LLD: Warehouse Handling and Reporting System

Requirements: Design a low-level system for warehouse handling and reporting: track inventory across warehouse locations, record stock movements (inbound/outbound/transfer), and generate reports (current stock levels, movement history) - deliverable includes sequence diagrams, class diagrams, and code for key operations using at least one design pattern.

Design: Core classes: Warehouse, InventoryItem, StockMovement (with a type enum: INBOUND/OUTBOUND/TRANSFER), and a ReportGenerator. Use the Strategy pattern for different report types (daily/weekly summary), Observer pattern to notify subscribers (e.g., a low-stock alert service) when stock crosses a threshold, and a Factory to construct the correct StockMovement subtype. Sequence diagram should show the flow from a movement request through validation, inventory update, and any triggered notifications; class diagram should show relationships (composition of Warehouse -> InventoryItem, and the movement/report class hierarchy).