/*
 * This file belongs to Hoist, an application development toolkit
 * developed by Extremely Heavy Industries (www.xh.io | info@xh.io)
 *
 * Copyright © 2026 Extremely Heavy Industries Inc.
 */
import {Aggregator} from './Aggregator';
import {isEmpty, isEqual} from 'lodash';

/** Returns the value if all rows share the same value, otherwise null. */
export class UniqueAggregator extends Aggregator {
    override aggregate(rows, fieldName) {
        if (isEmpty(rows)) return null;
        const val = rows[0].data[fieldName];
        return rows.every(it => isEqual(it.data[fieldName], val)) ? val : null;
    }

    override replace(rows, currAgg, update, context) {
        const {newValue, field} = update;
        if (rows.length === 1 || isEqual(newValue, currAgg)) return newValue;
        return this.aggregate(rows, field.name);
    }
}