books.php

<?php
session_start();
include "connection.php";

// Check if student is logged in
if (!isset($_SESSION['student_reg_no'])) {
    header("Location: student_login.php");
    exit();
}

$student_reg_no = $_SESSION['student_reg_no'];
$student_name = $_SESSION['student_name'] ?? '';

// Fetch student email and id from students table using registration number
$stmt_student_info = $db->prepare("SELECT id, email FROM students WHERE registration_no = ?");
$stmt_student_info->bind_param("s", $student_reg_no);
$stmt_student_info->execute();
$result_info = $stmt_student_info->get_result();
$student_email = '';
$student_id = null;
if ($row_info = $result_info->fetch_assoc()) {
    $student_email = $row_info['email'];
    $student_id = $row_info['id'];
}
$stmt_student_info->close();

// Fetch max_reservations from system_settings
$settings_result = mysqli_query($db, "SELECT max_reservations FROM system_settings WHERE id=1");
$max_reservations = 3; // default
if ($settings_result && mysqli_num_rows($settings_result) > 0) {
    $row = mysqli_fetch_assoc($settings_result);
    $max_reservations = intval($row['max_reservations']);
}

// Count current active bookings for the student
$current_bookings = 0;
if (!empty($student_email)) {
    $count_sql = "SELECT COUNT(*) as count FROM reservations WHERE student_email = ? AND status = 'Booked'";
    $stmt = $db->prepare($count_sql);
    $stmt->bind_param("s", $student_email);
    $stmt->execute();
    $result_count = $stmt->get_result();
    if ($row_count = $result_count->fetch_assoc()) {
        $current_bookings = intval($row_count['count']);
    }
    $stmt->close();
}

$message = '';
$message_type = '';

if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    if (isset($_POST['action'])) {
        $book_id = intval($_POST['book_id']);
        $action = $_POST['action'];

        if ($action === 'reserve') {
            // Validate book exists
            $stmt_check = $db->prepare("SELECT id FROM reservations WHERE student_email = ? AND book_id = ? AND status IN ('Booked', 'Issued')");
            $stmt_check->bind_param("si", $student_email, $book_id);
            $stmt_check->execute();
            $reservation_exists = $stmt_check->get_result()->num_rows > 0;
            $stmt_check->close();

            if ($reservation_exists) {
                $message = 'You have already booked this book!';
                $message_type = 'warning';
            } elseif ($current_bookings >= $max_reservations) {
                $message = "You have reached the maximum number of active reservations allowed ($max_reservations).";
                $message_type = 'warning';
            } else {
                // Check book quantity
                $stmt_quantity = $db->prepare("SELECT quantity FROM books WHERE id = ?");
                $stmt_quantity->bind_param("i", $book_id);
                $stmt_quantity->execute();
                $quantity_result = $stmt_quantity->get_result()->fetch_assoc();
                $stmt_quantity->close();

                if ($quantity_result && $quantity_result['quantity'] > 0) {
                    // Reserve the book
                    $stmt_reserve = $db->prepare("INSERT INTO reservations (student_name, student_email, book_id, status, reservation_date) VALUES (?, ?, ?, 'Booked', NOW())");
                    $stmt_reserve->bind_param("ssi", $student_name, $student_email, $book_id);
                    $reserved = $stmt_reserve->execute();
                    if (!$reserved) {
                        error_log("Failed to insert reservation: " . $stmt_reserve->error);
                    } else {
                        error_log("Reservation inserted: student_email={$student_email}, book_id={$book_id}");
                    }
                    $stmt_reserve->close();

                    if ($reserved) {
                        $message = 'Booked successfully!';
                        $message_type = 'success';

                        // Redirect to avoid form resubmission and stay on the same page
                        $redirect_url = 'books.php';
                        $query_params = [];
                        if (!empty($_GET['search'])) {
                            $query_params['search'] = $_GET['search'];
                        }
                        if (!empty($_GET['page'])) {
                            $query_params['page'] = $_GET['page'];
                        }
                        if (!empty($query_params)) {
                            $redirect_url .= '?' . http_build_query($query_params);
                        }
                        header("Location: $redirect_url");
                        exit();
                    } else {
                        $message = 'Failed to reserve the book. Please try again.';
                        $message_type = 'danger';
                    }
                } else {
                    $message = 'This book is currently unavailable.';
                    $message_type = 'warning';
                }
            }
        } elseif ($action === 'unreserve') {
            // Unbook the book
            $stmt_unreserve = $db->prepare("DELETE FROM reservations WHERE student_email = ? AND book_id = ?");
            $stmt_unreserve->bind_param("si", $student_email, $book_id);
            $unreserved = $stmt_unreserve->execute();
            $stmt_unreserve->close();

            if ($unreserved) {
                $message = 'Booking cancelled successfully!';
                $message_type = 'success';

                // Redirect to avoid form resubmission and stay on the same page
                $redirect_url = 'books.php';
                $query_params = [];
                if (!empty($_GET['search'])) {
                    $query_params['search'] = $_GET['search'];
                }
                if (!empty($_GET['page'])) {
                    $query_params['page'] = $_GET['page'];
                }
                if (!empty($query_params)) {
                    $redirect_url .= '?' . http_build_query($query_params);
                }
                header("Location: $redirect_url");
                exit();
            } else {
                $message = 'Failed to cancel the booking. Please try again.';
                $message_type = 'danger';
            }
        }
    } elseif (isset($_POST['selected_books']) && is_array($_POST['selected_books'])) {
        // Handle adding selected books to cart
        if (empty($student_email)) {
            $message = "Error: Student email not found. Cannot add books to cart.";
            $message_type = 'danger';
        } else {
            $selected_books = $_POST['selected_books'];
            $added_count = 0;
            foreach ($selected_books as $book_id) {
                $book_id = intval($book_id);
                // Check if already in cart
                $stmt_check_cart = $db->prepare("SELECT id FROM cart WHERE student_email = ? AND book_id = ?");
                $stmt_check_cart->bind_param("si", $student_email, $book_id);
                $stmt_check_cart->execute();
                $already_in_cart = $stmt_check_cart->get_result()->num_rows > 0;
                $stmt_check_cart->close();

                if (!$already_in_cart) {
                    // Insert into cart
                    $stmt_insert_cart = $db->prepare("INSERT INTO cart (student_email, book_id) VALUES (?, ?)");
                    $stmt_insert_cart->bind_param("si", $student_email, $book_id);
                    $inserted = $stmt_insert_cart->execute();
                    if (!$inserted) {
                        error_log("Failed to insert into cart: " . $stmt_insert_cart->error);
                    }
                    $stmt_insert_cart->close();

                    if ($inserted) {
                        $added_count++;
                    }
                }
            }
            if ($added_count > 0) {
                $message = "$added_count book(s) added to cart successfully!";
                $message_type = 'success';
            } else {
                $message = "This book has already been added!";
                $message_type = 'info';
            }
        }

        // Redirect to avoid form resubmission and stay on the same page
        $redirect_url = 'books.php';
        $query_params = [];
        if (!empty($_GET['search'])) {
            $query_params['search'] = $_GET['search'];
        }
        if (!empty($_GET['page'])) {
            $query_params['page'] = $_GET['page'];
        }
        if (!empty($query_params)) {
            $redirect_url .= '?' . http_build_query($query_params);
        }
        header("Location: $redirect_url");
        exit();
    }
}

$limit = 9;
$page = max(1, (int)($_GET['page'] ?? 1));
$offset = ($page - 1) * $limit;
$search = trim($_GET['search'] ?? '');

$search_sql = "";
$params = [];
$types = "";

if (!empty($search)) {
    $search_sql = " WHERE title LIKE ? OR author LIKE ?";
    $search_term = "%{$search}%";
    $params = [$search_term, $search_term];
    $types = "ss";
}

// Get total book count
$stmt_total = $db->prepare("SELECT COUNT(*) as total FROM books $search_sql");
if ($stmt_total === false) {
    error_log("Failed to prepare total count statement: " . $db->error);
}
if (!empty($params)) {
    // bind_param requires references, so use call_user_func_array
    $bind_params = [];
    $bind_params[] = & $types;
    for ($i = 0; $i < count($params); $i++) {
        $bind_params[] = & $params[$i];
    }
    call_user_func_array([$stmt_total, 'bind_param'], $bind_params);
}
$stmt_total->execute();
$total_books = $stmt_total->get_result()->fetch_assoc()['total'] ?? 0;
$stmt_total->close();

$total_pages = ceil($total_books / $limit);

// Fetch books
$fetch_sql = "SELECT * FROM books $search_sql ORDER BY title ASC LIMIT ? OFFSET ?";
$stmt_books = $db->prepare($fetch_sql);
if ($stmt_books === false) {
    error_log("Failed to prepare fetch books statement: " . $db->error);
}
if (!empty($params)) {
    $types_fetch = $types . "ii";
    $params_fetch = $params;
    $params_fetch[] = $limit;
    $params_fetch[] = $offset;

    $bind_params_fetch = [];
    $bind_params_fetch[] = & $types_fetch;
    for ($i = 0; $i < count($params_fetch); $i++) {
        $bind_params_fetch[] = & $params_fetch[$i];
    }
    call_user_func_array([$stmt_books, 'bind_param'], $bind_params_fetch);
} else {
    $stmt_books->bind_param("ii", $limit, $offset);
}
$stmt_books->execute();
$books = $stmt_books->get_result();
?>
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1" />
    <title>Booker Library</title>
    <link href="https://cdn.jsdelivr.net/npm/bootstrap@5.3.2/dist/css/bootstrap.min.css" rel="stylesheet" />
    <style>
        /* Styles omitted for brevity, keep existing styles */
    </style>
</head>
<body>
<nav class="navbar navbar-expand-lg navbar-dark bg-primary shadow-sm">
    <div class="container">
        <a class="navbar-brand fw-bold fs-4" href="student_dashboard.php">Booker Library</a>
        <form method="GET" action="books.php" class="d-flex ms-3" style="max-width: 320px;">
            <input type="search" name="search" class="form-control form-control-sm rounded-pill" placeholder="Search by title or author" aria-label="Search" value="<?= htmlspecialchars($search) ?>" />
            <button class="btn btn-light btn-sm ms-2 rounded-pill px-3" type="submit">Search</button>
        </form>
        <button class="navbar-toggler" type="button" data-bs-toggle="collapse" data-bs-target="#navbarNav" aria-controls="navbarNav" aria-expanded="false" aria-label="Toggle navigation">
            <span class="navbar-toggler-icon"></span>
        </button>
        <div class="collapse navbar-collapse" id="navbarNav">
            <ul class="navbar-nav ms-auto align-items-center">
                <li class="nav-item"><a class="nav-link fw-semibold text-white" href="student_dashboard.php">Dashboard</a></li>
                <li class="nav-item">
                    <button id="addSelectedToCartBtn" class="btn btn-outline-light btn-sm" disabled> Add Selected to Cart </button>
                </li>
                <li class="nav-item"><a class="nav-link fw-semibold text-white" href="my_cart.php">My Cart</a></li>
                <li class="nav-item"><a class="nav-link fw-semibold text-white" href="history.php">History</a></li>
                <li class="nav-item"><a class="nav-link fw-semibold text-white" href="student_logout.php">Logout</a></li>
            </ul>
        </div>
    </div>
</nav>

<div class="container" style="padding-top: 80px;">
    <?php if ($message): ?>
        <div class="alert alert-<?= htmlspecialchars($message_type) ?> alert-dismissible fade show" role="alert">
            <?= htmlspecialchars($message) ?>
            <button type="button" class="btn-close" data-bs-dismiss="alert"></button>
        </div>
    <?php endif; ?>

    <div class="row g-4">
        <?php while ($book = $books->fetch_assoc()): ?>
            <?php
                // Check reservation status and date for the book (all students)
                $stmt_check = $db->prepare("SELECT status, reservation_date, rejected_at FROM reservations WHERE book_id = ? ORDER BY reservation_date DESC");
                $stmt_check->bind_param("i", $book['id']);
                $stmt_check->execute();
                $result_reservation = $stmt_check->get_result();
                $reservations = [];
                while ($row = $result_reservation->fetch_assoc()) {
                    $reservations[] = $row;
                }
                $stmt_check->close();

                $is_booked = false;
                $is_rejected = false;
                $rejected_recently = false;
                $is_issued = false;

                if ($student_id !== null) {
                    // Check if book is currently issued to the current student and not returned
                    $stmt_check_issued = $db->prepare("SELECT id FROM issued_books WHERE book_id = ? AND student_id = ? AND return_date IS NULL LIMIT 1");
                    $stmt_check_issued->bind_param("ii", $book['id'], $student_id);
                    $stmt_check_issued->execute();
                    $result_issued = $stmt_check_issued->get_result();
                    $is_currently_issued = $result_issued->num_rows > 0;
                    $stmt_check_issued->close();

                    if ($is_currently_issued) {
                        $is_issued = true;
                    } else {
                        // Check if any reservation is booked or rejected within 24 hours
                        foreach ($reservations as $reservation) {
                            if ($reservation['status'] === 'Booked') {
                                $is_booked = true;
                                break;
                            } elseif ($reservation['status'] === 'Rejected') {
                                $is_rejected = true;
                                $rejection_time = strtotime($reservation['rejected_at'] ?? $reservation['reservation_date']);
                                $current_time = time();
                                if (($current_time - $rejection_time) < 24 * 3600) {
                                    $rejected_recently = true;
                                } else {
                                    // Rejection expired, reset status to allow booking
                                    $stmt_reset = $db->prepare("UPDATE reservations SET status = 'Booked', rejected_at = NULL WHERE book_id = ? AND student_email = ?");
                                    $stmt_reset->bind_param("is", $book['id'], $student_email);
                                    $stmt_reset->execute();
                                    $stmt_reset->close();
                                    $is_rejected = false;
                                    $rejected_recently = false;
                                }
                            }
                        }
                    }
                } else {
                    // If student_id is null, fallback to previous logic without student_id check
                    foreach ($reservations as $reservation) {
                        if ($reservation['status'] === 'Booked') {
                            $is_booked = true;
                            break;
                        } elseif ($reservation['status'] === 'Rejected') {
                            $is_rejected = true;
                            $rejection_time = strtotime($reservation['rejected_at'] ?? $reservation['reservation_date']);
                            $current_time = time();
                            if (($current_time - $rejection_time) < 24 * 3600) {
                                $rejected_recently = true;
                            } else {
                                // Rejection expired, reset status to allow booking
                                $stmt_reset = $db->prepare("UPDATE reservations SET status = 'Booked', rejected_at = NULL WHERE book_id = ? AND student_email = ?");
                                $stmt_reset->bind_param("is", $book['id'], $student_email);
                                $stmt_reset->execute();
                                $stmt_reset->close();
                                $is_rejected = false;
                                $rejected_recently = false;
                            }
                        }
                    }
                }

                // Determine if booking button should be disabled due to max reservations reached
                $disable_booking = false;
                $disable_reason = '';
                if ($current_bookings >= $max_reservations && !$is_booked && !$is_issued) {
                    $disable_booking = true;
                    $disable_reason = "You have reached the maximum number of active reservations allowed ($max_reservations).";
                }
            ?>
            <div class="col-md-4">
                <div class="book-card">
                    <div class="book-card-body">
                        <div class="book-title">
                            <input type="checkbox" name="selected_books[]" value="<?= $book['id'] ?>" id="select_book_<?= $book['id'] ?>" style="margin-right: 8px;">
                            <label for="select_book_<?= $book['id'] ?>"><?= htmlspecialchars($book['title']) ?></label>
                        </div>
                        <div class="book-info"><strong>Author:</strong> <?= htmlspecialchars($book['author']) ?></div>
                        <div class="book-info"><strong>Edition:</strong> <?= htmlspecialchars($book['edition']) ?></div>
                        <div class="book-info"><strong>Available:</strong> <?= (int)$book['quantity'] ?> copies</div>
                        <form method="POST" action="books.php" class="d-inline-block" onsubmit="return confirmBooking(this);">
                            <input type="hidden" name="book_id" value="<?= $book['id'] ?>">
                            <?php if ($is_issued): ?>
                                <button type="button" class="btn btn-success" disabled>Borrowed</button>
                            <?php elseif ($is_booked): ?>
                                <button type="submit" name="action" value="unreserve" class="btn btn-primary">Unbook</button>
                            <?php elseif ($is_rejected && $rejected_recently): ?>
                                <button type="button" class="btn btn-warning" disabled>Rejected</button>
                            <?php else: ?>
                                <button type="submit" name="action" value="reserve" class="btn btn-primary" <?= $disable_booking ? 'disabled title="' . htmlspecialchars($disable_reason) . '"' : '' ?>>Book</button>
                            <?php endif; ?>
                        </form>
                        <?php if (!empty($search)): ?>
                            <a href="books.php" class="btn btn-primary ms-2">Leave</a>
                        <?php endif; ?>
                    </div>
                </div>
            </div>
        <?php endwhile; ?>
    </div>

    <?php if ($total_pages > 1): ?>
        <nav class="mt-4">
            <ul class="pagination justify-content-center">
                <li class="page-item <?= $page <= 1 ? 'disabled' : '' ?>">
                    <a class="page-link" href="books.php?search=<?= urlencode($search) ?>&page=<?= max(1, $page - 1) ?>">Previous</a>
                </li>
                <?php for ($i = 1; $i <= $total_pages; $i++): ?>
                    <li class="page-item <?= $page == $i ? 'active' : '' ?>">
                        <a class="page-link" href="books.php?search=<?= urlencode($search) ?>&page=<?= $i ?>"><?= $i ?></a>
                    </li>
                <?php endfor; ?>
                <li class="page-item <?= $page >= $total_pages ? 'disabled' : '' ?>">
                    <a class="page-link" href="books.php?search=<?= urlencode($search) ?>&page=<?= min($total_pages, $page + 1) ?>">Next</a>
                </li>
            </ul>
        </nav>
    <?php endif; ?>

</div>

<footer class="text-center py-3">
    <p>&copy; <?= date('Y') ?> Booker Library. All rights reserved.</p>
</footer>

<script src="https://cdn.jsdelivr.net/npm/bootstrap@5.3.2/dist/js/bootstrap.bundle.min.js"></script>
<script>
    document.addEventListener('DOMContentLoaded', function () {
        const addToCartBtn = document.getElementById('addSelectedToCartBtn');
        const checkboxes = document.querySelectorAll('input[name="selected_books[]"]');

        function updateButtonState() {
            const anyChecked = Array.from(checkboxes).some(cb => cb.checked);
            addToCartBtn.disabled = !anyChecked;
        }

        checkboxes.forEach(cb => {
            cb.addEventListener('change', updateButtonState);
        });

        addToCartBtn.addEventListener('click', function () {
            const selectedBookIds = Array.from(checkboxes)
                .filter(cb => cb.checked)
                .map(cb => cb.value);

            if (selectedBookIds.length === 0) {
                return;
            }

            // Use AJAX to add selected books to cart without page reload
            fetch('update_cart_fixed.php', {
                method: 'POST',
                headers: {
                    'Content-Type': 'application/x-www-form-urlencoded',
                },
                body: selectedBookIds.map(id => 'selected_books[]=' + encodeURIComponent(id)).join('&'),
                credentials: 'same-origin'
            })
            .then(response => response.json())
            .then(data => {
                let addedCount = 0;
                for (const key in data) {
                    if (data[key] === 'added') {
                        addedCount++;
                    }
                }
                if (addedCount > 0) {
                    alert(addedCount + ' book(s) added to cart successfully!');
                    // Uncheck all checkboxes and disable button
                    checkboxes.forEach(cb => cb.checked = false);
                    addToCartBtn.disabled = true;
                    // Optionally, update the My Cart component dynamically if present
                    if (window.updateMyCart) {
                        window.updateMyCart();
                    }
                } else {
                    alert('book has already been added to cart!');
                }
            })
            .catch(error => {
                console.error('Error adding books to cart:', error);
                alert('Failed to add books to cart. Please try again.');
            });
        });
    });

    // Function to update My Cart component dynamically if loaded in dashboard
    window.updateMyCart = function() {
        fetch('my_cart.php', { credentials: 'same-origin' })
            .then(response => response.text())
            .then(html => {
                const myCartContainer = document.querySelector('#content-area .my-cart-container');
                if (myCartContainer) {
                    myCartContainer.innerHTML = html;
                }
            })
            .catch(error => {
                console.error('Failed to update My Cart component:', error);
            });
    };
</script>
</body>
</html>