workx_backend/employee/models.py

from django.contrib.auth.models import User
from django.db import models
from phonenumber_field.modelfields import PhoneNumberField
from project.models import Project


class Employee(models.Model):
    user = models.OneToOneField(User, on_delete=models.CASCADE)
    employee_id = models.CharField(max_length=15)
    phone = PhoneNumberField()
    salary = models.DecimalField(max_digits=15, decimal_places=2)
    start_date = models.DateField()
    end_date = models.DateField(null=True, blank=True)
    projects = models.ManyToManyField(Project)

    def __str__(self):
        return self.employee_id


class Perk(models.Model):
    employee = models.OneToOneField(Employee, on_delete=models.CASCADE)
    perk_per_month = models.DecimalField(max_digits=15, decimal_places=2)

    @property
    def total_perk(self):
        perks = self.perk_transactions.all()
        total = 0
        for perk in perks:
            if perk.type == 'INCOME':
                total += perk.amount
            else:
                total -= perk.amount
        return total


class PerkTransaction(models.Model):
    TRANSACTION_TYPE = (
        ("INCOME", "INCOME"),
        ("EXPENSE", "EXPENSE")
    )
    type = models.CharField(choices=TRANSACTION_TYPE, default="INCOME", max_length=10)
    amount = models.DecimalField(max_digits=15, decimal_places=2)
    perk = models.ForeignKey(Perk, on_delete=models.CASCADE)