# Phase 15: Reporting & Analytics - COMPLETE ✅

## Overview
Phase 15 implements comprehensive reporting and analytics functionality with sales, inventory, financial, tax, and shift reports. All reports support filtering by date ranges and other criteria.

## Implementation Details

### 1. Sales Reports Service
**File:** `server/modules/reports/services/salesReports.js`

Implemented the following report functions:

#### getSalesReportByDate
Generates sales report filtered by date range:
- Filters sales by date range (start_date, end_date)
- Only includes COMPLETED sales
- Calculates totals: total sales count, revenue, discount, tax, items sold
- Returns detailed sales data with items, customers, and cashiers

#### getSalesReportByProduct
Generates sales report grouped by product:
- Groups by product_id and variant_id
- Calculates total quantity sold, revenue, and sale count per product
- Supports filtering by date range and product_id
- Orders by total revenue descending
- Uses raw SQL for efficient aggregation

#### getSalesReportByCustomer
Generates sales report grouped by customer:
- Groups by customer_id
- Calculates sale count, revenue, and discount per customer
- Supports filtering by date range and customer_id
- Handles walk-in sales (customer_id = null)
- Orders by total revenue descending
- Uses raw SQL for efficient aggregation

#### getSalesReportByCashier
Generates sales report grouped by cashier (user):
- Groups by user_id
- Calculates sale count, revenue, and discount per cashier
- Supports filtering by date range and user_id
- Orders by total revenue descending
- Uses raw SQL for efficient aggregation

### 2. Inventory Reports Service
**File:** `server/modules/reports/services/inventoryReports.js`

Implemented the following report functions:

#### getFastMovingProducts
Retrieves products with highest sales velocity:
- Filters by date range (optional)
- Groups by product and variant
- Orders by total quantity sold descending
- Includes current stock levels
- Supports limit option (default: 20)
- Returns product details with sales statistics

#### getSlowMovingProducts
Retrieves products with lowest sales velocity:
- Filters by date range (optional)
- Groups by product and variant
- Orders by total quantity sold ascending
- Includes current stock levels
- Supports limit option (default: 20)
- Returns product details with sales statistics

#### getLowStockItems
Retrieves products below reorder level:
- Finds inventory items where quantity < reorder_level
- Includes product and variant details
- Calculates stock shortage (reorder_level - quantity)
- Determines stock status (OUT_OF_STOCK or LOW_STOCK)
- Supports category filtering (optional)
- Returns reorder alerts for inventory management

### 3. Financial Reports Service
**File:** `server/modules/reports/services/financialReports.js`

Implemented the following report functions:

#### getProfitLossReport
Calculates profit/loss based on sales revenue and cost of goods sold:
- Calculates total revenue from completed sales
- Calculates cost of goods sold (COGS) from GRNs
- Calculates gross profit (revenue - discount - COGS)
- Calculates gross profit margin percentage
- Supports date range filtering
- Returns comprehensive financial summary

### 4. Tax Reports Service
**File:** `server/modules/reports/services/taxReports.js`

Implemented the following report functions:

#### getTaxReport
Generates tax report for KRA compliance:
- Filters by date range and customer type (optional)
- Groups by B2C and B2B sales
- Calculates total VAT by customer type
- Tracks fiscalised vs non-fiscalised sales
- Includes fiscal receipt numbers
- Returns detailed tax breakdown for compliance

### 5. Shift Reports Service
**File:** `server/modules/reports/services/shiftReports.js`

Implemented the following report functions:

#### getShiftReport
Generates report for shifts:
- Filters by shift_id, date range, or user_id (optional)
- Includes all sales for each shift
- Calculates sales totals per shift
- Tracks cash counts and discrepancies
- Calculates expected vs actual closing cash
- Returns comprehensive shift statistics

### 6. Controllers
**File:** `server/modules/reports/controllers/index.js`

Implemented controllers for all report endpoints:
- getSalesReportByDate
- getSalesReportByProduct
- getSalesReportByCustomer
- getSalesReportByCashier
- getFastMovingProducts
- getSlowMovingProducts
- getLowStockItems
- getProfitLossReport
- getTaxReport
- getShiftReport

All controllers:
- Use asyncHandler for error handling
- Extract filters from request query parameters
- Call appropriate service functions
- Return standardized responses
- Log report generation

### 7. Validations
**File:** `server/modules/reports/validations/index.js`

Implemented comprehensive validation rules:
- Date range validation (ISO 8601 format)
- Product ID, Customer ID, User ID validation
- Category ID validation
- Limit validation (1-100)
- Customer type validation (B2C, B2B)
- Shift ID validation

### 8. Routes
**File:** `server/modules/reports/routes/index.js`

Implemented RESTful routes with Swagger documentation:
- `GET /api/reports/sales/date` - Sales report by date
- `GET /api/reports/sales/product` - Sales report by product
- `GET /api/reports/sales/customer` - Sales report by customer
- `GET /api/reports/sales/cashier` - Sales report by cashier
- `GET /api/reports/inventory/fast-moving` - Fast-moving products
- `GET /api/reports/inventory/slow-moving` - Slow-moving products
- `GET /api/reports/inventory/low-stock` - Low stock items
- `GET /api/reports/financial/profit-loss` - Profit/loss report
- `GET /api/reports/tax` - Tax report
- `GET /api/reports/shifts` - Shift report

All routes:
- Use authentication middleware
- Require manager or system_admin role
- Include request validation
- Have Swagger documentation

### 9. Routes Integration
**File:** `server/routes/index.js`

Added report routes to main routes file:
- `router.use('/reports', reportRoutes)`

## Key Features

### 1. Date Range Filtering
- All sales reports support start_date and end_date filtering
- Dates must be in ISO 8601 format
- End dates are set to end of day (23:59:59.999)
- Defaults to all available data if no dates provided

### 2. Efficient Aggregation
- Uses raw SQL queries for complex aggregations
- Optimized for performance with proper grouping
- Includes necessary joins for related data

### 3. Comprehensive Statistics
- Sales totals (revenue, discount, tax, count)
- Product performance metrics
- Customer sales analysis
- Cashier performance tracking
- Inventory movement analysis
- Financial profit/loss calculations
- Tax compliance reporting

### 4. Flexible Filtering
- Date range filtering
- Product, customer, cashier filtering
- Category filtering
- Customer type filtering (B2C/B2B)
- Shift filtering

### 5. Detailed Data
- Includes related model data (products, customers, users)
- Provides summary statistics
- Returns detailed records when needed
- Supports pagination where applicable

## API Endpoints Summary

### Sales Reports
- `GET /api/reports/sales/date` - Sales report by date range
- `GET /api/reports/sales/product` - Sales report by product
- `GET /api/reports/sales/customer` - Sales report by customer
- `GET /api/reports/sales/cashier` - Sales report by cashier

### Inventory Reports
- `GET /api/reports/inventory/fast-moving` - Fast-moving products
- `GET /api/reports/inventory/slow-moving` - Slow-moving products
- `GET /api/reports/inventory/low-stock` - Low stock items (reorder alerts)

### Financial Reports
- `GET /api/reports/financial/profit-loss` - Profit/loss report

### Tax Reports
- `GET /api/reports/tax` - Tax report (KRA compliance)

### Shift Reports
- `GET /api/reports/shifts` - Shift report

## Testing Checklist

- [x] Sales report by date
- [x] Sales report by product
- [x] Sales report by customer
- [x] Sales report by cashier
- [x] Fast-moving products report
- [x] Slow-moving products report
- [x] Low stock items report
- [x] Profit/loss report
- [x] Tax report
- [x] Shift report
- [x] Date range filtering
- [x] Additional filters (product_id, customer_id, user_id, etc.)

## Dependencies

- All previous phases (sales, inventory, products, customers, payments, shifts, tax, etc.)
- Sequelize for database queries
- Express for routing

## Notes

1. **Performance**: Uses raw SQL queries for complex aggregations to optimize performance
2. **Date Filtering**: All date-based reports support ISO 8601 date format
3. **Fiscal Receipts**: Tax reports track fiscalised sales for KRA compliance
4. **Stock Alerts**: Low stock report helps with inventory management and reordering
5. **Financial Analysis**: Profit/loss reports calculate COGS from GRN data
6. **Shift Tracking**: Shift reports include cash count discrepancies and sales statistics

## Next Steps

Phase 15 is complete. The reporting and analytics system is fully functional with comprehensive reports for sales, inventory, financial, tax, and shift data. All endpoints are operational with proper filtering and authentication.

