# Enterprise-Grade POS Models Review & Gap Analysis

## ✅ Current Models (21 Models)

### Authentication & Users
1. **User** - Users with roles (cashier, manager, system_admin) ✅

### Customers
2. **Customer** - Customers (B2B, B2C) ✅

### Products & Inventory
3. **Product** - Products (FG/RM) ✅
4. **ProductVariant** - Product variants ✅
5. **Inventory** - Quantity-based inventory ✅
6. **InventoryItem** - UID-based inventory ✅
7. **InventoryMovement** - Inventory audit trail ✅

### Procurement
8. **Vendor** - Suppliers/vendors ✅
9. **PurchaseOrder** - Purchase orders ✅
10. **GRN** - Goods Receipt Notes ✅
11. **GRNItem** - GRN items ✅

### Production
12. **BOM** - Bill of Materials ✅
13. **BOMItem** - BOM items ✅
14. **ProductionOrder** - Production orders ✅

### Sales
15. **Sale** - Sales transactions ✅
16. **SaleItem** - Sale items ✅

### Payments & Fiscal
17. **Payment** - Payments ✅
18. **FiscalReceipt** - KRA eTIMS receipts ✅

### Returns
19. **Return** - Returns ✅
20. **ReturnItem** - Return items ✅

### System
21. **SystemLog** - Audit logs ✅

---

## 🔍 Missing Enterprise-Grade Models

### 1. **Tax/VAT Configuration** ⚠️ CRITICAL
**What's Missing:**
- Tax rates are hardcoded in `Product.default_vat_rate` and `SaleItem.vat_rate`
- No support for multiple tax types (VAT, sales tax, excise duty)
- No tax categories or tax exemptions
- No tax reporting periods

**Needed Models:**
- `TaxRate` - Tax rates (VAT 16%, excise 8%, etc.)
- `TaxCategory` - Product tax categories
- `TaxExemption` - Customer/product exemptions

**Priority:** HIGH

---

### 2. **Product Categories** ⚠️ IMPORTANT
**What's Missing:**
- Products have no category organization
- Difficult to filter/search by category
- No category-based pricing or promotions

**Needed Models:**
- `Category` - Product categories (hierarchical: Electronics > Phones > Smartphones)
- `ProductCategory` - Product-to-category mapping (many-to-many)

**Priority:** HIGH

---

### 3. **Pricing & Discounts** ⚠️ CRITICAL
**What's Missing:**
- No discount codes/promotions
- No quantity-based pricing (bulk discounts)
- No customer-specific pricing
- Prices only in SaleItem (no price history)

**Needed Models:**
- `PriceList` - Different price lists (retail, wholesale, B2B)
- `ProductPrice` - Product prices by price list (with effective dates)
- `Discount` - Discount codes/promotions
- `DiscountRule` - Discount rules (percentage, fixed, buy-X-get-Y)

**Priority:** HIGH

---

### 4. **Multi-Location/Branch Support** ⚠️ ENTERPRISE
**What's Missing:**
- Single location assumption
- No branch/store management
- No stock transfers between locations
- No location-based inventory

**Needed Models:**
- `Location` - Stores/branches/warehouses
- `LocationInventory` - Inventory per location
- `StockTransfer` - Stock transfers between locations
- `StockTransferItem` - Transfer items

**Priority:** MEDIUM (if multi-location is needed)

---

### 5. **Expenses & Accounting** ⚠️ ENTERPRISE
**What's Missing:**
- No expense tracking
- No cost centers
- No accounting integration

**Needed Models:**
- `Expense` - Business expenses
- `ExpenseCategory` - Expense categories
- `CostCenter` - Cost centers/departments
- `Account` - Chart of accounts

**Priority:** MEDIUM

---

### 6. **Shift & Cash Management** ⚠️ CRITICAL FOR POS
**What's Missing:**
- No cashier shift tracking
- No opening/closing cash counts
- No cash drawer management
- No discrepancy tracking

**Needed Models:**
- `Shift` - Cashier shifts (open/close times, opening/closing cash)
- `CashCount` - Cash count entries (opening, closing, mid-shift)
- `CashDrawer` - Cash drawer assignments
- `CashDiscrepancy` - Cash discrepancies/variances

**Priority:** HIGH

---

### 7. **Refunds (Separate from Returns)** ⚠️ IMPORTANT
**What's Missing:**
- Returns and refunds are mixed
- No separate refund tracking
- No refund methods tracking

**Needed Models:**
- `Refund` - Refunds (separate from returns)
- `RefundItem` - Refund items

**Priority:** MEDIUM (can use Return + Payment for now)

---

### 8. **Notifications & Alerts** ⚠️ ENTERPRISE
**What's Missing:**
- No low stock alerts
- No reorder notifications
- No system alerts

**Needed Models:**
- `Notification` - System notifications
- `Alert` - Inventory/product alerts
- `AlertRule` - Alert configuration rules

**Priority:** LOW (can be handled by application logic initially)

---

### 9. **Loyalty Programs** ⚠️ OPTIONAL
**What's Missing:**
- No customer loyalty tracking
- No points/rewards system

**Needed Models:**
- `LoyaltyProgram` - Loyalty programs
- `LoyaltyPoints` - Customer points balance
- `LoyaltyTransaction` - Points earned/spent

**Priority:** LOW (optional feature)

---

### 10. **Receipt Templates** ⚠️ ENTERPRISE
**What's Missing:**
- No customizable receipt templates
- No multi-language receipts

**Needed Models:**
- `ReceiptTemplate` - Receipt templates
- `ReceiptTemplateField` - Template fields

**Priority:** LOW

---

### 11. **Product Media/Images** ⚠️ IMPORTANT
**What's Missing:**
- No product images
- No product documents

**Needed Models:**
- `ProductImage` - Product images
- `ProductDocument` - Product documents/attachments

**Priority:** MEDIUM

---

### 12. **Sales Channels** ⚠️ ENTERPRISE
**What's Missing:**
- No channel tracking (online, in-store, mobile)
- Limited by Sale.sale_type (POS/INVOICE only)

**Needed Models:**
- `SalesChannel` - Sales channels (Store, Online, Mobile App, etc.)
- Add `channel_id` to Sale model

**Priority:** MEDIUM

---

### 13. **Inventory Adjustments (Explicit)** ⚠️ IMPORTANT
**What's Missing:**
- Adjustments are in InventoryMovement but no explicit tracking
- No approval workflow for adjustments

**Needed Models:**
- `InventoryAdjustment` - Explicit adjustment records
- `InventoryAdjustmentItem` - Adjustment items
- Add approval workflow (status: PENDING, APPROVED, REJECTED)

**Priority:** MEDIUM

---

### 14. **Vendor Details Enhancement** ⚠️ ENTERPRISE
**What's Missing:**
- Vendor model is too basic (only name and type)
- No contact information, payment terms, address

**Enhancement:**
- Add fields to Vendor: email, phone, address, payment_terms, credit_limit

**Priority:** MEDIUM

---

### 15. **Settings/Configuration** ⚠️ ENTERPRISE
**What's Missing:**
- No system-wide settings storage
- Hardcoded configurations

**Needed Models:**
- `Setting` - System settings (key-value pairs)

**Priority:** MEDIUM

---

### 16. **Document Attachments** ⚠️ ENTERPRISE
**What's Missing:**
- No document attachments for sales, purchases, etc.
- No file management

**Needed Models:**
- `Document` - Document attachments (generic)
- `DocumentAttachment` - Links documents to entities (polymorphic)

**Priority:** LOW

---

### 17. **Reports & Report Templates** ⚠️ ENTERPRISE
**What's Missing:**
- No saved report configurations
- No report templates

**Needed Models:**
- `Report` - Saved reports
- `ReportTemplate` - Report templates

**Priority:** LOW (reports can be generated on-demand)

---

### 18. **Cash Float/Change Management** ⚠️ POS
**What's Missing:**
- No change/float tracking
- No denomination tracking

**Enhancement:**
- Add to Shift or create `CashFloat` model

**Priority:** MEDIUM

---

### 19. **Product Units of Measure** ⚠️ IMPORTANT
**What's Missing:**
- Products have unit field but no UOM management
- No conversions between units (e.g., 1 box = 12 pieces)

**Needed Models:**
- `UnitOfMeasure` - UOM definitions
- `UnitConversion` - Unit conversions

**Priority:** MEDIUM

---

### 20. **Barcode/QR Management** ⚠️ POS
**What's Missing:**
- Barcodes stored but no barcode type management
- No QR code generation for receipts

**Enhancement:**
- Add barcode_type to InventoryItem
- QR generation handled by application (can add QR storage to FiscalReceipt)

**Priority:** LOW

---

## 📊 Priority Summary

### 🔴 HIGH PRIORITY (Must Have)
1. **Tax/VAT Configuration** - Multi-tax support, exemptions
2. **Product Categories** - Essential for organization
3. **Pricing & Discounts** - Critical for sales
4. **Shift & Cash Management** - Essential for POS operations

### 🟡 MEDIUM PRIORITY (Should Have)
5. **Multi-Location Support** - If multi-branch needed
6. **Product Media/Images** - Important for product display
7. **Inventory Adjustments** - Explicit tracking with approval
8. **Sales Channels** - Track sales by channel
9. **Vendor Details Enhancement** - Better vendor management
10. **Product Units of Measure** - Better inventory tracking
11. **Cash Float Management** - Better cash handling
12. **Settings/Configuration** - System configurability

### 🟢 LOW PRIORITY (Nice to Have)
13. **Expenses & Accounting** - If full accounting needed
14. **Loyalty Programs** - Optional feature
15. **Receipt Templates** - Can hardcode initially
16. **Notifications** - Can handle in application
17. **Document Attachments** - Optional
18. **Reports** - Can generate on-demand

---

## 🎯 Recommended Immediate Additions

For a **production-ready, enterprise-grade POS**, add these models first:

1. **TaxRate** - Tax configuration
2. **Category** + **ProductCategory** - Product organization
3. **PriceList** + **ProductPrice** - Flexible pricing
4. **Discount** + **DiscountRule** - Promotions
5. **Shift** + **CashCount** - Cashier management
6. **Location** (if multi-location) - Store management

These 6-8 additional models will make the system much more enterprise-ready!

---

## 📝 Current Model Strengths

✅ Dual inventory model (quantity + UID) - Excellent!
✅ Optional customers (walk-ins) - Great for retail
✅ Decoupled fiscal receipts - Perfect for KRA
✅ Production with BOM - Good for manufacturing
✅ Returns with UID traceability - Excellent audit trail
✅ User roles and authentication - Security covered
✅ Audit logs - Compliance ready

The foundation is solid - we just need to add the enterprise features above!

