🐞 fix(shop): 修复弱网下商品可买次数为负问题

shared/db/UserShop.ts

@@ -95,6 +95,33 @@ export default class UserShop extends BaseModel {
         return rec;
     }
 
+    /**
+     * 防止并发操作的购买
+     *
+     * @static
+     * @param {string} roleId
+     * @param {string} roleName
+     * @param {number} activityId
+     * @param {{ id: number, goodId: number, refreshType: number, shop: number, type: number, createTime?: number }} dicShopItem
+     * @param {number} inc
+     * @param {number} seasonNum
+     * @param {number} maxAlreadyBuyTimes: 最大已买次数，通过这个参数防止并发购买
+     * @return {*} 
+     * @memberof UserShop
+     */
+    public static async protectedPurchase(roleId: string, roleName: string, activityId: number, dicShopItem: { id: number, goodId: number, refreshType: number, shop: number, type: number, createTime?: number }, inc: number, seasonNum: number, maxAlreadyBuyTimes: number) {
+        let code = genCode(8);
+        let timeCondition = this.getRefreshCondition(seasonNum);
+        let { id, goodId, refreshType, shop, type, createTime = 0 } = dicShopItem;
+
+        let rec: UserShopType = await UserShopModel.findOneAndUpdate(
+            { roleId, itemId: id, $or: timeCondition, shop, type, createTime, count: {$lte: maxAlreadyBuyTimes} }, 
+            { $setOnInsert: { roleName, code, goodId, refreshType, seasonNum }, $inc: { count: inc }, $set: { activityId } },
+            { new: true, upsert: true }
+        ).lean();
+        return rec;
+    }
+
     public static async deleteAccount(roleId: string) {
         let result = await UserShopModel.deleteMany({roleId});
         return result;