trigger Contactcallout on Contact (after insert, after update, before delete) {
Id RecordType1= [SELECT Id FROM RecordType WHERE SOBJECTTYPE=:'Contact' AND DeveloperName=:'Commercial'].Id;
Map<Id, String> m = new Map<Id, String>();
list<Contact> validContacts = new list<Contact>();
set<ID> accIds = new set<ID>();
if(Trigger.isDelete)
    {
        for (contact c : Trigger.old) 
        {
            if(c.RecordTypeId == RecordType1 && c.Reg__c == TRUE)    
            c.Status__c='Inactive';
            {
                validContacts.add(c);
                accIds.add(c.accountid);
            }   
        }
    }
    else
    {
for (contact c : Trigger.new) {
    if(c.RecordTypeId == RecordType1 && c.Reg__c == TRUE){
    if(Trigger.isUpdate){
        contact old = Trigger.oldMap.get(c.Id);
        if (c.Email != old.Email||c.FirstName!=old.FirstName||c.LastName!=old.LastName||c.phone!=old.phone||c.Title__c!=old.Title__c||c.status__c!=old.status__c||c.AccountID!=old.AccountID||c.Registered_on_ITV_Media__c == TRUE)
         {
             validContacts.add(c);
                accIds.add(c.accountid);
         }
         }else{
         validContacts.add(c);
                accIds.add(c.accountid);
                }
                }
         }   
}
map<ID, Account> accMap;
if(!accIds.IsEmpty()) // guard condition for SOQL
    accMap = new map<ID, Account>([select name from account where id in :accIds]);

for (contact c : validContacts) {
    Account acc = accMap.get(c.AccountID);
    string accName = acc == null ? null : acc.Name;
    WebServiceCallout.sendNotification(c.Id,c.Email,c.FirstName,c.LastName,c.phone,c.Title__c,accName,c.status__c);
              }
}