RAD 2 Homework 4 - Write a new trigger and handler class from scratch

CaseTriggerHandler.cls

public class CaseTriggerHandler {
    //Handler Methods
    public static void onBeforeInsert(List<Case> newCases) {
    //Set default Reason if not provided at case creation
        for ( Case c : newCases) {
            if (c.Reason == NULL) {
               System.debug('---->Case reason is '+c.Reason);
               c.Reason = 'Other';
            }
            else {
               System.debug('---->Case reason is '+c.Reason);
            }
        }
    }

    public static void onAfterInsert(List<Case> newCases) {

    }

    public static void onBeforeUpdate(List<Case> oldCases, List<Case> updatedCases, Map<Id, Case> oldCaseMap, Map<Id, Case> updatedCaseMap) {
    
    }
    
    public static void onAfterUpdate(List<Case> oldCases, List<Case> updatedCases, Map<Id, Case> oldCaseMap, Map<Id, Case> updatedCaseMap) {
    //Before closing the case, check if it has potential liability issues and create a Task for the Case Owner
    //will require newMap because we'll need IDs to work on the related records
    //need to bulkify in case records are updated in bulk

    //create a list to collect all tasks we will create 
        List<Task> TasksList = new List<Task>();

    //Loop through the Oppties we just updated and create a Task for each

        for ( Case c : updatedCases) {
            Case oldCase = oldCaseMap.get(c.Id);
            System.debug('---->Old Case Status is '+oldCase.Status+' and IsClosed='+oldCase.IsClosed);
            System.debug('---->New Case Status is '+c.Status+' and IsClosed='+c.IsClosed);
            if(c.PotentialLiability__c == 'Yes' && c.IsClosed == TRUE && oldCase.IsClosed == FALSE) {
                System.debug('---->Closing a Case with Potential Liability issues');

                Task t = new Task();
                t.OwnerId = c.OwnerId;//UserInfo.getUserId();
                t.Description ='Case \"' +c.CaseNumber+ '\" was closed on ' + c.ClosedDate +'. Please follow up with the customer.';
                t.Subject = 'Case with Potential Liability was closed';
                t.WhatId = c.Id;
                t.Status = 'Not Started';
                t.ActivityDate = Date.Today();
                System.debug('------> Added a Task');
                TasksList.add(t);
            }
        }
//bulk insert the Tasks list
        insert(TasksList);
        System.debug('------> Created ' + TasksList.size() + ' Tasks.');

    }
    
    public static void onBeforeDelete(List<Case> casesToDelete, Map<Id, Case> deletedCaseMap) {

    }

    public static void onAfterDelete(List<Case> deletedCases, Map<Id, Case> deletedCaseMap) {

    }
    
    public static void onUndelete(List<Case> undeletedCases, Map<Id, Case> recoveredCaseMap) {

    }
}