Fix Paddle coupon payload

app/Services/Paddle/PaddleDiscountService.php

@@ -88,19 +88,17 @@ class PaddleDiscountService
     protected function buildDiscountPayload(Coupon $coupon): array
     {
         $payload = [
-            'name' => $coupon->name,
             'code' => $coupon->code,
             'type' => $this->mapType($coupon->type),
             'amount' => $this->formatAmount($coupon),
-            'currency_code' => $coupon->currency ?? config('app.currency', 'EUR'),
+            'currency_code' => Str::upper((string) ($coupon->currency ?? config('app.currency', 'EUR'))),
             'enabled_for_checkout' => $coupon->enabled_for_checkout,
-            'description' => $coupon->description,
+            'description' => $this->resolveDescription($coupon),
             'mode' => $coupon->paddle_mode ?? 'standard',
             'usage_limit' => $coupon->usage_limit,
             'maximum_recurring_intervals' => null,
             'recur' => false,
             'restrict_to' => $this->resolveRestrictions($coupon),
-            'starts_at' => optional($coupon->starts_at)?->toIso8601String(),
             'expires_at' => optional($coupon->ends_at)?->toIso8601String(),
         ];
 
@@ -146,4 +144,27 @@ class PaddleDiscountService
 
         return $prices->isEmpty() ? null : $prices->all();
     }
+
+    protected function resolveDescription(Coupon $coupon): string
+    {
+        $description = trim((string) ($coupon->description ?? ''));
+
+        if ($description !== '') {
+            return $description;
+        }
+
+        $name = trim((string) ($coupon->name ?? ''));
+
+        if ($name !== '') {
+            return $name;
+        }
+
+        $code = trim((string) ($coupon->code ?? ''));
+
+        if ($code !== '') {
+            return sprintf('Coupon %s', $code);
+        }
+
+        return sprintf('Coupon %d', $coupon->id);
+    }
 }