type TimeShardType string

const (
    ShardTypeYear TimeShardType = "year"   // 按年分片
    ShardTypeWeek TimeShardType = "week"   // 按周分片
)

// 格式: {table}_y{year}  或  {table}_w{date}

func GetTableNameByTimestamp(table string, timeType TimeShardType, ts int64, cycles ...int) string {
    tm := time.UnixMilli(ts).In(time.Local)

    switch timeType {
    case ShardTypeYear:
        if len(cycles) > 0 && cycles[0] != 0 {
            tm = tm.AddDate(cycles[0], 0, 0)
        }
        return fmt.Sprintf("%s_y%s", table, tm.Format("2006"))

    case ShardTypeWeek:
        if len(cycles) > 0 && cycles[0] != 0 {
            tm = tm.AddDate(0, 0, 7*cycles[0])
        }
        monday := GetWeekMonday(tm)
        return fmt.Sprintf("%s_w%s", table, monday.Format("20060102"))
    }
    return table
}

func GetWeekMonday(t time.Time) time.Time {
    weekday := int(t.Weekday())
    if weekday == 0 {
        weekday = 7
    }
    monday := t.AddDate(0, 0, -weekday+1)
    return time.Date(monday.Year(), monday.Month(), monday.Day(), 0, 0, 0, 0, t.Location())
}

type ShardSvc struct {
    Db *gorm.DB
}

// 自动识别需要查询的表范围
func EventDataSetDo[T any](ctx context.Context, rDb *gorm.DB, baseTable string, shardType shard.TimeShardType, startTs, endTs int64) (lst []T, err error) {
    var (
        eg, egCtx = errgroup.WithContext(ctx)
        mu        sync.Mutex
    )

    // 计算需要查询的表
    tables := calculateTables(baseTable, shardType, startTs, endTs)

    for _, tableName := range tables {
        table := tableName
        eg.Go(func() error {
            var data []T
            err := rDb.WithContext(egCtx).
                Table(table).
                Where("create_time >= ? AND create_time <= ?", startTs, endTs).
                Find(&data).Error

            if err != nil {
                return err
            }
            mu.Lock()
            lst = append(lst, data...)
            mu.Unlock()
            return nil
        })
    }

    return eg.Wait()
}

// 查询最近一周的数据
startTime := time.Now().AddDate(0, 0, -7).UnixMilli()
endTime := time.Now().UnixMilli()

tables := []string{
    shard.GetTableNameByTimestamp("event_data", shard.ShardTypeWeek, startTime),
    shard.GetTableNameByTimestamp("event_data", shard.ShardTypeWeek, endTime),
}

// 或使用分表查询服务
results, err := shardSvc.EventDataSetDo[EventData](ctx, db, "event_data", shard.ShardTypeWeek, startTime, endTime)