//Incident Category = 1bf7c3561bce8d5099e265b1604bcb43
//Incident Subcategory = e02847961bce8d5099e265b1604bcba9

var definition = new GlideRecord("metric_definition");
definition.get("name", "Incident Category")
gs.print(definition.name);

var gr = new GlideRecord("incident");
    gr.addEncodedQuery("opened_at<=javascript:gs.endOfYesterday()");
    gr.setLimit(3);
    gr.query();

    gs.print('Found ' + gr.getRowCount());

// Update fieldname below for category or subcategory
while(gr.next()) {
    gs.print(gr.sys_id);
    history = new GlideRecord("sys_audit");
    history.addQuery("documentkey", gr.sys_id);
    history.addQuery("fieldname", "category");
    history.orderBy("sys_created_on");
    history.query();

    while(history.next()) {
        var grMetric = new GlideRecord('metric_instance');
        grMetric.addQuery('id', gr.getValue('sys_id'));
        grMetric.addQuery('definition', definition.getValue('sys_id'));
        grMetric.addQuery('value', gr.getDisplayValue('category'));
        // For original value, use the line below instead of the line above
        //grMetric.addQuery('value', history.getValue('oldvalue'));
        grMetric.query();

        var gdtStart = new GlideDateTime(history.sys_created_on);
        // For original time, use the line below instead of the line above
        //var gdtStart = new GlideDateTime(gr.opened_at);
        gs.print("Start "+gdtStart);
        if (!grMetric.hasNext()) {
                var now = new GlideDateTime();
                var instant = new GlideDuration(0);
                //var gdurCalendar = GlideDateTime.subtract(gdtStart, gdtEnd);

                grMetric = new GlideRecord('metric_instance');
                grMetric.initialize();
                grMetric.setValue('table', gr.getRecordClassName());
                grMetric.setValue('id', gr.getValue('sys_id'));
                grMetric.setValue('definition', definition.getValue('sys_id'));
                grMetric.setValue('field', definition.getValue('field'));
                // Update value below for category or subcategory
                grMetric.setValue('value', history.getValue('oldvalue'));
                grMetric.setValue('duration', instant);
                grMetric.setValue('calculation_complete', true);
                grMetric.setValue('start', gdtStart);
                grMetric.setValue('end', now);
                grMetric.insert();
        }
    }
}