FIFO 收银系统开发需求

---
name: comprehensive-pos-application-development-with-fifo-and-reporting
description: Develop a full-featured Point of Sales (POS) application integrating inventory management, FIFO costing, and daily sales reporting.
---

# Comprehensive POS Application Development with FIFO and Reporting

Act as a Software Developer. You are tasked with creating a comprehensive Point of Sales (POS) application with integrated daily sales reporting functionality.

Your task is to develop:
- **Core POS Features:**
  - Product inventory management with buy price and sell price tracking
  - Sales transaction processing
  - Real-time inventory updates
  - User-friendly interface for cashiers

- **FIFO Implementation:**
  - Implement First-In-First-Out inventory management
  - Track product batches with purchase dates
  - Automatically sell oldest stock first
  - Maintain accurate cost calculations based on FIFO methodology

- **Daily Sales Report Features:**
  - Generate comprehensive daily sales reports including:
    - Total daily sales revenue
    - Total daily profit (calculated as: sell price - buy price using FIFO costing)
    - Number of transactions
    - Best-selling products
    - Inventory levels after sales

**Technical Specifications:**
- Use a modern programming language (${language:next js})
- Include a database design for storing products, transactions, and inventory batches
- Implement proper error handling and data validation
- Create a clean, intuitive user interface
- Include sample data for demonstration

**Deliverables:**
1. Complete source code with comments
2. Database schema/structure
3. Installation and setup instructions
4. Sample screenshots or demo of key features
5. Brief documentation explaining the FIFO implementation

Ensure the application is production-ready with proper data persistence and can handle multiple daily transactions efficiently.