Add top DMs route and handlers

store/opentracinglayer/opentracinglayer.go

@@ -6007,6 +6007,24 @@ func (s *OpenTracingLayerPostStore) GetSingle(id string, inclDeleted bool) (*mod
 	return result, err
 }
 
+func (s *OpenTracingLayerPostStore) GetTopDMsForUserSince(userID string, since int64, offset int, limit int) (*model.TopDMList, error) {
+	origCtx := s.Root.Store.Context()
+	span, newCtx := tracing.StartSpanWithParentByContext(s.Root.Store.Context(), "PostStore.GetTopDMsForUserSince")
+	s.Root.Store.SetContext(newCtx)
+	defer func() {
+		s.Root.Store.SetContext(origCtx)
+	}()
+
+	defer span.Finish()
+	result, err := s.PostStore.GetTopDMsForUserSince(userID, since, offset, limit)
+	if err != nil {
+		span.LogFields(spanlog.Error(err))
+		ext.Error.Set(span, true)
+	}
+
+	return result, err
+}
+
 func (s *OpenTracingLayerPostStore) HasAutoResponsePostByUserSince(options model.GetPostsSinceOptions, userId string) (bool, error) {
 	origCtx := s.Root.Store.Context()
 	span, newCtx := tracing.StartSpanWithParentByContext(s.Root.Store.Context(), "PostStore.HasAutoResponsePostByUserSince")

store/retrylayer/retrylayer.go

@@ -6806,6 +6806,27 @@ func (s *RetryLayerPostStore) GetSingle(id string, inclDeleted bool) (*model.Pos
 
 }
 
+func (s *RetryLayerPostStore) GetTopDMsForUserSince(userID string, since int64, offset int, limit int) (*model.TopDMList, error) {
+
+	tries := 0
+	for {
+		result, err := s.PostStore.GetTopDMsForUserSince(userID, since, offset, limit)
+		if err == nil {
+			return result, nil
+		}
+		if !isRepeatableError(err) {
+			return result, err
+		}
+		tries++
+		if tries >= 3 {
+			err = errors.Wrap(err, "giving up after 3 consecutive repeatable transaction failures")
+			return result, err
+		}
+		timepkg.Sleep(100 * timepkg.Millisecond)
+	}
+
+}
+
 func (s *RetryLayerPostStore) HasAutoResponsePostByUserSince(options model.GetPostsSinceOptions, userId string) (bool, error) {
 
 	tries := 0

store/sqlstore/post_store.go

@@ -2963,3 +2963,55 @@ func (s *SqlPostStore) updateThreadsFromPosts(transaction *sqlxTxWrapper, posts
 	}
 	return nil
 }
+
+func (s *SqlPostStore) GetTopDMsForUserSince(userID string, since int64, offset int, limit int) (*model.TopDMList, error) {
+	channelSelector := s.getQueryBuilder().Select("Id", "TotalMsgCount").From("Channels").Join("ChannelMembers as cm on cm.ChannelId = Channels.Id").
+		Where(sq.And{
+			sq.Expr("Channels.Type = 'D'"),
+			sq.Eq{"cm.UserId": userID},
+		})
+	var aggregator string
+
+	if s.DriverName() == model.DatabaseDriverMysql {
+		aggregator = "group_concat(distinct cm.UserId) as Participants"
+	} else {
+		aggregator = "string_agg(distinct cm.UserId, ',') as Participants"
+	}
+
+	topDMsBuilder := s.getQueryBuilder().Select("count(p.id) as MessageCount", aggregator).FromSelect(channelSelector, "vch").
+		Join("ChannelMembers as cm on cm.ChannelId = vch.Id").
+		Join("Posts as p on p.ChannelId = vch.Id").
+		Where(sq.Gt{
+			"p.UpdateAt": since,
+		}).GroupBy("vch.id").
+		Limit(uint64(limit)).
+		Offset(uint64(offset))
+
+	topDMsBuilder = topDMsBuilder.OrderBy("MessageCount DESC").Limit(uint64(limit)).Offset(uint64(offset))
+
+	topDMs := make([]*model.TopDM, 0)
+	sql, args, err := topDMsBuilder.ToSql()
+	if err != nil {
+		return nil, errors.Wrap(err, "GetTopDMsForUserSince_ToSql")
+	}
+	err = s.GetReplicaX().Select(&topDMs, sql, args...)
+	if err != nil {
+		return nil, errors.Wrapf(err, "failed to find top DMs for user-id: %s", userID)
+	}
+
+	// fill SecondParticipant column
+	topDMs = postProcessTopDMs(userID, topDMs)
+	return model.GetTopDMListWithPagination(topDMs, limit), nil
+}
+
+func postProcessTopDMs(userID string, topDMs []*model.TopDM) []*model.TopDM {
+	for _, topDM := range topDMs {
+		participants := strings.Split(topDM.Participants, ",")
+		if participants[0] == userID {
+			topDM.SecondParticipant = participants[1]
+		} else {
+			topDM.SecondParticipant = participants[0]
+		}
+	}
+	return topDMs
+}

store/store.go

@@ -388,6 +388,9 @@ type PostStore interface {
 	GetPostsSinceForSync(options model.GetPostsSinceForSyncOptions, cursor model.GetPostsSinceForSyncCursor, limit int) ([]*model.Post, model.GetPostsSinceForSyncCursor, error)
 	// GetNthRecentPostTime returns the CreateAt time of the nth most recent post.
 	GetNthRecentPostTime(n int64) (int64, error)
+
+	// Insights - top DMs
+	GetTopDMsForUserSince(userID string, since int64, offset int, limit int) (*model.TopDMList, error)
 }
 
 type UserStore interface {

store/storetest/mocks/PostStore.go

@@ -700,6 +700,29 @@ func (_m *PostStore) GetSingle(id string, inclDeleted bool) (*model.Post, error)
 	return r0, r1
 }
 
+// GetTopDMsForUserSince provides a mock function with given fields: userID, since, offset, limit
+func (_m *PostStore) GetTopDMsForUserSince(userID string, since int64, offset int, limit int) (*model.TopDMList, error) {
+	ret := _m.Called(userID, since, offset, limit)
+
+	var r0 *model.TopDMList
+	if rf, ok := ret.Get(0).(func(string, int64, int, int) *model.TopDMList); ok {
+		r0 = rf(userID, since, offset, limit)
+	} else {
+		if ret.Get(0) != nil {
+			r0 = ret.Get(0).(*model.TopDMList)
+		}
+	}
+
+	var r1 error
+	if rf, ok := ret.Get(1).(func(string, int64, int, int) error); ok {
+		r1 = rf(userID, since, offset, limit)
+	} else {
+		r1 = ret.Error(1)
+	}
+
+	return r0, r1
+}
+
 // HasAutoResponsePostByUserSince provides a mock function with given fields: options, userId
 func (_m *PostStore) HasAutoResponsePostByUserSince(options model.GetPostsSinceOptions, userId string) (bool, error) {
 	ret := _m.Called(options, userId)

store/timerlayer/timerlayer.go

@@ -5434,6 +5434,22 @@ func (s *TimerLayerPostStore) GetSingle(id string, inclDeleted bool) (*model.Pos
 	return result, err
 }
 
+func (s *TimerLayerPostStore) GetTopDMsForUserSince(userID string, since int64, offset int, limit int) (*model.TopDMList, error) {
+	start := time.Now()
+
+	result, err := s.PostStore.GetTopDMsForUserSince(userID, since, offset, limit)
+
+	elapsed := float64(time.Since(start)) / float64(time.Second)
+	if s.Root.Metrics != nil {
+		success := "false"
+		if err == nil {
+			success = "true"
+		}
+		s.Root.Metrics.ObserveStoreMethodDuration("PostStore.GetTopDMsForUserSince", success, elapsed)
+	}
+	return result, err
+}
+
 func (s *TimerLayerPostStore) HasAutoResponsePostByUserSince(options model.GetPostsSinceOptions, userId string) (bool, error) {
 	start := time.Now()