import { Renderer2 } from '@angular/core';

export class HelperBlock {
    protected _helper: Element;
    private _added = false;

    constructor(
        protected parent: Element,
        protected renderer: Renderer2
    ) {
        // generate helper div
        let helper = renderer.createElement('div');
        renderer.setStyle(helper, 'position', 'absolute');
        renderer.setStyle(helper, 'width', '100%');
        renderer.setStyle(helper, 'height', '100%');
        renderer.setStyle(helper, 'background-color', 'transparent');
        renderer.setStyle(helper, 'top', '0');
        renderer.setStyle(helper, 'left', '0');

        // done
        this._helper = helper;
    }

    add() {
        // append div to parent
        if (this.parent && !this._added) {
            this.parent.appendChild(this._helper);
            this._added = true;
        }
    }

    remove() {
        if (this.parent && this._added) {
            this.parent.removeChild(this._helper);
            this._added = false;
        }
    }

    dispose() {
        this._helper = null;
        this._added = false;
    }

    get el() {
        return this._helper;
    }
}