[fix]: Loan fees

app/api/services/base_service.py

@@ -79,41 +79,51 @@ class BaseService:
             return {"error": "No charges found for the offer"}
 
         loan_charges = offer.charges
-        interest = cls.get_charge_detail(loan_charges, "INTEREST", amount)
-        management = cls.get_charge_detail(loan_charges, "MGTFEE", amount)
-        insurance = cls.get_charge_detail(loan_charges, "INSURANCE", amount)
-        vat = cls.get_charge_detail(loan_charges, "VAT", amount)
+        tenor = offer.tenor // 30 # Convert to months
+        interest = cls.get_charge_detail(charges = loan_charges, code = "INTEREST", amount = amount)
+        management = cls.get_charge_detail(charges = loan_charges, code = "MGTFEE", amount = amount)
+        insurance = cls.get_charge_detail(charges = loan_charges, code = "INSURANCE", amount = amount)
+        vat = cls.get_charge_detail(charges = loan_charges, code = "VAT", amount = amount, management_fee = management["fee"])
 
-        # Up-front payment: (principal + only those fees due immediately i.e due_days == 0)
-        upfront_payment = amount + sum(
-            amount * charge.percent / 100
-            for charge in loan_charges
-            if charge.due == 0
-        )
+        # Separate fees into upfront and postpaid
+        upfront_fees = [
+            fee["fee"]
+            for fee in [interest, management, insurance, vat]
+            if fee["due_days"] == 0
+        ]
 
-        # Total amount: (principal + all fees)
-        total_amount = amount + sum(
-            amount * charge.percent / 100
-            for charge in loan_charges
-        )
+        postpaid_fees = [
+            fee["fee"]
+            for fee in [interest, management, insurance, vat]
+            if fee["due_days"] != 0
+        ]
+
+        # Up-front payment: (only those fees due immediately i.e due_days == 0)
+        upfront_payment = sum(upfront_fees)
+
+          # Repayment amount: (principal + only those fees not due immediately i.e due_days != 0)
+        repayment_amount = amount + sum(postpaid_fees) * tenor
+
+        # Total amount: (upfront_payment + repayment_amount)
+        total_amount = upfront_payment + repayment_amount
 
         # Calculate the installment amount
-        tenor = offer.tenor
-        installment_amount = total_amount / tenor
+        installment_amount = repayment_amount / tenor
 
         return {
             "interest": interest,
             "management": management,
             "insurance": insurance,
             "vat": vat,
-            "upfront_payment": upfront_payment,
-            "total_amount": total_amount,
-            "installment_amount": installment_amount
+            "upfront_payment": round(upfront_payment, 2),
+            "repayment_amount": round(repayment_amount, 2),
+            "installment_amount": round(installment_amount, 2),
+            "total_amount": round(total_amount, 2)
         }
 
     
     @classmethod
-    def get_charge_detail(cls, charges, code, amount):
+    def get_charge_detail(cls, charges, code, amount, management_fee=None):
         """
         Get details for a specific charge code from a list of loan charges.
 
@@ -123,10 +133,16 @@ class BaseService:
         
         for charge in charges:
             if charge.code == code:
+                fee = (
+                    management_fee * charge.percent / 100
+                    if code == "VAT" and management_fee is not None
+                    else amount * charge.percent / 100
+                )
+            
                 return {
                     "rate": charge.percent,
-                    "fee": amount * charge.percent / 100,
-                    "due_days": charge.due,
+                    "fee": fee,
+                    "due_days": charge.due
                 }
             
         return {"rate": 0, "fee": 0, "due_days": 0}

app/api/services/provide_loan.py

@@ -65,7 +65,7 @@ class ProvideLoanService(BaseService):
 
                     charges = ProvideLoanService.calculate_charges(offer, amount)
                     upfront_fee = charges["upfront_payment"]
-                    repayment_amount = charges["total_amount"]
+                    repayment_amount = charges["repayment_amount"]
                     installment_amount = charges["installment_amount"]
                     
 

requirements.txt

@@ -37,5 +37,5 @@ confluent-kafka==1.9.2
 
 
 
-python-dateutil>=2.8.0
+python-dateutil