""" Update Mwamba product to 10% monthly interest and create a sample loan for 3 months. This script demonstrates that interest is calculated as: - Month 1: 10% of principal - Month 2: 10% of principal - Month 3: 10% of principal Total Interest = 30% of principal (10% × 3 months) """ import os import django import sys from decimal import Decimal # Setup Django os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'branch_system.settings') django.setup() from django.contrib.auth import get_user_model from loans.models import LoanProduct, LoanApplication, Loan from django.utils import timezone from datetime import timedelta User = get_user_model() def update_mwamba_and_create_loan(): """Update Mwamba product to 10% interest and create a sample loan""" print("=" * 80) print("UPDATING MWAMBA PRODUCT AND CREATING SAMPLE LOAN") print("=" * 80) # Step 1: Update Mwamba loan product to 10% interest print("\n1. Updating Mwamba loan product to 10% monthly interest...") try: mwamba_product = LoanProduct.objects.get(product_type='mwamba') print(f" Found Mwamba product: {mwamba_product.name}") print(f" Current interest rate: {mwamba_product.interest_rate}%") # Update to 10% mwamba_product.interest_rate = Decimal('10.00') mwamba_product.save() print(f" ✓ Updated interest rate to: {mwamba_product.interest_rate}%") except LoanProduct.DoesNotExist: print(" Creating Mwamba product with 10% interest...") mwamba_product = LoanProduct.objects.create( name="Mwamba Loan", product_type='mwamba', description="Medium-term loan product with 10% monthly interest", min_amount=Decimal('50000.00'), max_amount=Decimal('500000.00'), interest_rate=Decimal('10.00'), # 10% monthly processing_fee=Decimal('5.00'), # 5% processing fee late_payment_penalty=Decimal('5.00'), duration_months=3, min_duration=30, max_duration=365, available_repayment_methods=['monthly'], requires_guarantor=True, requires_collateral=False, is_active=True ) print(f" ✓ Created Mwamba product: {mwamba_product.name}") # Display product details print(f"\n Product Details:") print(f" - Interest Rate: {mwamba_product.interest_rate}% per month") print(f" - Processing Fee: {mwamba_product.processing_fee}%") print(f" - Duration: {mwamba_product.duration_months} months") # Step 2: Get or create a borrower print("\n2. Getting borrower...") borrower = User.objects.filter(role='borrower', is_active=True).first() if not borrower: print(" No borrower found. Creating sample borrower...") borrower = User.objects.create_user( username='mwamba_borrower', email='mwamba@example.com', password='password123', first_name='John', last_name='Mwamba', phone_number='+254712345678', role='borrower', is_active=True, status='active', monthly_income=Decimal('80000.00') ) print(f" ✓ Created borrower: {borrower.get_full_name()}") else: print(f" ✓ Using borrower: {borrower.get_full_name()}") # Step 3: Define loan parameters principal = Decimal('100000.00') # KES 100,000 duration_days = 90 # 3 months (90 days) months = Decimal('3') # 3 months print(f"\n3. Loan Parameters:") print(f" - Principal Amount: KES {principal:,.2f}") print(f" - Duration: {duration_days} days ({months} months)") print(f" - Interest Rate: {mwamba_product.interest_rate}% per month") # Step 4: Calculate loan amounts print(f"\n4. Calculating Loan Amounts:") # Interest calculation: 10% per month × 3 months interest_rate_decimal = mwamba_product.interest_rate / Decimal('100') interest_per_month = principal * interest_rate_decimal total_interest = interest_per_month * months print(f"\n Interest Calculation:") print(f" - Month 1: {mwamba_product.interest_rate}% of KES {principal:,.2f} = KES {interest_per_month:,.2f}") print(f" - Month 2: {mwamba_product.interest_rate}% of KES {principal:,.2f} = KES {interest_per_month:,.2f}") print(f" - Month 3: {mwamba_product.interest_rate}% of KES {principal:,.2f} = KES {interest_per_month:,.2f}") print(f" - Total Interest: KES {total_interest:,.2f}") # Processing fee calculation (one-time for Mwamba) processing_fee_rate = mwamba_product.processing_fee / Decimal('100') processing_fee = principal * processing_fee_rate print(f"\n Processing Fee Calculation:") print(f" - {mwamba_product.processing_fee}% of KES {principal:,.2f} = KES {processing_fee:,.2f}") # Total amount total_amount = principal + total_interest + processing_fee print(f"\n Total Loan Amount:") print(f" - Principal: KES {principal:,.2f}") print(f" - Interest (3 mo): KES {total_interest:,.2f}") print(f" - Processing Fee: KES {processing_fee:,.2f}") print(f" - TOTAL: KES {total_amount:,.2f}") # Step 5: Create loan application print(f"\n5. Creating Loan Application...") application = LoanApplication.objects.create( borrower=borrower, loan_product=mwamba_product, requested_amount=principal, requested_duration=duration_days, purpose="Business expansion - sample Mwamba loan with 10% monthly interest", repayment_method='monthly', interest_amount=total_interest, processing_fee_amount=processing_fee, total_amount=total_amount, status='pending' ) print(f" ✓ Application created: {application.application_number}") # Step 6: Approve and create loan print(f"\n6. Approving Application and Creating Loan...") # Get an admin user to approve admin = User.objects.filter(role='admin').first() if not admin: admin = User.objects.filter(is_superuser=True).first() if not admin: print(" Creating admin user for approval...") admin = User.objects.create_superuser( username='admin', email='admin@example.com', password='admin123', first_name='Admin', last_name='User' ) # Approve the application loan = application.approve( approved_by=admin, notes="Sample Mwamba loan for testing 10% monthly interest calculation", disbursement_date=timezone.now() ) print(f" ✓ Loan created: {loan.loan_number}") print(f" ✓ Status: {loan.status}") # Step 7: Display final loan details print(f"\n" + "=" * 80) print("LOAN CREATED SUCCESSFULLY") print("=" * 80) print(f"\nLoan Number: {loan.loan_number}") print(f"Borrower: {loan.borrower.get_full_name()}") print(f"Product: {mwamba_product.name}") print(f"\nLoan Details:") print(f" Principal Amount: KES {loan.principal_amount:,.2f}") print(f" Interest Amount: KES {loan.interest_amount:,.2f}") print(f" Processing Fee: KES {loan.processing_fee:,.2f}") print(f" Total Amount: KES {loan.total_amount:,.2f}") print(f"\nDates:") print(f" Disbursement Date: {loan.disbursement_date.strftime('%Y-%m-%d')}") print(f" Due Date: {loan.due_date.strftime('%Y-%m-%d')}") print(f" Duration: {loan.duration_days} days") print(f"\nInterest Breakdown (10% per month):") print(f" Month 1: 10% × KES {principal:,.2f} = KES {interest_per_month:,.2f}") print(f" Month 2: 10% × KES {principal:,.2f} = KES {interest_per_month:,.2f}") print(f" Month 3: 10% × KES {principal:,.2f} = KES {interest_per_month:,.2f}") print(f" Total: 30% × KES {principal:,.2f} = KES {total_interest:,.2f}") print(f"\nPayment Status:") print(f" Amount Paid: KES {loan.amount_paid:,.2f}") print(f" Outstanding: KES {loan.outstanding_amount:,.2f}") print(f" Status: {loan.status}") print(f"\n" + "=" * 80) print("VERIFICATION") print("=" * 80) # Verify the calculation expected_interest = principal * Decimal('0.10') * Decimal('3') actual_interest = loan.interest_amount print(f"\nInterest Calculation Verification:") print(f" Expected: KES {expected_interest:,.2f} (10% × 3 months)") print(f" Actual: KES {actual_interest:,.2f}") print(f" Match: {'✓ YES' if expected_interest == actual_interest else '✗ NO'}") if expected_interest == actual_interest: print(f"\n✓ SUCCESS: Interest is correctly calculated as 10% per month for 3 months!") print(f"✓ This means:") print(f" - Each month charges 10% of the principal") print(f" - Total interest = 10% + 10% + 10% = 30% of principal") print(f" - NOT compound interest (which would be 33.1%)") else: print(f"\n✗ WARNING: Interest calculation mismatch!") print(f" Expected: {expected_interest}") print(f" Got: {actual_interest}") return loan if __name__ == '__main__': try: loan = update_mwamba_and_create_loan() print(f"\n✓ Script completed successfully!") print(f"✓ Loan ID: {loan.id}") print(f"✓ Loan Number: {loan.loan_number}") except Exception as e: print(f"\n✗ Error: {str(e)}") import traceback traceback.print_exc() sys.exit(1)