/**
 * @description                     This service exposes methods that contain logic to make cloning an opportunity
 *                                  much easier and more functional.
 * @author                          Cloud Performer Inc. <cgary@cloudperformer.com>
 * @version                         1.0
 * @group                           Opportunity Cloning
 * @history                         2021-04-02 - CJG - Created
 */
public with sharing class OpportunityCloneService {
    /**
     * @description                 exception class that is thrown when something happens in the opportunity
     *                              clonde process.
     */
    public class CloneException extends System.Exception {}
    public static Map<String,Schema.DescribeSObjectResult> opportunityChildrenMap;
    static {
        List<Schema.ChildRelationship> childRelationshipList = 
            Schema.Opportunity.getSObjectType().getDescribe().getChildRelationships();
            opportunityChildrenMap = new Map<String, Schema.DescribeSObjectResult>();
            for(Schema.ChildRelationship childRel:childRelationshipList) {
                Schema.DescribeSObjectResult childObjRes = childRel.getChildSObject().getDescribe();
                opportunityChildrenMap.put(childObjRes.getName(),childObjRes);
            }
    }

    @AuraEnabled(cacheable=true)
    public static List<String> ObtainOpporunityChildRelationships(){
        return new List<String>(opportunityChildrenMap.keySet());
    }

    public static String ObtainQueryStringForOppAndChildren(Id oppRecordId, List<String> relationships) {
        String queryString = 'SELECT ';
        queryString += String.join(ObtainFieldsForObject('Opportunity'),',');
        List<String> subqueryList = new List<String>();
        for(String relationship:relationships){
            Schema.DescribeSObjectResult childObject = opportunityChildrenMap.get(relationship);
            String childQueryString = '(SELECT ' + String.join(ObtainFieldsForObject(childObject.getName()),',') + ' FROM ';
            childQueryString += relationship + ')';
            subqueryList.add(childQueryString);
        }
        queryString += ', ' + String.join(subqueryList,',') + 'FROM Opportunity WHERE Id =\'' + oppRecordId + '\'';
        
        return queryString;
    }
    /**
     * @description                 this method is responsible for getting the list of fields for a particular object
     */
    private static List<String> ObtainFieldsForObject(String objectName) {
        List<String> fieldNameList;
        List<String> objectListToDescribe = new List<String>{objectName};
        List<Schema.DescribeSObjectResult> describeItem = System.Schema.describeSObjects(objectListToDescribe);
        if(describeItem.isEmpty()) {
            throw new OpportunityCloneService.CloneException('Could not find info for ' + objectName + '.');
        }
        Map<String, Schema.SObjectField> fieldSObjectMapping = describeItem[0].fields.getMap();
        fieldNameList = new List<String>();
        for(Schema.SObjectField fieldToken:fieldSObjectMapping.values()) {
            Schema.DescribeFieldResult fieldTokenDescribe = fieldToken.getDescribe();
            if(fieldTokenDescribe.isCreateable() && fieldTokenDescribe.isUpdateable()) {
                fieldNameList.add(fieldTokenDescribe.getName());
            }
        }
        return fieldNameList;
    }
}