PLT-4430 improve slow channel switching (#4331)

* PLT-4430 improve slow channel switching

* Update client side unit tests

* Convert getChannelsUnread to getMyChannelMembers and address other feedback

* Pull channel members on websocket reconnect

3 files changed, 90 insertions, 21 deletions

diff --git a/store/sql_channel_store.go b/store/sql_channel_store.go
index f863d57fd..f1cf7f849 100644
--- a/store/sql_channel_store.go
+++ b/store/sql_channel_store.go
@@ -367,23 +367,16 @@ func (s SqlChannelStore) GetChannels(teamId string, userId string) StoreChannel
 	go func() {
 		result := StoreResult{}
 
-		var data []channelWithMember
-		_, err := s.GetReplica().Select(&data, "SELECT * FROM Channels, ChannelMembers WHERE Id = ChannelId AND UserId = :UserId AND DeleteAt = 0 AND (TeamId = :TeamId OR TeamId = '') ORDER BY DisplayName", map[string]interface{}{"TeamId": teamId, "UserId": userId})
+		data := &model.ChannelList{}
+		_, err := s.GetReplica().Select(data, "SELECT Channels.* FROM Channels, ChannelMembers WHERE Id = ChannelId AND UserId = :UserId AND DeleteAt = 0 AND (TeamId = :TeamId OR TeamId = '') ORDER BY DisplayName", map[string]interface{}{"TeamId": teamId, "UserId": userId})
 
 		if err != nil {
 			result.Err = model.NewLocAppError("SqlChannelStore.GetChannels", "store.sql_channel.get_channels.get.app_error", nil, "teamId="+teamId+", userId="+userId+", err="+err.Error())
 		} else {
-			channels := &model.ChannelList{make([]*model.Channel, len(data)), make(map[string]*model.ChannelMember)}
-			for i := range data {
-				v := data[i]
-				channels.Channels[i] = &v.Channel
-				channels.Members[v.Channel.Id] = &v.ChannelMember
-			}
-
-			if len(channels.Channels) == 0 {
+			if len(*data) == 0 {
 				result.Err = model.NewLocAppError("SqlChannelStore.GetChannels", "store.sql_channel.get_channels.not_found.app_error", nil, "teamId="+teamId+", userId="+userId)
 			} else {
-				result.Data = channels
+				result.Data = data
 			}
 		}
 
@@ -400,8 +393,8 @@ func (s SqlChannelStore) GetMoreChannels(teamId string, userId string) StoreChan
 	go func() {
 		result := StoreResult{}
 
-		var data []*model.Channel
-		_, err := s.GetReplica().Select(&data,
+		data := &model.ChannelList{}
+		_, err := s.GetReplica().Select(data,
 			`SELECT 
 			    *
 			FROM
@@ -426,7 +419,7 @@ func (s SqlChannelStore) GetMoreChannels(teamId string, userId string) StoreChan
 		if err != nil {
 			result.Err = model.NewLocAppError("SqlChannelStore.GetMoreChannels", "store.sql_channel.get_more_channels.get.app_error", nil, "teamId="+teamId+", userId="+userId+", err="+err.Error())
 		} else {
-			result.Data = &model.ChannelList{data, make(map[string]*model.ChannelMember)}
+			result.Data = data
 		}
 
 		storeChannel <- result
@@ -918,11 +911,12 @@ func (s SqlChannelStore) IncrementMentionCount(channelId string, userId string)
 			`UPDATE
 				ChannelMembers
 			SET
-				MentionCount = MentionCount + 1
+				MentionCount = MentionCount + 1,
+				LastUpdateAt = :LastUpdateAt
 			WHERE
 				UserId = :UserId
 					AND ChannelId = :ChannelId`,
-			map[string]interface{}{"ChannelId": channelId, "UserId": userId})
+			map[string]interface{}{"ChannelId": channelId, "UserId": userId, "LastUpdateAt": model.GetMillis()})
 		if err != nil {
 			result.Err = model.NewLocAppError("SqlChannelStore.IncrementMentionCount", "store.sql_channel.increment_mention_count.app_error", nil, "channel_id="+channelId+", user_id="+userId+", "+err.Error())
 		}
@@ -1032,3 +1026,32 @@ func (s SqlChannelStore) ExtraUpdateByUser(userId string, time int64) StoreChann
 
 	return storeChannel
 }
+
+func (s SqlChannelStore) GetMembersForUser(teamId string, userId string) StoreChannel {
+	storeChannel := make(StoreChannel, 1)
+
+	go func() {
+		result := StoreResult{}
+
+		members := &model.ChannelMembers{}
+		_, err := s.GetReplica().Select(members, `
+            SELECT cm.*
+            FROM ChannelMembers cm
+            INNER JOIN Channels c
+                ON c.Id = cm.ChannelId
+                AND c.TeamId = :TeamId
+            WHERE cm.UserId = :UserId
+		`, map[string]interface{}{"TeamId": teamId, "UserId": userId})
+
+		if err != nil {
+			result.Err = model.NewLocAppError("SqlChannelStore.GetMembersForUser", "store.sql_channel.get_members.app_error", nil, "teamId="+teamId+", userId="+userId+", err="+err.Error())
+		} else {
+			result.Data = members
+		}
+
+		storeChannel <- result
+		close(storeChannel)
+	}()
+
+	return storeChannel
+}
diff --git a/store/sql_channel_store_test.go b/store/sql_channel_store_test.go
index d80d54d52..8a51d2ae3 100644
--- a/store/sql_channel_store_test.go
+++ b/store/sql_channel_store_test.go
@@ -305,14 +305,14 @@ func TestChannelStoreDelete(t *testing.T) {
 	cresult := <-store.Channel().GetChannels(o1.TeamId, m1.UserId)
 	list := cresult.Data.(*model.ChannelList)
 
-	if len(list.Channels) != 1 {
+	if len(*list) != 1 {
 		t.Fatal("invalid number of channels")
 	}
 
 	cresult = <-store.Channel().GetMoreChannels(o1.TeamId, m1.UserId)
 	list = cresult.Data.(*model.ChannelList)
 
-	if len(list.Channels) != 1 {
+	if len(*list) != 1 {
 		t.Fatal("invalid number of channels")
 	}
 }
@@ -514,7 +514,7 @@ func TestChannelStoreGetChannels(t *testing.T) {
 	cresult := <-store.Channel().GetChannels(o1.TeamId, m1.UserId)
 	list := cresult.Data.(*model.ChannelList)
 
-	if list.Channels[0].Id != o1.Id {
+	if (*list)[0].Id != o1.Id {
 		t.Fatal("missing channel")
 	}
 
@@ -614,11 +614,11 @@ func TestChannelStoreGetMoreChannels(t *testing.T) {
 	cresult := <-store.Channel().GetMoreChannels(o1.TeamId, m1.UserId)
 	list := cresult.Data.(*model.ChannelList)
 
-	if len(list.Channels) != 1 {
+	if len(*list) != 1 {
 		t.Fatal("wrong list")
 	}
 
-	if list.Channels[0].Name != o3.Name {
+	if (*list)[0].Name != o3.Name {
 		t.Fatal("missing channel")
 	}
 
@@ -688,6 +688,51 @@ func TestChannelStoreGetChannelCounts(t *testing.T) {
 	}
 }
 
+func TestChannelStoreGetMembersForUser(t *testing.T) {
+	Setup()
+
+	t1 := model.Team{}
+	t1.DisplayName = "Name"
+	t1.Name = model.NewId()
+	t1.Email = model.NewId() + "@nowhere.com"
+	t1.Type = model.TEAM_OPEN
+	Must(store.Team().Save(&t1))
+
+	o1 := model.Channel{}
+	o1.TeamId = t1.Id
+	o1.DisplayName = "Channel1"
+	o1.Name = "a" + model.NewId() + "b"
+	o1.Type = model.CHANNEL_OPEN
+	Must(store.Channel().Save(&o1))
+
+	o2 := model.Channel{}
+	o2.TeamId = o1.TeamId
+	o2.DisplayName = "Channel2"
+	o2.Name = "a" + model.NewId() + "b"
+	o2.Type = model.CHANNEL_OPEN
+	Must(store.Channel().Save(&o2))
+
+	m1 := model.ChannelMember{}
+	m1.ChannelId = o1.Id
+	m1.UserId = model.NewId()
+	m1.NotifyProps = model.GetDefaultChannelNotifyProps()
+	Must(store.Channel().SaveMember(&m1))
+
+	m2 := model.ChannelMember{}
+	m2.ChannelId = o2.Id
+	m2.UserId = m1.UserId
+	m2.NotifyProps = model.GetDefaultChannelNotifyProps()
+	Must(store.Channel().SaveMember(&m2))
+
+	cresult := <-store.Channel().GetMembersForUser(o1.TeamId, m1.UserId)
+	members := cresult.Data.(*model.ChannelMembers)
+
+	// no unread messages
+	if len(*members) != 2 {
+		t.Fatal("wrong number of members")
+	}
+}
+
 func TestChannelStoreUpdateLastViewedAt(t *testing.T) {
 	Setup()
 
diff --git a/store/store.go b/store/store.go
index 51aada920..6cf216699 100644
--- a/store/store.go
+++ b/store/store.go
@@ -109,6 +109,7 @@ type ChannelStore interface {
 	IncrementMentionCount(channelId string, userId string) StoreChannel
 	AnalyticsTypeCount(teamId string, channelType string) StoreChannel
 	ExtraUpdateByUser(userId string, time int64) StoreChannel
+	GetMembersForUser(teamId string, userId string) StoreChannel
 }
 
 type PostStore interface {