[add]: Update loan status after repayment

app/models/loan.py

@@ -65,16 +65,35 @@ class Loan(db.Model):
             return False
         return True
     
+
     @classmethod
     def get_customer_loan(cls, loan_id, customer_id):
         """
-        Check if a loan with the given ID exists and if the loan belongs to the specified customer_id.
+        Get customer's active loans.
         """
-        loan = cls.query.filter_by(id=loan_id, customer_id=customer_id).first()
+        loan = cls.query.filter_by(id = loan_id, customer_id = customer_id).first()
         if not loan:
-            raise ValueError(f"Loan with ID {loan_id} does not exist or does not belong to customer {customer_id}.")
+            raise ValueError(f"Loan with ID {loan_id} does not exist or does not belong to customer {customer_id}.")        
         return loan
     
+    @classmethod
+    def update_status(cls, loan_id, status):
+        """
+        Update the status of the loan with the given loan_id.
+        """
+        # Retrieve loan 
+        loan = cls.query.get(loan_id)
+        
+        if not loan:
+            raise ValueError(f"Loan with ID {loan_id} does not exist.")
+        
+        if loan.status == status:
+            return
+        
+        # Update loan status and the updated_at timestamp
+        loan.status = status
+        
+        db.session.commit()
     
     def __repr__(self):
         return f'<Loan {self.id}>'

app/models/repayment.py

@@ -1,4 +1,5 @@
 from datetime import datetime, timezone
+from app.api.enums.loan_status import LoanStatus
 from app.extensions import db
 from app.models.customer import Customer
 from app.models.loan import Loan
@@ -29,8 +30,11 @@ class Repayment(db.Model):
 
         # Check loan exists
         loan = Loan.get_customer_loan(loan_id = loan_id, customer_id = customer_id)
-        if not loan:
-            raise ValueError("Loan not found for customer")
+        
+        # Check that the loan is active
+        if loan.status != LoanStatus.ACTIVE:
+            raise ValueError(f"Repayment cannot be processed. Loan status: ({loan.status})")
+        
 
         repayment = cls(
             customer_id=customer_id,