# Task ID: 3-f - Full-Stack Developer
## Task: Module Rapports (Reports)

### Objective
Create a comprehensive Reports (RAPPORTS) module for the OptiqueStock optical store management system with dashboard KPIs, sales reports, inventory reports, and export functionality.

### Work Completed

#### Frontend Development

1. **Created ReportsModule.tsx** (`/src/components/reports/ReportsModule.tsx`)
   - Comprehensive React component with tab-based interface
   - Three main sections: Dashboard, Sales Reports, Inventory Reports
   - Date range filter (today, week, month, year)
   - Export to CSV functionality
   - Real-time data fetching with loading states
   - Error handling with toast notifications
   - Responsive design using Tailwind CSS

2. **Dashboard Features**
   - 8 KPI cards displaying:
     - Daily sales count
     - Daily revenue (TTC)
     - Total clients
     - Pending workshop orders with alert
     - Weekly sales count
     - Weekly revenue
     - Monthly sales count
     - Monthly revenue
   - Top 5 selling products with quantity and revenue
   - Low stock alerts with visual indicators (red badges, triangle icons)
   - Scroll areas for long lists

3. **Sales Reports Features**
   - Bar chart showing sales evolution and revenue over time
   - Pie chart for sales distribution by product category
   - Horizontal bar chart for payment method distribution
   - Table showing sales by employee with performance metrics
   - Date range filtering affecting all data

4. **Inventory Reports Features**
   - Total stock valuation display
   - Bar chart showing stock value by category
   - Detailed category breakdown table with:
     - Total products count
     - Active products count
     - Total stock quantity
     - Stock value
   - Low stock items list with detailed information

5. **Visual Components**
   - Used shadcn/ui components: Card, Button, Tabs, Badge, ScrollArea, Select, Table
   - Integrated Recharts for data visualization:
     - BarChart for sales evolution and stock valuation
     - PieChart for category distribution
     - Responsive charts with tooltips and legends
   - Custom color scheme for different categories
   - Icons from Lucide React for visual enhancement

#### Backend API Development

6. **Created Dashboard API** (`/src/app/api/reports/dashboard/route.ts`)
   - Endpoint: `GET /api/reports/dashboard`
   - Calculates sales counts for today, week, month, year
   - Computes revenue (HT and TTC) for today and month
   - Retrieves total client count
   - Identifies top 5 selling products by quantity
   - Lists products below minimum stock level
   - Counts pending workshop orders (EN_ATTENTE status)
   - Returns aggregated KPI data

7. **Created Sales Reports API** (`/src/app/api/reports/sales/route.ts`)
   - Endpoint: `GET /api/reports/sales?range={today|week|month|year}`
   - Sales by date with grouping and formatting
   - Sales by product category with count and revenue
   - Sales by employee with performance metrics
   - Sales by payment method with amount distribution
   - Date range filtering using date-fns
   - Proper French labels for payment methods

8. **Created Inventory Reports API** (`/src/app/api/reports/inventory/route.ts`)
   - Endpoint: `GET /api/reports/inventory`
   - Stock valuation by category
   - Total stock value calculation
   - Low stock items with value calculation
   - Category breakdown with comprehensive statistics
   - Active/inactive product filtering

9. **Created Export APIs**
   - **Sales Export** (`/src/app/api/reports/export/sales/route.ts`)
     - Endpoint: `GET /api/reports/export/sales?range={today|week|month|year}`
     - Exports all sales with details (client, employee, products, payments)
     - CSV format with proper escaping
     - Includes: sale number, date, client, employee, products, quantities, amounts, discount, payment methods, workshop status
     - French date formatting
   
   - **Inventory Export** (`/src/app/api/reports/export/inventory/route.ts`)
     - Endpoint: `GET /api/reports/export/inventory`
     - Exports all active products with stock information
     - CSV format with comprehensive product data
     - Includes: reference, designation, category, brand, supplier, stock levels, prices, TVA, stock value, location, barcode, stock status
   
   - **Low Stock Export** (`/src/app/api/reports/export/lowStock/route.ts`)
     - Endpoint: `GET /api/reports/export/lowStock`
     - Exports products below minimum stock level
     - CSV format with reordering information
     - Includes: reference, designation, category, brand, supplier, current stock, minimum stock, deficit, purchase price, order value, location, barcode

#### Integration

10. **Integrated Reports Module into Main Navigation**
    - Added ReportsModule import to `/src/app/page.tsx`
    - Created render condition for RAPPORTS module
    - Consistent header styling with other modules (cyan color scheme)
    - Back to home button navigation
    - Module accessible from home page navigation grid

### Technical Implementation Details

- **State Management**: React useState for managing tabs, date range, loading states, and data
- **Data Fetching**: useEffect hooks with dependency arrays for reactive data loading
- **Error Handling**: Try-catch blocks with toast notifications for user feedback
- **Type Safety**: TypeScript interfaces for all data structures
- **Date Handling**: date-fns library for date manipulation and formatting
- **Chart Configuration**: Custom chart config object with category colors
- **CSV Generation**: Client-side download using Blob and URL.createObjectURL
- **API Design**: RESTful endpoints with proper error handling and JSON responses
- **Database Queries**: Prisma aggregations and groupBy for efficient data summarization
- **Performance**: Parallel database queries using Promise.all where applicable

### Files Created

1. `/src/components/reports/ReportsModule.tsx` - Main reports frontend component
2. `/src/app/api/reports/dashboard/route.ts` - Dashboard data API
3. `/src/app/api/reports/sales/route.ts` - Sales reports API
4. `/src/app/api/reports/inventory/route.ts` - Inventory reports API
5. `/src/app/api/reports/export/sales/route.ts` - Sales CSV export API
6. `/src/app/api/reports/export/inventory/route.ts` - Inventory CSV export API
7. `/src/app/api/reports/export/lowStock/route.ts` - Low stock CSV export API

### Files Modified

1. `/src/app/page.tsx` - Added ReportsModule import and render condition

### Key Features Delivered

✅ Dashboard with 8 KPIs (sales, revenue, clients, workshop orders)
✅ Top 5 selling products display
✅ Low stock alerts with visual indicators
✅ Sales reports by date, category, employee, and payment method
✅ Inventory reports with stock valuation and category breakdown
✅ Interactive charts using Recharts (bar charts, pie charts)
✅ Date range filtering for reports
✅ CSV export functionality for sales, inventory, and low stock
✅ Responsive design for mobile and desktop
✅ Consistent styling with shadcn/ui components
✅ French language interface
✅ Error handling and user feedback
✅ Integration with main application navigation

### Testing Notes

- Module is accessible from the home page under "Rapports"
- All API endpoints follow RESTful conventions
- CSV exports work with proper encoding and formatting
- Charts are responsive and include tooltips
- Date range filtering updates data dynamically
- Loading states provide good user feedback
- Error messages are displayed via toast notifications

### Limitations

- CSV export only (Excel and PDF not implemented due to library constraints)
- Charts use English labels internally but data is French
- No real-time updates (requires manual refresh or tab switch)
- Employee data may show "Inconnu" if employeId is null
- Some KPIs may show 0 if no data exists in the database

### Next Steps (Optional Enhancements)

- Add Excel export using xlsx library
- Add PDF export using jsPDF or similar
- Implement real-time updates with polling or WebSocket
- Add more advanced date range picker (custom date ranges)
- Add drill-down capabilities for chart items
- Add comparison views (e.g., compare with previous period)
- Add more report types (employee performance, product trends, etc.)
- Implement report scheduling and email delivery
- Add print-friendly layouts for reports