Get workflow reviewer Name - Display Method Ax 2012

public display name reviewerName() // get workflow reviewer Name
{
    PurchReqTable                   purchReqTable;
    PurchReqTableHistory            purchReqTableHistory;
    WorkflowTrackingStatusTable     workflowTrackingStatus;
    WorkflowTrackingTable           workflowTracking;
    utcdatetime                     validDate               = DateTimeUtil::utcNow();
    WorkflowStepName                stepName;
    TransDate                       stepSinceDate;
    PurchReqRequisitionStatus       status;
    TransDate                       statusSinceDate;
    RefRecId                        workflowTrackingStatusRecId;
    RefRecId                        workflowStepRecId;
    UserInfo                        userInfo;
    WorkflowTrackingWorkItem        workflowTrackingWorkItem;
    WorkflowWorkItemTable           workflowWorkItem;
    WorkflowWorkItemQueueAssignee   workItemQueueAssignee;
    PurchReqReviewStatus            reviewStatus;
    Name                            reviewer;
    select firstonly validTimeState(validDate)
        CreatedDateTime, RequisitionStatus from purchReqTable
            where purchReqTable.RecId == this.RecId
        outer join CreatedDateTime from purchReqTableHistory
            where purchReqTableHistory.PurchReqTable == this.RecId
        outer join RecId from workflowTrackingStatus
            order by workflowTrackingStatus.CreatedDateTime desc
            where workflowTrackingStatus.ContextTableId == this.TableId &&
                  workflowTrackingStatus.ContextRecId   == this.RecId;
    select firstonly RecId, Name, CreatedDateTime, TrackingContext, TrackingType from workflowTracking
        order by workflowTracking.CreatedDateTime desc
        where workflowTracking.WorkflowTrackingStatusTable == workflowTrackingStatus.RecId;
    if (workflowTracking.TrackingContext != WorkflowTrackingContext::LineItemElement ||
        workflowTracking.TrackingType    != WorkflowTrackingType::Creation)
    {
        select firstonly RecId, Name, CreatedDateTime, WorkflowStepTable
            from workflowTracking
            order by workflowTracking.CreatedDateTime desc
                where workflowTracking.WorkflowTrackingStatusTable == workflowTrackingStatus.RecId &&
                      workflowTracking.TrackingContext             == WorkflowTrackingContext::Step &&
                      workflowTracking.TrackingType                == WorkflowTrackingType::Creation;
    }
    workflowTrackingStatusRecId = workflowTrackingStatus.RecId;
    workflowStepRecId           = workflowTracking.WorkflowStepTable;

    select firstonly RecId, TrackingContext, TrackingType from workflowTracking
        order by CreatedDateTime desc
        where workflowTracking.WorkflowTrackingStatusTable == workflowTrackingStatusRecId;
    if (workflowTracking.TrackingContext != WorkflowTrackingContext::LineItemElement ||
        workflowTracking.TrackingType    != WorkflowTrackingType::Creation)
    {
        select firstonly RecId, Type, UserId, CreatedDateTime from workflowWorkItem
            order by workflowWorkItem.CreatedDateTime desc
                where workflowWorkItem.Status == WorkflowWorkItemStatus::Pending
            exists join workflowTrackingWorkItem
                where workflowTrackingWorkItem.WorkflowWorkItemTable == workflowWorkItem.RecId
            join workflowTracking
                where workflowTracking.RecId                       == workflowTrackingWorkItem.WorkflowTrackingTable &&
                      workflowTracking.TrackingContext             == WorkflowTrackingContext::WorkItem &&
                      workflowTracking.TrackingType                == WorkflowTrackingType::Creation &&
                      workflowTracking.WorkflowTrackingStatusTable == workflowTrackingStatusRecId;
        if (workflowWorkItem && (workflowWorkItem.Type == WorkflowWorkItemType::RequestChange ||
                                 workflowWorkItem.Type == WorkflowWorkItemType::Return))
        {
            select  userInfo where userInfo.id == workflowWorkItem.UserId;
            reviewer = userInfo.name;
        }
        else
        {
            select RecId, Status, Queue, IsClaimed, UserId, CreatedDateTime from workflowWorkItem order by RecId desc
                exists join workflowTrackingWorkItem
                    where workflowTrackingWorkItem.WorkflowWorkItemTable == workflowWorkItem.RecId
                join workflowTracking
                    where workflowTracking.RecId                       == workflowTrackingWorkItem.WorkflowTrackingTable &&
                          workflowTracking.TrackingContext             == WorkflowTrackingContext::WorkItem &&
                          workflowTracking.TrackingType                == WorkflowTrackingType::Creation &&
                          workflowTracking.WorkflowStepTable           == workflowStepRecId &&
                          workflowTracking.WorkflowTrackingStatusTable == workflowTrackingStatusRecId;
                if (workflowWorkItem.Status == WorkflowWorkItemStatus::Completed)
                {
                    reviewStatus = PurchReqReviewStatus::Approved;
                }
                else
                {
                    reviewStatus = PurchReqReviewStatus::Pending;
                }
                if (workflowWorkItem.Queue && workflowWorkItem.IsClaimed == NoYes::No)
                {
                    select User from workItemQueueAssignee
                        where workItemQueueAssignee.WorkitemQueue == workflowWorkItem.Queue;
                    select  userInfo where userInfo.id == workflowWorkItem.UserId;
                    reviewer = userInfo.name;
                }
                else
                {
                    select  userInfo where userInfo.id == workflowWorkItem.UserId;
                    reviewer = userInfo.name;
                }
        }
    }
    return reviewer;
}