<?php
require_once 'config.php';

class Cart {
    private $conn;

    public function __construct($conn) {
        $this->conn = $conn;
    }

    public function addToCart($product_id, $quantity = 1) {
        if (!is_logged_in()) {
            return ['success' => false, 'message' => 'يجب تسجيل الدخول لإضافة منتجات إلى السلة'];
        }

        // Check if product exists and has enough stock
        $stmt = $this->conn->prepare("SELECT stock_quantity FROM products WHERE id = ?");
        $stmt->bind_param("i", $product_id);
        $stmt->execute();
        $result = $stmt->get_result();
        
        if ($result->num_rows === 0) {
            return ['success' => false, 'message' => 'المنتج غير موجود'];
        }

        $product = $result->fetch_assoc();
        if ($product['stock_quantity'] < $quantity) {
            return ['success' => false, 'message' => 'الكمية المطلوبة غير متوفرة'];
        }

        // Check if product already in cart
        $stmt = $this->conn->prepare("SELECT id, quantity FROM shopping_cart WHERE user_id = ? AND product_id = ?");
        $stmt->bind_param("ii", $_SESSION['user_id'], $product_id);
        $stmt->execute();
        $result = $stmt->get_result();

        if ($result->num_rows > 0) {
            $cart_item = $result->fetch_assoc();
            $new_quantity = $cart_item['quantity'] + $quantity;
            
            if ($new_quantity > $product['stock_quantity']) {
                return ['success' => false, 'message' => 'الكمية المطلوبة تتجاوز المخزون المتوفر'];
            }

            $stmt = $this->conn->prepare("UPDATE shopping_cart SET quantity = ? WHERE id = ?");
            $stmt->bind_param("ii", $new_quantity, $cart_item['id']);
        } else {
            $stmt = $this->conn->prepare("INSERT INTO shopping_cart (user_id, product_id, quantity) VALUES (?, ?, ?)");
            $stmt->bind_param("iii", $_SESSION['user_id'], $product_id, $quantity);
        }

        if ($stmt->execute()) {
            return ['success' => true, 'message' => 'تمت إضافة المنتج إلى السلة'];
        }

        return ['success' => false, 'message' => 'حدث خطأ أثناء إضافة المنتج إلى السلة'];
    }

    public function updateCartItem($cart_id, $quantity) {
        if (!is_logged_in()) {
            return ['success' => false, 'message' => 'يجب تسجيل الدخول لتحديث السلة'];
        }

        // Check if cart item exists and belongs to user
        $stmt = $this->conn->prepare("
            SELECT c.*, p.stock_quantity 
            FROM shopping_cart c
            JOIN products p ON c.product_id = p.id
            WHERE c.id = ? AND c.user_id = ?
        ");
        $stmt->bind_param("ii", $cart_id, $_SESSION['user_id']);
        $stmt->execute();
        $result = $stmt->get_result();

        if ($result->num_rows === 0) {
            return ['success' => false, 'message' => 'المنتج غير موجود في السلة'];
        }

        $cart_item = $result->fetch_assoc();
        if ($quantity > $cart_item['stock_quantity']) {
            return ['success' => false, 'message' => 'الكمية المطلوبة غير متوفرة'];
        }

        if ($quantity <= 0) {
            return $this->removeFromCart($cart_id);
        }

        $stmt = $this->conn->prepare("UPDATE shopping_cart SET quantity = ? WHERE id = ? AND user_id = ?");
        $stmt->bind_param("iii", $quantity, $cart_id, $_SESSION['user_id']);
        
        if ($stmt->execute()) {
            return ['success' => true, 'message' => 'تم تحديث الكمية'];
        }

        return ['success' => false, 'message' => 'حدث خطأ أثناء تحديث الكمية'];
    }

    public function removeFromCart($cart_id) {
        if (!is_logged_in()) {
            return ['success' => false, 'message' => 'يجب تسجيل الدخول لحذف منتجات من السلة'];
        }

        $stmt = $this->conn->prepare("DELETE FROM shopping_cart WHERE id = ? AND user_id = ?");
        $stmt->bind_param("ii", $cart_id, $_SESSION['user_id']);
        
        if ($stmt->execute()) {
            return ['success' => true, 'message' => 'تم حذف المنتج من السلة'];
        }

        return ['success' => false, 'message' => 'حدث خطأ أثناء حذف المنتج من السلة'];
    }

    public function getCart() {
        if (!is_logged_in()) {
            return ['items' => [], 'total' => 0];
        }

        $query = "
            SELECT c.id as cart_id, c.quantity,
                   p.id as product_id, p.name, p.name_ar, p.price, p.sale_price,
                   (SELECT image_url FROM product_images WHERE product_id = p.id AND is_primary = 1 LIMIT 1) as image
            FROM shopping_cart c
            JOIN products p ON c.product_id = p.id
            WHERE c.user_id = ?
            ORDER BY c.created_at DESC
        ";

        $stmt = $this->conn->prepare($query);
        $stmt->bind_param("i", $_SESSION['user_id']);
        $stmt->execute();
        $result = $stmt->get_result();

        $items = [];
        $total = 0;
        while ($row = $result->fetch_assoc()) {
            $price = $row['sale_price'] ?? $row['price'];
            $subtotal = $price * $row['quantity'];
            $total += $subtotal;
            
            $row['price'] = $price;
            $row['subtotal'] = $subtotal;
            $items[] = $row;
        }

        return [
            'items' => $items,
            'total' => $total
        ];
    }

    public function clearCart() {
        if (!is_logged_in()) {
            return ['success' => false, 'message' => 'يجب تسجيل الدخول لتفريغ السلة'];
        }

        $stmt = $this->conn->prepare("DELETE FROM shopping_cart WHERE user_id = ?");
        $stmt->bind_param("i", $_SESSION['user_id']);
        
        if ($stmt->execute()) {
            return ['success' => true, 'message' => 'تم تفريغ السلة'];
        }

        return ['success' => false, 'message' => 'حدث خطأ أثناء تفريغ السلة'];
    }

    public function applyCoupon($code) {
        if (!is_logged_in()) {
            return ['success' => false, 'message' => 'يجب تسجيل الدخول لاستخدام الكوبون'];
        }

        $stmt = $this->conn->prepare("
            SELECT * FROM coupons 
            WHERE code = ? 
            AND is_active = 1 
            AND (start_date IS NULL OR start_date <= NOW())
            AND (end_date IS NULL OR end_date >= NOW())
            AND (usage_limit IS NULL OR used_count < usage_limit)
        ");
        $stmt->bind_param("s", $code);
        $stmt->execute();
        $result = $stmt->get_result();

        if ($result->num_rows === 0) {
            return ['success' => false, 'message' => 'الكوبون غير صالح'];
        }

        $coupon = $result->fetch_assoc();
        $cart = $this->getCart();
        
        if ($coupon['min_purchase'] && $cart['total'] < $coupon['min_purchase']) {
            return ['success' => false, 'message' => sprintf('الحد الأدنى للطلب %s ريال', $coupon['min_purchase'])];
        }

        $discount = $coupon['type'] === 'percentage' 
            ? $cart['total'] * ($coupon['value'] / 100)
            : $coupon['value'];

        if ($coupon['max_discount'] && $discount > $coupon['max_discount']) {
            $discount = $coupon['max_discount'];
        }

        $_SESSION['coupon'] = [
            'code' => $coupon['code'],
            'discount' => $discount
        ];

        return [
            'success' => true,
            'message' => 'تم تطبيق الكوبون',
            'discount' => $discount,
            'total_after_discount' => $cart['total'] - $discount
        ];
    }
}