update pay function

app.py

@@ -1323,40 +1323,96 @@ def calculate_subscription_price_simple(user_id, to_plan_name, to_cycle, promo_c
         if price <= 0:
             return {'error': f'{to_cycle} 周期价格未配置'}
 
-        # 4. 判断是新购还是续费
+        # 4. 判断订阅类型和计算价格
         is_renewal = False
+        is_upgrade = False
+        is_downgrade = False
         subscription_type = 'new'
         current_plan = None
         current_cycle = None
+        remaining_value = 0
+        final_price = price
 
         if current_sub and current_sub.subscription_type in ['pro', 'max']:
-            # 如果当前是付费用户，则为续费
-            is_renewal = True
-            subscription_type = 'renew'
             current_plan = current_sub.subscription_type
             current_cycle = current_sub.billing_cycle
 
-        # 5. 构建结果（续费和新购价格完全一致）
+            if current_plan == to_plan_name:
+                # 同级续费：延长时长，全价购买
+                is_renewal = True
+                subscription_type = 'renew'
+            elif current_plan == 'pro' and to_plan_name == 'max':
+                # 升级：Pro → Max，需要计算差价
+                is_upgrade = True
+                subscription_type = 'upgrade'
+
+                # 计算当前订阅的剩余价值
+                if current_sub.end_date and current_sub.end_date > datetime.utcnow():
+                    # 获取当前套餐的原始价格
+                    current_plan_obj = SubscriptionPlan.query.filter_by(name=current_plan, is_active=True).first()
+                    if current_plan_obj and current_plan_obj.pricing_options:
+                        try:
+                            pricing_opts = json.loads(current_plan_obj.pricing_options)
+                            current_price = None
+                            for opt in pricing_opts:
+                                if opt.get('cycle_key') == current_cycle:
+                                    current_price = float(opt.get('price', 0))
+                                    break
+
+                            if current_price and current_price > 0:
+                                # 计算剩余天数
+                                remaining_days = (current_sub.end_date - datetime.utcnow()).days
+
+                                # 计算总天数
+                                cycle_days_map = {
+                                    'monthly': 30,
+                                    'quarterly': 90,
+                                    'semiannual': 180,
+                                    'yearly': 365
+                                }
+                                total_days = cycle_days_map.get(current_cycle, 30)
+
+                                # 计算剩余价值
+                                if total_days > 0 and remaining_days > 0:
+                                    remaining_value = current_price * (remaining_days / total_days)
+                                    # 实付金额 = 新套餐价格 - 剩余价值
+                                    final_price = max(0, price - remaining_value)
+                        except:
+                            pass
+            elif current_plan == 'max' and to_plan_name == 'pro':
+                # 降级：Max → Pro，到期后切换，全价购买
+                is_downgrade = True
+                subscription_type = 'downgrade'
+            else:
+                # 其他情况视为新购
+                subscription_type = 'new'
+
+        # 5. 构建结果
         result = {
             'is_renewal': is_renewal,
+            'is_upgrade': is_upgrade,
+            'is_downgrade': is_downgrade,
             'subscription_type': subscription_type,
             'current_plan': current_plan,
             'current_cycle': current_cycle,
             'new_plan_price': price,
+            'original_price': price,  # 新套餐原价
+            'remaining_value': remaining_value,  # 当前订阅剩余价值（仅升级时有效）
             'original_amount': price,
             'discount_amount': 0,
-            'final_amount': price,
+            'final_amount': final_price,
             'promo_code': None,
             'promo_error': None
         }
 
-        # 6. 应用优惠码
+        # 6. 应用优惠码（基于差价后的金额）
         if promo_code and promo_code.strip():
-            promo, error = validate_promo_code(promo_code, to_plan_name, to_cycle, price, user_id)
+            # 优惠码作用于差价后的金额
+            promo, error = validate_promo_code(promo_code, to_plan_name, to_cycle, final_price, user_id)
             if promo:
-                discount = calculate_discount(promo, price)
+                discount = calculate_discount(promo, final_price)
                 result['discount_amount'] = float(discount)
-                result['final_amount'] = price - float(discount)
+                result['final_amount'] = final_price - float(discount)
                 result['promo_code'] = promo.code
             elif error:
                 result['promo_error'] = error