fix: 优化列表切片长度处理逻辑

internal/tools/bbxt/bbxt.go

@@ -368,7 +368,13 @@ func (b *BbxtTools) GetProfitRankingSum(now time.Time) (report *ReportRes, err e
 	if err != nil {
 		return
 	}
-
+	if len(data.List) == 0 {
+		return nil, nil
+	}
+	maxLen := 20
+	if len(data.List) < maxLen {
+		maxLen = len(data.List)
+	}
 	//排序
 	sort.Slice(data.List, func(i, j int) bool {
 		return data.List[i].HistoryOneDiff > data.List[j].HistoryOneDiff
@@ -376,7 +382,7 @@ func (b *BbxtTools) GetProfitRankingSum(now time.Time) (report *ReportRes, err e
 	//取前20和后20
 	var (
 		total  [][]string
-		top    = data.List[:20]
+		top    = data.List[:maxLen]
 		bottom = data.List[len(data.List)-20:]
 	)
 	//合并前20和后20