feat: update finance models

finance/models.py

@@ -1,3 +1,149 @@
 from django.db import models
+from django.contrib.auth import get_user_model
 
-# Create your models here.
+User = get_user_model()
+
+class Transaction(models.Model):
+    user = models.ForeignKey(User, on_delete=models.CASCADE, related_name='transactions')
+    date = models.DateField()
+    merchant = models.CharField(max_length=255)
+    amount = models.DecimalField(max_digits=12, decimal_places=2)
+    category = models.CharField(max_length=100)
+    category_key = models.CharField(max_length=50)
+    time = models.TimeField(null=True, blank=True)
+    payment_method = models.CharField(max_length=100, null=True, blank=True)
+    note = models.TextField(null=True, blank=True)
+    created_at = models.DateTimeField(auto_now_add=True)
+    updated_at = models.DateTimeField(auto_now=True)
+
+    class Meta:
+        ordering = ['-date', '-time', '-created_at']
+
+    def __str__(self):
+        return f"{self.merchant} - {self.amount}"
+
+class Budget(models.Model):
+    user = models.ForeignKey(User, on_delete=models.CASCADE, related_name='budgets')
+    name = models.CharField(max_length=100)
+    category_key = models.CharField(max_length=50)
+    budget_amount = models.DecimalField(max_digits=12, decimal_places=2)
+    spent_amount = models.DecimalField(max_digits=12, decimal_places=2, default=0)
+    remaining_amount = models.DecimalField(max_digits=12, decimal_places=2, default=0)
+    status = models.CharField(max_length=50, default='good') # good, warning, danger
+    warning_message = models.TextField(null=True, blank=True)
+    created_at = models.DateTimeField(auto_now_add=True)
+    updated_at = models.DateTimeField(auto_now=True)
+    
+    def save(self, *args, **kwargs):
+        self.remaining_amount = self.budget_amount - self.spent_amount
+        percentage = (self.spent_amount / self.budget_amount) * 100 if self.budget_amount > 0 else 0
+        
+        if percentage >= 90:
+            self.status = 'danger'
+        elif percentage >= 70:
+            self.status = 'warning'
+        else:
+            self.status = 'good'
+            
+        super().save(*args, **kwargs)
+
+    def __str__(self):
+        return f"{self.name} Budget - {self.user.email}"
+
+class Goal(models.Model):
+    user = models.ForeignKey(User, on_delete=models.CASCADE, related_name='goals')
+    name = models.CharField(max_length=255)
+    current_amount = models.DecimalField(max_digits=12, decimal_places=2, default=0)
+    target_amount = models.DecimalField(max_digits=12, decimal_places=2)
+    deadline = models.DateField(null=True, blank=True)
+    monthly_target = models.DecimalField(max_digits=12, decimal_places=2, default=0)
+    priority = models.CharField(max_length=50, default='medium') # low, medium, high
+    category = models.CharField(max_length=100, null=True, blank=True)
+    auto_save = models.BooleanField(default=False)
+    created_at = models.DateTimeField(auto_now_add=True)
+    updated_at = models.DateTimeField(auto_now=True)
+
+    def __str__(self):
+        return f"{self.name} - {self.user.email}"
+
+class Subscription(models.Model):
+    user = models.ForeignKey(User, on_delete=models.CASCADE, related_name='subscriptions')
+    name = models.CharField(max_length=255)
+    amount = models.DecimalField(max_digits=10, decimal_places=2)
+    renewal_date = models.DateField(null=True, blank=True)
+    usage_level = models.CharField(max_length=50, default='Medium')
+    value_score = models.IntegerField(default=3) # 1 to 5
+    status = models.CharField(max_length=50, default='active') # active, unused
+    last_used_date = models.DateField(null=True, blank=True)
+    warning = models.TextField(null=True, blank=True)
+    potential_saving = models.DecimalField(max_digits=10, decimal_places=2, default=0)
+    created_at = models.DateTimeField(auto_now_add=True)
+    updated_at = models.DateTimeField(auto_now=True)
+
+    def __str__(self):
+        return f"{self.name} - {self.user.email}"
+
+from django.db.models.signals import pre_save, post_save, post_delete
+from django.dispatch import receiver
+from django.db.models import Sum
+from users.models import FinancialProfile
+
+@receiver(pre_save, sender=Transaction)
+def store_original_amount(sender, instance, **kwargs):
+    if instance.pk:
+        try:
+            original = Transaction.objects.get(pk=instance.pk)
+            instance._original_amount = original.amount
+        except Transaction.DoesNotExist:
+            instance._original_amount = 0
+    else:
+        instance._original_amount = 0
+
+@receiver(post_save, sender=Transaction)
+def update_profile_balances(sender, instance, created, **kwargs):
+    try:
+        profile, _ = FinancialProfile.objects.get_or_create(user=instance.user)
+        if created:
+            profile.cash_available += instance.amount
+            profile.net_worth += instance.amount
+        else:
+            original_amount = getattr(instance, '_original_amount', 0)
+            diff = instance.amount - original_amount
+            profile.cash_available += diff
+            profile.net_worth += diff
+        profile.save()
+    except Exception as e:
+        print("Error in update_profile_balances signal:", e)
+
+@receiver(post_delete, sender=Transaction)
+def update_profile_balances_on_delete(sender, instance, **kwargs):
+    try:
+        profile, _ = FinancialProfile.objects.get_or_create(user=instance.user)
+        profile.cash_available -= instance.amount
+        profile.net_worth -= instance.amount
+        profile.save()
+    except Exception as e:
+        print("Error in update_profile_balances_on_delete signal:", e)
+
+@receiver(post_save, sender=Transaction)
+@receiver(post_delete, sender=Transaction)
+def update_budget_spent(sender, instance, **kwargs):
+    try:
+        cat_key = instance.category_key
+        if cat_key == 'dining' or cat_key == 'food':
+            budgets = Budget.objects.filter(user=instance.user, category_key__in=['dining', 'food'])
+        else:
+            budgets = Budget.objects.filter(user=instance.user, category_key=cat_key)
+            
+        for budget in budgets:
+            filter_keys = ['dining', 'food'] if cat_key in ['dining', 'food'] else [cat_key]
+            expenses_sum = Transaction.objects.filter(
+                user=instance.user,
+                category_key__in=filter_keys,
+                amount__lt=0
+            ).aggregate(total=Sum('amount'))['total'] or 0
+            
+            budget.spent_amount = abs(expenses_sum)
+            budget.save()
+    except Exception as e:
+        print("Error in update_budget_spent signal:", e)