get the transition name in Jira listener

I am using use a listener in Jira to execute some code if a specific transition was made. I need to retrieve the transition name to only fire the event if the transition is called "MounaTransition". It seems that the following code is not working to get the transition name in the listener. 

 import com.atlassian.jira.component.ComponentAccessor
 def workflow = ComponentAccessor.getWorkflowManager().getWorkflow(issue)
 def wfd = workflow.getDescriptor() 
def actionName = wfd.getAction(transientVars["actionId"] as int).getName()

 Here is the code I have written so far in my listener to try to do the same thing that I was doing with the custom post function before. Any idea on how to get the transition name/ID? I can only operate and execute my script if the tranition name matches the one I am interested in. 

import org.ofbiz.core.entity.GenericValue

import com.opensymphony.workflow.WorkflowContext

import com.atlassian.jira.issue.Issue;

import java.util.List;

import org.apache.log4j.Logger;

import com.atlassian.jira.issue.ModifiedValue;

import com.atlassian.jira.issue.fields.CustomField;

import com.atlassian.jira.component.ComponentAccessor

import org.ofbiz.core.entity.GenericDelegator;

import com.atlassian.jira.issue.changehistory.ChangeHistoryManager;

import com.atlassian.jira.issue.history.ChangeItemBean;

import com.atlassian.jira.issue.comments.Comment

import com.atlassian.jira.workflow.JiraWorkflow

import com.atlassian.jira.workflow.WorkflowManager

import com.atlassian.jira.issue.changehistory.ChangeHistoryItem

import com.onresolve.scriptrunner.runner.util.UserMessageUtil

import com.atlassian.jira.config.SubTaskManager

import com.atlassian.jira.issue.Issue

import com.atlassian.jira.issue.link.LinkCollectionImpl;

import com.atlassian.jira.issue.link.IssueLink;

import com.atlassian.crowd.embedded.api.User;

import com.atlassian.jira.issue.comments.CommentManager;

import com.atlassian.jira.issue.link.IssueLinkManager;

import com.atlassian.jira.user.ApplicationUser;

import com.atlassian.jira.util.ErrorCollection;

import com.atlassian.jira.util.JiraUtils;

import com.atlassian.jira.workflow.JiraWorkflow;

import com.atlassian.jira.workflow.WorkflowManager;

import com.atlassian.jira.workflow.WorkflowTransitionUtil;

import com.atlassian.jira.workflow.WorkflowTransitionUtilImpl;

import com.atlassian.jira.workflow.function.issue.AbstractJiraFunctionProvider;

import com.opensymphony.module.propertyset.PropertySet;

import com.opensymphony.workflow.WorkflowException;

import com.opensymphony.workflow.loader.StepDescriptor;

import com.opensymphony.workflow.spi.SimpleStep;

import com.atlassian.jira.config.ConstantsManager

import com.atlassian.jira.workflow.ImmutableWorkflowDescriptor

import com.atlassian.jira.web.action.admin.workflow.ViewWorkflowStep

import com.opensymphony.workflow.loader.ActionDescriptor

import com.atlassian.jira.issue.IssueInputParametersImpl

import com.atlassian.jira.issue.IssueInputParameters

import com.atlassian.jira.bc.issue.IssueService.IssueValidationResult

import com.atlassian.jira.user.ApplicationUser

import com.atlassian.jira.workflow.WorkflowTransitionUtil

import com.atlassian.jira.workflow.WorkflowTransitionUtilFactory

import com.atlassian.jira.workflow.TransitionOptions

import com.atlassian.jira.bc.issue.IssueService

import com.atlassian.jira.bc.issue.IssueService.TransitionValidationResult

import com.atlassian.event.Event

import com.atlassian.jira.event.issue.AbstractIssueEventListener;

import com.atlassian.jira.event.issue.IssueEvent;

def log = Logger.getLogger("atlassian-jira.log")

log.warn("This is the last action ")

Issue issue = event.getIssue();

 log.warn("CAM 0 ")

 log.warn("CAM 0.1 ")

//Get worklflowname By actionId

  GenericValue changeLog = event.getChangeLog();

                log.warn("HERE 1")

        

        List<GenericValue> changeItems = ComponentAccessor.getChangeHistoryManager().getAllChangeItems(issue)

              //  changeItems = changeLog.internalDelegator.findByAnd("ChangeItem", fields); 

            //changeItems = changeLog

                log.warn("HERE 5::: "+ changeItems)

        log.warn("MOUNA IS HERE AFTER HERE 5 " +changeItems.size());

        log.warn("VALUES 1");

      int lastIndex= changeItems.size()-1; 

 log.warn("CAM 0.2")

 ChangeHistoryItem value= changeItems.get(lastIndex) as ChangeHistoryItem; 

 def workflow = ComponentAccessor.getWorkflowManager().getWorkflow(issue)

def wfd = workflow.getDescriptor()

      log.warn("GENERIC VALUE "+ transientVars["actionId"] +" ");

def actionName = wfd.getAction(transientVars["actionId"] as int).getName()

      log.warn("GENERIC VALUE "+ actionName +" ");

Hmm. I know that the transition name is not recorded in the issue History, just the old and new status names and ids. But actionId is likely what you are looking for. I'm not sure why it is not returning anything for you.