public class QueueableSubStepMaster implements Queueable, Database.AllowsCallouts {
    
    //class variable of type List
    private List<Sub_Step_Master__c> subStepMasterList;
    
    //Constructor
	public QueueableSubStepMaster(List<Sub_Step_Master__c> listSubStepMaster){
		this.subStepMasterList = listSubStepMaster;
	}
	
	public void execute(QueueableContext qc){
		for(Sub_Step_Master__c subStepMaster : subStepMasterList){
            //Map<String,String> layoutFieldMap = new Map<String,String>{'Sub_Step__c'=> 'String'}; to test batch (batch seems to work OK)!!!
			Map<String,String> layoutFieldMap = getFieldsOnLayoutForRecordType('Sub_Step__c',subStepMaster.RecordTypeName__c);
            subStepMaster.Layout_Field__c = prettyPrintLayoutFields(layoutFieldMap);
		}
		update subStepMasterList;
	}
    
    private String prettyPrintLayoutFields(Map<String,String> layoutFieldMap){
        
        //Print Map Key-Value pairs using toString();
        String result;
        result = layoutFieldMap.toString();
        
        //Print keys from Map using String.join(); //string.join(map.keyset(),',');
        /*String result = '';
        set<string> strSet = layoutFieldMap.keySet();
        List<String> StrList = new List<String>();
        StrList.addall(strSet);
        result = String.join(StrList , ',');*/
	
        System.debug('String result ' +result);
        return result;
    }
    
	private static Map<String,String> getFieldsOnLayoutForRecordType(String sobjectName, String recordTypeName){
		Map<String,String> result = new Map<String,String>();
		
		String url = system.URL.getSalesforceBaseUrl().toExternalForm() 
				   + '/services/data/v52.0/sobjects/'
				   + sObjectName
				   + '/describe/layouts/' 
				   + getRecordTypeId(sobjectName, recordTypeName);
        system.debug(url);
		httprequest req = buildRequest(url);
		try{
			http h = new http();
			httpresponse res = h.send(req);
			if(res.getStatusCode() == 200){
				result = getFieldsFromLayoutString(res.getBody());
			}
		}catch(exception ex){
			system.debug('ERROR: ' + ex.getMessage());
		}
		return result;
	}
	private static Map<String,String> getFieldsFromLayoutString(String jsonString){
		Map<String,String> result = new Map<String,String>();
        
        Map<String,Object> layoutMap = (Map<String,Object>)JSON.deserializeUntyped(jsonString);
        
        List<Map<String, Object>> data = new List<Map<String, Object>>();
        
		List<Object> detailSectionList = (List<Object>)layoutMap.get('detailLayoutSections'); //added H.O
        
		for(Object section : detailSectionList){
			Map<String,Object> sectionMap = (Map<String,Object>)section;
			for(Object sectionLayoutRow : (List<Object>)sectionMap.get('layoutRows')){
				Map<String,Object> sectionLayoutRowMap = (Map<String,Object>)sectionLayoutRow;
				for(Object liObject : (List<Object>)sectionLayoutRowMap.get('layoutItems')){
                    LayoutItem li = new LayoutItem((Map<String,Object>)liObject);
					String label = li.label;
					if(label != null && label != ''){
                        for(Object lc : li.layoutComponents){
                            Map<String,Object> lcMap = (Map<String,Object>)lc;
                            if((String)lcMap.get('type') == 'field'){
                            	String field = (String)lcMap.get('value');
                                result.put(field,label);
                            }
                        }
					}
				}
			}
		}
		return result;
	}
    
	private static String getRecordTypeId(String sobjectName, String recordTypeName){
        //use condition to avoid RecordType returning null
        if(Schema.getGlobalDescribe().get(sObjectName).getDescribe().getRecordTypeInfosByName().get(recordTypeName) != null) {
            return Schema.getGlobalDescribe().get(sObjectName).getDescribe().getRecordTypeInfosByName().get(recordTypeName).getRecordTypeId();

        } else {
            return null;
        }
	}

	private static HttpRequest buildRequest(String url){
		HttpRequest result = new HttpRequest();
		system.debug(url);
		result.setendpoint(url);
		result.setmethod('GET');
		result.setHeader('Authorization', 'OAuth ' + UserInfo.getSessionId());       
		result.setHeader('Authorization', 'Bearer ' + UserInfo.getSessionID());
		return result;
	}
	
	private class LayoutItem{
		public boolean editableForNew;
		public boolean editableForUpdate;
		public string label;
		public List<Object> layoutComponents;
		public boolean placeholder;
		public boolean required;
        
        public LayoutItem(Map<String,Object> liMap){
            editableForNew = (Boolean)liMap.get('editableForNew');
            editableForUpdate = (Boolean)liMap.get('editableForUpdate');
            label = (String)liMap.get('label');
            layoutComponents = (List<Object>)liMap.get('layoutComponents');
            placeholder = (Boolean)liMap.get('placeholder');
            required = (Boolean)liMap.get('required');
        }
	}
	
}

public class BatchSubStepMasterProcessor implements Schedulable, Database.Batchable<sObject> {
    
    public void execute(SchedulableContext sc) {
        Id batchProcessId = Database.executeBatch(this);
    }
    
    public Database.QueryLocator start(Database.BatchableContext bc) {
        return Database.getQueryLocator('SELECT Id, Name, Layout_Field__c, RecordTypeName__c FROM Sub_Step_Master__c');  
    }
    
    public void execute(Database.BatchableContext bc, List<Sub_Step_Master__c > scope) {
        System.enqueueJob(new QueueableSubStepMaster(new List<Sub_Step_Master__c>(scope)));
        System.debug('#### UPDATED Scope Size ' + scope.size());
    }
    
    public void finish(Database.BatchableContext info) {
       System.debug('Done'); 
    }

}

//Database.executeBatch(new BatchSubStepMasterProcessor());