Borrowing-TrackerBackend/equipment_tracker/equipments/views.py

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
from django.core.cache import cache
# -- Equipment Viewsets


class EquipmentViewSet(viewsets.ModelViewSet):
    if (not DEBUG):
        permission_classes = [IsAuthenticated]
    serializer_class = serializers.EquipmentSerializer
    queryset = Equipment.objects.all().order_by('id')

    def get_queryset(self):
        key = 'equipments'

        queryset = cache.get(key)
        if not queryset:
            queryset = super().get_queryset()
            cache.set(key, queryset, timeout=60*60*24)
        return queryset

# For viewing all  logs for all equipments


class EquipmentsLogsViewSet(generics.ListAPIView):
    if (not DEBUG):
        permission_classes = [IsAuthenticated, IsTechnician]
    serializer_class = serializers.EquipmentLogsSerializer
    queryset = Equipment.history.all().order_by('-history_date')

# For viewing logs per individual equipment


class EquipmentLogViewSet(viewsets.ReadOnlyModelViewSet):
    if (not DEBUG):
        permission_classes = [IsAuthenticated, IsTechnician]
    serializer_class = serializers.EquipmentLogSerializer

    def get_queryset(self):
        equipment_id = self.kwargs['equipment_id']
        return Equipment.objects.filter(id=equipment_id)

# Last changed equipment


class LastUpdatedEquipmentViewSet(generics.ListAPIView):
    if (not DEBUG):
        permission_classes = [IsAuthenticated, IsTechnician]
    serializer_class = serializers.EquipmentSerializer
    queryset = Equipment.objects.all().order_by('-date_added')

    def get_queryset(self):
        return super().get_queryset()[:1]

# -- Equipment Instance Viewsets


class EquipmentInstanceViewSet(viewsets.ModelViewSet):
    if (not DEBUG):
        permission_classes = [IsAuthenticated]
    serializer_class = serializers.EquipmentInstanceSerializer
    queryset = EquipmentInstance.objects.all().order_by('id')

    def get_queryset(self):
        key = 'equipment_instances'
        queryset = cache.get(key)
        if not queryset:
            queryset = super().get_queryset()
            cache.set(key, queryset, timeout=60*60*24)
        return queryset


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.
        """
        key = 'available_equipment_instances'

        queryset = cache.get(key)
        if not queryset:
            # Get all non-finalized transactions
            non_finalized_transactions = Transaction.objects.filter(
                ~Q(transaction_status__in=[
                    'Finalized', 'Rejected', 'Cancelled'])
            ).prefetch_related('equipments')

            # Get all equipment instances associated with non-finalized transactions
            non_finalized_equipments = EquipmentInstance.objects.filter(
                transaction__in=non_finalized_transactions
            ).order_by('id').prefetch_related('equipment')

            # 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)
            )
            cache.set(key, queryset, timeout=60*60*24)

        return queryset.prefetch_related('equipment')

# For viewing all equipment instance logs


class EquipmentInstancesLogsViewSet(generics.ListAPIView):
    if (not DEBUG):
        permission_classes = [IsAuthenticated, IsTechnician]
    serializer_class = serializers.EquipmentInstanceLogsSerializer
    queryset = EquipmentInstance.history.all().order_by('-history_date')

# For viewing logs per individual equipment instance


class EquipmentInstanceLogViewSet(viewsets.ReadOnlyModelViewSet):
    if (not DEBUG):
        permission_classes = [IsAuthenticated, IsTechnician]
    serializer_class = serializers.EquipmentInstanceLogSerializer

    def get_queryset(self):
        equipment_id = self.kwargs['equipment_id']
        return EquipmentInstance.objects.filter(id=equipment_id)

# Last changed equipment instance


class LastUpdatedEquipmentInstanceViewSet(generics.ListAPIView):
    if (not DEBUG):
        permission_classes = [IsAuthenticated, IsTechnician]
    serializer_class = serializers.EquipmentInstanceSerializer
    queryset = EquipmentInstance.objects.all().order_by('-date_added')

    def get_queryset(self):
        return super().get_queryset()[:1]