fix: 添加代理生成卡密余额检查和扣费逻辑

- 检查代理余额是否足够
- 检查并限制生成数量(1-100)
- 使用事务确保数据一致性
- 扣除代理余额
- 记录消费记录

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

backend/internal/router/agent/agent.go

@@ -1,6 +1,7 @@
 package agent
 
 import (
+	"fmt"
 	"math/rand"
 	"strconv"
 	"time"
@@ -235,6 +236,12 @@ func handleGenerateCards(c *gin.Context) {
 		return
 	}
 
+	// 限制最大生成数量
+	if req.Quantity <= 0 || req.Quantity > 100 {
+		response.Error(c, 400, "生成数量必须在1-100之间")
+		return
+	}
+
 	// 兼容 app_id 和 application_id
 	appID := req.ApplicationID
 	if appID == 0 {
@@ -254,13 +261,24 @@ func handleGenerateCards(c *gin.Context) {
 		return
 	}
 
-	// 获取卡类信息以计算价格
-	var cardType model.CardType
-	if err := database.DB.First(&cardType, req.CardTypeID).Error; err != nil {
-		response.Error(c, 404, "卡类不存在")
+	// 计算总价格
+	totalPrice := agentCardType.Price * float64(req.Quantity)
+
+	// 获取代理余额并检查是否足够
+	var user model.User
+	if err := database.DB.First(&user, userID).Error; err != nil {
+		response.Error(c, 404, "用户不存在")
 		return
 	}
 
+	if user.Balance < totalPrice {
+		response.Error(c, 400, fmt.Sprintf("余额不足，当前余额: %.2f，需要: %.2f", user.Balance, totalPrice))
+		return
+	}
+
+	// 使用事务确保数据一致性
+	tx := database.DB.Begin()
+
 	cards := make([]model.Card, req.Quantity)
 	for i := 0; i < req.Quantity; i++ {
 		cards[i] = model.Card{
@@ -273,11 +291,36 @@ func handleGenerateCards(c *gin.Context) {
 		}
 	}
 
-	if err := database.DB.Create(&cards).Error; err != nil {
+	if err := tx.Create(&cards).Error; err != nil {
+		tx.Rollback()
 		response.Error(c, 500, "生成卡密失败")
 		return
 	}
 
+	// 扣除余额
+	if err := tx.Model(&user).Update("balance", user.Balance-totalPrice).Error; err != nil {
+		tx.Rollback()
+		response.Error(c, 500, "扣除余额失败")
+		return
+	}
+
+	// 记录消费记录
+	consumeRecord := model.RechargeRecord{
+		UserID:      userID,
+		OrderNo:     fmt.Sprintf("CARD%d%d", userID, time.Now().UnixNano()),
+		Amount:      -totalPrice,
+		Status:      "success",
+		PaymentType: "balance",
+		Remark:      fmt.Sprintf("生成卡密 %d 张", req.Quantity),
+	}
+	if err := tx.Create(&consumeRecord).Error; err != nil {
+		tx.Rollback()
+		response.Error(c, 500, "记录消费失败")
+		return
+	}
+
+	tx.Commit()
+
 	// 返回生成的卡号
 	codes := make([]string, req.Quantity)
 	for i, card := range cards {
@@ -285,8 +328,10 @@ func handleGenerateCards(c *gin.Context) {
 	}
 
 	response.Success(c, gin.H{
-		"count": req.Quantity,
-		"codes": codes,
+		"count":      req.Quantity,
+		"codes":      codes,
+		"totalPrice": totalPrice,
+		"balance":    user.Balance - totalPrice,
 	})
 }