and validated_data['transaction_status'] == "Finalized":
+
-                BreakageReport.objects.create(
+            # If the transaction changes from Returned: Pending Checking to With Breakages, we create a Breakage Report instance
+            if instance.transaction_status == "Returned: Pending Checking" and validated_data.get('transaction_status') == "With Breakages: Pending Resolution":
+                equipments = instance.equipments.all()
+                report = BreakageReport.objects.create(
                     transaction=instance,
-                    equipments=instance.equipments.all(),
                     resolved=False
                 )
+                report.equipments.set(equipments)
+                return super().update(instance, validated_data)
             # Changing equipment status of broken items when there are breakages is handled in breakage reports
 
         return super().update(instance, validated_data)