Hi team,

I'm trying to capture the last completed event date on the contact object but I'm struggling with the trigger.

Here is the Apex Class - no errors

public class LastCompletedEventDate{
    //Grab list of contacts
    protected final Contact[] contactNewList = new Contact[] {};
        protected final Contact[] contactOldList = new Contact[] {};
            
            public LastCompletedEventDate(Contact[] contactOldList, Contact[] contactNewList) {
                this.contactNewList.addAll(contactNewList == null ? new Contact[] {} : contactNewList);
                this.contactOldList.addAll(contactOldList == null ? new Contact[] {} : contactOldList);
            }
    
    public void execute() {
        //find all events associated to contacts
        Event[] eventList = [select ActivityDate, WhoId, EndDateTime, Subject, ActivityDateTime from Event where WhoId in :contactNewList];
        
        Map<Id, Contact> contactMap = new Map<Id, Contact>(contactNewList);
        for(Contact contact : contactNewList) {
            contact.Last_Completed_Event__c = null;
        }
        
        //create if else statement to display most current completed event date
        for(Event event : eventList) {
            Contact contact = contactMap.get(event.WhoId);
            
            if(Event.EndDateTime < Date.Today())
                Contact.Last_Completed_Event__c = Event.EndDateTime;
        }
    }
}

Here is the trigger with the error 

trigger LastCompletedEventDate on Contact (before update) {
    if(EventID= true) {
        Set<ID> sID = new Set<ID>(trigger.newMap.keySet());
        new LastCompletedEventDate(trigger.old, trigger.new).execute();
    }
}

Any ideas on what I'm doing wrong?