System Design

1. Sequence Diagram

Purpose: Shows the interaction between the Admin, Customer, Web Interface, Invoice System, and Payment System for creating, viewing, and managing invoices.

Key Steps:

1. Create Invoice:

   • Admin enters details in the Web Interface.

   • Web Interface creates the invoice in the Invoice System and shows it to the Admin.

2. View Invoice (Customer):

   • Customer receives an email with the invoice link.

   • Customer views the invoice via the Web Interface.

3. Track Payment Status:

   • Admin checks payment status through the Web Interface.

   • Web Interface retrieves and displays the status from the Invoice System.

4. Send Payment Reminder:

   • Admin triggers a payment reminder.

   • System sends reminders to Customer(s) via email.

5. Update Invoice Status:

   • Admin updates the invoice status.

   • Web Interface updates and displays the new status.

2. Use Case Diagram

Actors:

1. Admin - Manages customers, invoices, and generates reports. Sends payment reminders to customers.

2. Customer - Views invoices via email and pays invoices. Cannot search invoices.

3. System - Sends payment reminders only when triggered by the Admin. Displays customer payment statuses for Admin to act on.

Use Cases:

1. Create Invoice – The Admin creates an invoice for a Customer. This process includes defining the invoice details, such as items, amounts, and due dates.

2. View Invoice – The Customer views their invoice details via email. The system sends the invoice as an email notification but does not allow the Customer to search or directly access invoices through a web interface.

3. Track Payment Status – Both the Admin and Customer can track the payment status of invoices. Admin has full access to see all payment statuses for all customers, while the Customer only views the status of their own invoices.

4. Generate Report – The Admin generates financial reports on invoices, showing total sales, outstanding payments, and other metrics.

5. Send Payment Reminder – The System sends payment reminders only when triggered by the Admin. The reminder is sent via email for overdue invoices, but it does not send reminders automatically.

6. Search Invoices – The Admin can search for invoices based on customer name or invoice number. Customers cannot search for invoices themselves.

7. Update Invoice Status – The Admin updates the invoice status (Paid/Unpaid) after receiving payments from customers.