trigger MatchTrigger on Match__c (after insert, after update, after delete, before delete)
 {

     if (Trigger.isAfter && (Trigger.isInsert || Trigger.isDelete))
    {
       System.debug('*** Started calculation matches: ' + Trigger.new);
        Set<Id> aDemandIdSet = new Set<Id>();
         Set<Id> aSupplyIdSet = new Set<Id>();
         //Find all the properties involved in changes matches.
        for (Match__c aMatch : Trigger.isInsert ? Trigger.new : Trigger.old)
        {
            if (aMatch.Supply__c != null)
            {
                aSupplyIdSet.add(aMatch.Supply__c);
            }
            if (aMatch.Demand__c != null)
            {
                aDemandIdSet.add(aMatch.Demand__c);
            }
        }
     //Perform search for count of matches in two types: when Property is set as Property1__c in match object
        //and when it was set as EnquiringProperty__c.
        List<AggregateResult> aMatchCountResult = [SELECT COUNT_DISTINCT(Demand__c) counter, Supply__c FROM Match__c WHERE Supply__c IN :aSupplyIdSet GROUP BY Supply__c];
        List<AggregateResult> aMatchCountResult2 = [SELECT COUNT_DISTINCT(Supply__c) counter, Demand__c FROM Match__c WHERE Demand__c IN :aDemandIdSet GROUP BY Demand__c];
        Map<Id, Supply__c> anUpdateMap = new Map<Id, Supply__c>();
         Map<Id, Demand__c> anUpdateMap1 = new Map<Id, Demand__c>();
        
        //Calculate total count as sum of two values.
        for (AggregateResult anAgrRes : aMatchCountResult)
        {
            Id anId = (Id) anAgrRes.get('Supply__c');
            if (anId!= null)
            {
                System.debug('*** Result count for Id ' + anId + ': ' + anAgrRes.get('counter'));
                anUpdateMap.put(anId, new Supply__c(Id = anId, MatchedProperties__c = (Decimal)anAgrRes.get('counter')));
            }
        }
        for (AggregateResult anAgrRes : aMatchCountResult2)
        {
            Id anId = (Id) anAgrRes.get('Demand__c');
            if (anId != null)
            {
                System.debug('*** Result2 count for Id ' + anId + ': ' + anAgrRes.get('counter'));
                Demand__c aProp = anUpdateMap1.get(anId);
                if (aProp == null)
                {
                    aProp = new Demand__c(Id = anId, MatchedProperties__c = 0);
                    anUpdateMap1.put(anId, aProp);
                }
                aProp.MatchedProperties__c += (Decimal)anAgrRes.get('counter');
            }
        }
        //For all the rest propertis set count as 0.
        for (Id aPropId: aSupplyIdSet)
        {
            if (!anUpdateMap.containsKey(aPropId))
            {
                anUpdateMap.put(aPropId,  new Supply__c(Id = aPropId, MatchedProperties__c = 0));
            }
        }
        System.debug('*** Uptdate Matches count for Properties: ' + anUpdateMap.values());
        update anUpdateMap.values();
    }
        /**
        Share a new match.
    */
    if(Trigger.isInsert && Trigger.isAfter)
    {
        // We only execute the trigger after a Match record has been inserted 
        // because we need the Id of the Match record to already exist.
        // Match_Share is the "Share" table that was created when the
        // Organization Wide Default sharing setting was set to "Private".
        // Allocate storage for a list of Match__Share records.
        List<Match__Share> matchShares  = new List<Match__Share>();
        
        // For each of the Match records being inserted, do the following:
        for (Match__c match : trigger.new)
        {
            // Create a new Match__Share record to be inserted in to the Match_Share table.
            Match__Share matchBrokerShare = new Match__Share();
                
            //Populate the Match__Share record with the ID of the record to be shared.
            matchBrokerShare.ParentId = match.Id;
                
            // Then, set the ID of user or group being granted access. In this case,
            // we’re setting the Id of the Hiring Manager that was specified by 
            // the Recruiter in the Hiring_Manager__c lookup field on the Match record.  
            // (See Image 1 to review the Match object's schema.)
            matchBrokerShare.UserOrGroupId = match.Match_Property_Broker__c;
                
            // Specify that the Hiring Manager should have edit access for 
            // this particular Match record.
            matchBrokerShare.AccessLevel = 'edit';
            // Specify that the reason the Hiring Manager can edit the record is 
            // because he’s the Hiring Manager.
            // (Hiring_Manager_Access__c is the Apex Sharing Reason that we defined earlier.)
            matchBrokerShare.RowCause = Schema.Match__Share.RowCause.Suggested_Property_Broker__c;
                
            // Add the new Share record to the list of new Share records.
            
            matchShares.add(matchBrokerShare);
        }
        // Insert all of the newly created Share records and capture save result 
        Database.SaveResult[] matchShareInsertResult = Database.insert(matchShares, false);
        for(Database.SaveResult aSaveRes: matchShareInsertResult)
        {
            if(!aSaveRes.isSuccess())
            {
                Database.Error[] anErrors = aSaveRes.getErrors();
                for (Database.Error anError: anErrors)
                {
                    System.debug('*** Got an error on insert Deal sharing: ' + anError.getMessage());
                }
            }
        } 
    }
    
    /**
        If we change match Interested_in_Dealing__c  status to true, a new deal will be created.
    */
    if (Trigger.isUpdate && Trigger.isAfter)
    {
        // A new record is created on Deal object like opportunity created between both the Property Record owners on one match
        // if they wish to work together. it is triggerd by field Interested in dealing when checked by either of the record owner.
        List<Deal__c> dealsList = new List<Deal__c>();
        for(Match__c aMatchObject: Trigger.new)
        {
            Match__c anOldMatch = Trigger.oldMap.get(aMatchObject.Id);
            //Check if match is set as interested and both properties are available.
            if (aMatchObject.Interested_in_Dealing__c == true
                      && anOldMatch.Interested_in_Dealing__c == false
                      && (aMatchObject.Status_Match__c == 'Available' || aMatchObject.Status_Match__c == 'Duplicate')
                      && (aMatchObject.Demand_Status_Match__c == 'Available' || aMatchObject.Demand_Status_Match__c == 'Duplicate'))
            {
                //Create new deal for such properties and match object.
                 
                Deal__c newOpportunity = new Deal__c(); 
                newOpportunity.Name = aMatchObject.Name + 'On' + aMatchObject.Id + '-' + aMatchObject.Supply__c;
                newOpportunity.Close_Date__c = Date.today().addDays(30);
                newOpportunity.Stage__c = 'Shortlisted'; 
                newOpportunity.Match__c = aMatchObject.Id;
                newOpportunity.Demand__c = aMatchObject.Demand__c;
                newOpportunity.Supply__c= aMatchObject.Supply__c;
                dealsList.add(newOpportunity);
                System.debug('*** Create new deal: ' + newOpportunity);
                
            }
        }
        insert dealsList;
    }
            
            /**
        When we remove the match object, the related deal will be also deleted.
    */
    if (Trigger.isBefore && Trigger.isDelete)
    {
        List<Deal__c> aDeleteDeals = new List<Deal__c>();
        //Find all deals for the removed matches
        List<Deal__c> aFullList = [SELECT Id, Stage__c FROM Deal__c WHERE Match__c IN :Trigger.oldMap.keySet()];
        for (Deal__c aDeal: aFullList)
        {
            if (aDeal.Stage__c != 'Deal Closed Won')
            {
                aDeleteDeals.add(aDeal);
            }
        }
        System.debug('Remove deals: ' + aDeleteDeals);
        delete aDeleteDeals;
   }
      }