feat(notifications): Add notification system with service layer and UI integration

src/App.tsx

@@ -24,6 +24,7 @@ import AnalyticsRevenuePage from "@/pages/admin/analytics/revenue"
 import AnalyticsStoragePage from "@/pages/admin/analytics/storage"
 import AnalyticsApiPage from "@/pages/admin/analytics/api"
 import HealthPage from "@/pages/admin/health"
+import NotificationsPage from "@/pages/notifications"
 
 function App() {
   return (
@@ -62,6 +63,7 @@ function App() {
         <Route path="admin/analytics/storage" element={<AnalyticsStoragePage />} />
         <Route path="admin/analytics/api" element={<AnalyticsApiPage />} />
         <Route path="admin/health" element={<HealthPage />} />
+        <Route path="notifications" element={<NotificationsPage />} />
       </Route>
       <Route path="*" element={<Navigate to="/admin/dashboard" replace />} />
     </Routes>

src/layouts/app-shell.tsx

@@ -12,15 +12,23 @@ import {
   Activity,
   Heart,
   Search,
-  Mail,
   Bell,
   LogOut,
 } from "lucide-react"
 import { Button } from "@/components/ui/button"
 import { Input } from "@/components/ui/input"
 import { Avatar, AvatarFallback } from "@/components/ui/avatar"
+import {
+  DropdownMenu,
+  DropdownMenuContent,
+  DropdownMenuItem,
+  DropdownMenuLabel,
+  DropdownMenuSeparator,
+  DropdownMenuTrigger,
+} from "@/components/ui/dropdown-menu"
 import { cn } from "@/lib/utils"
 import { authService } from "@/services"
+import { toast } from "sonner"
 
 interface User {
   email: string
@@ -46,6 +54,7 @@ export function AppShell() {
   const location = useLocation()
   const navigate = useNavigate()
   const [user, setUser] = useState<User | null>(null)
+  const [searchQuery, setSearchQuery] = useState("")
 
   useEffect(() => {
     const userStr = localStorage.getItem('user')
@@ -75,6 +84,28 @@ export function AppShell() {
     navigate('/login', { replace: true })
   }
 
+  const handleSearch = (e: React.FormEvent) => {
+    e.preventDefault()
+    if (searchQuery.trim()) {
+      const currentPath = location.pathname
+      navigate(`${currentPath}?search=${encodeURIComponent(searchQuery)}`)
+      toast.success(`Searching for: ${searchQuery}`)
+    }
+  }
+
+  const handleSearchChange = (e: React.ChangeEvent<HTMLInputElement>) => {
+    setSearchQuery(e.target.value)
+  }
+
+  const handleNotificationClick = () => {
+    console.log('Notification button clicked')
+    navigate('/notifications')
+  }
+
+  const handleProfileClick = () => {
+    navigate('/admin/settings')
+  }
+
   const getUserInitials = () => {
     if (user?.firstName && user?.lastName) {
       return `${user.firstName[0]}${user.lastName[0]}`.toUpperCase()
@@ -155,24 +186,50 @@ export function AppShell() {
         <header className="h-16 border-b bg-background flex items-center justify-between px-6">
           <h1 className="text-2xl font-bold">{getPageTitle()}</h1>
           <div className="flex items-center gap-4">
-            <div className="relative">
+            <form onSubmit={handleSearch} className="relative">
               <Search className="absolute left-3 top-1/2 -translate-y-1/2 w-4 h-4 text-muted-foreground" />
               <Input
                 placeholder="Quick Search..."
                 className="pl-10 w-64"
+                value={searchQuery}
+                onChange={handleSearchChange}
               />
-            </div>
+            </form>
-            <Button variant="ghost" size="icon" className="relative">
+            <Button variant="ghost" size="icon" className="relative" onClick={handleNotificationClick}>
-              <Mail className="w-5 h-5" />
-              <span className="absolute top-1 right-1 w-2 h-2 bg-red-500 rounded-full" />
-            </Button>
-            <Button variant="ghost" size="icon" className="relative">
               <Bell className="w-5 h-5" />
-              <span className="absolute top-1 right-1 w-2 h-2 bg-red-500 rounded-full" />
+              <span className="absolute top-1 right-1 w-2 h-2 bg-red-500 rounded-full pointer-events-none" />
             </Button>
-            <Avatar>
+            <DropdownMenu>
-              <AvatarFallback>{getUserInitials()}</AvatarFallback>
+              <DropdownMenuTrigger asChild>
-            </Avatar>
+                <Button variant="ghost" size="icon" className="rounded-full">
+                  <Avatar>
+                    <AvatarFallback>{getUserInitials()}</AvatarFallback>
+                  </Avatar>
+                </Button>
+              </DropdownMenuTrigger>
+              <DropdownMenuContent align="end" className="w-56">
+                <DropdownMenuLabel>
+                  <div className="flex flex-col space-y-1">
+                    <p className="text-sm font-medium">{getUserDisplayName()}</p>
+                    <p className="text-xs text-muted-foreground">{user?.email}</p>
+                  </div>
+                </DropdownMenuLabel>
+                <DropdownMenuSeparator />
+                <DropdownMenuItem onClick={handleProfileClick}>
+                  <Settings className="w-4 h-4 mr-2" />
+                  Profile Settings
+                </DropdownMenuItem>
+                <DropdownMenuItem onClick={() => navigate('/notifications')}>
+                  <Bell className="w-4 h-4 mr-2" />
+                  Notifications
+                </DropdownMenuItem>
+                <DropdownMenuSeparator />
+                <DropdownMenuItem onClick={handleLogout}>
+                  <LogOut className="w-4 h-4 mr-2" />
+                  Logout
+                </DropdownMenuItem>
+              </DropdownMenuContent>
+            </DropdownMenu>
           </div>
         </header>
 

src/pages/admin/dashboard/index.tsx

@@ -33,7 +33,40 @@ export default function DashboardPage() {
   })
 
   const handleExport = () => {
-    toast.success("Exporting dashboard data...")
+    try {
+      // Create CSV content from current dashboard data
+      const csvContent = [
+        ['Metric', 'Value'],
+        ['Total Users', overview?.users?.total || 0],
+        ['Active Users', overview?.users?.active || 0],
+        ['Inactive Users', overview?.users?.inactive || 0],
+        ['Total Invoices', overview?.invoices?.total || 0],
+        ['Total Revenue', overview?.revenue?.total || 0],
+        ['Storage Used', overview?.storage?.totalSize || 0],
+        ['Total Documents', overview?.storage?.documents || 0],
+        ['Error Rate', errorRate?.errorRate || 0],
+        ['Total Errors', errorRate?.errors || 0],
+        ['Export Date', new Date().toISOString()],
+      ]
+        .map(row => row.join(','))
+        .join('\n')
+
+      // Create and download the file
+      const blob = new Blob([csvContent], { type: 'text/csv;charset=utf-8;' })
+      const url = window.URL.createObjectURL(blob)
+      const link = document.createElement('a')
+      link.href = url
+      link.download = `admin-dashboard-${new Date().toISOString().split('T')[0]}.csv`
+      document.body.appendChild(link)
+      link.click()
+      document.body.removeChild(link)
+      window.URL.revokeObjectURL(url)
+      
+      toast.success("Dashboard data exported successfully!")
+    } catch (error) {
+      toast.error("Failed to export data. Please try again.")
+      console.error('Export error:', error)
+    }
   }
 
   const formatCurrency = (amount: number) => {

src/pages/dashboard/index.tsx

@@ -17,7 +17,36 @@ export default function DashboardPage() {
   })
 
   const handleExport = () => {
-    toast.success("Exporting your data...")
+    try {
+      // Create CSV content from current stats
+      const csvContent = [
+        ['Metric', 'Value'],
+        ['Total Invoices', stats?.totalInvoices || 0],
+        ['Pending Invoices', stats?.pendingInvoices || 0],
+        ['Total Transactions', stats?.totalTransactions || 0],
+        ['Total Revenue', stats?.totalRevenue || 0],
+        ['Growth Percentage', stats?.growthPercentage || 0],
+        ['Export Date', new Date().toISOString()],
+      ]
+        .map(row => row.join(','))
+        .join('\n')
+
+      // Create and download the file
+      const blob = new Blob([csvContent], { type: 'text/csv;charset=utf-8;' })
+      const url = window.URL.createObjectURL(blob)
+      const link = document.createElement('a')
+      link.href = url
+      link.download = `dashboard-export-${new Date().toISOString().split('T')[0]}.csv`
+      document.body.appendChild(link)
+      link.click()
+      document.body.removeChild(link)
+      window.URL.revokeObjectURL(url)
+      
+      toast.success("Data exported successfully!")
+    } catch (error) {
+      toast.error("Failed to export data. Please try again.")
+      console.error('Export error:', error)
+    }
   }
 
   const formatCurrency = (amount: number) => {

src/pages/notifications/index.tsx

@@ -1,3 +1,5 @@
+import { useState, useMemo } from "react"
+import { useQuery } from "@tanstack/react-query"
 import { Card, CardContent, CardHeader, CardTitle } from "@/components/ui/card"
 import { Button } from "@/components/ui/button"
 import { Input } from "@/components/ui/input"
@@ -10,17 +12,161 @@ import {
   TableHeader,
   TableRow,
 } from "@/components/ui/table"
-import { Search, Download, Eye, MoreVertical, Bell } from "lucide-react"
+import { Search, Download, Eye, CheckCheck, Bell, Loader2 } from "lucide-react"
+import { notificationService } from "@/services/notification.service"
+import { toast } from "sonner"
 
 export default function NotificationsPage() {
+  const [searchQuery, setSearchQuery] = useState("")
+  const [typeFilter, setTypeFilter] = useState("")
+  const [statusFilter, setStatusFilter] = useState("")
+
+  const { data: notifications, isLoading, refetch } = useQuery({
+    queryKey: ['notifications'],
+    queryFn: () => notificationService.getNotifications(),
+  })
+
+  const { data: unreadCount } = useQuery({
+    queryKey: ['notifications', 'unread-count'],
+    queryFn: () => notificationService.getUnreadCount(),
+  })
+
+  // Client-side filtering
+  const filteredNotifications = useMemo(() => {
+    if (!notifications) return []
+    
+    return notifications.filter((notification) => {
+      // Type filter
+      if (typeFilter && notification.type !== typeFilter) return false
+      
+      // Status filter
+      if (statusFilter === 'read' && !notification.isRead) return false
+      if (statusFilter === 'unread' && notification.isRead) return false
+      
+      // Search filter
+      if (searchQuery) {
+        const query = searchQuery.toLowerCase()
+        return (
+          notification.title.toLowerCase().includes(query) ||
+          notification.message.toLowerCase().includes(query) ||
+          notification.recipient.toLowerCase().includes(query)
+        )
+      }
+      
+      return true
+    })
+  }, [notifications, typeFilter, statusFilter, searchQuery])
+
+  const handleExport = () => {
+    try {
+      if (!filteredNotifications || filteredNotifications.length === 0) {
+        toast.error("No notifications to export")
+        return
+      }
+
+      const csvData = [
+        ['Notification ID', 'Title', 'Message', 'Type', 'Recipient', 'Status', 'Created Date', 'Read Date'],
+        ...filteredNotifications.map(n => [
+          n.id,
+          n.title,
+          n.message,
+          n.type,
+          n.recipient,
+          n.isRead ? 'Read' : 'Unread',
+          new Date(n.createdAt).toLocaleString(),
+          n.readAt ? new Date(n.readAt).toLocaleString() : '-'
+        ])
+      ]
+
+      const csvContent = csvData.map(row => 
+        row.map(cell => `"${String(cell).replace(/"/g, '""')}"`).join(',')
+      ).join('\n')
+
+      const blob = new Blob([csvContent], { type: 'text/csv;charset=utf-8;' })
+      const url = window.URL.createObjectURL(blob)
+      const link = document.createElement('a')
+      link.href = url
+      link.download = `notifications-${new Date().toISOString().split('T')[0]}.csv`
+      document.body.appendChild(link)
+      link.click()
+      document.body.removeChild(link)
+      window.URL.revokeObjectURL(url)
+      
+      toast.success("Notifications exported successfully!")
+    } catch (error) {
+      toast.error("Failed to export notifications")
+      console.error('Export error:', error)
+    }
+  }
+
+  const handleMarkAsRead = async (id: string) => {
+    try {
+      await notificationService.markAsRead(id)
+      toast.success("Notification marked as read")
+      refetch()
+    } catch (error) {
+      toast.error("Failed to mark notification as read")
+      console.error('Mark as read error:', error)
+    }
+  }
+
+  const handleMarkAllAsRead = async () => {
+    try {
+      await notificationService.markAllAsRead()
+      toast.success("All notifications marked as read")
+      refetch()
+    } catch (error) {
+      toast.error("Failed to mark all as read")
+      console.error('Mark all as read error:', error)
+    }
+  }
+
+  const formatDate = (dateString: string) => {
+    return new Date(dateString).toLocaleDateString('en-US', {
+      year: 'numeric',
+      month: '2-digit',
+      day: '2-digit',
+    })
+  }
+
+  const formatDateTime = (dateString?: string) => {
+    if (!dateString) return '-'
+    return new Date(dateString).toLocaleString('en-US', {
+      year: 'numeric',
+      month: '2-digit',
+      day: '2-digit',
+      hour: '2-digit',
+      minute: '2-digit',
+    })
+  }
+
+  const getStatusBadge = (isRead: boolean) => {
+    return isRead ? 'bg-gray-500' : 'bg-orange-500'
+  }
+
   return (
     <div className="space-y-6">
       <div className="flex items-center justify-between">
-        <h2 className="text-3xl font-bold">Notifications</h2>
+        <div>
-        <Button>
+          <h2 className="text-3xl font-bold">Notifications</h2>
-          <Bell className="w-4 h-4 mr-2" />
+          {unreadCount !== undefined && unreadCount > 0 && (
-          Create Notification
+            <p className="text-sm text-muted-foreground mt-1">
-        </Button>
+              You have {unreadCount} unread notification{unreadCount !== 1 ? 's' : ''}
+            </p>
+          )}
+        </div>
+        <div className="flex gap-2">
+          {unreadCount !== undefined && unreadCount > 0 && (
+            <Button variant="outline" onClick={handleMarkAllAsRead}>
+              <CheckCheck className="w-4 h-4 mr-2" />
+              Mark All as Read
+            </Button>
+          )}
+          <Button>
+            <Bell className="w-4 h-4 mr-2" />
+            Settings
+          </Button>
+        </div>
       </div>
 
       <Card>
@@ -33,20 +179,32 @@ export default function NotificationsPage() {
                 <Input
                   placeholder="Search notification..."
                   className="pl-10 w-64"
+                  value={searchQuery}
+                  onChange={(e) => setSearchQuery(e.target.value)}
                 />
               </div>
-              <select className="px-3 py-2 border rounded-md text-sm">
+              <select 
-                <option>All Types</option>
+                className="px-3 py-2 border rounded-md text-sm"
-                <option>System</option>
+                value={typeFilter}
-                <option>User</option>
+                onChange={(e) => setTypeFilter(e.target.value)}
-                <option>Alert</option>
+              >
+                <option value="">All Types</option>
+                <option value="system">System</option>
+                <option value="user">User</option>
+                <option value="alert">Alert</option>
+                <option value="invoice">Invoice</option>
+                <option value="payment">Payment</option>
               </select>
-              <select className="px-3 py-2 border rounded-md text-sm">
+              <select 
-                <option>All Status</option>
+                className="px-3 py-2 border rounded-md text-sm"
-                <option>Read</option>
+                value={statusFilter}
-                <option>Unread</option>
+                onChange={(e) => setStatusFilter(e.target.value)}
+              >
+                <option value="">All Status</option>
+                <option value="read">Read</option>
+                <option value="unread">Unread</option>
               </select>
-              <Button variant="outline">
+              <Button variant="outline" onClick={handleExport}>
                 <Download className="w-4 h-4 mr-2" />
                 Export
               </Button>
@@ -54,68 +212,64 @@ export default function NotificationsPage() {
           </div>
         </CardHeader>
         <CardContent>
-          <Table>
+          {isLoading ? (
-            <TableHeader>
+            <div className="flex items-center justify-center py-8">
-              <TableRow>
+              <Loader2 className="w-8 h-8 animate-spin text-muted-foreground" />
-                <TableHead>Notification ID</TableHead>
+            </div>
-                <TableHead>Title</TableHead>
+          ) : filteredNotifications && filteredNotifications.length > 0 ? (
-                <TableHead>Type</TableHead>
+            <Table>
-                <TableHead>Recipient</TableHead>
+              <TableHeader>
-                <TableHead>Status</TableHead>
+                <TableRow>
-                <TableHead>Created Date</TableHead>
+                  <TableHead>Notification ID</TableHead>
-                <TableHead>Sent Date</TableHead>
+                  <TableHead>Title</TableHead>
-                <TableHead>Action</TableHead>
+                  <TableHead>Message</TableHead>
-              </TableRow>
+                  <TableHead>Type</TableHead>
-            </TableHeader>
+                  <TableHead>Status</TableHead>
-            <TableBody>
+                  <TableHead>Created Date</TableHead>
-              <TableRow>
+                  <TableHead>Read Date</TableHead>
-                <TableCell className="font-medium">NOT001</TableCell>
+                  <TableHead>Action</TableHead>
-                <TableCell>System Update Available</TableCell>
+                </TableRow>
-                <TableCell>
+              </TableHeader>
-                  <Badge variant="outline">System</Badge>
+              <TableBody>
-                </TableCell>
+                {filteredNotifications.map((notification) => (
-                <TableCell>All Users</TableCell>
+                  <TableRow key={notification.id} className={!notification.isRead ? 'bg-blue-50' : ''}>
-                <TableCell>
+                    <TableCell className="font-medium">{notification.id}</TableCell>
-                  <Badge className="bg-blue-500">Sent</Badge>
+                    <TableCell className="font-medium">{notification.title}</TableCell>
-                </TableCell>
+                    <TableCell className="max-w-xs truncate">{notification.message}</TableCell>
-                <TableCell>2024-01-15</TableCell>
+                    <TableCell>
-                <TableCell>2024-01-15 10:00</TableCell>
+                      <Badge variant="outline" className="capitalize">{notification.type}</Badge>
-                <TableCell>
+                    </TableCell>
-                  <div className="flex items-center gap-2">
+                    <TableCell>
-                    <Button variant="ghost" size="icon">
+                      <Badge className={getStatusBadge(notification.isRead)}>
-                      <Eye className="w-4 h-4" />
+                        {notification.isRead ? 'Read' : 'Unread'}
-                    </Button>
+                      </Badge>
-                    <Button variant="ghost" size="icon">
+                    </TableCell>
-                      <MoreVertical className="w-4 h-4" />
+                    <TableCell>{formatDate(notification.createdAt)}</TableCell>
-                    </Button>
+                    <TableCell>{formatDateTime(notification.readAt)}</TableCell>
-                  </div>
+                    <TableCell>
-                </TableCell>
+                      {!notification.isRead && (
-              </TableRow>
+                        <Button 
-              <TableRow>
+                          variant="ghost" 
-                <TableCell className="font-medium">NOT002</TableCell>
+                          size="icon"
-                <TableCell>Payment Received</TableCell>
+                          onClick={() => handleMarkAsRead(notification.id)}
-                <TableCell>
+                          title="Mark as read"
-                  <Badge variant="outline">User</Badge>
+                        >
-                </TableCell>
+                          <Eye className="w-4 h-4" />
-                <TableCell>john@example.com</TableCell>
+                        </Button>
-                <TableCell>
+                      )}
-                  <Badge className="bg-green-500">Delivered</Badge>
+                    </TableCell>
-                </TableCell>
+                  </TableRow>
-                <TableCell>2024-01-14</TableCell>
+                ))}
-                <TableCell>2024-01-14 14:30</TableCell>
+              </TableBody>
-                <TableCell>
+            </Table>
-                  <div className="flex items-center gap-2">
+          ) : (
-                    <Button variant="ghost" size="icon">
+            <div className="text-center py-8 text-muted-foreground">
-                      <Eye className="w-4 h-4" />
+              {searchQuery || typeFilter || statusFilter 
-                    </Button>
+                ? 'No notifications match your filters'
-                    <Button variant="ghost" size="icon">
+                : 'No notifications found'
-                      <MoreVertical className="w-4 h-4" />
+              }
-                    </Button>
+            </div>
-                  </div>
+          )}
-                </TableCell>
-              </TableRow>
-            </TableBody>
-          </Table>
         </CardContent>
       </Card>
     </div>

src/services/analytics.service.ts

@@ -102,6 +102,16 @@ class AnalyticsService {
     const response = await apiClient.get('/admin/analytics/storage')
     return response.data
   }
+
+  /**
+   * Export analytics data
+   */
+  async exportData(): Promise<Blob> {
+    const response = await apiClient.get('/admin/analytics/export', {
+      responseType: 'blob',
+    })
+    return response.data
+  }
 }
 
 export const analyticsService = new AnalyticsService()

src/services/dashboard.service.ts

@@ -49,6 +49,16 @@ class DashboardService {
     })
     return response.data
   }
+
+  /**
+   * Export user dashboard data
+   */
+  async exportData(): Promise<Blob> {
+    const response = await apiClient.get('/user/export', {
+      responseType: 'blob',
+    })
+    return response.data
+  }
 }
 
 export const dashboardService = new DashboardService()

src/services/index.ts

@@ -8,6 +8,7 @@ export { announcementService } from './announcement.service'
 export { auditService } from './audit.service'
 export { settingsService } from './settings.service'
 export { dashboardService } from './dashboard.service'
+export { notificationService } from './notification.service'
 
 // Export types
 export type { LoginRequest, LoginResponse } from './auth.service'
@@ -19,3 +20,6 @@ export type { Announcement, CreateAnnouncementData, UpdateAnnouncementData } fro
 export type { AuditLog, GetAuditLogsParams, AuditStats } from './audit.service'
 export type { Setting, CreateSettingData, UpdateSettingData } from './settings.service'
 export type { UserDashboardStats, UserProfile } from './dashboard.service'
+export type { Notification } from './notification.service'
+export type { NotificationSettings } from './notification.service'
+export type { NotificationSettings } from './notification.service'

src/services/notification.service.ts

@@ -0,0 +1,133 @@
+import apiClient from './api/client'
+
+export interface Notification {
+  id: string
+  title: string
+  message: string
+  type: 'system' | 'user' | 'alert' | 'invoice' | 'payment'
+  recipient: string
+  status: 'sent' | 'delivered' | 'read' | 'unread'
+  isRead: boolean
+  createdAt: string
+  sentAt?: string
+  readAt?: string
+}
+
+export interface NotificationSettings {
+  emailNotifications: boolean
+  pushNotifications: boolean
+  invoiceReminders: boolean
+  paymentAlerts: boolean
+  systemUpdates: boolean
+}
+
+class NotificationService {
+  /**
+   * Get all notifications for current user
+   */
+  async getNotifications(params?: {
+    type?: string
+    status?: string
+    search?: string
+  }): Promise<Notification[]> {
+    const response = await apiClient.get<Notification[]>('/notifications', {
+      params,
+    })
+    return response.data
+  }
+
+  /**
+   * Get unread notification count
+   */
+  async getUnreadCount(): Promise<number> {
+    const response = await apiClient.get<{ count: number }>('/notifications/unread-count')
+    return response.data.count
+  }
+
+  /**
+   * Mark notification as read
+   */
+  async markAsRead(id: string): Promise<void> {
+    await apiClient.post(`/notifications/${id}/read`)
+  }
+
+  /**
+   * Mark all notifications as read
+   */
+  async markAllAsRead(): Promise<void> {
+    await apiClient.post('/notifications/read-all')
+  }
+
+  /**
+   * Send notification (ADMIN only)
+   */
+  async sendNotification(data: {
+    title: string
+    message: string
+    type: string
+    recipient?: string
+    recipientType?: 'user' | 'all'
+  }): Promise<Notification> {
+    const response = await apiClient.post<Notification>('/notifications/send', data)
+    return response.data
+  }
+
+  /**
+   * Subscribe to push notifications
+   */
+  async subscribeToPush(subscription: PushSubscription): Promise<void> {
+    await apiClient.post('/notifications/subscribe', subscription)
+  }
+
+  /**
+   * Unsubscribe from push notifications
+   */
+  async unsubscribeFromPush(endpoint: string): Promise<void> {
+    await apiClient.delete(`/notifications/unsubscribe/${encodeURIComponent(endpoint)}`)
+  }
+
+  /**
+   * Get notification settings
+   */
+  async getSettings(): Promise<NotificationSettings> {
+    const response = await apiClient.get<NotificationSettings>('/notifications/settings')
+    return response.data
+  }
+
+  /**
+   * Update notification settings
+   */
+  async updateSettings(settings: Partial<NotificationSettings>): Promise<NotificationSettings> {
+    const response = await apiClient.put<NotificationSettings>('/notifications/settings', settings)
+    return response.data
+  }
+
+  /**
+   * Send invoice reminder
+   */
+  async sendInvoiceReminder(invoiceId: string): Promise<void> {
+    await apiClient.post(`/notifications/invoice/${invoiceId}/reminder`)
+  }
+
+  /**
+   * Export notifications (creates CSV from current data)
+   */
+  async exportNotifications(notifications: Notification[]): Promise<Blob> {
+    const csvContent = [
+      ['ID', 'Title', 'Message', 'Type', 'Status', 'Created Date', 'Read Date'],
+      ...notifications.map(n => [
+        n.id,
+        n.title,
+        n.message,
+        n.type,
+        n.status,
+        n.createdAt,
+        n.readAt || '-'
+      ])
+    ].map(row => row.join(',')).join('\n')
+
+    return new Blob([csvContent], { type: 'text/csv;charset=utf-8;' })
+  }
+}
+
+export const notificationService = new NotificationService()