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 ()
- 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.