import { Injectable, Renderer2, RendererFactory2 } from '@angular/core';

import { NgClassInterface } from '../interfaces/ng-class';

@Injectable()
export class UpdateHostClassService {
    private classMap = {};
    readonly renderer: Renderer2;

    updateHostClass(el: HTMLElement, classMap: object): void {
        this.removeClass(el, this.classMap, this.renderer);
        this.classMap = { ...classMap };
        this.addClass(el, this.classMap, this.renderer);
    }

    private removeClass(el: HTMLElement, classMap: NgClassInterface, renderer: Renderer2): void {
        for (const i in classMap) {
            if (classMap.hasOwnProperty(i)) {
                renderer.removeClass(el, i);
            }
        }
    }

    private addClass(el: HTMLElement, classMap: NgClassInterface, renderer: Renderer2): void {
        for (const i in classMap) {
            if (classMap.hasOwnProperty(i) && classMap[i]) {
                renderer.addClass(el, i);
            }
        }
    }

    constructor(rendererFactory2: RendererFactory2) {
        this.renderer = rendererFactory2.createRenderer(null, null);
    }
}