Add customer management

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;
+}

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,
+    });
+}