import { Directive, EventEmitter, Input, Output } from '@angular/core';
import { debounceTime, takeUntil, tap } from 'rxjs/operators';
import { fromEvent, Subject } from 'rxjs';
import * as i0 from "@angular/core";
import * as i1 from "@angular/material/select";
/** The height of the select items in `em` units. */
const SELECT_ITEM_HEIGHT_EM = 3;
export class MatSelectInfiniteScrollDirective {
    constructor(matSelect, ngZone) {
        this.matSelect = matSelect;
        this.ngZone = ngZone;
        this.threshold = '15%';
        this.debounceTime = 150;
        this.infiniteScroll = new EventEmitter();
        this.thrPx = 0;
        this.thrPc = 0;
        this.singleOptionHeight = SELECT_ITEM_HEIGHT_EM;
        this.destroyed$ = new Subject();
    }
    ngOnInit() {
        this.evaluateThreshold();
    }
    ngAfterViewInit() {
        this.matSelect.openedChange.pipe(takeUntil(this.destroyed$)).subscribe((opened) => {
            if (opened) {
                this.panel = this.matSelect.panel.nativeElement;
                this.singleOptionHeight = this.getSelectItemHeightPx();
                this.registerScrollListener();
            }
        });
    }
    ngOnDestroy() {
        this.destroyed$.next(true);
        this.destroyed$.complete();
    }
    evaluateThreshold() {
        if (this.threshold.lastIndexOf('%') > -1) {
            this.thrPx = 0;
            this.thrPc = (parseFloat(this.threshold) / 100);
        }
        else {
            this.thrPx = parseFloat(this.threshold);
            this.thrPc = 0;
        }
    }
    registerScrollListener() {
        fromEvent(this.panel, 'scroll').pipe(takeUntil(this.destroyed$), debounceTime(this.debounceTime), tap((event) => {
            this.handleScrollEvent(event);
        })).subscribe();
    }
    handleScrollEvent(event) {
        this.ngZone.runOutsideAngular(() => {
            if (this.complete) {
                return;
            }
            const countOfRenderedOptions = this.matSelect.options.length;
            const infiniteScrollDistance = this.singleOptionHeight * countOfRenderedOptions;
            const threshold = this.thrPc !== 0 ? (infiniteScrollDistance * this.thrPc) : this.thrPx;
            const scrolledDistance = this.panel.clientHeight + event.target.scrollTop;
            if ((scrolledDistance + threshold) >= infiniteScrollDistance) {
                this.ngZone.run(() => this.infiniteScroll.emit());
            }
        });
    }
    getSelectItemHeightPx() {
        return parseFloat(getComputedStyle(this.panel).fontSize) * SELECT_ITEM_HEIGHT_EM;
    }
}
MatSelectInfiniteScrollDirective.ɵfac = i0.ɵɵngDeclareFactory({ minVersion: "12.0.0", version: "14.1.3", ngImport: i0, type: MatSelectInfiniteScrollDirective, deps: [{ token: i1.MatSelect }, { token: i0.NgZone }], target: i0.ɵɵFactoryTarget.Directive });
MatSelectInfiniteScrollDirective.ɵdir = i0.ɵɵngDeclareDirective({ minVersion: "14.0.0", version: "14.1.3", type: MatSelectInfiniteScrollDirective, selector: "[msInfiniteScroll]", inputs: { threshold: "threshold", debounceTime: "debounceTime", complete: "complete" }, outputs: { infiniteScroll: "infiniteScroll" }, ngImport: i0 });
i0.ɵɵngDeclareClassMetadata({ minVersion: "12.0.0", version: "14.1.3", ngImport: i0, type: MatSelectInfiniteScrollDirective, decorators: [{
            type: Directive,
            args: [{
                    selector: '[msInfiniteScroll]'
                }]
        }], ctorParameters: function () { return [{ type: i1.MatSelect }, { type: i0.NgZone }]; }, propDecorators: { threshold: [{
                type: Input
            }], debounceTime: [{
                type: Input
            }], complete: [{
                type: Input
            }], infiniteScroll: [{
                type: Output
            }] } });
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