book.php

<?php
/**
 * Book Detail Page
 * Shows full book information and reservation options
 */
$page_title = "Book Details";
require_once 'includes/header.php';
require_once 'includes/functions.php';

// Get book ID from URL
$book_id = isset($_GET['id']) ? (int)$_GET['id'] : 0;

if ($book_id <= 0) {
    header("Location: books.php");
    exit();
}

// Get book details
$book = getBookById($book_id);

if (!$book) {
    header("Location: books.php");
    exit();
}

// Handle reservation
$message = '';
$error = '';

if ($_SERVER['REQUEST_METHOD'] === 'POST' && isset($_POST['action']) && $_POST['action'] === 'reserve') {
    if (!isLoggedIn()) {
        header("Location: login.php");
        exit();
    }
    
    $user_id = getCurrentUserId();
    
    // Check if user already has an active reservation for this book
    if (hasActiveReservation($user_id, $book_id)) {
        $error = "You already have an active reservation for this book.";
    } elseif ($book['available_copies'] <= 0) {
        $error = "No copies available for reservation.";
    } else {
        // Create reservation
        global $pdo;
        $stmt = $pdo->prepare("INSERT INTO reservations (user_id, book_id, status) VALUES (?, ?, 'ACTIVE')");
        if ($stmt->execute([$user_id, $book_id])) {
            $message = "Book reserved successfully!";
            // Refresh book data to show updated availability
            $book = getBookById($book_id);
        } else {
            $error = "Failed to reserve book. Please try again.";
        }
    }
}
?>

<h1>Book Details</h1>

<div class="book-detail">
    <!-- Placeholder for book cover -->
    <img src="https://placehold.co/200x300?text=Book+Cover" alt="Book Cover" class="book-cover">
    
    <div class="book-info">
        <h2><?php echo htmlspecialchars($book['title']); ?></h2>
        <p class="book-meta"><strong>Author:</strong> <?php echo htmlspecialchars($book['author']); ?></p>
        <p class="book-meta"><strong>Category:</strong> <?php echo htmlspecialchars($book['category']); ?></p>
        <p class="book-meta"><strong>ISBN:</strong> <?php echo htmlspecialchars($book['isbn'] ?? 'N/A'); ?></p>
        <p class="book-meta"><strong>Total Copies:</strong> <?php echo $book['total_copies']; ?></p>
        <p class="book-meta"><strong>Available Copies:</strong> 
            <?php if ($book['available_copies'] > 0): ?>
                <span class="status-active"><?php echo $book['available_copies']; ?> available</span>
            <?php else: ?>
                <span class="status-rejected">Not available</span>
            <?php endif; ?>
        </p>
        
        <?php if ($message): ?>
            <div class="alert alert-success"><?php echo $message; ?></div>
        <?php endif; ?>
        
        <?php if ($error): ?>
            <div class="alert alert-error"><?php echo $error; ?></div>
        <?php endif; ?>
        
        <div class="book-description">
            <h3>Description</h3>
            <p><?php echo htmlspecialchars($book['description'] ?? 'No description available.'); ?></p>
        </div>
        
        <div class="book-actions">
            <?php if (isLoggedIn()): ?>
                <?php if ($book['available_copies'] > 0 && !hasActiveReservation(getCurrentUserId(), $book_id)): ?>
                    <form method="post" style="display: inline;">
                        <input type="hidden" name="action" value="reserve">
                        <input type="hidden" name="book_id" value="<?php echo $book['id']; ?>">
                        <button type="submit" class="btn btn-success" onclick="return confirm('Are you sure you want to reserve this book?')">Reserve (Mark as Mine)</button>
                    </form>
                <?php elseif (hasActiveReservation(getCurrentUserId(), $book_id)): ?>
                    <button class="btn btn-warning" disabled>Already Reserved</button>
                    <p><em>You have an active reservation for this book.</em></p>
                <?php else: ?>
                    <button class="btn btn-danger" disabled>Not Available</button>
                    <p><em>There are no copies available for reservation at this time.</em></p>
                <?php endif; ?>
            <?php else: ?>
                <p><a href="login.php" class="btn btn-primary">Log in to Reserve</a></p>
                <p><em>Log in to reserve this book.</em></p>
            <?php endif; ?>
        </div>
    </div>
</div>

<div style="clear: both;"></div>

<h3>Similar Books</h3>
<div class="grid">
    <?php
    // Get similar books (same category, excluding current book)
    global $pdo;
    $stmt = $pdo->prepare("
        SELECT b.*, 
               (b.total_copies - COALESCE(r.reserved_count, 0)) as available_copies
        FROM books b
        LEFT JOIN (
            SELECT book_id, COUNT(*) as reserved_count
            FROM reservations
            WHERE status = 'ACTIVE'
            GROUP BY book_id
        ) r ON b.id = r.book_id
        WHERE b.category = ? AND b.id != ?
        ORDER BY b.title ASC
        LIMIT 3
    ");
    $stmt->execute([$book['category'], $book['id']]);
    $similar_books = $stmt->fetchAll();
    
    foreach ($similar_books as $similar_book):
    ?>
    <div class="card">
        <div class="card-content">
            <h3 class="card-title"><?php echo htmlspecialchars($similar_book['title']); ?></h3>
            <p class="card-author">by <?php echo htmlspecialchars($similar_book['author']); ?></p>
            <span class="card-category"><?php echo htmlspecialchars($similar_book['category']); ?></span>
            
            <?php if ($similar_book['available_copies'] > 0): ?>
                <span class="availability-badge available"><?php echo $similar_book['available_copies']; ?> available</span>
            <?php else: ?>
                <span class="availability-badge unavailable">Not available</span>
            <?php endif; ?>
            
            <div class="card-actions">
                <a href="book.php?id=<?php echo $similar_book['id']; ?>" class="btn btn-primary">View Details</a>
            </div>
        </div>
    </div>
    <?php endforeach; ?>
    
    <?php if (empty($similar_books)): ?>
    <div class="alert alert-info">
        <p>No similar books found in this category.</p>
    </div>
    <?php endif; ?>
</div>

<?php require_once 'includes/footer.php'; ?>