Add customer management

2025-07-06 08:31:48 +00:00
parent 2bd76aa6bb
commit 916dbfcf95
57 changed files with 2442 additions and 161 deletions
--- a/internal_frontend/app/api/customers/customerRoutes.ts
+++ b/internal_frontend/app/api/customers/customerRoutes.ts
@@ -0,0 +1,4 @@
+export const customerRoutes = {
+    create: "/customers",
+    validate: "/customers/validate",
+};
--- a/internal_frontend/app/api/customers/route.ts
+++ b/internal_frontend/app/api/customers/route.ts
@@ -0,0 +1,14 @@
+import {NextRequest, NextResponse} from "next/server";
+import {serverCall} from "@/lib/api/serverCall";
+
+export async function GET() {
+    const data = await serverCall("/customers", "GET");
+    const customers = await data.json();
+    return NextResponse.json(customers);
+}
+
+export async function POST(req: NextRequest) {
+    const body = await req.json()
+    const result = await serverCall("/customers", "POST", body);
+    return NextResponse.json(result.json());
+}
--- a/internal_frontend/app/customers/page.tsx
+++ b/internal_frontend/app/customers/page.tsx
@@ -0,0 +1,196 @@
+"use client";
+
+import {useState, useEffect, useMemo} from "react";
+import {useRouter} from "next/navigation";
+import {Button} from "@/components/ui/button";
+import {Input} from "@/components/ui/input";
+import {Card, CardContent} from "@/components/ui/card";
+import {
+    Pagination,
+    PaginationContent,
+    PaginationItem,
+    PaginationNext,
+    PaginationPrevious
+} from "@/components/ui/pagination";
+import {
+    Table,
+    TableBody,
+    TableCell,
+    TableHead,
+    TableHeader,
+    TableRow
+} from "@/components/ui/table";
+import {motion} from "framer-motion";
+import {ArrowRight} from "lucide-react";
+import {NewCustomerModal} from "@/components/customers/modal/NewCustomerModal";
+import axios from "axios";
+
+export interface CustomerPhoneNumber {
+    number: string;
+    note: string;
+    creator: string;
+    lastModifier: string;
+    createdAt: string;
+    updatedAt: string;
+}
+
+export interface CustomerNote {
+    text: string;
+    creator: string;
+    lastModifier: string;
+    createdAt: string;
+    updatedAt: string;
+}
+
+export interface Customer {
+    id: string;
+    email: string;
+    name: string;
+    companyName: string;
+    phoneNumbers: CustomerPhoneNumber[];
+    street: string;
+    zip: string;
+    city: string;
+    notes: CustomerNote[];
+    createdAt: string;
+}
+
+export default function CustomersPage() {
+    const router = useRouter();
+    const [customers, setCustomers] = useState<Customer[]>([]);
+    const [search, setSearch] = useState("");
+    const [loading, setLoading] = useState(true);
+    const [page, setPage] = useState(1);
+    const pageSize = 15;
+
+    useEffect(() => {
+        axios.get("/api/customers").then((res) => {
+            setCustomers(res.data);
+            setLoading(false);
+        });
+    }, []);
+
+    const filtered = useMemo(() => {
+        return customers.filter(
+            (c) =>
+                c.name.toLowerCase().includes(search.toLowerCase()) ||
+                c.email.toLowerCase().includes(search.toLowerCase())
+        );
+    }, [customers, search]);
+
+    const paginated = useMemo(() => {
+        const start = (page - 1) * pageSize;
+        return filtered.slice(start, start + pageSize);
+    }, [filtered, page]);
+
+    const totalPages = Math.ceil(filtered.length / pageSize);
+
+    return (
+        <div className="p-6 space-y-6 text-sm overflow-x-auto">
+            <motion.div
+                initial={{opacity: 0}}
+                animate={{opacity: 1}}
+                transition={{duration: 0.3}}
+                className="grid grid-cols-1 md:grid-cols-3 gap-4"
+            >
+                <Card>
+                    <CardContent>
+                        <div className="text-sm text-muted-foreground">Kunden</div>
+                        <div className="text-3xl font-bold">{customers.length}</div>
+                    </CardContent>
+                </Card>
+                <Card>
+                    <CardContent>
+                        <div className="text-sm text-muted-foreground">Demo-Statistik</div>
+                        <div className="text-3xl font-bold">–</div>
+                    </CardContent>
+                </Card>
+                <Card>
+                    <CardContent>
+                        <div className="text-sm text-muted-foreground">Letzte Aktivität</div>
+                        <div className="text-3xl font-bold">–</div>
+                    </CardContent>
+                </Card>
+            </motion.div>
+
+            <motion.div initial={{opacity: 0}} animate={{opacity: 1}} transition={{duration: 0.3}}>
+                <Card>
+                    <CardContent className="space-y-6">
+                        <div className="flex flex-col md:flex-row justify-between items-center gap-4">
+                            <Input placeholder="Suche" value={search} onChange={(e) => setSearch(e.target.value)}/>
+                            <NewCustomerModal/>
+                        </div>
+
+                        {customers.length === 0 && loading ? (
+                            <div className="text-center text-muted-foreground">Lade Kunden...</div>
+                        ) : (
+                            <div className="overflow-x-auto">
+                                <Table className="text-xs min-w-[700px]">
+                                    <TableHeader>
+                                        <TableRow>
+                                            <TableHead>Name</TableHead>
+                                            <TableHead>E-Mail</TableHead>
+                                            <TableHead>Firma</TableHead>
+                                            <TableHead>Telefon</TableHead>
+                                            <TableHead>Straße</TableHead>
+                                            <TableHead>PLZ</TableHead>
+                                            <TableHead>Ort</TableHead>
+                                            <TableHead>Erstellt am</TableHead>
+                                            <TableHead>Aktionen</TableHead>
+                                        </TableRow>
+                                    </TableHeader>
+                                    <TableBody>
+                                        {paginated.map((customer) => (
+                                            <TableRow key={customer.id}>
+                                                <TableCell
+                                                    className="max-w-[180px] truncate">{customer.name}</TableCell>
+                                                <TableCell
+                                                    className="max-w-[180px] truncate">{customer.email}</TableCell>
+                                                <TableCell
+                                                    className="max-w-[180px] truncate">{customer.companyName}</TableCell>
+                                                <TableCell className="max-w-[140px] truncate">
+                                                    {customer.phoneNumbers?.[0]?.number}
+                                                </TableCell>
+                                                <TableCell
+                                                    className="max-w-[180px] truncate">{customer.street}</TableCell>
+                                                <TableCell>{customer.zip}</TableCell>
+                                                <TableCell>{customer.city}</TableCell>
+                                                <TableCell>{new Date(customer.createdAt).toLocaleString()}</TableCell>
+                                                <TableCell>
+                                                    <Button
+                                                        variant="ghost"
+                                                        size="icon"
+                                                        onClick={() => router.push(`/customers/${customer.id}`)}
+                                                    >
+                                                        <ArrowRight className="w-4 h-4"/>
+                                                    </Button>
+                                                </TableCell>
+                                            </TableRow>
+                                        ))}
+                                    </TableBody>
+                                </Table>
+                            </div>
+                        )}
+
+                        <Pagination className="justify-center pt-4">
+                            <PaginationContent>
+                                <PaginationItem>
+                                    <PaginationPrevious
+                                        onClick={() => setPage((p) => Math.max(1, p - 1))}
+                                        className={page === 1 ? "pointer-events-none opacity-50" : ""}
+                                    />
+                                </PaginationItem>
+                                <PaginationItem>
+                                    <PaginationNext
+                                        onClick={() => setPage((p) => Math.min(totalPages, p + 1))}
+                                        className={page === totalPages ? "pointer-events-none opacity-50" : ""}
+                                    />
+                                </PaginationItem>
+                            </PaginationContent>
+                        </Pagination>
+                    </CardContent>
+                </Card>
+            </motion.div>
+        </div>
+    );
+}
--- a/internal_frontend/app/layout.tsx
+++ b/internal_frontend/app/layout.tsx
@@ -41,22 +41,21 @@ export default async function RootLayout({
                    }
                >
                    <AppSidebar/>
-                    <main>
-                        <SidebarInset>
-                            <header
-                                className="flex h-16 shrink-0 items-center gap-2 transition-[width,height] ease-linear group-has-data-[collapsible=icon]/sidebar-wrapper:h-12">
-                                <div className="flex items-center gap-2 px-4">
-                                    <SidebarTrigger className="-ml-1"/>
-                                    <Separator
-                                        orientation="vertical"
-                                        className="mr-2 data-[orientation=vertical]:h-4"
-                                    />
-                                    <DynamicBreadcrumb/>
-                                </div>
-                            </header>
-                        </SidebarInset>
+
+                    <SidebarInset>
+                        <header
+                            className="flex h-16 shrink-0 items-center gap-2 transition-[width,height] ease-linear group-has-data-[collapsible=icon]/sidebar-wrapper:h-12">
+                            <div className="flex items-center gap-2 px-4">
+                                <SidebarTrigger className="-ml-1"/>
+                                <Separator
+                                    orientation="vertical"
+                                    className="mr-2 data-[orientation=vertical]:h-4"
+                                />
+                                <DynamicBreadcrumb/>
+                            </div>
+                        </header>
                        {children}
-                    </main>
+                    </SidebarInset>
                </SidebarProvider>
            ) : (
                <LoginScreen/>
--- a/internal_frontend/components/app-sidebar.tsx
+++ b/internal_frontend/components/app-sidebar.tsx
@@ -5,7 +5,7 @@ import {
    Home,
    Scale,
    User2,
-    Settings
+    Settings, LayoutDashboard
 } from "lucide-react";

 import {
@@ -50,6 +50,14 @@ const rheinItems = [
    },
 ];

+const customerItems = [
+    {
+        title: "Kundenübersicht",
+        url: "/customers",
+        icon: LayoutDashboard,
+    },
+];
+
 export function AppSidebar() {
    return (
        <Sidebar>
@@ -77,6 +85,27 @@ export function AppSidebar() {
                    </SidebarGroupContent>
                </SidebarGroup>

+                <SidebarGroup>
+                    <SidebarGroupLabel>Kunden</SidebarGroupLabel>
+                    <SidebarGroupContent>
+                        <SidebarMenu className="flex flex-col gap-y-1">
+                            {customerItems.map((item) => (
+                                <SidebarMenuItem key={item.title}>
+                                    <SidebarMenuButton
+                                        asChild
+                                        className="hover:bg-accent hover:text-accent-foreground"
+                                    >
+                                        <a href={item.url}>
+                                            <item.icon/>
+                                            <span>{item.title}</span>
+                                        </a>
+                                    </SidebarMenuButton>
+                                </SidebarMenuItem>
+                            ))}
+                        </SidebarMenu>
+                    </SidebarGroupContent>
+                </SidebarGroup>
+
                {/* Demos section */}
                <SidebarGroup>
                    <SidebarGroupLabel>Demos</SidebarGroupLabel>
--- a/internal_frontend/components/customers/modal/NewCustomerModal.tsx
+++ b/internal_frontend/components/customers/modal/NewCustomerModal.tsx
@@ -0,0 +1,280 @@
+"use client";
+
+import {useState} from "react";
+import {motion} from "framer-motion";
+import {Trash2} from "lucide-react";
+import {Button} from "@/components/ui/button";
+import {Dialog, DialogContent, DialogHeader, DialogTitle, DialogTrigger,} from "@/components/ui/dialog";
+import {Label} from "@/components/ui/label";
+import {Input} from "@/components/ui/input";
+import {Textarea} from "@/components/ui/textarea";
+import {Progress} from "@/components/ui/progress";
+import {Card, CardContent, CardHeader} from "@/components/ui/card";
+import {CreateCustomerDto, NoteDto, PhoneNumberDto} from "@/services/customers/dtos/createCustomer.dto";
+import {addCustomer} from "@/services/customers/usecases/addCustomer";
+import {validateCustomer} from "@/services/customers/usecases/validateCustomer";
+
+export function NewCustomerModal() {
+    const [step, setStep] = useState(1);
+    const [open, setOpen] = useState(false);
+    const [email, setEmail] = useState("");
+    const [name, setName] = useState("");
+    const [companyName, setCompanyName] = useState("");
+    const [phoneNumbers, setPhoneNumbers] = useState<PhoneNumberDto[]>([{note: "", number: ""}]);
+    const [notes, setNotes] = useState<NoteDto[]>([{text: ""}]);
+    const [street, setStreet] = useState("");
+    const [zip, setZip] = useState("");
+    const [city, setCity] = useState("");
+    const [matches, setMatches] = useState<CustomerMatch[]>([]);
+    const [showDetailModal, setShowDetailModal] = useState(false);
+    const [selectedCustomer] = useState<CustomerMatch | null>(null);
+
+    type CustomerMatch = {
+        id: string;
+        name: string;
+        email: string;
+        companyName: string;
+        street: string;
+        zip: string;
+        city: string;
+    };
+
+    const emailExists = matches.some(m => m.email.toLowerCase() === email.toLowerCase());
+    const companyExists = matches.some(m => m.companyName.toLowerCase() === companyName.toLowerCase());
+    const addressExists = matches.some(m =>
+        m.street.toLowerCase() === street.toLowerCase() &&
+        m.zip.toLowerCase() === zip.toLowerCase() &&
+        m.city.toLowerCase() === city.toLowerCase()
+    );
+
+    const validateField = async () => {
+        try {
+            const result = await validateCustomer({email, companyName, street, zip, city});
+            setMatches(result);
+        } catch (err) {
+            console.error("Validation failed", err);
+        }
+    };
+
+    const handleSubmit = async () => {
+        if (!email || !name || !companyName || !street || !zip || !city) return;
+        const payload: CreateCustomerDto = {email, name, companyName, street, zip, city, phoneNumbers, notes};
+        await addCustomer(payload);
+        location.reload();
+    };
+
+    const renderFormInput = (
+        label: string,
+        value: string,
+        onChange: (value: string) => void,
+        error?: boolean,
+        className?: string
+    ) => (
+        <div className="space-y-2">
+            <Label>{label} *</Label>
+            <Input
+                value={value}
+                onChange={(e) => onChange(e.target.value)}
+                onBlur={validateField}
+                className={error ? "border border-red-500" : className}
+            />
+        </div>
+    );
+
+    const renderCustomerInfo = (customer: CustomerMatch) => (
+        <div className="space-y-1 text-sm">
+            <div><strong>Name:</strong> {customer.name}</div>
+            <div><strong>Firma:</strong> {customer.companyName}</div>
+            <div><strong>E-Mail:</strong> {customer.email}</div>
+            <div><strong>Adresse:</strong> {customer.street}, {customer.zip} {customer.city}</div>
+        </div>
+    );
+
+    const updatePhoneNumber = (i: number, key: keyof PhoneNumberDto, value: string) => {
+        const updated = [...phoneNumbers];
+        updated[i][key] = value;
+        setPhoneNumbers(updated);
+    };
+
+    const removePhoneNumber = (i: number) => {
+        setPhoneNumbers(phoneNumbers.filter((_, idx) => idx !== i));
+    };
+
+    const updateNote = (i: number, value: string) => {
+        const updated = [...notes];
+        updated[i].text = value;
+        setNotes(updated);
+    };
+
+    const renderStepOne = () => (
+        <div className="space-y-4">
+            <div className="space-y-2">
+                {renderFormInput("Name", name, setName)}
+                {renderFormInput("Firma", companyName, setCompanyName, companyExists)}
+                {renderFormInput("E-Mail", email, setEmail, emailExists)}
+                {emailExists && (
+                    <div className="text-red-500 text-sm">Ein Kunde mit dieser E-Mail existiert bereits.</div>
+                )}
+            </div>
+            <div className="space-y-2">
+                <Label>Telefonnummern *</Label>
+                {phoneNumbers.map((p, i) => (
+                    <div key={i} className="grid grid-cols-[2fr_3fr_auto] gap-2 items-center w-full">
+                        <Input
+                            placeholder="Nummer"
+                            value={p.number}
+                            onChange={(e) => updatePhoneNumber(i, "number", e.target.value)}
+                        />
+                        <Input
+                            placeholder="Notiz"
+                            value={p.note}
+                            onChange={(e) => updatePhoneNumber(i, "note", e.target.value)}
+                        />
+                        <Button variant="ghost" size="icon" onClick={() => removePhoneNumber(i)}>
+                            <Trash2 className="w-4 h-4"/>
+                        </Button>
+                    </div>
+                ))}
+                <Button
+                    variant="outline"
+                    size="sm"
+                    onClick={() => setPhoneNumbers([...phoneNumbers, {note: "", number: ""}])}
+                >
+                    + Telefonnummer hinzufügen
+                </Button>
+            </div>
+        </div>
+    );
+
+    const renderStepTwo = () => (
+        <div className="space-y-4">
+            <div className="grid grid-cols-12 gap-4">
+                <div className="col-span-6">
+                    {renderFormInput("Straße", street, setStreet, addressExists)}
+                </div>
+                <div className="col-span-3">
+                    {renderFormInput("PLZ", zip, setZip, addressExists)}
+                </div>
+                <div className="col-span-3">
+                    {renderFormInput("Ort", city, setCity, addressExists)}
+                </div>
+            </div>
+            <div className="space-y-2">
+                <Label>Notizen</Label>
+                {notes.map((note, i) => (
+                    <div key={i} className="flex items-start gap-2">
+                        <Textarea
+                            placeholder={`Notiz ${i + 1}`}
+                            value={note.text}
+                            rows={3}
+                            className="w-full resize-y"
+                            onChange={(e) => updateNote(i, e.target.value)}
+                        />
+                        <Button
+                            type="button"
+                            variant="ghost"
+                            size="icon"
+                            onClick={() => setNotes(notes.filter((_, idx) => idx !== i))}
+                        >
+                            <Trash2 className="w-4 h-4"/>
+                        </Button>
+                    </div>
+                ))}
+                <Button
+                    type="button"
+                    onClick={() => setNotes([...notes, {text: ""}])}
+                    variant="outline"
+                    size="sm"
+                >
+                    + Notiz hinzufügen
+                </Button>
+            </div>
+        </div>
+    );
+
+    const renderDuplicationCard = () => (
+        <motion.div initial={{opacity: 0}} animate={{opacity: 1}} transition={{duration: 0.3}} className="mt-6">
+            <Card
+                className={emailExists ? "border-red-500 bg-red-100 dark:bg-red-900/20" : "border-yellow-500 bg-yellow-100 dark:bg-yellow-900/20"}>
+                <CardHeader className="text-sm font-semibold">
+                    {matches.length} mögliche Duplikate gefunden
+                </CardHeader>
+                <CardContent>
+                    <Button variant="outline" size="sm" className="w-full"
+                            onClick={() => setShowDetailModal(true)}>Details</Button>
+                </CardContent>
+            </Card>
+        </motion.div>
+    );
+
+    return (
+        <>
+            <Dialog open={open} onOpenChange={setOpen}>
+                <DialogTrigger asChild>
+                    <Button onClick={() => {
+                        setOpen(true);
+                        setStep(1);
+                    }}>Neue Kunde</Button>
+                </DialogTrigger>
+                <DialogContent className="w-full max-w-5xl max-h-[95vh] overflow-y-auto">
+                    <DialogHeader><DialogTitle>Neuen Kunden anlegen</DialogTitle></DialogHeader>
+                    <div className="mb-4">
+                        <div className="text-xs font-semibold mb-2">Schritt {step} von 2</div>
+                        <Progress value={step === 1 ? 50 : 100}/>
+                    </div>
+
+                    {step === 1 ? renderStepOne() : renderStepTwo()}
+                    {matches.length > 0 && renderDuplicationCard()}
+
+                    <div className="flex justify-between mt-6">
+                        <Button variant="secondary" disabled={step === 1} onClick={() => setStep(step - 1)}>
+                            Zurück
+                        </Button>
+                        {step === 1 ? (
+                            <Button
+                                onClick={() => setStep(2)}
+                                disabled={!email || !name || !companyName || phoneNumbers.length === 0 || !phoneNumbers.some(p => p.number.trim()) || emailExists}
+                            >
+                                Weiter
+                            </Button>
+                        ) : (
+                            <Button onClick={handleSubmit} disabled={!street || !zip || !city}>
+                                Anlegen
+                            </Button>
+                        )}
+                    </div>
+                </DialogContent>
+            </Dialog>
+
+            <Dialog open={showDetailModal} onOpenChange={setShowDetailModal}>
+                <DialogContent className="max-w-3xl max-h-[90vh] overflow-y-auto space-y-4">
+                    <DialogHeader>
+                        <DialogTitle>Kundendetails</DialogTitle>
+                    </DialogHeader>
+                    {matches.length === 1 ? (
+                        renderCustomerInfo(matches[0])
+                    ) : (
+                        <div className="space-y-4">
+                            {matches.map((customer) => (
+                                <Card key={customer.id}>
+                                    <CardContent className="pt-4">
+                                        {renderCustomerInfo(customer)}
+                                    </CardContent>
+                                </Card>
+                            ))}
+                            {selectedCustomer && (
+                                <motion.div
+                                    initial={{opacity: 0, y: 10}}
+                                    animate={{opacity: 1, y: 0}}
+                                    className="p-4 border rounded-md bg-muted"
+                                >
+                                    {renderCustomerInfo(selectedCustomer)}
+                                </motion.div>
+                            )}
+                        </div>
+                    )}
+                </DialogContent>
+            </Dialog>
+        </>
+    );
+}
--- a/internal_frontend/components/ui/dialog.tsx
+++ b/internal_frontend/components/ui/dialog.tsx
@@ -0,0 +1,143 @@
+"use client"
+
+import * as React from "react"
+import * as DialogPrimitive from "@radix-ui/react-dialog"
+import { XIcon } from "lucide-react"
+
+import { cn } from "@/lib/utils"
+
+function Dialog({
+  ...props
+}: React.ComponentProps<typeof DialogPrimitive.Root>) {
+  return <DialogPrimitive.Root data-slot="dialog" {...props} />
+}
+
+function DialogTrigger({
+  ...props
+}: React.ComponentProps<typeof DialogPrimitive.Trigger>) {
+  return <DialogPrimitive.Trigger data-slot="dialog-trigger" {...props} />
+}
+
+function DialogPortal({
+  ...props
+}: React.ComponentProps<typeof DialogPrimitive.Portal>) {
+  return <DialogPrimitive.Portal data-slot="dialog-portal" {...props} />
+}
+
+function DialogClose({
+  ...props
+}: React.ComponentProps<typeof DialogPrimitive.Close>) {
+  return <DialogPrimitive.Close data-slot="dialog-close" {...props} />
+}
+
+function DialogOverlay({
+  className,
+  ...props
+}: React.ComponentProps<typeof DialogPrimitive.Overlay>) {
+  return (
+    <DialogPrimitive.Overlay
+      data-slot="dialog-overlay"
+      className={cn(
+        "data-[state=open]:animate-in data-[state=closed]:animate-out data-[state=closed]:fade-out-0 data-[state=open]:fade-in-0 fixed inset-0 z-50 bg-black/50",
+        className
+      )}
+      {...props}
+    />
+  )
+}
+
+function DialogContent({
+  className,
+  children,
+  showCloseButton = true,
+  ...props
+}: React.ComponentProps<typeof DialogPrimitive.Content> & {
+  showCloseButton?: boolean
+}) {
+  return (
+    <DialogPortal data-slot="dialog-portal">
+      <DialogOverlay />
+      <DialogPrimitive.Content
+        data-slot="dialog-content"
+        className={cn(
+          "bg-background data-[state=open]:animate-in data-[state=closed]:animate-out data-[state=closed]:fade-out-0 data-[state=open]:fade-in-0 data-[state=closed]:zoom-out-95 data-[state=open]:zoom-in-95 fixed top-[50%] left-[50%] z-50 grid w-full max-w-[calc(100%-2rem)] translate-x-[-50%] translate-y-[-50%] gap-4 rounded-lg border p-6 shadow-lg duration-200 sm:max-w-lg",
+          className
+        )}
+        {...props}
+      >
+        {children}
+        {showCloseButton && (
+          <DialogPrimitive.Close
+            data-slot="dialog-close"
+            className="ring-offset-background focus:ring-ring data-[state=open]:bg-accent data-[state=open]:text-muted-foreground absolute top-4 right-4 rounded-xs opacity-70 transition-opacity hover:opacity-100 focus:ring-2 focus:ring-offset-2 focus:outline-hidden disabled:pointer-events-none [&_svg]:pointer-events-none [&_svg]:shrink-0 [&_svg:not([class*='size-'])]:size-4"
+          >
+            <XIcon />
+            <span className="sr-only">Close</span>
+          </DialogPrimitive.Close>
+        )}
+      </DialogPrimitive.Content>
+    </DialogPortal>
+  )
+}
+
+function DialogHeader({ className, ...props }: React.ComponentProps<"div">) {
+  return (
+    <div
+      data-slot="dialog-header"
+      className={cn("flex flex-col gap-2 text-center sm:text-left", className)}
+      {...props}
+    />
+  )
+}
+
+function DialogFooter({ className, ...props }: React.ComponentProps<"div">) {
+  return (
+    <div
+      data-slot="dialog-footer"
+      className={cn(
+        "flex flex-col-reverse gap-2 sm:flex-row sm:justify-end",
+        className
+      )}
+      {...props}
+    />
+  )
+}
+
+function DialogTitle({
+  className,
+  ...props
+}: React.ComponentProps<typeof DialogPrimitive.Title>) {
+  return (
+    <DialogPrimitive.Title
+      data-slot="dialog-title"
+      className={cn("text-lg leading-none font-semibold", className)}
+      {...props}
+    />
+  )
+}
+
+function DialogDescription({
+  className,
+  ...props
+}: React.ComponentProps<typeof DialogPrimitive.Description>) {
+  return (
+    <DialogPrimitive.Description
+      data-slot="dialog-description"
+      className={cn("text-muted-foreground text-sm", className)}
+      {...props}
+    />
+  )
+}
+
+export {
+  Dialog,
+  DialogClose,
+  DialogContent,
+  DialogDescription,
+  DialogFooter,
+  DialogHeader,
+  DialogOverlay,
+  DialogPortal,
+  DialogTitle,
+  DialogTrigger,
+}
--- a/internal_frontend/components/ui/label.tsx
+++ b/internal_frontend/components/ui/label.tsx
@@ -0,0 +1,24 @@
+"use client"
+
+import * as React from "react"
+import * as LabelPrimitive from "@radix-ui/react-label"
+
+import { cn } from "@/lib/utils"
+
+function Label({
+  className,
+  ...props
+}: React.ComponentProps<typeof LabelPrimitive.Root>) {
+  return (
+    <LabelPrimitive.Root
+      data-slot="label"
+      className={cn(
+        "flex items-center gap-2 text-sm leading-none font-medium select-none group-data-[disabled=true]:pointer-events-none group-data-[disabled=true]:opacity-50 peer-disabled:cursor-not-allowed peer-disabled:opacity-50",
+        className
+      )}
+      {...props}
+    />
+  )
+}
+
+export { Label }
--- a/internal_frontend/components/ui/pagination.tsx
+++ b/internal_frontend/components/ui/pagination.tsx
@@ -0,0 +1,127 @@
+import * as React from "react"
+import {
+  ChevronLeftIcon,
+  ChevronRightIcon,
+  MoreHorizontalIcon,
+} from "lucide-react"
+
+import { cn } from "@/lib/utils"
+import { Button, buttonVariants } from "@/components/ui/button"
+
+function Pagination({ className, ...props }: React.ComponentProps<"nav">) {
+  return (
+    <nav
+      role="navigation"
+      aria-label="pagination"
+      data-slot="pagination"
+      className={cn("mx-auto flex w-full justify-center", className)}
+      {...props}
+    />
+  )
+}
+
+function PaginationContent({
+  className,
+  ...props
+}: React.ComponentProps<"ul">) {
+  return (
+    <ul
+      data-slot="pagination-content"
+      className={cn("flex flex-row items-center gap-1", className)}
+      {...props}
+    />
+  )
+}
+
+function PaginationItem({ ...props }: React.ComponentProps<"li">) {
+  return <li data-slot="pagination-item" {...props} />
+}
+
+type PaginationLinkProps = {
+  isActive?: boolean
+} & Pick<React.ComponentProps<typeof Button>, "size"> &
+  React.ComponentProps<"a">
+
+function PaginationLink({
+  className,
+  isActive,
+  size = "icon",
+  ...props
+}: PaginationLinkProps) {
+  return (
+    <a
+      aria-current={isActive ? "page" : undefined}
+      data-slot="pagination-link"
+      data-active={isActive}
+      className={cn(
+        buttonVariants({
+          variant: isActive ? "outline" : "ghost",
+          size,
+        }),
+        className
+      )}
+      {...props}
+    />
+  )
+}
+
+function PaginationPrevious({
+  className,
+  ...props
+}: React.ComponentProps<typeof PaginationLink>) {
+  return (
+    <PaginationLink
+      aria-label="Go to previous page"
+      size="default"
+      className={cn("gap-1 px-2.5 sm:pl-2.5", className)}
+      {...props}
+    >
+      <ChevronLeftIcon />
+      <span className="hidden sm:block">Previous</span>
+    </PaginationLink>
+  )
+}
+
+function PaginationNext({
+  className,
+  ...props
+}: React.ComponentProps<typeof PaginationLink>) {
+  return (
+    <PaginationLink
+      aria-label="Go to next page"
+      size="default"
+      className={cn("gap-1 px-2.5 sm:pr-2.5", className)}
+      {...props}
+    >
+      <span className="hidden sm:block">Next</span>
+      <ChevronRightIcon />
+    </PaginationLink>
+  )
+}
+
+function PaginationEllipsis({
+  className,
+  ...props
+}: React.ComponentProps<"span">) {
+  return (
+    <span
+      aria-hidden
+      data-slot="pagination-ellipsis"
+      className={cn("flex size-9 items-center justify-center", className)}
+      {...props}
+    >
+      <MoreHorizontalIcon className="size-4" />
+      <span className="sr-only">More pages</span>
+    </span>
+  )
+}
+
+export {
+  Pagination,
+  PaginationContent,
+  PaginationLink,
+  PaginationItem,
+  PaginationPrevious,
+  PaginationNext,
+  PaginationEllipsis,
+}
--- a/internal_frontend/components/ui/progress.tsx
+++ b/internal_frontend/components/ui/progress.tsx
@@ -0,0 +1,31 @@
+"use client"
+
+import * as React from "react"
+import * as ProgressPrimitive from "@radix-ui/react-progress"
+
+import { cn } from "@/lib/utils"
+
+function Progress({
+  className,
+  value,
+  ...props
+}: React.ComponentProps<typeof ProgressPrimitive.Root>) {
+  return (
+    <ProgressPrimitive.Root
+      data-slot="progress"
+      className={cn(
+        "bg-primary/20 relative h-2 w-full overflow-hidden rounded-full",
+        className
+      )}
+      {...props}
+    >
+      <ProgressPrimitive.Indicator
+        data-slot="progress-indicator"
+        className="bg-primary h-full w-full flex-1 transition-all"
+        style={{ transform: `translateX(-${100 - (value || 0)}%)` }}
+      />
+    </ProgressPrimitive.Root>
+  )
+}
+
+export { Progress }
--- a/internal_frontend/components/ui/table.tsx
+++ b/internal_frontend/components/ui/table.tsx
@@ -0,0 +1,116 @@
+"use client"
+
+import * as React from "react"
+
+import { cn } from "@/lib/utils"
+
+function Table({ className, ...props }: React.ComponentProps<"table">) {
+  return (
+    <div
+      data-slot="table-container"
+      className="relative w-full overflow-x-auto"
+    >
+      <table
+        data-slot="table"
+        className={cn("w-full caption-bottom text-sm", className)}
+        {...props}
+      />
+    </div>
+  )
+}
+
+function TableHeader({ className, ...props }: React.ComponentProps<"thead">) {
+  return (
+    <thead
+      data-slot="table-header"
+      className={cn("[&_tr]:border-b", className)}
+      {...props}
+    />
+  )
+}
+
+function TableBody({ className, ...props }: React.ComponentProps<"tbody">) {
+  return (
+    <tbody
+      data-slot="table-body"
+      className={cn("[&_tr:last-child]:border-0", className)}
+      {...props}
+    />
+  )
+}
+
+function TableFooter({ className, ...props }: React.ComponentProps<"tfoot">) {
+  return (
+    <tfoot
+      data-slot="table-footer"
+      className={cn(
+        "bg-muted/50 border-t font-medium [&>tr]:last:border-b-0",
+        className
+      )}
+      {...props}
+    />
+  )
+}
+
+function TableRow({ className, ...props }: React.ComponentProps<"tr">) {
+  return (
+    <tr
+      data-slot="table-row"
+      className={cn(
+        "hover:bg-muted/50 data-[state=selected]:bg-muted border-b transition-colors",
+        className
+      )}
+      {...props}
+    />
+  )
+}
+
+function TableHead({ className, ...props }: React.ComponentProps<"th">) {
+  return (
+    <th
+      data-slot="table-head"
+      className={cn(
+        "text-foreground h-10 px-2 text-left align-middle font-medium whitespace-nowrap [&:has([role=checkbox])]:pr-0 [&>[role=checkbox]]:translate-y-[2px]",
+        className
+      )}
+      {...props}
+    />
+  )
+}
+
+function TableCell({ className, ...props }: React.ComponentProps<"td">) {
+  return (
+    <td
+      data-slot="table-cell"
+      className={cn(
+        "p-2 align-middle whitespace-nowrap [&:has([role=checkbox])]:pr-0 [&>[role=checkbox]]:translate-y-[2px]",
+        className
+      )}
+      {...props}
+    />
+  )
+}
+
+function TableCaption({
+  className,
+  ...props
+}: React.ComponentProps<"caption">) {
+  return (
+    <caption
+      data-slot="table-caption"
+      className={cn("text-muted-foreground mt-4 text-sm", className)}
+      {...props}
+    />
+  )
+}
+
+export {
+  Table,
+  TableHeader,
+  TableBody,
+  TableFooter,
+  TableHead,
+  TableRow,
+  TableCell,
+  TableCaption,
+}
--- a/internal_frontend/components/ui/textarea.tsx
+++ b/internal_frontend/components/ui/textarea.tsx
@@ -0,0 +1,18 @@
+import * as React from "react"
+
+import { cn } from "@/lib/utils"
+
+function Textarea({ className, ...props }: React.ComponentProps<"textarea">) {
+  return (
+    <textarea
+      data-slot="textarea"
+      className={cn(
+        "border-input placeholder:text-muted-foreground focus-visible:border-ring focus-visible:ring-ring/50 aria-invalid:ring-destructive/20 dark:aria-invalid:ring-destructive/40 aria-invalid:border-destructive dark:bg-input/30 flex field-sizing-content min-h-16 w-full rounded-md border bg-transparent px-3 py-2 text-base shadow-xs transition-[color,box-shadow] outline-none focus-visible:ring-[3px] disabled:cursor-not-allowed disabled:opacity-50 md:text-sm",
+        className
+      )}
+      {...props}
+    />
+  )
+}
+
+export { Textarea }
--- a/internal_frontend/lib/api/callApi.ts
+++ b/internal_frontend/lib/api/callApi.ts
@@ -0,0 +1,28 @@
+// lib/api/callApi.ts
+import {serverCall} from "@/lib/api/serverCall";
+
+export async function callApi<TResponse, TRequest = unknown>(
+    path: string,
+    method: "GET" | "POST" | "PUT" | "DELETE" | "PATCH",
+    body?: TRequest
+): Promise<TResponse> {
+    const res = await serverCall(path, method, body);
+
+    const contentType = res.headers.get("content-type") ?? "";
+    const isJson = contentType.includes("application/json");
+
+    const rawBody = isJson ? await res.json() : await res.text();
+
+    console.log(`[api ${path}] Response:`, res.status, rawBody);
+
+    if (!res.ok) {
+        const errorMessage = isJson
+            ? (rawBody?.message ?? rawBody?.errors?.join(", ")) ?? "Unbekannter Fehler"
+            : String(rawBody);
+
+        console.error(`[api ${path}] Error:`, errorMessage);
+        throw new Error(errorMessage);
+    }
+
+    return rawBody as TResponse;
+}
--- a/internal_frontend/lib/api/serverCall.ts
+++ b/internal_frontend/lib/api/serverCall.ts
@@ -0,0 +1,28 @@
+// lib/callBackendApi.ts
+import {getServerSession} from "next-auth";
+import {authOptions} from "@/lib/auth/authOptions";
+
+export async function serverCall(
+    path: string,
+    method: "GET" | "POST" | "PUT" | "DELETE" | "PATCH",
+    body?: unknown
+): Promise<Response> {
+    const url = `${process.env.INTERNAL_BACKEND_URL ?? "http://localhost:8080/api"}${path}`;
+    const session = await getServerSession(authOptions);
+
+    const headers: Record<string, string> = {
+        "Content-Type": "application/json",
+    };
+
+    if (session != null) {
+        headers["Authorization"] = `Bearer ${session.accessToken}`;
+    }
+
+    console.log("[api] Calling backend API: ", method, url, body);
+
+    return fetch(url, {
+        method,
+        headers,
+        body: body ? JSON.stringify(body) : undefined,
+    });
+}
--- a/internal_frontend/lib/auth/authOptions.ts
+++ b/internal_frontend/lib/auth/authOptions.ts
@@ -15,10 +15,10 @@ const {
    NEXTAUTH_SECRET,
 } = process.env;

-if (!KEYCLOAK_CLIENT_ID) throw new Error("Missing KEYCLOAK_CLIENT_ID");
-if (!KEYCLOAK_CLIENT_SECRET) throw new Error("Missing KEYCLOAK_CLIENT_SECRET");
-if (!KEYCLOAK_ISSUER) throw new Error("Missing KEYCLOAK_ISSUER");
-if (!NEXTAUTH_SECRET) throw new Error("Missing NEXTAUTH_SECRET");
+// if (!KEYCLOAK_CLIENT_ID) throw new Error("Missing KEYCLOAK_CLIENT_ID");
+// if (!KEYCLOAK_CLIENT_SECRET) throw new Error("Missing KEYCLOAK_CLIENT_SECRET");
+// if (!KEYCLOAK_ISSUER) throw new Error("Missing KEYCLOAK_ISSUER");
+// if (!NEXTAUTH_SECRET) throw new Error("Missing NEXTAUTH_SECRET");

 console.log("[auth] Using Keycloak provider:");
 console.log("  - Client ID:", KEYCLOAK_CLIENT_ID);
@@ -42,8 +42,8 @@ async function isTokenValid(token: string): Promise<boolean> {
 export const authOptions: NextAuthOptions = {
    providers: [
        KeycloakProvider({
-            clientId: KEYCLOAK_CLIENT_ID,
-            clientSecret: KEYCLOAK_CLIENT_SECRET,
+            clientId: KEYCLOAK_CLIENT_ID as string,
+            clientSecret: KEYCLOAK_CLIENT_SECRET as string,
            issuer: KEYCLOAK_ISSUER,
        }),
    ],
--- a/internal_frontend/lib/breadcrumb-map.ts
+++ b/internal_frontend/lib/breadcrumb-map.ts
@@ -4,5 +4,6 @@ export const breadcrumbMap: Record<string, string> = {
    'settings': 'Settings',
    'demo': 'Demo',
    'users': 'User Management',
+    'customers': 'Kundenübersicht',
    // Add more mappings as needed
 };
--- a/internal_frontend/lib/ui/showError.ts
+++ b/internal_frontend/lib/ui/showError.ts
@@ -0,0 +1,16 @@
+// lib/ui/showError.ts
+import {toast} from "sonner";
+
+export function showError(error: unknown, fallback = "Ein unbekannter Fehler ist aufgetreten") {
+    let message: string;
+
+    if (error instanceof Error) {
+        message = error.message;
+    } else if (typeof error === "string") {
+        message = error;
+    } else {
+        message = fallback;
+    }
+
+    toast.error(message);
+}
--- a/internal_frontend/package-lock.json
+++ b/internal_frontend/package-lock.json
@@ -11,9 +11,12 @@
        "@radix-ui/react-collapsible": "^1.1.11",
        "@radix-ui/react-dialog": "^1.1.14",
        "@radix-ui/react-dropdown-menu": "^2.1.15",
+        "@radix-ui/react-label": "^2.1.7",
+        "@radix-ui/react-progress": "^1.1.7",
        "@radix-ui/react-separator": "^1.1.7",
        "@radix-ui/react-slot": "^1.2.3",
        "@radix-ui/react-tooltip": "^1.2.7",
+        "axios": "^1.10.0",
        "class-variance-authority": "^0.7.1",
        "clsx": "^2.1.1",
        "framer-motion": "^12.22.0",
@@ -24,7 +27,9 @@
        "next-themes": "^0.4.6",
        "react": "^19.0.0",
        "react-dom": "^19.0.0",
-        "tailwind-merge": "^3.3.1"
+        "sonner": "^2.0.6",
+        "tailwind-merge": "^3.3.1",
+        "zustand": "^5.0.6"
      },
      "devDependencies": {
        "@eslint/eslintrc": "^3",
@@ -1308,6 +1313,29 @@
        }
      }
    },
+    "node_modules/@radix-ui/react-label": {
+      "version": "2.1.7",
+      "resolved": "https://registry.npmjs.org/@radix-ui/react-label/-/react-label-2.1.7.tgz",
+      "integrity": "sha512-YT1GqPSL8kJn20djelMX7/cTRp/Y9w5IZHvfxQTVHrOqa2yMl7i/UfMqKRU5V7mEyKTrUVgJXhNQPVCG8PBLoQ==",
+      "license": "MIT",
+      "dependencies": {
+        "@radix-ui/react-primitive": "2.1.3"
+      },
+      "peerDependencies": {
+        "@types/react": "*",
+        "@types/react-dom": "*",
+        "react": "^16.8 || ^17.0 || ^18.0 || ^19.0 || ^19.0.0-rc",
+        "react-dom": "^16.8 || ^17.0 || ^18.0 || ^19.0 || ^19.0.0-rc"
+      },
+      "peerDependenciesMeta": {
+        "@types/react": {
+          "optional": true
+        },
+        "@types/react-dom": {
+          "optional": true
+        }
+      }
+    },
    "node_modules/@radix-ui/react-menu": {
      "version": "2.1.15",
      "resolved": "https://registry.npmjs.org/@radix-ui/react-menu/-/react-menu-2.1.15.tgz",
@@ -1451,6 +1479,30 @@
        }
      }
    },
+    "node_modules/@radix-ui/react-progress": {
+      "version": "1.1.7",
+      "resolved": "https://registry.npmjs.org/@radix-ui/react-progress/-/react-progress-1.1.7.tgz",
+      "integrity": "sha512-vPdg/tF6YC/ynuBIJlk1mm7Le0VgW6ub6J2UWnTQ7/D23KXcPI1qy+0vBkgKgd38RCMJavBXpB83HPNFMTb0Fg==",
+      "license": "MIT",
+      "dependencies": {
+        "@radix-ui/react-context": "1.1.2",
+        "@radix-ui/react-primitive": "2.1.3"
+      },
+      "peerDependencies": {
+        "@types/react": "*",
+        "@types/react-dom": "*",
+        "react": "^16.8 || ^17.0 || ^18.0 || ^19.0 || ^19.0.0-rc",
+        "react-dom": "^16.8 || ^17.0 || ^18.0 || ^19.0 || ^19.0.0-rc"
+      },
+      "peerDependenciesMeta": {
+        "@types/react": {
+          "optional": true
+        },
+        "@types/react-dom": {
+          "optional": true
+        }
+      }
+    },
    "node_modules/@radix-ui/react-roving-focus": {
      "version": "1.1.10",
      "resolved": "https://registry.npmjs.org/@radix-ui/react-roving-focus/-/react-roving-focus-1.1.10.tgz",
@@ -2892,6 +2944,12 @@
        "node": ">= 0.4"
      }
    },
+    "node_modules/asynckit": {
+      "version": "0.4.0",
+      "resolved": "https://registry.npmjs.org/asynckit/-/asynckit-0.4.0.tgz",
+      "integrity": "sha512-Oei9OH4tRh0YqU3GxhX79dM/mwVgvbZJaSNaRk+bshkj0S5cfHcgYakreBjrHwatXKbz+IoIdYLxrKim2MjW0Q==",
+      "license": "MIT"
+    },
    "node_modules/available-typed-arrays": {
      "version": "1.0.7",
      "resolved": "https://registry.npmjs.org/available-typed-arrays/-/available-typed-arrays-1.0.7.tgz",
@@ -2918,6 +2976,17 @@
        "node": ">=4"
      }
    },
+    "node_modules/axios": {
+      "version": "1.10.0",
+      "resolved": "https://registry.npmjs.org/axios/-/axios-1.10.0.tgz",
+      "integrity": "sha512-/1xYAC4MP/HEG+3duIhFr4ZQXR4sQXOIe+o6sdqzeykGLx6Upp/1p8MHqhINOvGeP7xyNHe7tsiJByc4SSVUxw==",
+      "license": "MIT",
+      "dependencies": {
+        "follow-redirects": "^1.15.6",
+        "form-data": "^4.0.0",
+        "proxy-from-env": "^1.1.0"
+      }
+    },
    "node_modules/axobject-query": {
      "version": "4.1.0",
      "resolved": "https://registry.npmjs.org/axobject-query/-/axobject-query-4.1.0.tgz",
@@ -2993,7 +3062,6 @@
      "version": "1.0.2",
      "resolved": "https://registry.npmjs.org/call-bind-apply-helpers/-/call-bind-apply-helpers-1.0.2.tgz",
      "integrity": "sha512-Sp1ablJ0ivDkSzjcaJdxEunN5/XvksFJ2sMBFfq6x0ryhQV/2b/KwFe21cMpmHtPOSij8K99/wSfoEuTObmuMQ==",
-      "dev": true,
      "license": "MIT",
      "dependencies": {
        "es-errors": "^1.3.0",
@@ -3149,6 +3217,18 @@
        "simple-swizzle": "^0.2.2"
      }
    },
+    "node_modules/combined-stream": {
+      "version": "1.0.8",
+      "resolved": "https://registry.npmjs.org/combined-stream/-/combined-stream-1.0.8.tgz",
+      "integrity": "sha512-FQN4MRfuJeHf7cBbBMJFXhKSDq+2kAArBlmRBvcvFE5BB1HZKXtSFASDhdlz9zOYwxh8lDdnvmMOe/+5cdoEdg==",
+      "license": "MIT",
+      "dependencies": {
+        "delayed-stream": "~1.0.0"
+      },
+      "engines": {
+        "node": ">= 0.8"
+      }
+    },
    "node_modules/concat-map": {
      "version": "0.0.1",
      "resolved": "https://registry.npmjs.org/concat-map/-/concat-map-0.0.1.tgz",
@@ -3309,6 +3389,15 @@
        "url": "https://github.com/sponsors/ljharb"
      }
    },
+    "node_modules/delayed-stream": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/delayed-stream/-/delayed-stream-1.0.0.tgz",
+      "integrity": "sha512-ZySD7Nf91aLB0RxL4KGrKHBXl7Eds1DAmEdcoVawXnLD7SDhpNgtuII2aAkg7a7QS41jxPSZ17p4VdGnMHk3MQ==",
+      "license": "MIT",
+      "engines": {
+        "node": ">=0.4.0"
+      }
+    },
    "node_modules/detect-libc": {
      "version": "2.0.4",
      "resolved": "https://registry.npmjs.org/detect-libc/-/detect-libc-2.0.4.tgz",
@@ -3342,7 +3431,6 @@
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-      "dev": true,
      "license": "MIT",
      "dependencies": {
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@@ -3447,7 +3535,6 @@
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-      "dev": true,
      "license": "MIT",
      "engines": {
        "node": ">= 0.4"
@@ -3457,7 +3544,6 @@
      "version": "1.3.0",
      "resolved": "https://registry.npmjs.org/es-errors/-/es-errors-1.3.0.tgz",
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-      "dev": true,
      "license": "MIT",
      "engines": {
        "node": ">= 0.4"
@@ -3495,7 +3581,6 @@
      "version": "1.1.1",
      "resolved": "https://registry.npmjs.org/es-object-atoms/-/es-object-atoms-1.1.1.tgz",
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-      "dev": true,
      "license": "MIT",
      "dependencies": {
        "es-errors": "^1.3.0"
@@ -3508,7 +3593,6 @@
      "version": "2.1.0",
      "resolved": "https://registry.npmjs.org/es-set-tostringtag/-/es-set-tostringtag-2.1.0.tgz",
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-      "dev": true,
      "license": "MIT",
      "dependencies": {
        "es-errors": "^1.3.0",
@@ -4115,6 +4199,26 @@
      "dev": true,
      "license": "ISC"
    },
+    "node_modules/follow-redirects": {
+      "version": "1.15.9",
+      "resolved": "https://registry.npmjs.org/follow-redirects/-/follow-redirects-1.15.9.tgz",
+      "integrity": "sha512-gew4GsXizNgdoRyqmyfMHyAmXsZDk6mHkSxZFCzW9gwlbtOW44CDtYavM+y+72qD/Vq2l550kMF52DT8fOLJqQ==",
+      "funding": [
+        {
+          "type": "individual",
+          "url": "https://github.com/sponsors/RubenVerborgh"
+        }
+      ],
+      "license": "MIT",
+      "engines": {
+        "node": ">=4.0"
+      },
+      "peerDependenciesMeta": {
+        "debug": {
+          "optional": true
+        }
+      }
+    },
    "node_modules/for-each": {
      "version": "0.3.5",
      "resolved": "https://registry.npmjs.org/for-each/-/for-each-0.3.5.tgz",
@@ -4131,6 +4235,22 @@
        "url": "https://github.com/sponsors/ljharb"
      }
    },
+    "node_modules/form-data": {
+      "version": "4.0.3",
+      "resolved": "https://registry.npmjs.org/form-data/-/form-data-4.0.3.tgz",
+      "integrity": "sha512-qsITQPfmvMOSAdeyZ+12I1c+CKSstAFAwu+97zrnWAbIr5u8wfsExUzCesVLC8NgHuRUqNN4Zy6UPWUTRGslcA==",
+      "license": "MIT",
+      "dependencies": {
+        "asynckit": "^0.4.0",
+        "combined-stream": "^1.0.8",
+        "es-set-tostringtag": "^2.1.0",
+        "hasown": "^2.0.2",
+        "mime-types": "^2.1.12"
+      },
+      "engines": {
+        "node": ">= 6"
+      }
+    },
    "node_modules/framer-motion": {
      "version": "12.22.0",
      "resolved": "https://registry.npmjs.org/framer-motion/-/framer-motion-12.22.0.tgz",
@@ -4162,7 +4282,6 @@
      "version": "1.1.2",
      "resolved": "https://registry.npmjs.org/function-bind/-/function-bind-1.1.2.tgz",
      "integrity": "sha512-7XHNxH7qX9xG5mIwxkhumTox/MIRNcOgDrxWsMt2pAr23WHp6MrRlN7FBSFpCpr+oVO0F744iUgR82nJMfG2SA==",
-      "dev": true,
      "license": "MIT",
      "funding": {
        "url": "https://github.com/sponsors/ljharb"
@@ -4203,7 +4322,6 @@
      "version": "1.3.0",
      "resolved": "https://registry.npmjs.org/get-intrinsic/-/get-intrinsic-1.3.0.tgz",
      "integrity": "sha512-9fSjSaos/fRIVIp+xSJlE6lfwhES7LNtKaCBIamHsjr2na1BiABJPo0mOjjz8GJDURarmCPGqaiVg5mfjb98CQ==",
-      "dev": true,
      "license": "MIT",
      "dependencies": {
        "call-bind-apply-helpers": "^1.0.2",
@@ -4237,7 +4355,6 @@
      "version": "1.0.1",
      "resolved": "https://registry.npmjs.org/get-proto/-/get-proto-1.0.1.tgz",
      "integrity": "sha512-sTSfBjoXBp89JvIKIefqw7U2CCebsc74kiY6awiGogKtoSGbgjYE/G/+l9sF3MWFPNc9IcoOC4ODfKHfxFmp0g==",
-      "dev": true,
      "license": "MIT",
      "dependencies": {
        "dunder-proto": "^1.0.1",
@@ -4325,7 +4442,6 @@
      "version": "1.2.0",
      "resolved": "https://registry.npmjs.org/gopd/-/gopd-1.2.0.tgz",
      "integrity": "sha512-ZUKRh6/kUFoAiTAtTYPZJ3hw9wNxx+BIBOijnlG9PnrJsCcSjs1wyyD6vJpaYtgnzDrKYRSqf3OO6Rfa93xsRg==",
-      "dev": true,
      "license": "MIT",
      "engines": {
        "node": ">= 0.4"
@@ -4404,7 +4520,6 @@
      "version": "1.1.0",
      "resolved": "https://registry.npmjs.org/has-symbols/-/has-symbols-1.1.0.tgz",
      "integrity": "sha512-1cDNdwJ2Jaohmb3sg4OmKaMBwuC48sYni5HUw2DvsC8LjGTLK9h+eb1X6RyuOHe4hT0ULCW68iomhjUoKUqlPQ==",
-      "dev": true,
      "license": "MIT",
      "engines": {
        "node": ">= 0.4"
@@ -4417,7 +4532,6 @@
      "version": "1.0.2",
      "resolved": "https://registry.npmjs.org/has-tostringtag/-/has-tostringtag-1.0.2.tgz",
      "integrity": "sha512-NqADB8VjPFLM2V0VvHUewwwsw0ZWBaIdgo+ieHtK3hasLz4qeCRjYcqfB6AQrBggRKppKF8L52/VqdVsO47Dlw==",
-      "dev": true,
      "license": "MIT",
      "dependencies": {
        "has-symbols": "^1.0.3"
@@ -4433,7 +4547,6 @@
      "version": "2.0.2",
      "resolved": "https://registry.npmjs.org/hasown/-/hasown-2.0.2.tgz",
      "integrity": "sha512-0hJU9SCPvmMzIBdZFqNPXWa6dqh7WdH0cII9y+CyS8rG3nL48Bclra9HmKhVVUHyPWNH5Y7xDwAB7bfgSjkUMQ==",
-      "dev": true,
      "license": "MIT",
      "dependencies": {
        "function-bind": "^1.1.2"
@@ -5393,7 +5506,6 @@
      "version": "1.1.0",
      "resolved": "https://registry.npmjs.org/math-intrinsics/-/math-intrinsics-1.1.0.tgz",
      "integrity": "sha512-/IXtbwEk5HTPyEwyKX6hGkYXxM9nbj64B+ilVJnC/R6B0pH5G4V3b0pVbL7DBj4tkhBAppbQUlf6F6Xl9LHu1g==",
-      "dev": true,
      "license": "MIT",
      "engines": {
        "node": ">= 0.4"
@@ -5423,6 +5535,27 @@
        "node": ">=8.6"
      }
    },
+    "node_modules/mime-db": {
+      "version": "1.52.0",
+      "resolved": "https://registry.npmjs.org/mime-db/-/mime-db-1.52.0.tgz",
+      "integrity": "sha512-sPU4uV7dYlvtWJxwwxHD0PuihVNiE7TyAbQ5SWxDCB9mUYvOgroQOwYQQOKPJ8CIbE+1ETVlOoK1UC2nU3gYvg==",
+      "license": "MIT",
+      "engines": {
+        "node": ">= 0.6"
+      }
+    },
+    "node_modules/mime-types": {
+      "version": "2.1.35",
+      "resolved": "https://registry.npmjs.org/mime-types/-/mime-types-2.1.35.tgz",
+      "integrity": "sha512-ZDY+bPm5zTTF+YpCrAU9nK0UgICYPT0QtT1NZWFv4s++TNkcgVaT0g6+4R2uI4MjQjzysHB1zxuWL50hzaeXiw==",
+      "license": "MIT",
+      "dependencies": {
+        "mime-db": "1.52.0"
+      },
+      "engines": {
+        "node": ">= 0.6"
+      }
+    },
    "node_modules/minimatch": {
      "version": "3.1.2",
      "resolved": "https://registry.npmjs.org/minimatch/-/minimatch-3.1.2.tgz",
@@ -6050,6 +6183,12 @@
        "react-is": "^16.13.1"
      }
    },
+    "node_modules/proxy-from-env": {
+      "version": "1.1.0",
+      "resolved": "https://registry.npmjs.org/proxy-from-env/-/proxy-from-env-1.1.0.tgz",
+      "integrity": "sha512-D+zkORCbA9f1tdWRK0RaCR3GPv50cMxcrz4X8k5LTSUD1Dkw47mKJEZQNunItRTkWwgtaUSo1RVFRIG9ZXiFYg==",
+      "license": "MIT"
+    },
    "node_modules/punycode": {
      "version": "2.3.1",
      "resolved": "https://registry.npmjs.org/punycode/-/punycode-2.3.1.tgz",
@@ -6572,6 +6711,16 @@
        "is-arrayish": "^0.3.1"
      }
    },
+    "node_modules/sonner": {
+      "version": "2.0.6",
+      "resolved": "https://registry.npmjs.org/sonner/-/sonner-2.0.6.tgz",
+      "integrity": "sha512-yHFhk8T/DK3YxjFQXIrcHT1rGEeTLliVzWbO0xN8GberVun2RiBnxAjXAYpZrqwEVHBG9asI/Li8TAAhN9m59Q==",
+      "license": "MIT",
+      "peerDependencies": {
+        "react": "^18.0.0 || ^19.0.0 || ^19.0.0-rc",
+        "react-dom": "^18.0.0 || ^19.0.0 || ^19.0.0-rc"
+      }
+    },
    "node_modules/source-map-js": {
      "version": "1.2.1",
      "resolved": "https://registry.npmjs.org/source-map-js/-/source-map-js-1.2.1.tgz",
@@ -7305,6 +7454,35 @@
      "funding": {
        "url": "https://github.com/sponsors/sindresorhus"
      }
+    },
+    "node_modules/zustand": {
+      "version": "5.0.6",
+      "resolved": "https://registry.npmjs.org/zustand/-/zustand-5.0.6.tgz",
+      "integrity": "sha512-ihAqNeUVhe0MAD+X8M5UzqyZ9k3FFZLBTtqo6JLPwV53cbRB/mJwBI0PxcIgqhBBHlEs8G45OTDTMq3gNcLq3A==",
+      "license": "MIT",
+      "engines": {
+        "node": ">=12.20.0"
+      },
+      "peerDependencies": {
+        "@types/react": ">=18.0.0",
+        "immer": ">=9.0.6",
+        "react": ">=18.0.0",
+        "use-sync-external-store": ">=1.2.0"
+      },
+      "peerDependenciesMeta": {
+        "@types/react": {
+          "optional": true
+        },
+        "immer": {
+          "optional": true
+        },
+        "react": {
+          "optional": true
+        },
+        "use-sync-external-store": {
+          "optional": true
+        }
+      }
    }
  }
 }
--- a/internal_frontend/package.json
+++ b/internal_frontend/package.json
@@ -12,9 +12,12 @@
    "@radix-ui/react-collapsible": "^1.1.11",
    "@radix-ui/react-dialog": "^1.1.14",
    "@radix-ui/react-dropdown-menu": "^2.1.15",
+    "@radix-ui/react-label": "^2.1.7",
+    "@radix-ui/react-progress": "^1.1.7",
    "@radix-ui/react-separator": "^1.1.7",
    "@radix-ui/react-slot": "^1.2.3",
    "@radix-ui/react-tooltip": "^1.2.7",
+    "axios": "^1.10.0",
    "class-variance-authority": "^0.7.1",
    "clsx": "^2.1.1",
    "framer-motion": "^12.22.0",
@@ -25,7 +28,9 @@
    "next-themes": "^0.4.6",
    "react": "^19.0.0",
    "react-dom": "^19.0.0",
-    "tailwind-merge": "^3.3.1"
+    "sonner": "^2.0.6",
+    "tailwind-merge": "^3.3.1",
+    "zustand": "^5.0.6"
  },
  "devDependencies": {
    "@eslint/eslintrc": "^3",
--- a/internal_frontend/services/customers/dtos/createCustomer.dto.ts
+++ b/internal_frontend/services/customers/dtos/createCustomer.dto.ts
@@ -0,0 +1,19 @@
+export interface PhoneNumberDto {
+    number: string;
+    note: string;
+}
+
+export interface NoteDto {
+    text: string;
+}
+
+export interface CreateCustomerDto {
+    email: string;
+    name: string;
+    companyName: string;
+    phoneNumbers: PhoneNumberDto[];
+    street: string;
+    zip: string;
+    city: string;
+    notes: NoteDto[];
+}
--- a/internal_frontend/services/customers/entities/customer.ts
+++ b/internal_frontend/services/customers/entities/customer.ts
@@ -0,0 +1,32 @@
+export interface PhoneNumber {
+    number: string;
+    note: string;
+    createdBy: string;
+    createdAt: string;
+    updatedBy: string;
+    updatedAt: string;
+}
+
+export interface Note {
+    text: string;
+    createdBy: string;
+    createdAt: string;
+    updatedBy: string;
+    updatedAt: string;
+}
+
+export interface Customer {
+    id: string;
+    email: string;
+    name: string;
+    companyName: string;
+    phoneNumbers: PhoneNumber[];
+    street: string;
+    zip: string;
+    city: string;
+    notes: Note[];
+    createdBy: string;
+    createdAt: string;
+    updatedBy: string;
+    updatedAt: string;
+}
--- a/internal_frontend/services/customers/repositories/customerRepository.ts
+++ b/internal_frontend/services/customers/repositories/customerRepository.ts
@@ -0,0 +1,13 @@
+import {Customer} from "@/services/customers/entities/customer";
+import {CreateCustomerDto} from "@/services/customers/dtos/createCustomer.dto";
+import {callApi} from "@/lib/api/callApi";
+
+export class CustomerRepository {
+    static async getAll(): Promise<Customer[]> {
+        return await callApi<Customer[]>("/customers", "GET");
+    }
+
+    static async create(payload: CreateCustomerDto): Promise<void> {
+        await callApi<void, CreateCustomerDto>("/customers", "POST", payload);
+    }
+}
--- a/internal_frontend/services/customers/usecases/addCustomer.ts
+++ b/internal_frontend/services/customers/usecases/addCustomer.ts
@@ -0,0 +1,21 @@
+"use server";
+
+import {CreateCustomerDto} from "@/services/customers/dtos/createCustomer.dto";
+import {CustomerRepository} from "@/services/customers/repositories/customerRepository";
+
+export async function addCustomer(params: CreateCustomerDto): Promise<void> {
+    const {email, name, companyName, street, zip, city, phoneNumbers, notes} = params;
+
+    const payload: CreateCustomerDto = {
+        email,
+        name,
+        companyName,
+        street,
+        zip,
+        city,
+        phoneNumbers,
+        notes: notes.map(({text}) => ({text})),
+    };
+
+    await CustomerRepository.create(payload);
+}
--- a/internal_frontend/services/customers/usecases/validateCustomer.ts
+++ b/internal_frontend/services/customers/usecases/validateCustomer.ts
@@ -0,0 +1,15 @@
+"use server";
+
+import {callApi} from "@/lib/api/callApi";
+import {Customer} from "@/app/customers/page";
+import {customerRoutes} from "@/app/api/customers/customerRoutes";
+
+export async function validateCustomer(input: {
+    email: string;
+    companyName: string;
+    street: string;
+    zip: string;
+    city: string;
+}): Promise<Customer[]> {
+    return await callApi<Customer[]>(customerRoutes.validate, "POST", input);
+}