import { AfterViewInit, ChangeDetectorRef, OnDestroy, OnInit } from '@angular/core';
import { BehaviorSubject, Observable, Subject } from 'rxjs';
import { NgxMatSelectOptionType } from '../../select-model';
import { NgxMatSelectComponent } from '../../select';
import * as i0 from "@angular/core";
export interface NgxMatSelectFetchOptions {
    filteredOptions$: Observable<unknown[]>;
    loading$: Observable<boolean>;
    hasSearchBox: boolean | undefined | null;
    searchBoxPlaceholder: string | null | undefined;
}
export declare abstract class NgxMatSelectFetchOptionsDirective implements OnDestroy, OnInit, NgxMatSelectFetchOptions, AfterViewInit {
    protected host: NgxMatSelectComponent;
    protected _changeDetectorRef: ChangeDetectorRef;
    /**
     * Function used to sort the values in a select in multiple mode.
     * Follows the same logic as `Array.prototype.sort`.
     * in the server-side mode you should provide sortComparator in order to sort the selected options,
     * but in the client-side mode all the selected options and values would order with the order of received options
     */
    sortComparator?: (a: unknown, b: unknown, options: unknown[]) => number;
    /**
     * if it's true the search-box will appear inside the panel
     */
    get hasSearchBox(): boolean | undefined | null;
    set hasSearchBox(value: boolean | undefined | null);
    private _hasSearchBox;
    /**
     * a placeholder for the search-box to be shown if nothing is written in the search-box
     */
    set searchBoxPlaceholder(value: string | undefined | null);
    /**
     * an observable to manage the filtered options state
     */
    filteredOptions$: BehaviorSubject<unknown[]>;
    /**
     * when the main stream is busy with fetching data from the server, the loading is true
     */
    loading$: BehaviorSubject<boolean>;
    /**
     * to handle the search
     */
    abstract search: (searchTerm: string) => void;
    /**
     * all the options which are provided up to now
     * @protected
     */
    protected abstract options: unknown[] | undefined | null;
    /**
     * an observable to manage destroying the other observables
     * @protected
     */
    protected destroy$: Subject<void>;
    /**
     * the type of received options
     * @protected
     */
    protected optionType: NgxMatSelectOptionType;
    /**
     * if every input initialized or not
     * @private
     */
    private initialized;
    /**
     * to recognize the first empty search
     * @private
     */
    private isFirstEmptySearch;
    private searchSubscription?;
    protected constructor(host: NgxMatSelectComponent, _changeDetectorRef: ChangeDetectorRef);
    /**
     * to sync the value with selection Model, and check the possibility of fill incomplete values from the
     * received options
     * @private
     */
    protected abstract syncValueAndOptions: () => void;
    /** Sorts the selected values in the selected based on their order in the panel. */
    protected abstract sortValues: () => void;
    ngOnInit(): void;
    ngAfterViewInit(): void;
    ngOnDestroy(): void;
    /**
     * to check the type of the options to realize there are primitive or an object
     * @protected
     */
    protected checkOptionsType(): void;
    /**
     * to listen to the search-box input changes, and filter the options through the searchTerm
     * @private
     */
    private initializeSearch;
    /**
     * to check value member and display-member are required if they are required, checking they are provided or not
     * @private
     */
    private checkOptionLabel;
    /**
     * to sync the selected items with the value of the select-box
     * @private
     */
    private listenToValueChanges;
    /**
     * to scroll to the selected option when the select has a value.
     * it works just in client side because we have whole the options and the selection mode has to be single selection,
     * @private
     */
    private initScrollIntoSelectedOption;
    /**
     * @returns - a boolean to find out whether we are successful in scroll to the selected option or not
     * it depends on whether the corresponding option is present in the options.
     * @param selected - the selected item
     * @private
     */
    private scrollIntoVisibleOptionView;
    /**
     * to sort the selected option and values with order of received options, whenever the selection or value changes
     * @private
     */
    private initSortValues;
    static ɵfac: i0.ɵɵFactoryDeclaration<NgxMatSelectFetchOptionsDirective, never>;
    static ɵdir: i0.ɵɵDirectiveDeclaration<NgxMatSelectFetchOptionsDirective, never, never, { "sortComparator": { "alias": "sortComparator"; "required": false; }; "hasSearchBox": { "alias": "hasSearchBox"; "required": false; }; "searchBoxPlaceholder": { "alias": "searchBoxPlaceholder"; "required": false; }; }, {}, never, never, false, never>;
}