Invoice Management Web APP

Project Overview:
Develop an invoice management web application using React, Vue, or Angular with a cost-effective backend (e.g., Node.js, Express, or Laravel or Firebase). The app will have a single user type, Sales Person, who will manage customer invoices. The application should be optimized for offline use as well, and print invoices using the Epson TM-T82 thermal printer (3-inch roll).
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User Features:
1. User Authentication:
o Employees log in with username and password.
2. Invoice Creation Flow:
o Step 1: Enter customer mobile number.
o Step 2: Enter the following details for each product:
 Product Name
 MRP (Maximum Retail Price)
 Discounted Price
 Quantity
 Reward Points (manual input)
o Step 3: The invoice table updates dynamically with the following fields:
 Product
 MRP
 Quantity
 Discounted Price
 Rewards
 Total Discounted Price (Discounted Price × Quantity)
3. Draft Invoice Review:
o Once all items are entered, the Draft Invoice is displayed.
o The draft invoice shows the following auto-generated summary:
 Original Bill Amount: Sum of (MRP × Quantity).
 Total Reward Points: Sum of (Reward Points × Quantity).
 Total Discounted Price: Sum of Total Discounted Price for each item.
 Old Rewards Utilized: Manual input to deduct existing customer rewards.
 Final Amount to Pay: (Total Discounted Price) - (Old Rewards Utilized).
o Salesperson confirms before generating the final invoice.
4. Invoice Generation and Printing:
o After confirmation, the invoice is printed using the Epson TM-T82 thermal printer.
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Additional Features to Include:
1. Invoice Search:
o Search for invoices by:
 Date Range
 Customer Mobile Number
 Invoice Amount
2. Invoice Reports:
o Generate reports based on:
 Daily/Monthly Sales
 Top-selling products
 Total rewards given
 Total discounts provided
3. Invoice Copy Printing:
o Allow printing copies of invoices on request.
4. Invoice Editing & History:
o Edit invoices before confirmation and store the invoice history for future reference.
5. Export Functionality:
o Allow sales data export to CSV/Excel for offline access.
6. Error Handling & Validation:
o Input validation for:
 Mobile number format.
 MRP and Discounted price (ensure valid prices).
 Quantity (positive numbers only).
o Error messages should be clear and actionable.
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Backend and Database Considerations:
• Backend: Node.js with Express or Laravel.
• Database: Since no customer or product tables are needed, invoices can be stored in a single invoice table.
o The table should capture:
 Invoice Number
 Customer Mobile Number
 List of products and details (MRP, quantity, etc.)
 Date and Time
 Total Amount, Rewards, and Final Amount
o Ensure proper indexing for search features based on date, mobile number, and amount.
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Non-functional Requirements:
• Responsiveness: The app should work seamlessly on desktop, tablets, and mobile devices.
• Performance: Optimize for low-latency interactions, especially for the search and invoice generation modules.
• Offline Capability: Provide basic offline functionality for creating and printing invoices even without internet access (if feasible).