#4755 Combining consecutive user join/leave system messages to single message and few other changes. (#5945)

fix 7 and 8

remove @ at "{username} joined the channel"

refactor and update test

3 files changed, 62 insertions, 2 deletions

diff --git a/store/sql_post_store.go b/store/sql_post_store.go
index e89b5e042..c66e44274 100644
--- a/store/sql_post_store.go
+++ b/store/sql_post_store.go
@@ -97,8 +97,7 @@ func (s SqlPostStore) Save(post *model.Post) StoreChannel {
 		} else {
 			time := post.UpdateAt
 
-			if post.Type != model.POST_JOIN_LEAVE && post.Type != model.POST_JOIN_CHANNEL && post.Type != model.POST_LEAVE_CHANNEL &&
-				post.Type != model.POST_ADD_REMOVE && post.Type != model.POST_ADD_TO_CHANNEL && post.Type != model.POST_REMOVE_FROM_CHANNEL {
+			if !post.IsUserActivitySystemMessage() {
 				s.GetMaster().Exec("UPDATE Channels SET LastPostAt = :LastPostAt, TotalMsgCount = TotalMsgCount + 1 WHERE Id = :ChannelId", map[string]interface{}{"LastPostAt": time, "ChannelId": post.ChannelId})
 			} else {
 				// don't update TotalMsgCount for unimportant messages so that the channel isn't marked as unread
@@ -1355,3 +1354,29 @@ func (s SqlPostStore) GetPostsBatchForIndexing(startTime int64, limit int) Store
 
 	return storeChannel
 }
+
+func (s SqlPostStore) GetLastPostForChannel(channelId string) StoreChannel {
+	storeChannel := make(StoreChannel, 1)
+
+	go func() {
+		result := StoreResult{}
+
+		var post model.Post
+		query := `
+			SELECT * FROM Posts 
+			WHERE ChannelId = :channelId AND DeleteAt = 0
+			ORDER BY CreateAt DESC
+			LIMIT 1
+		`
+
+		if err := s.GetReplica().SelectOne(&post, query, map[string]interface{}{"channelId": channelId}); err != nil {
+			l4g.Error(err)
+		}
+
+		result.Data = &post
+		storeChannel <- result
+		close(storeChannel)
+	}()
+
+	return storeChannel
+}
diff --git a/store/sql_post_store_test.go b/store/sql_post_store_test.go
index 27e816996..761e0dcdf 100644
--- a/store/sql_post_store_test.go
+++ b/store/sql_post_store_test.go
@@ -1661,3 +1661,37 @@ func TestPostStoreGetPostsBatchForIndexing(t *testing.T) {
 		}
 	}
 }
+
+func TestGetLastPostForChannel(t *testing.T) {
+	Setup()
+
+	o1 := &model.Post{}
+	o1.ChannelId = model.NewId()
+	o1.UserId = model.NewId()
+	o1.Message = ""
+	o1.Type = model.POST_JOIN_CHANNEL
+
+	o1 = (<-store.Post().Save(o1)).Data.(*model.Post)
+
+	if r1 := <-store.Post().GetLastPostForChannel(o1.ChannelId); r1.Err != nil {
+		t.Fatal(r1.Err)
+	} else {
+		if r1.Data.(*model.Post).Id != o1.Id {
+			t.Fatal("invalid returned post")
+		}
+	}
+
+	o2 := &model.Post{}
+	o2.ChannelId = o1.ChannelId
+	o2.UserId = model.NewId()
+	o2.Message = ""
+
+	o2 = (<-store.Post().Save(o2)).Data.(*model.Post)
+	if r2 := <-store.Post().GetLastPostForChannel(o2.ChannelId); r2.Err != nil {
+		t.Fatal(r2.Err)
+	} else {
+		if r2.Data.(*model.Post).Id != o2.Id {
+			t.Fatal("invalid returned post")
+		}
+	}
+}
diff --git a/store/store.go b/store/store.go
index d883ea5a2..9824ec213 100644
--- a/store/store.go
+++ b/store/store.go
@@ -170,6 +170,7 @@ type PostStore interface {
 	Overwrite(post *model.Post) StoreChannel
 	GetPostsByIds(postIds []string) StoreChannel
 	GetPostsBatchForIndexing(startTime int64, limit int) StoreChannel
+	GetLastPostForChannel(channelId string) StoreChannel
 }
 
 type UserStore interface {