/**
 * @NApiVersion 2.1
 * @NScriptType UserEventScript
 */
define(['N/search', 'N/log'], function(search, log) {

    function beforeLoad(context) {
        var rec = context.newRecord;

        // Current Item Internal ID
        var itemInternalId = rec.id; 
        log.debug('Current Item Internal ID', itemInternalId);

        // Search in custom record for this item
        var customRecSearch = search.create({
            type: 'customrecord_item_aa',
            filters: [
                ['custrecord_itemid', 'is', itemInternalId] // Match by internal ID
            ],
            columns: ['custrecord_item_avg_a']
        });

        var result = customRecSearch.run().getRange({ start: 0, end: 1 });
        log.debug('Search Result Length', result.length);

        if (result.length > 0) {
            var avgAging = result[0].getValue('custrecord_item_avg_a');
            log.debug('Average Aging from Custom Record', avgAging);

            // Set values in following mode : (VIEW, EDIT, CREATE)
            rec.setValue({
                fieldId: 'custitem_cal_aa',
                value: avgAging
            });
            log.debug('Value Set on Item Record Field', 'Average Aging: ' + avgAging);
        } else {
            log.debug('No Custom Record Found', 'Item Internal ID: ' + itemInternalId);
        }
    }

    return {
        beforeLoad: beforeLoad
    };
});