borrow.php

<?php
session_start();
include 'includes/db.php';
/** @var mysqli $conn */

// 1. Security Check: Only logged-in users can borrow
if (!isset($_SESSION['user_id'])) {
    header("Location: login.php");
    exit();
}

// 2. Capture the Book ID from the link (e.g., borrow.php?book_id=5)
if (isset($_GET['book_id'])) {
    $book_id = (int)$_GET['book_id']; // Cast to integer for safety
    $user_id = $_SESSION['user_id'];

    // 3. Automated Dates (Matching your table columns)
    $issue_date = date('Y-m-d');
    $return_date = date('Y-m-d', strtotime('+14 days'));
    $status = 'Borrowed';

    // 4. Prepared Statement for your 'transactions' table
    $query = "INSERT INTO transactions (user_id, book_id, issue_date, return_date, status) VALUES (?, ?, ?, ?, ?)";
    $stmt = $conn->prepare($query);

    // "ii" for two integers, "sss" for three strings (dates & status)
    $stmt->bind_param("iisss", $user_id, $book_id, $issue_date, $return_date, $status);

    if ($stmt->execute()) {
        // Success! Go back to dashboard
        header("Location: dashboard.php?msg=borrow_success");
    } else {
        // Error handling
        echo "Error recording transaction: " . $stmt->error;
    }

    $stmt->close();
} else {
    // If no book was selected, send them to the search page
    header("Location: search.php");
    exit();
}