feat: Implement loan management features including fetching, creating, and deleting loans

- Added database functions for managing loans: getLoans, getUserLoans, deleteLoan, and createLoan.
- Updated frontend to include new Form4 for displaying user loans and handling loan deletions.
- Replaced Form3 with Form4 in App component.
- Enhanced Form1 to set borrowing dates and fetch available items.
- Improved Form2 to display borrowable items and allow selection for loans.
- Introduced utility functions for handling loan creation and deletion in userHandler.
- Added event listeners for local storage updates to keep UI in sync.
- Updated fetchData utility to retrieve loans and user loans from the backend.

backend/routes/api.js

@@ -1,5 +1,13 @@
 import express from "express";
-import { loginFunc, getItemsFromDatabase } from "../services/database.js";
+import {
+  loginFunc,
+  getItemsFromDatabase,
+  getLoansFromDatabase,
+  getUserLoansFromDatabase,
+  deleteLoanFromDatabase,
+  getBorrowableItemsFromDatabase,
+  createLoanInDatabase,
+} from "../services/database.js";
 import { authenticate, generateToken } from "../services/tokenService.js";
 const router = express.Router();
 
@@ -27,4 +35,114 @@ router.get("/items", authenticate, async (req, res) => {
   }
 });
 
+router.get("/loans", authenticate, async (req, res) => {
+  const result = await getLoansFromDatabase();
+  if (result.success) {
+    res.status(200).json(result.data);
+  } else {
+    res.status(500).json({ message: "Failed to fetch loans" });
+  }
+});
+
+router.get("/userLoans", authenticate, async (req, res) => {
+  const result = await getUserLoansFromDatabase(req.user.username);
+  if (result.success) {
+    res.status(200).json(result.data);
+  } else {
+    res.status(500).json({ message: "Failed to fetch user loans" });
+  }
+});
+
+router.delete("/deleteLoan/:id", authenticate, async (req, res) => {
+  const loanId = req.params.id;
+  const result = await deleteLoanFromDatabase(loanId);
+  if (result.success) {
+    res.status(200).json({ message: "Loan deleted successfully" });
+  } else {
+    res.status(500).json({ message: "Failed to delete loan" });
+  }
+});
+
+router.post("/borrowableItems", authenticate, async (req, res) => {
+  const { startDate, endDate } = req.body || {};
+  if (!startDate || !endDate) {
+    return res
+      .status(400)
+      .json({ message: "startDate and endDate are required" });
+  }
+
+  const result = await getBorrowableItemsFromDatabase(
+    startDate,
+    endDate,
+    req.user.role
+  );
+  if (result.success) {
+    // return the array directly for consistency with /items
+    return res.status(200).json(result.data);
+  } else {
+    return res
+      .status(500)
+      .json({ message: "Failed to fetch borrowable items" });
+  }
+});
+
+router.post("/createLoan", authenticate, async (req, res) => {
+  try {
+    const { items, startDate, endDate } = req.body || {};
+
+    if (!Array.isArray(items) || items.length === 0) {
+      return res.status(400).json({ message: "Items array is required" });
+    }
+
+    // If dates are not provided, default to now .. +7 days
+    const start =
+      startDate ?? new Date().toISOString().slice(0, 19).replace("T", " ");
+    const end =
+      endDate ??
+      new Date(Date.now() + 7 * 24 * 60 * 60 * 1000)
+        .toISOString()
+        .slice(0, 19)
+        .replace("T", " ");
+
+    // Coerce item IDs to numbers and filter invalids
+    const itemIds = items
+      .map((v) => Number(v))
+      .filter((n) => Number.isFinite(n));
+
+    if (itemIds.length === 0) {
+      return res.status(400).json({ message: "No valid item IDs provided" });
+    }
+
+    const result = await createLoanInDatabase(
+      req.user.username,
+      start,
+      end,
+      itemIds
+    );
+
+    if (result.success) {
+      return res.status(201).json({
+        message: "Loan created successfully",
+        loanId: result.data.id,
+        loanCode: result.data.loan_code,
+      });
+    }
+
+    if (result.code === "CONFLICT") {
+      return res
+        .status(409)
+        .json({ message: "Items not available in the selected period" });
+    }
+
+    if (result.code === "BAD_REQUEST") {
+      return res.status(400).json({ message: result.message });
+    }
+
+    return res.status(500).json({ message: "Failed to create loan" });
+  } catch (err) {
+    console.error("createLoan error:", err);
+    return res.status(500).json({ message: "Failed to create loan" });
+  }
+});
+
 export default router;

backend/scheme.sql

@@ -20,6 +20,7 @@ CREATE TABLE `loans` (
   `returned_date` timestamp NULL DEFAULT NULL,
   `created_at` timestamp NULL DEFAULT CURRENT_TIMESTAMP,
   `loaned_items_id` json NOT NULL DEFAULT ('[]'),
+  `loaned_items_name` json NOT NULL DEFAULT ('[]'),
   PRIMARY KEY (`id`),
   UNIQUE KEY `loan_code` (`loan_code`)
 );
@@ -27,7 +28,7 @@ CREATE TABLE `loans` (
 CREATE TABLE `items` (
   `id` int NOT NULL AUTO_INCREMENT,
   `item_name` varchar(255) NOT NULL,
-  `can_borrow_role` varchar(255) NOT NULL,
+  `can_borrow_role` INT NOT NULL,
   `inSafe` tinyint(1) NOT NULL DEFAULT '1',
   PRIMARY KEY (`id`),
   UNIQUE KEY `item_name` (`item_name`)
@@ -42,28 +43,95 @@ CREATE TABLE `lockers` (
   UNIQUE KEY `locker_number` (`locker_number`)
 );
 
--- Mock data
+-- Mock data for users
+INSERT INTO `users` (`username`, `password`, `role`) VALUES
+('alice', 'password1', 1),
+('bob', 'password2', 2),
+('carol', 'password3', 1),
+('dave', 'password4', 3),
+('eve', 'password5', 2),
+('frank', 'password6', 1),
+('grace', 'password7', 2),
+('heidi', 'password8', 3),
+('ivan', 'password9', 1),
+('judy', 'password10', 2),
+('mallory', 'password11', 1),
+('oscar', 'password12', 3),
+('peggy', 'password13', 2),
+('trent', 'password14', 1),
+('victor', 'password15', 2),
+('wendy', 'password16', 3),
+('zoe', 'password17', 1),
+('quinn', 'password18', 2),
+('ruth', 'password19', 1),
+('sam', 'password20', 3);
 
--- Users
+-- Mock data for loans
-INSERT INTO users (username, password) VALUES
+INSERT INTO `loans` (`username`, `loan_code`, `start_date`, `end_date`, `returned_date`, `loaned_items_id`, `loaned_items_name`)
-('alice', 'password123'),
+VALUES
-('bob', 'securepass'),
+('alice', 1001, '2025-08-01 09:00:00', '2025-08-10 09:00:00', NULL, '[1,2]', '["Laptop","Projector"]'),
-('charlie', 'charliepwd');
+('bob', 1002, '2025-08-02 10:00:00', '2025-08-12 10:00:00', NULL, '[3]', '["Tablet"]'),
+('carol', 1003, '2025-08-03 11:00:00', '2025-08-13 11:00:00', NULL, '[4,5]', '["Camera","Tripod"]'),
+('dave', 1004, '2025-08-04 12:00:00', '2025-08-14 12:00:00', NULL, '[6]', '["Microphone"]'),
+('eve', 1005, '2025-08-05 13:00:00', '2025-08-15 13:00:00', NULL, '[7,8]', '["Speaker","Monitor"]'),
+('frank', 1006, '2025-08-06 14:00:00', '2025-08-16 14:00:00', NULL, '[9]', '["Keyboard"]'),
+('grace', 1007, '2025-08-07 15:00:00', '2025-08-17 15:00:00', NULL, '[10,11]', '["Mouse","Printer"]'),
+('heidi', 1008, '2025-08-08 16:00:00', '2025-08-18 16:00:00', NULL, '[12]', '["Scanner"]'),
+('ivan', 1009, '2025-08-09 17:00:00', '2025-08-19 17:00:00', NULL, '[13,14]', '["Router","Switch"]'),
+('judy', 1010, '2025-08-10 18:00:00', '2025-08-20 18:00:00', NULL, '[15]', '["Projector"]'),
+('mallory', 1011, '2025-08-11 09:00:00', '2025-08-21 09:00:00', NULL, '[16,17]', '["Laptop","Tablet"]'),
+('oscar', 1012, '2025-08-12 10:00:00', '2025-08-22 10:00:00', NULL, '[18]', '["Camera"]'),
+('peggy', 1013, '2025-08-13 11:00:00', '2025-08-23 11:00:00', NULL, '[19,20]', '["Tripod","Microphone"]'),
+('trent', 1014, '2025-08-14 12:00:00', '2025-08-24 12:00:00', NULL, '[1]', '["Laptop"]'),
+('victor', 1015, '2025-08-15 13:00:00', '2025-08-25 13:00:00', NULL, '[2,3]', '["Projector","Tablet"]'),
+('wendy', 1016, '2025-08-16 14:00:00', '2025-08-26 14:00:00', NULL, '[4]', '["Camera"]'),
+('zoe', 1017, '2025-08-17 15:00:00', '2025-08-27 15:00:00', NULL, '[5,6]', '["Tripod","Microphone"]'),
+('quinn', 1018, '2025-08-18 16:00:00', '2025-08-28 16:00:00', NULL, '[7]', '["Speaker"]'),
+('ruth', 1019, '2025-08-19 17:00:00', '2025-08-29 17:00:00', NULL, '[8,9]', '["Monitor","Keyboard"]'),
+('sam', 1020, '2025-08-20 18:00:00', '2025-08-30 18:00:00', NULL, '[10]', '["Mouse"]');
 
--- Items
+-- Mock data for items
-INSERT INTO items (item_name, can_borrow_role) VALUES
+INSERT INTO `items` (`item_name`, `can_borrow_role`, `inSafe`) VALUES
-('Laptop', 'student'),
+('Laptop', 1, 1),
-('Projector', 'teacher'),
+('Projector', 2, 1),
-('Tablet', 'student,teacher');
+('Tablet', 1, 1),
+('Camera', 2, 1),
+('Tripod', 1, 1),
+('Microphone', 3, 1),
+('Speaker', 2, 1),
+('Monitor', 1, 1),
+('Keyboard', 2, 1),
+('Mouse', 1, 1),
+('Printer', 3, 1),
+('Scanner', 2, 1),
+('Router', 1, 1),
+('Switch', 2, 1),
+('Charger', 1, 1),
+('USB Cable', 2, 1),
+('HDMI Cable', 1, 1),
+('Webcam', 3, 1),
+('Headphones', 2, 1),
+('Smartphone', 1, 1);
 
--- Loans
+-- Mock data for lockers
-INSERT INTO loans (username, loan_code, start_date, end_date, returned_date) VALUES
+INSERT INTO `lockers` (`item`, `locker_number`) VALUES
-('alice', 100001, '2025-08-01 09:00:00', '2025-08-10 17:00:00', NULL),
-('bob', 100002, '2025-08-05 10:00:00', '2025-08-12 15:00:00', '2025-08-12 14:30:00'),
-('charlie', 100003, '2025-08-07 11:00:00', '2025-08-15 16:00:00', NULL);
-
--- Lockers
-INSERT INTO lockers (item, locker_number) VALUES
 ('Laptop', 101),
 ('Projector', 102),
-('Tablet', 103);
+('Tablet', 103),
+('Camera', 104),
+('Tripod', 105),
+('Microphone', 106),
+('Speaker', 107),
+('Monitor', 108),
+('Keyboard', 109),
+('Mouse', 110),
+('Printer', 111),
+('Scanner', 112),
+('Router', 113),
+('Switch', 114),
+('Charger', 115),
+('USB Cable', 116),
+('HDMI Cable', 117),
+('Webcam', 118),
+('Headphones', 119),
+('Smartphone', 120);

backend/services/database.js

@@ -41,3 +41,211 @@ export const getItemsFromDatabase = async (role) => {
   }
   return { success: false };
 };
+
+export const getLoansFromDatabase = async () => {
+  const [result] = await pool.query("SELECT * FROM loans;");
+  if (result.length > 0) {
+    return { success: true, data: result };
+  }
+  return { success: false };
+};
+
+export const getUserLoansFromDatabase = async (username) => {
+  const [result] = await pool.query("SELECT * FROM loans WHERE username = ?;", [
+    username,
+  ]);
+  if (result.length > 0) {
+    return { success: true, data: result };
+  } else if (result.length == 0) {
+    return { success: true, data: "No loans found for this user" };
+  } else {
+    return { success: false };
+  }
+};
+
+export const deleteLoanFromDatabase = async (loanId) => {
+  const [result] = await pool.query("DELETE FROM loans WHERE id = ?;", [
+    loanId,
+  ]);
+  if (result.affectedRows > 0) {
+    return { success: true };
+  } else {
+    return { success: false };
+  }
+};
+
+export const getBorrowableItemsFromDatabase = async (
+  startDate,
+  endDate,
+  role = 0
+) => {
+  // Overlap if: loan.start < end AND effective_end > start
+  // effective_end is returned_date if set, otherwise end_date
+  const hasRoleFilter = Number(role) > 0;
+
+  const sql = `
+    SELECT i.*
+    FROM items i
+    WHERE ${hasRoleFilter ? "i.can_borrow_role >= ? AND " : ""}NOT EXISTS (
+      SELECT 1
+      FROM loans l
+      JOIN JSON_TABLE(l.loaned_items_id, '$[*]' COLUMNS (item_id INT PATH '$')) jt
+      WHERE jt.item_id = i.id
+        AND l.start_date < ?
+        AND COALESCE(l.returned_date, l.end_date) > ?
+    );
+  `;
+
+  const params = hasRoleFilter
+    ? [role, endDate, startDate]
+    : [endDate, startDate];
+
+  const [rows] = await pool.query(sql, params);
+  if (rows.length > 0) {
+    return { success: true, data: rows };
+  }
+  return { success: false };
+};
+
+export const createLoanInDatabase = async (
+  username,
+  startDate,
+  endDate,
+  itemIds
+) => {
+  if (!username)
+    return { success: false, code: "BAD_REQUEST", message: "Missing username" };
+  if (!Array.isArray(itemIds) || itemIds.length === 0)
+    return {
+      success: false,
+      code: "BAD_REQUEST",
+      message: "No items provided",
+    };
+  if (!startDate || !endDate)
+    return { success: false, code: "BAD_REQUEST", message: "Missing dates" };
+
+  const start = new Date(startDate);
+  const end = new Date(endDate);
+  if (
+    !(start instanceof Date) ||
+    isNaN(start.getTime()) ||
+    !(end instanceof Date) ||
+    isNaN(end.getTime()) ||
+    start >= end
+  ) {
+    return {
+      success: false,
+      code: "BAD_REQUEST",
+      message: "Invalid date range",
+    };
+  }
+
+  const conn = await pool.getConnection();
+  try {
+    await conn.beginTransaction();
+
+    // Ensure all items exist and collect names
+    const [itemsRows] = await conn.query(
+      "SELECT id, item_name FROM items WHERE id IN (?)",
+      [itemIds]
+    );
+    if (!itemsRows || itemsRows.length !== itemIds.length) {
+      await conn.rollback();
+      return {
+        success: false,
+        code: "BAD_REQUEST",
+        message: "One or more items not found",
+      };
+    }
+    const itemNames = itemIds
+      .map(
+        (id) => itemsRows.find((r) => Number(r.id) === Number(id))?.item_name
+      )
+      .filter(Boolean);
+
+    // Check availability (no overlap with existing loans)
+    const [confRows] = await conn.query(
+      `
+      SELECT COUNT(*) AS conflicts
+      FROM loans l
+      JOIN JSON_TABLE(l.loaned_items_id, '$[*]' COLUMNS (item_id INT PATH '$')) jt
+        ON TRUE
+      WHERE jt.item_id IN (?)
+        AND l.start_date < ?
+        AND COALESCE(l.returned_date, l.end_date) > ?
+      `,
+      [itemIds, end, start]
+    );
+    if (confRows?.[0]?.conflicts > 0) {
+      await conn.rollback();
+      return {
+        success: false,
+        code: "CONFLICT",
+        message: "One or more items are not available in the selected period",
+      };
+    }
+
+    // Generate unique loan_code (retry a few times)
+    let loanCode = null;
+    for (let i = 0; i < 6; i++) {
+      const candidate = Math.floor(1000 + Math.random() * 900000); // 4-6 digits
+      const [exists] = await conn.query(
+        "SELECT 1 FROM loans WHERE loan_code = ? LIMIT 1",
+        [candidate]
+      );
+      if (exists.length === 0) {
+        loanCode = candidate;
+        break;
+      }
+    }
+    if (!loanCode) {
+      await conn.rollback();
+      return {
+        success: false,
+        code: "SERVER_ERROR",
+        message: "Failed to generate unique loan code",
+      };
+    }
+
+    // Insert loan
+    const [insertRes] = await conn.query(
+      `
+      INSERT INTO loans (username, loan_code, start_date, end_date, loaned_items_id, loaned_items_name)
+      VALUES (?, ?, ?, ?, CAST(? AS JSON), CAST(? AS JSON))
+      `,
+      [
+        username,
+        loanCode,
+        // Use DATETIME/TIMESTAMP friendly format
+        new Date(start).toISOString().slice(0, 19).replace("T", " "),
+        new Date(end).toISOString().slice(0, 19).replace("T", " "),
+        JSON.stringify(itemIds.map((n) => Number(n))),
+        JSON.stringify(itemNames),
+      ]
+    );
+
+    await conn.commit();
+    return {
+      success: true,
+      data: {
+        id: insertRes.insertId,
+        loan_code: loanCode,
+        username,
+        start_date: start,
+        end_date: end,
+        items: itemIds,
+        item_names: itemNames,
+      },
+    };
+  } catch (err) {
+    await conn.rollback();
+    console.error("createLoanInDatabase error:", err);
+    return {
+      success: false,
+      code: "SERVER_ERROR",
+      message: "Failed to create loan",
+    };
+  } finally {
+    conn.release();
+  }
+};

frontend/src/App.tsx

@@ -3,7 +3,7 @@ import Layout from "./layout/Layout";
 import { useEffect, useState } from "react";
 import Form1 from "./components/Form1";
 import Form2 from "./components/Form2";
-import Form3 from "./components/Form3";
+import Form4 from "./components/Form4";
 import LoginForm from "./components/LoginForm";
 import Cookies from "js-cookie";
 import { fetchAllData, ALL_ITEMS_UPDATED_EVENT } from "./utils/fetchData";
@@ -20,13 +20,15 @@ function App() {
     }
 
     localStorage.setItem("borrowableItems", JSON.stringify([]));
-    localStorage.setItem("borrowCode", "123456");
   }, []);
 
   // Mock flow without real logic: show the three sections stacked for design preview
   const handleLogout = () => {
     Cookies.remove("token");
     localStorage.removeItem("allItems");
+    localStorage.removeItem("allLoans");
+    localStorage.removeItem("userLoans");
+    localStorage.removeItem("borrowableItems");
     // Let listeners refresh from empty state
     window.dispatchEvent(new Event(ALL_ITEMS_UPDATED_EVENT));
     myToast("Logged out successfully!", "success");
@@ -40,7 +42,7 @@ function App() {
         <div className="h-px bg-blue-100" />
         <Form2 />
         <div className="h-px bg-blue-100" />
-        <Form3 />
+        <Form4 />
       </div>
     </Layout>
   ) : (

frontend/src/components/Form1.tsx

@@ -1,10 +1,25 @@
 import React from "react";
+import Cookies from "js-cookie";
+import { getBorrowableItems } from "../utils/fetchData";
 
 const Form1: React.FC = () => {
   return (
     <div className="space-y-6">
       <h2 className="text-xl font-bold text-blue-700">1. Zeitraum wählen</h2>
-      <form className="space-y-4">
+      <form
+        className="space-y-4"
+        onSubmit={(e) => {
+          e.preventDefault();
+          const form = e.currentTarget as HTMLFormElement;
+          const fd = new FormData(form);
+          const start = (fd.get("startDate") as string) || "";
+          const end = (fd.get("endDate") as string) || "";
+          Cookies.set("startDate", start);
+          Cookies.set("endDate", end);
+          getBorrowableItems();
+          console.log("Zeitraum erfolgreich gesetzt!");
+        }}
+      >
         <div>
           <label
             htmlFor="startDate"
@@ -15,6 +30,7 @@ const Form1: React.FC = () => {
           <input
             type="datetime-local"
             id="startDate"
+            name="startDate"
             className="w-full border border-blue-200 rounded-lg px-3 py-2 focus:ring-2 focus:ring-blue-400 focus:outline-none bg-white/70"
           />
         </div>
@@ -28,6 +44,7 @@ const Form1: React.FC = () => {
           <input
             type="datetime-local"
             id="endDate"
+            name="endDate"
             className="w-full border border-blue-200 rounded-lg px-3 py-2 focus:ring-2 focus:ring-blue-400 focus:outline-none bg-white/70"
           />
         </div>

frontend/src/components/Form2.tsx

@@ -1,59 +1,170 @@
 import React from "react";
+import Cookies from "js-cookie";
+import { createLoan } from "../utils/userHandler";
+import { addToRemove, rmFromRemove } from "../utils/userHandler";
+import { BORROWABLE_ITEMS_UPDATED_EVENT } from "../utils/fetchData";
+
+interface BorrowItem {
+  id: number;
+  item_name: string;
+  can_borrow_role: string;
+  inSafe: number;
+}
+
+const LOCAL_STORAGE_KEY = "borrowableItems";
+
+// Einfache Type-Guard/Validierung
+const isBorrowItem = (v: any): v is BorrowItem =>
+  v &&
+  typeof v.id === "number" &&
+  (typeof v.item_name === "string" || typeof v.name === "string") &&
+  (typeof v.can_borrow_role === "string" || typeof v.role === "string");
+
+// Helfer: unterschiedliche Server-Shapes normalisieren
+function normalizeBorrowable(data: any): BorrowItem[] {
+  const rawArr = Array.isArray(data)
+    ? data
+    : Array.isArray(data?.items)
+    ? data.items
+    : Array.isArray(data?.data)
+    ? data.data
+    : [];
+
+  return rawArr
+    .map((raw: any) => {
+      const idRaw =
+        raw.id ?? raw.item_id ?? raw.itemId ?? raw.itemID ?? raw.itemIdPk;
+      const id = Number(idRaw);
+      const item_name = String(raw.item_name ?? raw.name ?? raw.title ?? "");
+      const can_borrow_role = String(
+        raw.can_borrow_role ?? raw.role ?? raw.requiredRole ?? ""
+      );
+      const inSafeRaw =
+        raw.inSafe ?? raw.in_safe ?? raw.inLocker ?? raw.isInSafe ?? raw.safe;
+      const inSafe =
+        typeof inSafeRaw === "boolean"
+          ? Number(inSafeRaw)
+          : Number(isNaN(Number(inSafeRaw)) ? 0 : Number(inSafeRaw));
+
+      if (!Number.isFinite(id) || !item_name) return null;
+      return { id, item_name, can_borrow_role, inSafe };
+    })
+    .filter(Boolean) as BorrowItem[];
+}
+
+// Hook, der automatisch aus dem Local Storage liest und auf Änderungen hört
+function useBorrowableItems() {
+  const [items, setItems] = React.useState<BorrowItem[]>([]);
+
+  const readFromStorage = React.useCallback(() => {
+    try {
+      const raw = localStorage.getItem(LOCAL_STORAGE_KEY) || "[]";
+      const parsed = JSON.parse(raw);
+      const arr = normalizeBorrowable(parsed);
+      setItems(arr);
+    } catch {
+      setItems([]);
+    }
+  }, []);
+
+  React.useEffect(() => {
+    // Initial read
+    readFromStorage();
+
+    // Cross-tab updates
+    const onStorage = (e: StorageEvent) => {
+      if (e.key === LOCAL_STORAGE_KEY) readFromStorage();
+    };
+    window.addEventListener("storage", onStorage);
+
+    // Same-tab updates via Custom Event
+    const onBorrowableUpdated = () => readFromStorage();
+    window.addEventListener(
+      BORROWABLE_ITEMS_UPDATED_EVENT,
+      onBorrowableUpdated
+    );
+
+    return () => {
+      window.removeEventListener("storage", onStorage);
+      window.removeEventListener(
+        BORROWABLE_ITEMS_UPDATED_EVENT,
+        onBorrowableUpdated
+      );
+    };
+  }, [readFromStorage]);
+
+  return items;
+}
 
 const Form2: React.FC = () => {
-  const items = JSON.parse(localStorage.getItem("borrowableItems") || "[]");
+  const items = useBorrowableItems();
+
   return (
     <div className="space-y-6">
       <h2 className="text-xl font-bold text-blue-700">
         2. Gegenstand auswählen
       </h2>
-      <form className="space-y-4">
-        {items.length === 0 ? (
-          <div className="text-red-600 font-medium text-center bg-red-50 border border-red-200 rounded-xl p-4">
-            Keine Gegenstände verfügbar für diesen Zeitraum.
-          </div>
-        ) : (
-          <div className="grid grid-cols-1 sm:grid-cols-2 gap-4">
-            {items.map((item: any) => (
-              <label
-                key={item.id}
-                htmlFor={String(item.id)}
-                className="group cursor-pointer bg-white/80 rounded-xl p-4 shadow hover:shadow-md transition border border-blue-100 flex items-start gap-3"
-              >
-                <input
-                  type="checkbox"
-                  name={String(item.id)}
-                  id={String(item.id)}
-                  className="mt-1 h-4 w-4 rounded border-blue-300 text-blue-600 focus:ring-blue-400"
-                />
-                <div>
-                  <h3 className="text-sm font-semibold text-blue-800">
-                    {item.title}
-                  </h3>
-                  <p className="text-xs text-blue-500/80 line-clamp-2">
-                    {item.description}
-                  </p>
-                </div>
-              </label>
-            ))}
-          </div>
-        )}
 
-        <div className="flex flex-col sm:flex-row gap-3 pt-2">
+      {items.length === 0 ? (
-          <button
+        <div className="text-red-600 font-medium text-center bg-red-50 border border-red-200 rounded-xl p-4">
-            type="button"
+          Keine Gegenstände verfügbar für diesen Zeitraum.
-            className="flex-1 sm:flex-none sm:w-36 bg-white text-blue-700 border border-blue-200 hover:bg-blue-50 font-medium py-2 px-4 rounded-xl shadow-sm transition"
-          >
-            Zurück
-          </button>
-          <button
-            type="submit"
-            className="flex-1 sm:flex-none sm:w-40 bg-gradient-to-r from-blue-600 to-blue-400 hover:from-blue-700 hover:to-blue-500 text-white font-bold py-2 px-4 rounded-xl shadow transition"
-          >
-            Ausleihen
-          </button>
         </div>
-      </form>
+      ) : (
+        <div className="overflow-x-auto rounded-xl border border-blue-100 shadow-sm bg-white/80">
+          <table className="min-w-full divide-y divide-blue-100">
+            <thead className="bg-blue-50/60">
+              <tr>
+                <th className="px-4 py-2 text-left text-xs font-semibold text-blue-700">
+                  Gegenstand
+                </th>
+                <th className="px-4 py-2 text-left text-xs font-semibold text-blue-700">
+                  <input type="checkbox" className="invisible" />
+                </th>
+              </tr>
+            </thead>
+            <tbody className="divide-y divide-blue-50">
+              {items.map((item) => (
+                <tr
+                  key={item.id}
+                  className="hover:bg-blue-50/40 transition-colors"
+                >
+                  <td className="px-4 py-2 text-sm font-medium text-blue-900">
+                    {item.item_name}
+                  </td>
+                  <td className="px-4 py-2 text-sm text-blue-700">
+                    <input
+                      type="checkbox"
+                      onChange={(e) => {
+                        if (e.target.checked) {
+                          addToRemove(item.id);
+                        } else {
+                          rmFromRemove(item.id);
+                        }
+                      }}
+                      id={`item-${item.id}`}
+                    />
+                  </td>
+                </tr>
+              ))}
+            </tbody>
+          </table>
+        </div>
+      )}
+
+      <div className="flex flex-col sm:flex-row gap-3 pt-2">
+        <button
+          onClick={() => {
+            createLoan(
+              Cookies.get("startDate") ?? "",
+              Cookies.get("endDate") ?? ""
+            );
+          }}
+          type="button"
+          className="flex-1 sm:flex-none sm:w-40 bg-gradient-to-r from-blue-600 to-blue-400 hover:from-blue-700 hover:to-blue-500 text-white font-bold py-2 px-4 rounded-xl shadow transition"
+        >
+          Ausleihen
+        </button>
+      </div>
     </div>
   );
 };

frontend/src/components/Form3.tsx

@@ -1,22 +0,0 @@
-import React from "react";
-
-const Form3: React.FC = () => {
-  const code = localStorage.getItem("borrowCode") ?? "—";
-
-  return (
-    <div className="space-y-4">
-      <h2 className="text-xl font-bold text-blue-700">3. Ausleihe bestätigt</h2>
-      <div className="mt-2 p-6 bg-blue-50/80 border border-blue-200 rounded-2xl text-center shadow-lg">
-        <p className="text-blue-800 font-semibold">Ihr Ausleihcode lautet</p>
-        <div className="text-3xl font-extrabold tracking-widest text-blue-700 mt-1">
-          {code}
-        </div>
-        <p className="text-blue-600 mt-2 text-sm">
-          Bitte merken Sie sich diesen Code, um das Schließfach zu öffnen.
-        </p>
-      </div>
-    </div>
-  );
-};
-
-export default Form3;

frontend/src/components/Form4.tsx

@@ -0,0 +1,161 @@
+import React, { useEffect, useState } from "react";
+import { Trash, ArrowLeftRight } from "lucide-react";
+import { handleDeleteLoan } from "../utils/userHandler";
+
+type Loan = {
+  id: number;
+  username: string;
+  loan_code: number;
+  start_date: string;
+  end_date: string;
+  returned_date: string | null;
+  created_at: string;
+  loaned_items_id: number[];
+  loaned_items_name: string[];
+};
+
+const formatDate = (iso: string | null) => {
+  if (!iso) return "-";
+  const d = new Date(iso);
+  if (Number.isNaN(d.getTime())) return iso;
+  return d.toLocaleString("de-DE", { dateStyle: "short", timeStyle: "short" });
+};
+
+const readUserLoansFromStorage = (): Loan[] => {
+  const raw = localStorage.getItem("userLoans");
+  if (!raw || raw === '"No loans found for this user"') return [];
+  try {
+    const parsed = JSON.parse(raw);
+    return Array.isArray(parsed) ? (parsed as Loan[]) : [];
+  } catch {
+    return [];
+  }
+};
+
+const Form4: React.FC = () => {
+  const [userLoans, setUserLoans] = useState<Loan[]>(() =>
+    readUserLoansFromStorage()
+  );
+
+  // Keep in sync if localStorage changes (e.g., other tabs or parts of the app)
+  useEffect(() => {
+    const onStorage = (e: StorageEvent) => {
+      if (e.key === "userLoans") {
+        setUserLoans(readUserLoansFromStorage());
+      }
+    };
+    window.addEventListener("storage", onStorage);
+    return () => window.removeEventListener("storage", onStorage);
+  }, []);
+
+  const onDelete = async (loanID: number) => {
+    const ok = await handleDeleteLoan(loanID);
+    if (ok) {
+      setUserLoans((prev) =>
+        prev.filter((l) => Number(l.id) !== Number(loanID))
+      );
+    }
+  };
+
+  if (userLoans.length === 0) {
+    return (
+      <div className="rounded-xl border border-gray-200 bg-white p-6 text-center text-gray-600 shadow-sm">
+        <p>Keine Ausleihen gefunden.</p>
+      </div>
+    );
+  }
+
+  return (
+    <div className="space-y-3">
+      <p className="text-lg font-semibold tracking-tight text-gray-900">
+        Meine Ausleihen
+      </p>
+      <p className="text-sm text-gray-600">
+        Wenn du eine Ausleihe ändern oder löschen möchtest, klicke auf das
+        Papierkorb-Symbol.
+      </p>
+
+      <div className="rounded-xl border border-gray-200 bg-white shadow-sm">
+        <div className="overflow-x-auto">
+          <table className="min-w-full text-sm text-gray-700">
+            <thead className="sticky top-0 z-10 bg-gray-50">
+              <tr className="border-b border-gray-200">
+                <th className="px-4 py-3 text-left text-xs font-semibold uppercase tracking-wider text-gray-600">
+                  Leihcode
+                </th>
+                <th className="px-4 py-3 text-left text-xs font-semibold uppercase tracking-wider text-gray-600">
+                  Start
+                </th>
+                <th className="px-4 py-3 text-left text-xs font-semibold uppercase tracking-wider text-gray-600">
+                  Ende
+                </th>
+                <th className="px-4 py-3 text-left text-xs font-semibold uppercase tracking-wider text-gray-600">
+                  Zurückgegeben
+                </th>
+                <th className="px-4 py-3 text-left text-xs font-semibold uppercase tracking-wider text-gray-600">
+                  Erstellt
+                </th>
+                <th className="px-4 py-3 text-left text-xs font-semibold uppercase tracking-wider text-gray-600">
+                  Gegenstände
+                </th>
+                <th className="px-4 py-3 text-right text-xs font-semibold uppercase tracking-wider text-gray-600">
+                  Aktionen
+                </th>
+              </tr>
+            </thead>
+            <tbody className="divide-y divide-gray-100">
+              {userLoans.map((loan) => (
+                <tr
+                  key={loan.id}
+                  className="odd:bg-white even:bg-gray-50 hover:bg-gray-100/60 transition-colors"
+                >
+                  <td className="px-4 py-3 whitespace-nowrap font-mono tabular-nums text-gray-900">
+                    {loan.loan_code}
+                  </td>
+                  <td className="px-4 py-3 whitespace-nowrap font-mono tabular-nums text-gray-900">
+                    {formatDate(loan.start_date)}
+                  </td>
+                  <td className="px-4 py-3 whitespace-nowrap font-mono tabular-nums text-gray-900">
+                    {formatDate(loan.end_date)}
+                  </td>
+                  <td className="px-4 py-3 whitespace-nowrap font-mono tabular-nums text-gray-900">
+                    {formatDate(loan.returned_date)}
+                  </td>
+                  <td className="px-4 py-3 whitespace-nowrap font-mono tabular-nums text-gray-900">
+                    {formatDate(loan.created_at)}
+                  </td>
+                  <td className="px-4 py-3">
+                    <div className="max-w-[22rem] truncate text-gray-900">
+                      {Array.isArray(loan.loaned_items_name)
+                        ? loan.loaned_items_name.join(", ")
+                        : "-"}
+                    </div>
+                  </td>
+                  <td className="px-4 py-3 text-right">
+                    <button
+                      onClick={() => onDelete(loan.id)}
+                      aria-label="Ausleihe löschen"
+                      className="inline-flex items-center rounded-md p-2 text-gray-500 hover:bg-red-50 hover:text-red-600 focus:outline-none focus:ring-2 focus:ring-red-500/30"
+                    >
+                      <Trash className="h-4 w-4" />
+                    </button>
+                  </td>
+                </tr>
+              ))}
+            </tbody>
+          </table>
+        </div>
+
+        {/* Scroll hint */}
+        <div className="border-t border-gray-100 px-4 py-2">
+          <div className="flex items-center gap-2 text-xs text-gray-500">
+            <ArrowLeftRight className="h-4 w-4 text-gray-400" />
+            <span>Hinweis: Horizontal scrollen, um alle Spalten zu sehen.</span>
+          </div>
+        </div>
+      </div>
+    </div>
+  );
+};
+
+export default Form4;

frontend/src/components/Object.tsx

@@ -7,12 +7,9 @@ type ObjectProps = {
 
 const Object: React.FC<ObjectProps> = ({ title, description }) => {
   return (
-    <div className="flex items-start gap-3">
+    <div>
-      <div className="shrink-0 w-3 h-3 mt-1.5 rounded-full bg-green-400" />
+      <h3 className="text-sm font-semibold text-blue-800">{title}</h3>
-      <div>
+      <p className="text-xs text-blue-500/80 line-clamp-2">{description}</p>
-        <h3 className="text-sm font-semibold text-blue-800">{title}</h3>
-        <p className="text-xs text-blue-500/80 line-clamp-2">{description}</p>
-      </div>
     </div>
   );
 };

frontend/src/components/Sidebar.tsx

@@ -18,37 +18,67 @@ const Sidebar: React.FC = () => {
     return () => window.removeEventListener(ALL_ITEMS_UPDATED_EVENT, handler);
   }, []);
 
+  const outCount = items.reduce((n, it) => n + (it.inSafe ? 0 : 1), 0);
+  const sorted = [...items].sort((a, b) => Number(a.inSafe) - Number(b.inSafe)); // außerhalb zuerst
+
   return (
-    <aside className="w-full md:w-80 md:min-h-screen bg-white/90 backdrop-blur md:border-r border-blue-100 shadow-xl flex flex-col p-6">
+    <aside className="w-full md:w-80 md:h-screen md:sticky md:top-0 overflow-y-auto bg-white/90 backdrop-blur md:border-r border-blue-100 shadow-xl flex flex-col p-6">
-      <h2 className="text-2xl font-extrabold mb-4 text-blue-700 tracking-tight flex items-center gap-2">
+      <h2 className="text-2xl font-extrabold mb-4 text-blue-700 tracking-tight flex items-center justify-between">
-        <svg
+        <span className="flex items-center gap-2">
-          className="w-6 h-6 text-blue-500"
+          <svg
-          fill="none"
+            className="w-6 h-6 text-blue-500"
-          stroke="currentColor"
+            fill="none"
-          strokeWidth={2}
+            stroke="currentColor"
-          viewBox="0 0 24 24"
+            strokeWidth={2}
-        >
+            viewBox="0 0 24 24"
-          <path
+          >
-            strokeLinecap="round"
+            <path
-            strokeLinejoin="round"
+              strokeLinecap="round"
-            d="M16.5 7.5V4.75A2.25 2.25 0 0 0 14.25 2.5h-4.5A2.25 2.25 0 0 0 7.5 4.75V7.5m9 0h-9m9 0v11.75A2.25 2.25 0 0 1 14.25 21.5h-4.5A2.25 2.25 0 0 1 7.5 19.25V7.5m9 0h-9"
+              strokeLinejoin="round"
-          />
+              d="M16.5 7.5V4.75A2.25 2.25 0 0 0 14.25 2.5h-4.5A2.25 2.25 0 0 0 7.5 4.75V7.5m9 0h-9m9 0v11.75A2.25 2.25 0 0 1 14.25 21.5h-4.5A2.25 2.25 0 0 1 7.5 19.25V7.5m9 0h-9"
-        </svg>
+            />
-        Geräte Übersicht
+          </svg>
+          Geräte Übersicht
+        </span>
+        {outCount > 0 && (
+          <span className="text-xs px-2 py-0.5 rounded-full bg-red-100 text-red-700">
+            {outCount} außerhalb
+          </span>
+        )}
       </h2>
 
-      <div className="space-y-4 flex-1 overflow-auto pr-1">
+      <div className="space-y-4 flex-1 pr-1">
-        {items.map((item: any) => (
+        {sorted.map((item: any) => (
           <div
             key={item.item_name}
-            className="bg-white/80 rounded-xl p-4 shadow hover:shadow-md transition"
+            className={`bg-white/80 rounded-xl p-4 shadow hover:shadow-md transition ${
+              item.inSafe ? "" : "ring-1 ring-red-200"
+            }`}
           >
-            <Object
+            <div className="flex items-start gap-3">
-              title={item.item_name}
+              <span className="relative mt-1 inline-flex" aria-hidden="true">
-              description={
+                {!item.inSafe && (
-                item.inSafe ? "Im Schließfach" : "Nicht im Schließfach"
+                  <span className="absolute inline-flex h-3 w-3 rounded-full bg-red-400 opacity-75 animate-ping"></span>
-              }
+                )}
-            />
+                <span
+                  className={`inline-block w-3 h-3 rounded-full ${
+                    item.inSafe ? "bg-green-400" : "bg-red-500"
+                  }`}
+                  title={
+                    item.inSafe ? "Im Schließfach" : "Nicht im Schließfach"
+                  }
+                  aria-label={
+                    item.inSafe ? "Im Schließfach" : "Nicht im Schließfach"
+                  }
+                />
+              </span>
+              <Object
+                title={item.item_name}
+                description={
+                  item.inSafe ? "Im Schließfach" : "Nicht im Schließfach"
+                }
+              />
+            </div>
           </div>
         ))}
       </div>

frontend/src/utils/fetchData.ts

@@ -3,11 +3,12 @@ import { myToast } from "./toastify";
 
 // Event name used to notify the app when the list of items has been updated
 export const ALL_ITEMS_UPDATED_EVENT = "allItemsUpdated";
+export const BORROWABLE_ITEMS_UPDATED_EVENT = "borrowableItemsUpdated";
 
 export const fetchAllData = async (token: string | undefined) => {
   if (!token) return;
+  // First we fetch all items that are potentially available for borrowing
   try {
-    // First we fetch all items that are potentially available for borrowing
     const response = await fetch("http://localhost:8002/api/items", {
       method: "GET",
       headers: {
@@ -27,6 +28,50 @@ export const fetchAllData = async (token: string | undefined) => {
   } catch (error) {
     myToast("An error occurred", "error");
   }
+
+  // get all loans
+  try {
+    const response = await fetch("http://localhost:8002/api/loans", {
+      method: "GET",
+      headers: {
+        Authorization: `Bearer ${token}`,
+      },
+    });
+
+    if (!response.ok) {
+      myToast("Failed to fetch loans!", "error");
+      return;
+    }
+
+    const data = await response.json();
+    localStorage.setItem("allLoans", JSON.stringify(data));
+    // Notify listeners (e.g., Sidebar) that loans have been updated
+    window.dispatchEvent(new Event(ALL_ITEMS_UPDATED_EVENT));
+  } catch (error) {
+    myToast("An error occurred", "error");
+  }
+
+  // get user loans
+  try {
+    const response = await fetch("http://localhost:8002/api/userLoans", {
+      method: "GET",
+      headers: {
+        Authorization: `Bearer ${token}`,
+      },
+    });
+
+    if (!response.ok) {
+      myToast("Failed to fetch user loans!", "error");
+      return;
+    }
+
+    const data = await response.json();
+    localStorage.setItem("userLoans", JSON.stringify(data));
+    // Notify listeners (e.g., Sidebar) that loans have been updated
+    window.dispatchEvent(new Event(ALL_ITEMS_UPDATED_EVENT));
+  } catch (error) {
+    myToast("An error occurred", "error");
+  }
 };
 
 export const loginUser = async (username: string, password: string) => {
@@ -56,3 +101,37 @@ export const loginUser = async (username: string, password: string) => {
     return { success: false } as const;
   }
 };
+
+export const getBorrowableItems = async () => {
+  const startDate = Cookies.get("startDate");
+  const endDate = Cookies.get("endDate");
+
+  if (!startDate || !endDate) {
+    myToast("Bitte wähle einen Zeitraum aus.", "error");
+    return;
+  }
+
+  try {
+    const response = await fetch("http://localhost:8002/api/borrowableItems", {
+      method: "POST",
+      headers: {
+        Authorization: `Bearer ${Cookies.get("token") || ""}`,
+        "Content-Type": "application/json",
+        Accept: "application/json",
+      },
+      body: JSON.stringify({ startDate, endDate }),
+    });
+
+    if (!response.ok) {
+      myToast("Failed to fetch borrowable items", "error");
+      return;
+    }
+
+    const data = await response.json();
+    localStorage.setItem("borrowableItems", JSON.stringify(data));
+    window.dispatchEvent(new Event(BORROWABLE_ITEMS_UPDATED_EVENT)); // notify same-tab listeners
+    console.log("Borrowable items fetched successfully");
+  } catch (error) {
+    myToast("An error occurred", "error");
+  }
+};

frontend/src/utils/userHandler.ts

@@ -0,0 +1,96 @@
+import { myToast } from "./toastify";
+import Cookies from "js-cookie";
+
+export const handleDeleteLoan = async (loanID: number): Promise<boolean> => {
+  try {
+    const response = await fetch(
+      `http://localhost:8002/api/deleteLoan/${loanID}`,
+      {
+        method: "DELETE",
+        headers: {
+          Authorization: `Bearer ${Cookies.get("token") || ""}`,
+        },
+      }
+    );
+
+    if (!response.ok) {
+      myToast("Fehler beim Löschen der Ausleihe", "error");
+      return false;
+    }
+
+    const raw = localStorage.getItem("userLoans");
+    let current: Array<{ id: number }> = [];
+
+    try {
+      const parsed = raw ? JSON.parse(raw) : [];
+      current = Array.isArray(parsed) ? parsed : [];
+    } catch {
+      current = [];
+    }
+
+    const updated = current.filter(
+      (loan) => Number(loan.id) !== Number(loanID)
+    );
+    localStorage.setItem("userLoans", JSON.stringify(updated));
+
+    myToast("Ausleihe erfolgreich gelöscht!", "success");
+    return true;
+  } catch (error) {
+    console.error("Error deleting loan:", error);
+    myToast("Fehler beim löschen der Ausleihe", "error");
+    return false;
+  }
+};
+
+// Parse existing cookie and coerce to numbers
+let removeArr: number[] = (() => {
+  try {
+    const raw = Cookies.get("removeArr");
+    const parsed = raw ? JSON.parse(raw) : [];
+    return Array.isArray(parsed)
+      ? parsed.map((v) => Number(v)).filter((n) => Number.isFinite(n))
+      : [];
+  } catch {
+    return [];
+  }
+})();
+
+const rawCookies = Cookies.withConverter({
+  write: (value: string) => value, // store raw JSON
+});
+
+export const addToRemove = (itemID: number) => {
+  if (!Number.isFinite(itemID)) return;
+  if (!removeArr.includes(itemID)) {
+    removeArr.push(itemID);
+    rawCookies.set("removeArr", JSON.stringify(removeArr));
+  }
+};
+
+export const rmFromRemove = (itemID: number) => {
+  removeArr = removeArr.filter((item) => item !== itemID);
+  rawCookies.set("removeArr", JSON.stringify(removeArr));
+};
+
+export const createLoan = async (startDate: string, endDate: string) => {
+  const items = removeArr;
+  const response = await fetch("http://localhost:8002/api/createLoan", {
+    method: "POST",
+    headers: {
+      "Content-Type": "application/json",
+      Authorization: `Bearer ${Cookies.get("token") || ""}`,
+    },
+    body: JSON.stringify({ items, startDate, endDate }),
+  });
+
+  if (!response.ok) {
+    myToast("Fehler beim Erstellen der Ausleihe", "error");
+    return false;
+  }
+
+  // Clear selection on success
+  removeArr = [];
+  Cookies.set("removeArr", "[]");
+  myToast("Ausleihe erfolgreich erstellt!", "success");
+  return true;
+};