MM-31713 Server/API: GetUserThread method (#16659)

Co-authored-by: Mattermod <mattermod@users.noreply.github.com>

app/user.go

@@ -2371,6 +2371,19 @@ func (a *App) GetThreadsForUser(userId, teamId string, options model.GetUserThre
 	return threads, nil
 }
 
+func (a *App) GetThreadForUser(userId, teamId, threadId string, extended bool) (*model.ThreadResponse, *model.AppError) {
+	thread, err := a.Srv().Store.Thread().GetThreadForUser(userId, teamId, threadId, extended)
+	if err != nil {
+		return nil, model.NewAppError("GetThreadForUser", "app.user.get_threads_for_user.app_error", nil, err.Error(), http.StatusInternalServerError)
+	}
+	if thread == nil {
+		return nil, model.NewAppError("GetThreadForUser", "app.user.get_threads_for_user.not_found", nil, "thread not found/followed", http.StatusNotFound)
+	}
+	a.sanitizeProfiles(thread.Participants, false)
+	thread.Post.SanitizeProps()
+	return thread, nil
+}
+
 func (a *App) UpdateThreadsReadForUser(userId, teamId string) *model.AppError {
 	nErr := a.Srv().Store.Thread().MarkAllAsRead(userId, teamId)
 	if nErr != nil {