<?php
require_once __DIR__ . '/../config.php';
require_once __DIR__ . '/../includes/functions.php';

// Check admin login
if (!isset($_SESSION['admin_logged_in']) || !$_SESSION['admin_logged_in']) {
    header('Location: login.php');
    exit;
}

$pageTitle = 'Produkte verwalten';
$message = '';
$messageType = '';

function handleImageUpload($fileInputName = 'image_file') {
    if (!isset($_FILES[$fileInputName]) || $_FILES[$fileInputName]['error'] === UPLOAD_ERR_NO_FILE) {
        return ['success' => true, 'filename' => null];
    }

    $file = $_FILES[$fileInputName];
    if ($file['error'] !== UPLOAD_ERR_OK) {
        return ['success' => false, 'message' => 'Upload fehlgeschlagen. Bitte erneut versuchen.'];
    }

    $allowedExtensions = ['jpg', 'jpeg', 'png', 'webp', 'gif'];
    $originalName = basename($file['name']);
    $extension = strtolower(pathinfo($originalName, PATHINFO_EXTENSION));
    if (!in_array($extension, $allowedExtensions, true)) {
        return ['success' => false, 'message' => 'Ungültiger Dateityp. Erlaubt: JPG, PNG, WEBP, GIF.'];
    }

    $finfo = new finfo(FILEINFO_MIME_TYPE);
    $mimeType = $finfo->file($file['tmp_name']);
    $allowedMimes = ['image/jpeg', 'image/png', 'image/webp', 'image/gif'];
    if (!in_array($mimeType, $allowedMimes, true)) {
        return ['success' => false, 'message' => 'Die hochgeladene Datei ist kein gültiges Bild.'];
    }

    $imagesDir = __DIR__ . '/../assets/images';
    if (!is_dir($imagesDir)) {
        mkdir($imagesDir, 0755, true);
    }

    $safeBaseName = preg_replace('/[^a-zA-Z0-9_-]/', '-', pathinfo($originalName, PATHINFO_FILENAME));
    $safeBaseName = trim($safeBaseName, '-');
    if ($safeBaseName === '') {
        $safeBaseName = 'bild';
    }
    $targetFilename = $safeBaseName . '.' . $extension;
    $targetPath = $imagesDir . '/' . $targetFilename;
    $counter = 1;
    while (file_exists($targetPath)) {
        $targetFilename = $safeBaseName . '-' . $counter . '.' . $extension;
        $targetPath = $imagesDir . '/' . $targetFilename;
        $counter++;
    }

    if (!move_uploaded_file($file['tmp_name'], $targetPath)) {
        return ['success' => false, 'message' => 'Bild konnte nicht gespeichert werden.'];
    }

    return ['success' => true, 'filename' => $targetFilename];
}

// Handle product operations
if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    $products = getProducts();
    
    if (isset($_POST['add_product'])) {
        $uploadResult = handleImageUpload();
        if (!$uploadResult['success']) {
            $message = $uploadResult['message'];
            $messageType = 'error';
        } else {
        // Generate new ID
        $newId = 1;
        if (!empty($products)) {
            $ids = array_column($products, 'id');
            $newId = max($ids) + 1;
        }
        
        $newProduct = [
            'id' => $newId,
            'name' => sanitize($_POST['name']),
            'description' => sanitize($_POST['description']),
            'price' => (float)$_POST['price'],
            'category' => sanitize($_POST['category']),
            'image' => $uploadResult['filename'] !== null ? $uploadResult['filename'] : sanitize($_POST['image'])
        ];
        
        // Handle stock - per size for apparel, general for merch
        if ($newProduct['category'] === 'apparel' && !empty($_POST['sizes'])) {
            $sizes = sanitize($_POST['sizes']);
            $newProduct['sizes'] = $sizes; // Store as comma-separated string
            
            // Initialize stock_by_size
            $sizeArray = array_map('trim', explode(',', $sizes));
            $newProduct['stock_by_size'] = [];
            foreach ($sizeArray as $size) {
                $stockKey = 'stock_' . str_replace([' ', ','], '_', $size);
                $newProduct['stock_by_size'][$size] = isset($_POST[$stockKey]) ? (int)$_POST[$stockKey] : 0;
            }
        } else {
            $newProduct['stock'] = (int)$_POST['stock'];
        }
        
        $products[] = $newProduct;
        saveProducts($products);
        $message = 'Produkt erfolgreich hinzugefügt.';
        $messageType = 'success';
        }
    }
    
    if (isset($_POST['update_product'])) {
        $uploadResult = handleImageUpload();
        if (!$uploadResult['success']) {
            $message = $uploadResult['message'];
            $messageType = 'error';
        } else {
        $productId = (int)$_POST['product_id'];
        foreach ($products as &$product) {
            if ($product['id'] == $productId) {
                $product['name'] = sanitize($_POST['name']);
                $product['description'] = sanitize($_POST['description']);
                $product['price'] = (float)$_POST['price'];
                $product['category'] = sanitize($_POST['category']);
                $product['image'] = $uploadResult['filename'] !== null ? $uploadResult['filename'] : sanitize($_POST['image']);
                
                // Update stock - per size for apparel, general for merch
                if ($product['category'] === 'apparel') {
                    if (!empty($_POST['sizes'])) {
                        $product['sizes'] = sanitize($_POST['sizes']);
                        
                        // Update stock_by_size
                        $sizeArray = array_map('trim', explode(',', $product['sizes']));
                        if (!isset($product['stock_by_size']) || !is_array($product['stock_by_size'])) {
                            $product['stock_by_size'] = [];
                        }
                        foreach ($sizeArray as $size) {
                            $stockKey = 'stock_' . str_replace([' ', ','], '_', $size);
                            $product['stock_by_size'][$size] = isset($_POST[$stockKey]) ? (int)$_POST[$stockKey] : (isset($product['stock_by_size'][$size]) ? $product['stock_by_size'][$size] : 0);
                        }
                        // Remove sizes that are no longer in the list
                        $product['stock_by_size'] = array_intersect_key($product['stock_by_size'], array_flip($sizeArray));
                        unset($product['stock']); // Remove general stock for apparel
                    } else {
                        unset($product['sizes']);
                        unset($product['stock_by_size']);
                    }
                } else {
                    $product['stock'] = (int)$_POST['stock'];
                    unset($product['sizes']);
                    unset($product['stock_by_size']);
                }
                break;
            }
        }
        saveProducts($products);
        $message = 'Produkt erfolgreich aktualisiert.';
        $messageType = 'success';
        }
    }
    
    if (isset($_POST['delete_product'])) {
        $productId = (int)$_POST['product_id'];
        $products = array_filter($products, function($product) use ($productId) {
            return $product['id'] != $productId;
        });
        $products = array_values($products); // Re-index
        saveProducts($products);
        $message = 'Produkt erfolgreich gelöscht.';
        $messageType = 'success';
    }
}

$products = getProducts();
$editingProduct = null;

if (isset($_GET['edit'])) {
    $editingProduct = getProductById((int)$_GET['edit']);
}

$bodyClass = 'admin-page';
include __DIR__ . '/../includes/header.php';
?>

<div class="admin-header">
    <h2>Produkte verwalten</h2>
    <div>
        <a href="index.php" class="btn btn-secondary">Zurück zum Dashboard</a>
    </div>
</div>

<?php if ($message): ?>
    <div class="alert alert-<?php echo $messageType; ?>">
        <?php echo htmlspecialchars($message); ?>
    </div>
<?php endif; ?>

<?php if ($editingProduct): ?>
    <div class="panel" style="padding: 2rem;">
        <h3>Produkt bearbeiten</h3>
        <form method="POST" enctype="multipart/form-data">
            <input type="hidden" name="product_id" value="<?php echo $editingProduct['id']; ?>">
            <div class="form-group">
                <label for="name">Name *</label>
                <input type="text" id="name" name="name" required value="<?php echo htmlspecialchars($editingProduct['name']); ?>">
            </div>
            <div class="form-group">
                <label for="description">Beschreibung</label>
                <textarea id="description" name="description" rows="4"><?php echo htmlspecialchars($editingProduct['description']); ?></textarea>
            </div>
            <div class="form-group">
                <label for="price">Preis (€) *</label>
                <input type="number" id="price" name="price" step="0.01" min="0" required value="<?php echo $editingProduct['price']; ?>">
            </div>
            <div class="form-group">
                <label for="category">Kategorie *</label>
                <select id="category" name="category" required onchange="toggleStockFields()">
                    <option value="apparel" <?php echo $editingProduct['category'] === 'apparel' ? 'selected' : ''; ?>>Bekleidung</option>
                    <option value="merch" <?php echo $editingProduct['category'] === 'merch' ? 'selected' : ''; ?>>Merchandise</option>
                </select>
            </div>
            <div class="form-group" id="stock-group" style="<?php echo $editingProduct['category'] === 'merch' ? '' : 'display: none;'; ?>">
                <label for="stock">Lagerbestand *</label>
                <input type="number" id="stock" name="stock" min="0" value="<?php echo isset($editingProduct['stock']) ? (int)$editingProduct['stock'] : 0; ?>">
            </div>
            <div class="form-group" id="sizes-group" style="<?php echo $editingProduct['category'] === 'apparel' ? '' : 'display: none;'; ?>">
                <label for="sizes">Größen (kommagetrennt, z.B. S,M,L,XL,XXL)</label>
                <input type="text" id="sizes" name="sizes" value="<?php echo isset($editingProduct['sizes']) ? htmlspecialchars($editingProduct['sizes']) : ''; ?>" placeholder="S,M,L,XL" onchange="updateSizeStockFields()">
            </div>
            <div id="size-stock-group" style="<?php echo $editingProduct['category'] === 'apparel' ? '' : 'display: none;'; ?>">
                <?php if ($editingProduct['category'] === 'apparel' && !empty($editingProduct['sizes'])): ?>
                    <?php 
                    $sizes = array_map('trim', explode(',', $editingProduct['sizes']));
                    $stockBySize = isset($editingProduct['stock_by_size']) && is_array($editingProduct['stock_by_size']) ? $editingProduct['stock_by_size'] : [];
                    foreach ($sizes as $size): 
                    ?>
                        <div class="form-group">
                            <label>Lagerbestand für Größe "<?php echo htmlspecialchars($size); ?>" *</label>
                            <input type="number" name="stock_<?php echo htmlspecialchars(str_replace([' ', ','], '_', $size)); ?>" min="0" value="<?php echo isset($stockBySize[$size]) ? (int)$stockBySize[$size] : 0; ?>" required>
                        </div>
                    <?php endforeach; ?>
                <?php endif; ?>
            </div>
            <div class="form-group">
                <label for="image">Bilddateiname (z.B. tshirt.jpg)</label>
                <input type="text" id="image" name="image" value="<?php echo htmlspecialchars($editingProduct['image']); ?>">
            </div>
            <div class="form-group">
                <label for="image_file">Oder neues Bild hochladen</label>
                <input type="file" id="image_file" name="image_file" accept=".jpg,.jpeg,.png,.webp,.gif,image/*">
                <small>Upload nach <code>assets/images</code>; ersetzt den Dateinamen oben automatisch.</small>
            </div>
            <script>
                function toggleStockFields() {
                    const category = document.getElementById('category').value;
                    const stockGroup = document.getElementById('stock-group');
                    const sizesGroup = document.getElementById('sizes-group');
                    const sizeStockGroup = document.getElementById('size-stock-group');
                    
                    if (category === 'apparel') {
                        stockGroup.style.display = 'none';
                        sizesGroup.style.display = 'block';
                        sizeStockGroup.style.display = 'block';
                        updateSizeStockFields();
                    } else {
                        stockGroup.style.display = 'block';
                        sizesGroup.style.display = 'none';
                        sizeStockGroup.style.display = 'none';
                    }
                }
                
                function updateSizeStockFields() {
                    const sizesInput = document.getElementById('sizes');
                    const sizeStockGroup = document.getElementById('size-stock-group');
                    const sizes = sizesInput.value.split(',').map(s => s.trim()).filter(s => s);
                    
                    let html = '';
                    sizes.forEach(size => {
                        const safeName = size.replace(/[ ,]/g, '_');
                        html += '<div class="form-group">';
                        html += '<label>Lagerbestand für Größe "' + size + '" *</label>';
                        html += '<input type="number" name="stock_' + safeName + '" min="0" value="0" required>';
                        html += '</div>';
                    });
                    sizeStockGroup.innerHTML = html;
                }
            </script>
            <button type="submit" name="update_product" class="btn">Produkt aktualisieren</button>
            <a href="products.php" class="btn btn-secondary">Abbrechen</a>
        </form>
    </div>
<?php else: ?>
    <div class="panel" style="padding: 2rem;">
        <h3>Neues Produkt hinzufügen</h3>
        <form method="POST" enctype="multipart/form-data">
            <div class="form-group">
                <label for="name">Name *</label>
                <input type="text" id="name" name="name" required>
            </div>
            <div class="form-group">
                <label for="description">Beschreibung</label>
                <textarea id="description" name="description" rows="4"></textarea>
            </div>
            <div class="form-group">
                <label for="price">Preis (€) *</label>
                <input type="number" id="price" name="price" step="0.01" min="0" required>
            </div>
            <div class="form-group">
                <label for="category">Kategorie *</label>
                <select id="category" name="category" required onchange="toggleStockFields()">
                    <option value="apparel">Bekleidung</option>
                    <option value="merch">Merchandise</option>
                </select>
            </div>
            <div class="form-group" id="stock-group" style="display: none;">
                <label for="stock">Lagerbestand *</label>
                <input type="number" id="stock" name="stock" min="0" value="0">
            </div>
            <div class="form-group" id="sizes-group" style="display: none;">
                <label for="sizes">Größen (kommagetrennt, z.B. S,M,L,XL,XXL)</label>
                <input type="text" id="sizes" name="sizes" placeholder="S,M,L,XL" onchange="updateSizeStockFields()">
            </div>
            <div id="size-stock-group" style="display: none;"></div>
            <div class="form-group">
                <label for="image">Bilddateiname (z.B. tshirt.jpg)</label>
                <input type="text" id="image" name="image">
            </div>
            <div class="form-group">
                <label for="image_file">Oder Bild hochladen</label>
                <input type="file" id="image_file" name="image_file" accept=".jpg,.jpeg,.png,.webp,.gif,image/*">
                <small>Upload nach <code>assets/images</code>; Dateiname wird automatisch übernommen.</small>
            </div>
            <script>
                function toggleStockFields() {
                    const category = document.getElementById('category').value;
                    const stockGroup = document.getElementById('stock-group');
                    const sizesGroup = document.getElementById('sizes-group');
                    const sizeStockGroup = document.getElementById('size-stock-group');
                    
                    if (category === 'apparel') {
                        stockGroup.style.display = 'none';
                        sizesGroup.style.display = 'block';
                        sizeStockGroup.style.display = 'block';
                        updateSizeStockFields();
                    } else {
                        stockGroup.style.display = 'block';
                        sizesGroup.style.display = 'none';
                        sizeStockGroup.style.display = 'none';
                    }
                }
                
                function updateSizeStockFields() {
                    const sizesInput = document.getElementById('sizes');
                    const sizeStockGroup = document.getElementById('size-stock-group');
                    const sizes = sizesInput.value.split(',').map(s => s.trim()).filter(s => s);
                    
                    let html = '';
                    sizes.forEach(size => {
                        const safeName = size.replace(/[ ,]/g, '_');
                        html += '<div class="form-group">';
                        html += '<label>Lagerbestand für Größe "' + size + '" *</label>';
                        html += '<input type="number" name="stock_' + safeName + '" min="0" value="0" required>';
                        html += '</div>';
                    });
                    sizeStockGroup.innerHTML = html;
                }
            </script>
            <button type="submit" name="add_product" class="btn">Produkt hinzufügen</button>
        </form>
    </div>
<?php endif; ?>

<h3>Alle Produkte</h3>
<?php if (empty($products)): ?>
    <p>Keine Produkte vorhanden.</p>
<?php else: ?>
    <table class="responsive-table">
        <thead>
            <tr>
                <th>ID</th>
                <th>Name</th>
                <th>Kategorie</th>
                <th>Preis</th>
                <th>Lagerbestand</th>
                <th>Aktionen</th>
            </tr>
        </thead>
        <tbody>
            <?php foreach ($products as $product): ?>
                <tr>
                <td data-label="ID"><?php echo $product['id']; ?></td>
                <td data-label="Name"><?php echo htmlspecialchars($product['name']); ?></td>
                <td data-label="Kategorie"><?php echo $product['category'] === 'apparel' ? 'Bekleidung' : 'Merchandise'; ?></td>
                <td data-label="Preis"><?php echo formatPrice($product['price']); ?></td>
                <td data-label="Lagerbestand">
                    <?php 
                    if ($product['category'] === 'apparel' && isset($product['stock_by_size']) && is_array($product['stock_by_size'])) {
                        $stockInfo = [];
                        foreach ($product['stock_by_size'] as $size => $stock) {
                            $stockInfo[] = "$size: $stock";
                        }
                        echo implode(', ', $stockInfo) ?: '0';
                    } else {
                        echo isset($product['stock']) ? (int)$product['stock'] : 0;
                    }
                    ?>
                </td>
                    <td data-label="Aktionen">
                        <a href="?edit=<?php echo $product['id']; ?>" class="btn btn-small">Bearbeiten</a>
                        <form method="POST" style="display: inline;" onsubmit="return confirm('Möchten Sie dieses Produkt wirklich löschen?');">
                            <input type="hidden" name="product_id" value="<?php echo $product['id']; ?>">
                            <button type="submit" name="delete_product" class="btn btn-secondary btn-small">Löschen</button>
                        </form>
                    </td>
                </tr>
            <?php endforeach; ?>
        </tbody>
    </table>
<?php endif; ?>

<?php include __DIR__ . '/../includes/footer.php'; ?>