fina autoamtiona adn billing and credits

backend/igny8_core/business/billing/models.py

@@ -3,6 +3,7 @@ Billing Models for Credit System
 """
 from django.db import models
 from django.core.validators import MinValueValidator
+from django.conf import settings
 from igny8_core.auth.models import AccountBaseModel
 
 
@@ -75,3 +76,85 @@ class CreditUsageLog(AccountBaseModel):
         account = getattr(self, 'account', None)
         return f"{self.get_operation_type_display()} - {self.credits_used} credits - {account.name if account else 'No Account'}"
 
+
+class CreditCostConfig(models.Model):
+    """
+    Configurable credit costs per AI function
+    Admin-editable alternative to hardcoded constants
+    """
+    # Operation identification
+    operation_type = models.CharField(
+        max_length=50,
+        unique=True,
+        choices=CreditUsageLog.OPERATION_TYPE_CHOICES,
+        help_text="AI operation type"
+    )
+    
+    # Cost configuration
+    credits_cost = models.IntegerField(
+        validators=[MinValueValidator(0)],
+        help_text="Credits required for this operation"
+    )
+    
+    # Unit of measurement
+    UNIT_CHOICES = [
+        ('per_request', 'Per Request'),
+        ('per_100_words', 'Per 100 Words'),
+        ('per_200_words', 'Per 200 Words'),
+        ('per_item', 'Per Item'),
+        ('per_image', 'Per Image'),
+    ]
+    
+    unit = models.CharField(
+        max_length=50,
+        default='per_request',
+        choices=UNIT_CHOICES,
+        help_text="What the cost applies to"
+    )
+    
+    # Metadata
+    display_name = models.CharField(max_length=100, help_text="Human-readable name")
+    description = models.TextField(blank=True, help_text="What this operation does")
+    
+    # Status
+    is_active = models.BooleanField(default=True, help_text="Enable/disable this operation")
+    
+    # Audit fields
+    created_at = models.DateTimeField(auto_now_add=True)
+    updated_at = models.DateTimeField(auto_now=True)
+    updated_by = models.ForeignKey(
+        settings.AUTH_USER_MODEL,
+        null=True,
+        blank=True,
+        on_delete=models.SET_NULL,
+        related_name='credit_cost_updates',
+        help_text="Admin who last updated"
+    )
+    
+    # Change tracking
+    previous_cost = models.IntegerField(
+        null=True,
+        blank=True,
+        help_text="Cost before last update (for audit trail)"
+    )
+    
+    class Meta:
+        app_label = 'billing'
+        db_table = 'igny8_credit_cost_config'
+        verbose_name = 'Credit Cost Configuration'
+        verbose_name_plural = 'Credit Cost Configurations'
+        ordering = ['operation_type']
+    
+    def __str__(self):
+        return f"{self.display_name} - {self.credits_cost} credits {self.unit}"
+    
+    def save(self, *args, **kwargs):
+        # Track cost changes
+        if self.pk:
+            try:
+                old = CreditCostConfig.objects.get(pk=self.pk)
+                if old.credits_cost != self.credits_cost:
+                    self.previous_cost = old.credits_cost
+            except CreditCostConfig.DoesNotExist:
+                pass
+        super().save(*args, **kwargs)