Microtec POS Application Specifications & Business Logic

This document provides a comprehensive overview of the Microtec POS application, a professional-grade Point of Sale system built with Flutter.

1. Technical Specifications (Technical Stack)

• Framework: Flutter (Targeting Windows, Android, and iOS).
• Architecture: Clean Architecture with BLOC for state management.
• Local Database: ObjectBox (High-performance NoSQL database for offline-first capabilities).
• Communication:
  • gRPC & Protobuf: Used for high-speed, real-time communication (KDS, CDS, and local network).
  • REST API (Dio): For synchronization with the main web backend.
• Peripherals & Integrations:
  • Printing: ESC/POS printer support via a custom manager.
  • Payments: Integration with external payment terminals.
  • Hardware: Support for Barcode Scanners and Weighing Scales.
  • Multi-Display: Support for Customer Display Systems (CDS) and multi-window desktop setups.
• Monitoring: Sentry for error tracking and performance monitoring.

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2. Business Features

The application is a hybrid system supporting both Retail and Restaurant business models.

Core POS Features:

• Sales Operations: Item scanning (barcode), manual search, and category-based selection.
• Restaurant Management:
  • Floor & Table Management: Visual representation of tables and floors.
  • Kitchen Flow: Sending orders to Kitchen Display Systems (KDS) or kitchen printers.
  • Menu Customization: Support for "Options" (addons) and "Ingredients" (modifications).
• Transaction Types: Support for Invoices, Returns (Full/Partial), and Reservations.
• Customer Management (CRM): Customer profiles, groups, and loyalty points system.
• Discounts & Promotions:
  • Manual and automatic discounts.
  • Surcharges and service charges.
  • Offer/Promotion engine.

Backend & Management:

• Shift Management: Opening/Closing sessions with cash drawer reconciliation (Tender counting).
• Offline-First Sync: Advanced sync managers that handle data consistency between local storage and the cloud.
• Reporting: On-device business date reports and transaction history.
• Barcode Printing: Utility for generating and printing product barcodes.

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3. Business Logic & Calculations

• Pricing Engine: Calculates prices based on base price, addons/options, item-level vs. order-level discounts, and tax (VAT) per item or order.
• Order Lifecycle: Orders move through states: Draft -> Hold (Sent to Kitchen) -> Unpaid/Partial -> Paid -> Closed.
• Audit Trail: The system tracks "Removed Items" from orders for security and auditing purposes.
• Business Date Logic: Decouples the "Business Date" from the "System Date," allowing shifts to span across midnight without breaking reports.

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4. Application Flow (User Journey)

Phase 1: Authentication & Setup

1. Login: User authenticates via credentials.
2. Initialization: App syncs latest data (products, prices, settings).
3. Session Start: User opens a "Session" (Shift) by entering the opening cash balance.

Phase 2: The Sales Process

1. Entry Point: User selects "Sell" (Retail) or a Table (Restaurant) from the main dashboard.
2. Cart Building:
   • Scan items or pick from categories.
   • Configure modifiers (addons/ingredients).
   • Add order-level notes.
3. Order Handling: Save order and send to kitchen (Hold) or proceed to payment.

Phase 3: Payment & Finalization

1. Payment Screen: Choose payment method (Cash, Credit Card, Loyalty Points, or Split Payment).
2. Terminal Integration: If card is selected, the app triggers the physical payment terminal.
3. Finalization: Invoice is generated, local DB is updated, and a receipt is printed.
4. Sync: The order is queued for background synchronization to the cloud.

Phase 4: Closing the Loop

1. End of Shift: User closes the session.
2. Reconciliation: User enters actual cash/card totals; system identifies variances.
3. Reporting: Shift report is printed, and the user is logged out.