fix(vip): preserve layered membership expirations

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/Admin/Schema/SchemaPayment.php

@@ -129,7 +129,7 @@ class SchemaPayment {
                         ]],
                         ['key' => 'points_exchange', 'title' => '积分兑换会员', 'fields' => [
                             ['key' => 'pay_vip_points_exchange_s', 'label' => '启用积分兑换', 'type' => 'switch', 'default' => false],
-                            ['key' => 'payment_vip_points_packages', 'label' => '兑换套餐', 'type' => 'textarea', 'default' => "1|500|30|积分月卡\n1|5000|0|积分永久", 'dependsOn' => ['key' => 'pay_vip_points_exchange_s', 'value' => true], 'help' => '每行：等级|积分|天数|标题（天数 0=永久；仅未开通会员可兑）'],
+                            ['key' => 'payment_vip_points_packages', 'label' => '兑换套餐', 'type' => 'textarea', 'default' => "1|500|30|积分月卡\n1|5000|0|积分永久", 'dependsOn' => ['key' => 'pay_vip_points_exchange_s', 'value' => true], 'help' => '每行：等级|积分|天数|标题（天数 0=永久；普通用户可开通，已有会员可续费同等级或升级更高等级）'],
                             ['key' => 'pay_vip_points_exchange_desc', 'label' => '兑换说明', 'type' => 'textarea', 'default' => '', 'dependsOn' => ['key' => 'pay_vip_points_exchange_s', 'value' => true]],
                         ]],
                         ['key' => 'benefit', 'title' => '下载权益', 'fields' => [

src/Content/VipServicePurchase.php

@@ -515,6 +515,16 @@ trait VipServicePurchase {
 
         $previous_level = (int) get_user_meta($user_id, 'aksrt_vip_level', true);
         $previous_expiry = (int) get_user_meta($user_id, 'aksrt_vip_expires', true);
+        $finite_duration = $time > 0 || $days > 0;
+        if ($previous_level > 0 && $previous_expiry === 0 && $level > $previous_level && $finite_duration) {
+            // Preserve a permanent lower tier while a finite higher-tier upgrade is active.
+            update_user_meta($user_id, 'aksrt_vip_base_level', $previous_level);
+            update_user_meta($user_id, 'aksrt_vip_base_expires', 0);
+        } else {
+            // Only a finite higher-tier upgrade may keep a layered base membership.
+            delete_user_meta($user_id, 'aksrt_vip_base_level');
+            delete_user_meta($user_id, 'aksrt_vip_base_expires');
+        }
         $fulfilled = false;
         // unit upgrade: raise level only, keep current expiry (zibll).
         if ($upgrade_mode === 'unit') {
@@ -574,14 +584,15 @@ trait VipServicePurchase {
 
         if ($days <= 0) {
             // Permanent.
+            delete_user_meta($user_id, 'aksrt_vip_base_level');
+            delete_user_meta($user_id, 'aksrt_vip_base_expires');
             update_user_meta($user_id, 'aksrt_vip_expires', 0);
             return;
         }
 
         $current_exp = (int) get_user_meta($user_id, 'aksrt_vip_expires', true);
-        if ($current_exp === 0 && $current_level > 0) {
-            // Already permanent — keep permanent.
-            return;
+        if ($current_exp === 0 && $current_level > 0 && $level <= $current_level) {
+            return; // keep an existing permanent level when not upgrading it
         }
         $base = max($current_exp, time());
         update_user_meta($user_id, 'aksrt_vip_expires', $base + ($days * DAY_IN_SECONDS));
@@ -603,13 +614,15 @@ trait VipServicePurchase {
         delete_user_meta($user_id, 'aksrt_vip_level_expired');
 
         if ($time <= 0) {
+            delete_user_meta($user_id, 'aksrt_vip_base_level');
+            delete_user_meta($user_id, 'aksrt_vip_base_expires');
             update_user_meta($user_id, 'aksrt_vip_expires', 0);
             return;
         }
 
         $current_exp = (int) get_user_meta($user_id, 'aksrt_vip_expires', true);
-        if ($current_exp === 0 && $current_level > 0) {
-            return; // keep permanent
+        if ($current_exp === 0 && $current_level > 0 && $level <= $current_level) {
+            return; // keep an existing permanent level when not upgrading it
         }
         $base = max($current_exp, time());
         $modifier = $unit === 'month'