Add checkin count in attendance and event api

Signed-off-by: Asai Neko <sugar@sne.moe>

data/attendance.go

@@ -149,6 +149,29 @@ func (self *Attendance) CountUsersByEventID(ctx context.Context, eventID uuid.UU
 		Where("event_id = ?", eventID).
 		Count(&count).Error
 
+	if err == gorm.ErrRecordNotFound {
+		return 0, nil
+	}
+
+	if err != nil {
+		return 0, err
+	}
+
+	return count, nil
+}
+
+func (self *Attendance) CountCheckedInUsersByEventID(ctx context.Context, eventID uuid.UUID) (int64, error) {
+	var count int64
+
+	err := Database.WithContext(ctx).
+		Model(&Attendance{}).
+		Where("event_id = ? AND checkin_at IS NOT NULL AND checkin_at > ?", eventID, time.Time{}). // 过滤未签到用户
+		Count(&count).Error
+
+	if err == gorm.ErrRecordNotFound {
+		return 0, nil
+	}
+
 	if err != nil {
 		return 0, err
 	}