update pay function

src/components/Subscription/SubscriptionContentNew.tsx

@@ -270,6 +270,46 @@ export default function SubscriptionContentNew() {
     try {
       const price = priceInfo?.final_amount || getCurrentPrice(selectedPlan);
 
+      // 检查是否为免费升级（剩余价值足够抵扣新套餐价格）
+      if (price === 0 && priceInfo?.is_upgrade) {
+        const response = await fetch('/api/subscription/free-upgrade', {
+          method: 'POST',
+          headers: {
+            'Content-Type': 'application/json',
+          },
+          credentials: 'include',
+          body: JSON.stringify({
+            plan_name: selectedPlan.name,
+            billing_cycle: selectedCycle,
+          }),
+        });
+
+        const data = await response.json();
+        if (data.success) {
+          subscriptionEvents.trackPaymentSuccessful({
+            planName: selectedPlan.name,
+            paymentMethod: 'free_upgrade',
+            amount: 0,
+            orderId: 'free_upgrade',
+            transactionId: 'free_upgrade',
+          });
+
+          toast({
+            title: '升级成功！',
+            description: data.message,
+            status: 'success',
+            duration: 5000,
+            isClosable: true,
+          });
+
+          onClose();
+          setTimeout(() => window.location.reload(), 2000);
+          return;
+        } else {
+          throw new Error(data.error || '免费升级失败');
+        }
+      }
+
       subscriptionEvents.trackPaymentInitiated({
         planName: selectedPlan.name,
         paymentMethod: 'wechat_pay',
@@ -1122,7 +1162,9 @@ export default function SubscriptionContentNew() {
                         <HStack spacing={2}>
                           <Icon as={FaCheck} color="green.400" />
                           <Text color="green.400" fontSize="sm" fontWeight="medium">
-                            升级到{selectedPlan.displayName}，立即生效！按差价补缴费用
+                            {priceInfo.final_amount === 0
+                              ? `恭喜！您的当前订阅剩余价值足够直接升级到${selectedPlan.displayName}，无需支付额外费用！`
+                              : `升级到${selectedPlan.displayName}，立即生效！按差价补缴费用`}
                           </Text>
                         </HStack>
                       </Box>
@@ -1293,7 +1335,9 @@ export default function SubscriptionContentNew() {
                     bgGradient: 'linear-gradient(135deg, #F4E3A7, #D4AF37)',
                   }}
                 >
-                  创建微信支付订单
+                  {priceInfo?.is_upgrade && priceInfo?.final_amount === 0
+                    ? '立即免费升级'
+                    : '创建微信支付订单'}
                 </Button>
               </VStack>
             ) : (