/*
 * 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 {XH} from '@xh/hoist/core';
import {throwIf} from '@xh/hoist/utils/js';
import {isFunction} from 'lodash';
import {Store} from '../Store';
import {Filter} from './Filter';
import {FunctionFilterSpec, FilterTestFn} from './Types';

/**
 * Filters via a custom function specified by the developer or generated by a component such as
 * StoreFilterField.
 *
 * Immutable.
 */
export class FunctionFilter extends Filter {
    static isFunctionFilter(obj: unknown): obj is FunctionFilter {
        return obj instanceof FunctionFilter;
    }

    readonly key: string;
    readonly testFn: FilterTestFn;

    /**
     * Constructor - not typically called by apps - create via {@link parseFilter} instead.
     * @internal
     */
    constructor({key, testFn}: FunctionFilterSpec) {
        super();
        throwIf(!key, 'FunctionFilter requires a `key`');
        throwIf(!isFunction(testFn), 'FunctionFilter requires a `testFn`');

        this.key = key;
        this.testFn = testFn;

        Object.freeze(this);
    }

    //-----------------
    // Overrides
    //-----------------
    override getTestFn(store?: Store): FilterTestFn {
        return this.testFn;
    }

    override equals(other: Filter) {
        if (other === this) return true;
        return other instanceof FunctionFilter && this.testFn === other.testFn;
    }

    override toJSON(): FunctionFilterSpec {
        throw XH.exception('FunctionFilter.toJSON() not supported.');
    }

    override removeFieldFilters(field: string = null): Filter {
        return this;
    }

    override removeFunctionFilters(key: string = null): Filter {
        return !key || this.key === key ? null : this;
    }
}