Add coupons, newsletter, country-based shipping, sale prices, USP bar

- Gutscheincodes: DB-Verwaltung (%, €-Rabatt, Mindestbestellwert, Ablauf),
  Eingabefeld im Checkout, Admin unter Marketing → Gutscheine
- Newsletter: Double-Opt-In per E-Mail, Formular im Footer,
  Admin-Liste mit CSV-Export
- Länderzonen-Versand: DE / DACH / EU / WORLD, Versandkosten nach
  Lieferland dynamisch berechnet, Coupon-Rabatt in Bestellung gespeichert
- Sale-Preise: sale_price auf Produkten, durchgestrichener UVP auf
  Produktkarte, Sonderangebote-Sektion auf Startseite
- USP-Leiste auf Startseite: Versand, Zahlung, Rückgabe, Service

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/Http/Controllers/Shop/CheckoutController.php

@@ -3,6 +3,7 @@
 namespace App\Http\Controllers\Shop;
 
 use App\Http\Controllers\Controller;
+use App\Models\Coupon;
 use App\Models\ShippingRate;
 use App\Services\CartService;
 use App\Services\OrderService;
@@ -21,12 +22,49 @@ class CheckoutController extends Controller
             return redirect()->route('cart.index')->with('error', 'Ihr Warenkorb ist leer.');
         }
         $subtotal     = $this->cart->subtotal();
-        $shippingRate = ShippingRate::forCart($subtotal);
+        $country      = session('checkout_country', 'DE');
+        $shippingRate = ShippingRate::forCart($subtotal, $country);
         $shippingCost = $shippingRate ? $shippingRate->getCostForTotal($subtotal) : 0;
-        $total        = $subtotal + $shippingCost;
+        $discount     = $this->getCouponDiscount($subtotal);
+        $total        = max(0, $subtotal - $discount) + $shippingCost;
         $userAddresses = auth()->user()?->addresses ?? collect();
+        $couponCode   = session('coupon_code');
 
-        return view('shop.checkout.index', compact('subtotal', 'shippingCost', 'total', 'userAddresses'));
+        return view('shop.checkout.index', compact('subtotal', 'shippingCost', 'total', 'userAddresses', 'discount', 'couponCode'));
+    }
+
+    public function applyCoupon(Request $request)
+    {
+        $code = trim($request->input('coupon_code', ''));
+        if (!$code) {
+            return back()->with('coupon_error', 'Bitte Gutscheincode eingeben.');
+        }
+        $coupon = Coupon::findValid($code);
+        if (!$coupon) {
+            return back()->with('coupon_error', 'Gutscheincode ungültig oder abgelaufen.');
+        }
+        $subtotal = $this->cart->subtotal();
+        if ($coupon->min_order_value && $subtotal < $coupon->min_order_value) {
+            return back()->with('coupon_error', 'Mindestbestellwert von ' . number_format($coupon->min_order_value, 2, ',', '.') . ' € nicht erreicht.');
+        }
+        session(['coupon_code' => $coupon->code]);
+        return back()->with('coupon_success', 'Gutschein "' . $coupon->code . '" angewendet!');
+    }
+
+    public function removeCoupon()
+    {
+        session()->forget('coupon_code');
+        return back()->with('coupon_success', 'Gutschein entfernt.');
+    }
+
+    public function shippingCost(Request $request)
+    {
+        $country = strtoupper($request->input('country', 'DE'));
+        session(['checkout_country' => $country]);
+        $subtotal     = $this->cart->subtotal();
+        $shippingRate = ShippingRate::forCart($subtotal, $country);
+        $cost         = $shippingRate ? $shippingRate->getCostForTotal($subtotal) : 0;
+        return response()->json(['cost' => $cost, 'formatted' => number_format($cost, 2, ',', '.') . ' €']);
     }
 
     public function storeAddress(Request $request)
@@ -83,10 +121,13 @@ class CheckoutController extends Controller
         if ($request->isMethod('get')) {
             $items        = $this->cart->get();
             $subtotal     = $this->cart->subtotal();
-            $shippingRate = ShippingRate::forCart($subtotal);
+            $country      = $checkoutData['shipping']['country'] ?? $checkoutData['billing']['country'] ?? 'DE';
+            $shippingRate = ShippingRate::forCart($subtotal, $country);
             $shippingCost = $shippingRate ? $shippingRate->getCostForTotal($subtotal) : 0;
-            $total        = $subtotal + $shippingCost;
-            return view('shop.checkout.confirm', compact('checkoutData', 'items', 'subtotal', 'shippingCost', 'total'));
+            $discount     = $this->getCouponDiscount($subtotal);
+            $total        = max(0, $subtotal - $discount) + $shippingCost;
+            $couponCode   = session('coupon_code');
+            return view('shop.checkout.confirm', compact('checkoutData', 'items', 'subtotal', 'shippingCost', 'total', 'discount', 'couponCode'));
         }
 
         $order = $this->orderService->createFromSession(
@@ -94,7 +135,7 @@ class CheckoutController extends Controller
             $checkoutData['payment_method']
         );
 
-        session()->forget('checkout_data');
+        session()->forget(['checkout_data', 'checkout_country']);
 
         return redirect()->route('checkout.thankyou', $order->order_number);
     }
@@ -104,4 +145,15 @@ class CheckoutController extends Controller
         $order = \App\Models\Order::where('order_number', $order)->firstOrFail();
         return view('shop.checkout.thankyou', compact('order'));
     }
+
+    private function getCouponDiscount(float $subtotal): float
+    {
+        if ($code = session('coupon_code')) {
+            $coupon = Coupon::findValid($code);
+            if ($coupon) {
+                return $coupon->calcDiscount($subtotal);
+            }
+        }
+        return 0;
+    }
 }