<?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 = "Kategorien verwalten";
$message = "";
$messageType = "";
$categories = getCategories();
$products = getProducts();

if ($_SERVER["REQUEST_METHOD"] === "POST") {
    // Validate CSRF token
    if (!validateCsrfToken($_POST["csrf_token"] ?? "")) {
        $message = "Ungültiges Token. Bitte versuchen Sie es erneut.";
        $messageType = "error";
    } else {
        if (isset($_POST["add_category"])) {
            $label = normalizeCategoryLabel($_POST["label"] ?? "");

            if (!isValidCategoryLabel($label)) {
                $message =
                    "Bitte geben Sie einen Kategorienamen mit maximal 80 Zeichen ein.";
                $messageType = "error";
            } else {
                $categoryId = generateCategoryIdFromLabel($label, $categories);
                $categories[] = [
                    "id" => $categoryId,
                    "label" => $label,
                ];
                saveCategories($categories);
                logAccess("Admin added category", [
                    "category_id" => $categoryId,
                    "label" => $label,
                ]);
                $message = "Kategorie wurde erfolgreich angelegt.";
                $messageType = "success";
            }
        }

        if (isset($_POST["update_category"])) {
            $categoryId = normalizeCategoryId($_POST["category_id"] ?? "");
            $label = normalizeCategoryLabel($_POST["label"] ?? "");
            $found = false;

            if (!isValidCategoryLabel($label)) {
                $message =
                    "Bitte geben Sie einen Kategorienamen mit maximal 80 Zeichen ein.";
                $messageType = "error";
            } else {
                foreach ($categories as &$category) {
                    if ($category["id"] === $categoryId) {
                        $category["label"] = $label;
                        $found = true;
                        break;
                    }
                }
                unset($category);

                if (!$found) {
                    $message = "Kategorie nicht gefunden.";
                    $messageType = "error";
                } else {
                    saveCategories($categories);
                    logAccess("Admin updated category", [
                        "category_id" => $categoryId,
                        "label" => $label,
                    ]);
                    $message = "Kategorie wurde erfolgreich aktualisiert.";
                    $messageType = "success";
                }
            }
        }

        if (isset($_POST["delete_category"])) {
            $categoryId = normalizeCategoryId($_POST["category_id"] ?? "");
            $label = "";
            $found = false;

            if (isCategoryInUse($categoryId)) {
                $message =
                    "Diese Kategorie wird noch von Produkten verwendet und kann nicht gelöscht werden.";
                $messageType = "error";
            } else {
                $categories = array_values(
                    array_filter($categories, function ($category) use (
                        $categoryId,
                        &$found,
                        &$label,
                    ) {
                        if ($category["id"] === $categoryId) {
                            $found = true;
                            $label = $category["label"];
                            return false;
                        }
                        return true;
                    }),
                );

                if (!$found) {
                    $message = "Kategorie nicht gefunden.";
                    $messageType = "error";
                } else {
                    saveCategories($categories);
                    logAccess("Admin deleted category", [
                        "category_id" => $categoryId,
                        "label" => $label,
                    ]);
                    $message = "Kategorie wurde gelöscht.";
                    $messageType = "success";
                }
            }
        }

        $categories = getCategories();
        $products = getProducts();
    }
}

$editCategoryId = normalizeCategoryId($_GET["edit"] ?? "");
$editingCategory = null;
if ($editCategoryId !== "") {
    $editingCategory = getCategoryById($editCategoryId);
    if ($editingCategory === null && $message === "") {
        $message = "Ausgewählte Kategorie wurde nicht gefunden.";
        $messageType = "error";
    }
}

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

<div class="admin-header">
    <h2>Kategorien 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 ($editingCategory !== null): ?>
    <div class="panel panel-lg">
        <h3>Kategorie bearbeiten</h3>
        <form method="POST">
            <?php echo csrfField(); ?>
            <input type="hidden" name="category_id" value="<?php echo htmlspecialchars(
                $editingCategory["id"],
            ); ?>">
            <div class="form-group">
                <label for="category_id_display">ID</label>
                <input type="text" id="category_id_display" value="<?php echo htmlspecialchars(
                    $editingCategory["id"],
                ); ?>" readonly>
                <small>Die ID sollte gleichbleiben, damit Produktzuordnungen und Filter-URLs gültig bleiben.</small>
            </div>
            <div class="form-group">
                <label for="label_edit">Name *</label>
                <input type="text" id="label_edit" name="label" maxlength="80" required value="<?php echo htmlspecialchars(
                    $editingCategory["label"],
                ); ?>">
            </div>
            <button type="submit" name="update_category" class="btn">Kategorie aktualisieren</button>
            <a href="categories.php" class="btn btn-secondary">Abbrechen</a>
        </form>
    </div>
<?php else: ?>
    <div class="panel panel-lg">
        <h3>Neue Kategorie anlegen</h3>
        <form method="POST">
            <div class="form-group">
                <label for="label">Name *</label>
                <input type="text" id="label" name="label" maxlength="80" required placeholder="z.B. Accessoires">
                <small>Die technische ID wird einmalig automatisch aus dem Namen erzeugt.</small>
            </div>
            <button type="submit" name="add_category" class="btn">Kategorie anlegen</button>
        </form>
    </div>
<?php endif; ?>

<div class="panel">
    <h3>Kategorien</h3>
    <div class="table-responsive">
        <table class="responsive-table">
            <thead>
                <tr>
                    <th>Name</th>
                    <th>ID</th>
                    <th>Produkte</th>
                    <th>Aktionen</th>
                </tr>
            </thead>
            <tbody>
                <?php foreach ($categories as $category): ?>
                    <?php
                    $productCount = 0;
                    foreach ($products as $product) {
                        if (productHasCategory($product, $category["id"])) {
                            $productCount++;
                        }
                    }
                    ?>
                    <tr>
                        <td data-label="Name"><?php echo htmlspecialchars(
                            $category["label"],
                        ); ?></td>
                        <td data-label="ID"><code><?php echo htmlspecialchars(
                            $category["id"],
                        ); ?></code></td>
                        <td data-label="Produkte"><?php echo $productCount; ?></td>
                        <td data-label="Aktionen">
                            <a href="categories.php?edit=<?php echo urlencode(
                                $category["id"],
                            ); ?>" class="btn btn-small btn-secondary">Bearbeiten</a>
                            <form method="POST" class="inline-form" onsubmit="return confirm('Kategorie wirklich löschen?');">
                                <?php echo csrfField(); ?>
                                <input type="hidden" name="category_id" value="<?php echo htmlspecialchars(
                                    $category["id"],
                                ); ?>">
                                <button type="submit" name="delete_category" class="btn btn-small">Löschen</button>
                            </form>
                        </td>
                    </tr>
                <?php endforeach; ?>
            </tbody>
        </table>
    </div>
</div>

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