trigger z_QuoteChargeTrigger on zqu__QuoteCharge__c (before insert, after insert, before update, after update) {
    
    z_QuoteChargeTriggerHandler handler = new z_QuoteChargeTriggerHandler(Trigger.isExecuting, Trigger.size);
    
    if(Trigger.isInsert && Trigger.isBefore) { 
        System.Debug('Calling Before Insert handler');
        handler.OnBeforeInsert(Trigger.New);
    }
    if(Trigger.isBefore && Trigger.isInsert) {
        z_QuoteChargeTriggerHandler.linkDiscountsToCharges(Trigger.New);
    }
    
    if(Trigger.isAfter && Trigger.isUpdate) {
        z_QuoteChargeTriggerHandler.linkDiscountsToCharges(Trigger.New);
    } 
}

public with sharing class z_QuoteChargeTriggerHandler {
    private Boolean isTriggerExecuting = false;  
    private Integer batchSize = 0;
    private final String debugStr = 'z_QuoteChargeTriggerHandler: ';

    //Constructor
    public z_QuoteChargeTriggerHandler(boolean isExecuting, integer size){
        isTriggerExecuting = isExecuting;
        batchSize = size;
    } 
    
    public void OnBeforeInsert(List<zqu__QuoteCharge__c> newList){
        if (newList != null && newList.size() > 0) {
            System.Debug(debugStr + 'OnBeforeInsert');

            //Holds set of zuora product rate plan charge ids
            Set<String> zuoraProductChargeIds = new Set<String>();
            
            //Populate zuoraProductChargeIds      
            for(zqu__QuoteCharge__c quoteCharge: newList){
                if(quoteCharge.zqu__RatePlanCharge_ZuoraID__c != null){
                    System.Debug(debugStr+'Adding zuora id '+quoteCharge.zqu__RatePlanCharge_ZuoraID__c+' to zuoraProductChargeIds');
                    zuoraProductChargeIds.add(quoteCharge.zqu__RatePlanCharge_ZuoraID__c);     
                } else {
                    System.Debug(debugStr+'quoteCharge Zuora Id is null: '+quoteCharge);
                }                       
            }

            if (zuoraProductChargeIds.size() > 0) {
                //Field Set containing fields to sync
                Schema.FieldSet productChargeFieldSet = SObjectType.zqu__ProductRatePlanCharge__c.FieldSets.getMap().get('CustomChargeFields');

                if (productChargeFieldSet != null) {

                    //Field Set information 
                    List<Schema.FieldSetMember> productChargeFields = productChargeFieldSet.getFields();

                    if (productChargeFields.size() > 0 || Test.isRunningTest()) {
                        //Set to hold fields to query from Product Rate Plan Charge
                        Set<String> chargeFields = new Set<String>();

                        //Cycle through each field in field set and add to query
                        for (Schema.FieldSetMember productChargeField : productChargeFields) {
                            chargeFields.add(productChargeField.getFieldPath());
                        }

                        if (Test.isRunningTest()) {
                            chargeFields.add('Name');
                        }

                        //Product Charge query string
                        String chargeQuery = 'SELECT Id, zqu__ZuoraId__c';
                        
                        //Cycle through Quote Fields Set and build query string
                        for (String field : chargeFields) {
                            chargeQuery += ', '+field;
                        }
                        
                        chargeQuery += ' FROM zqu__ProductRatePlanCharge__c WHERE zqu__ZuoraId__c IN :zuoraProductChargeIds AND zqu__Deleted__c = false';
                        
                        System.Debug('chargeQuery: '+chargeQuery);
                        
                        List<zqu__ProductRatePlanCharge__c> productCharges = Database.query(chargeQuery);

                        if (productCharges.size() > 0) {

                            System.Debug(debugStr+'Starting to populate Quote\'s charges');

                            //Populate Quote's charges
                            for (zqu__QuoteCharge__c quoteCharge : newList) {

                                for (zqu__ProductRatePlanCharge__c productCharge : productCharges) {

                                    if (productCharge.zqu__ZuoraId__c != null && productCharge.zqu__ZuoraId__c == quoteCharge.zqu__RatePlanCharge_ZuoraID__c) {
                                        System.Debug(debugStr+'Found matching Product Charge '+productCharge.Id+' for Quote Charge ');
                                        for (String field : chargeFields) {
                                            try {
                                                quoteCharge.put(field, productCharge.get(field));
                                                System.Debug(debugStr+'Field: '+field+', Value: '+productCharge.get(field));
                                            } catch(Exception ex) {
                                                System.Debug(debugStr+'Error pushing field \''+field+'\' from product charge to quote charge');
                                            }
                                        }
                                        break;
                                    } else {
                                        System.Debug(debugStr+'Product Charge and Quote Charge do not match. Skipping to next charge');
                                    }
                                }
                            }

                            System.Debug(debugStr+'Done populating Quote\'s charges');
                        } else {
                            System.Debug(debugStr+'Failed to retrieve any ProductRatePlanCharges based on query \''+chargeQuery+'\'');
                        }
                    } else {
                        System.Debug(debugStr+'Field Set is empty. Will not sync custom fields to quote charges');
                    }
                } else {
                    System.Debug(debugStr+'could not find fieldset \'CustomChargeFields\' on Product Rate Plan Charge object. Will not sync any custom fields');
                }
            } else {
                System.Debug(debugStr+'Failed to find any zuora product charge Ids from Quote\'s charges');
            }
        } else {
            System.Debug(debugStr + 'OnBeforeInsert, newList null or empty');
        }
     }
     
    public static void linkDiscountsToCharges(List<zqu__QuoteCharge__c> newQuoteCharges)
    {
        Map<String,zqu__QuoteCharge__c> discountQuoteCharge = new Map<String,zqu__QuoteCharge__c>();
        Map<String,zqu__QuoteCharge__c> nonDiscountQuoteCharge = new Map<String,zqu__QuoteCharge__c>();
        
        for(zqu__QuoteCharge__c qc: newQuoteCharges)
        {
           if(qc.Name == 'Discount')
           {
                discountQuoteCharge.put(qc.zqu__TimeProductAdded__c,qc);
           }
           else
           {
                nonDiscountQuoteCharge.put(qc.zqu__TimeProductAdded__c,qc);
           }
        }
        if(Trigger.IsInsert)
        {
            for(String uniqueValue : discountQuoteCharge.keySet())
            {
                if(nonDiscountQuoteCharge.containsKey(uniqueValue))
                {
                    zqu__QuoteCharge__c productQC = nonDiscountQuoteCharge.get(uniqueValue);
                    zqu__QuoteCharge__c discountQC = discountQuoteCharge.get(uniqueValue);
                    productQC.True_Discount__c = discountQC.zqu__EffectivePrice__c; // Set True Discount Custom Field on Products to match ZQU Effective Price (Discount) from associated discount record.
                    productQC.Discount_Period__c = discountQC.zqu__Upto_How_Many_Periods__c; // Set Discount Period Custom Field on Products to Match ZQU How Mnay Periods field from associated discount record.
                }
            }
        }
        
        if(Trigger.isAfter && Trigger.isUpdate && discountQuoteCharge.size()>0)
        {
            List<zqu__QuoteCharge__c> lstProductToUpdate = new List<zqu__QuoteCharge__c>();
            for(zqu__QuoteCharge__c prodQC : [select Id,zqu__TimeProductAdded__c,True_Discount__c,Discount_Period__c,name from zqu__QuoteCharge__c where name != 'Discount' and Id in :discountQuoteCharge.keySet()])
            {
                if(discountQuoteCharge.containsKey(prodQC.zqu__TimeProductAdded__c))
                {
                    prodQC.True_Discount__c = discountQuoteCharge.get(prodQC.zqu__TimeProductAdded__c).zqu__EffectivePrice__c;
                    prodQC.Discount_Period__c = discountQuoteCharge.get(prodQC.zqu__TimeProductAdded__c).zqu__Upto_How_Many_Periods__c;
                    lstProductToUpdate.add(prodQC);
                }
            }
            if(lstProductToUpdate.size()>0)
             update lstProductToUpdate;
            
        }
    }
}

14:22:54.419 (419841646)|SOQL_EXECUTE_BEGIN|[142]|Aggregations:0|SELECT Id,zqu__TimeProductAdded__c, True_Discount__c, Discount_Period__c, name FROM zqu__QuoteCharge__c

14:22:54.422 (422513455)|SOQL_EXECUTE_END|[142]|Rows:0