implement user authentication with login functionality and database integration

frontend/src/utils/fetchData.ts

@@ -0,0 +1,53 @@
+import Cookies from "js-cookie";
+import { myToast } from "./toastify";
+
+export const fetchAllData = async (token: string | undefined) => {
+  if (!token) return;
+  try {
+    // First we fetch all items that are potentially available for borrowing
+    const response = await fetch("http://localhost:8002/api/items", {
+      method: "GET",
+      headers: {
+        Authorization: `Bearer ${token}`,
+      },
+    });
+
+    if (!response.ok) {
+      myToast("Failed to fetch items", "error");
+      return;
+    }
+
+    const data = await response.json();
+    localStorage.setItem("allItems", JSON.stringify(data));
+  } catch (error) {
+    myToast("An error occurred", "error");
+  }
+};
+
+export const loginUser = async (username: string, password: string) => {
+  try {
+    const response = await fetch("http://localhost:8002/api/login", {
+      method: "POST",
+      headers: {
+        "Content-Type": "application/json",
+      },
+      body: JSON.stringify({ username, password }),
+    });
+
+    if (!response.ok) {
+      return { success: false } as const;
+    }
+
+    const data = await response.json();
+    if (data?.token) {
+      Cookies.set("token", data.token);
+      myToast("Login successful!", "success");
+      fetchAllData(Cookies.get("token"));
+      return { success: true, token: data.token } as const;
+    }
+
+    return { success: false } as const;
+  } catch (e) {
+    return { success: false } as const;
+  }
+};