Borrowing-TrackerBackend/equipment_tracker/equipments/models.py

from django.db import models
from django.utils.timezone import now
from simple_history.models import HistoricalRecords
from django.db.models.signals import post_migrate
from django.dispatch import receiver


class Equipment(models.Model):
    EQUIPMENT_CATEGORY_CHOICES = (
        ('Glassware', 'Glassware'),
        ('Miscellaneous', 'Miscellaneous')
    )
    name = models.CharField(max_length=40)
    category = models.CharField(
        max_length=20, choices=EQUIPMENT_CATEGORY_CHOICES, default='Miscellaneous')
    description = models.TextField(max_length=512, null=True)
    date_added = models.DateTimeField(default=now, editable=False)
    last_updated = models.DateTimeField(auto_now=True, editable=False)
    history = HistoricalRecords()

    def __str__(self):
        return f'{self.name} ID:{self.id}'


class EquipmentInstance(models.Model):
    EQUIPMENT_INSTANCE_STATUS_CHOICES = (
        ('Available', 'Available'),
        ('Broken', 'Broken'),
        ('Borrowed', 'Borrowed'),
    )
    equipment = models.ForeignKey(Equipment, on_delete=models.CASCADE)
    status = models.CharField(
        max_length=20, choices=EQUIPMENT_INSTANCE_STATUS_CHOICES, default='Available')
    remarks = models.TextField(max_length=512, null=True)
    date_added = models.DateTimeField(default=now, editable=False)
    last_updated = models.DateTimeField(auto_now=True, editable=False)
    history = HistoricalRecords()

    def __str__(self):
        return f'{self.equipment.name} ID:{self.id}'


@receiver(post_migrate)
def create_superuser(sender, **kwargs):
    if sender.name == 'equipments':
        equipment_data = [
            {
                'name': 'Pyrex Beaker',
                'description': '',
                'category': 'Glassware',
                'remarks': 'First beaker of equipment tracker!'
            },
            {
                'name': 'Bunsen Burner',
                'description': '',
                'category': 'Miscellaneous',
                'remarks': 'First bunsen burner of equipment tracker!'
            },
            {
                'name': 'Microscope',
                'description': '',
                'category': 'Miscellaneous',
                'remarks': 'First microscope of equipment tracker!'
            }
        ]

        for data in equipment_data:
            EQUIPMENT, CREATED = Equipment.objects.get_or_create(
                name=data['name'],
                description=data['description'],
                category=data['category']
            )
            if (CREATED):
                print('Created Equipment: ' + data['name'])
            # Generate 3 equipment instances per SKU
            for x in range(3):
                EQUIPMENT_INSTANCE = EquipmentInstance.objects.create(
                    equipment=EQUIPMENT,
                    status='Available',
                    remarks=data['remarks']
                )
                print('Created Equipment Instances: ' +
                      EQUIPMENT_INSTANCE.equipment.name)