/**
 * Copyright (c) 2020 Burst Apps Team
 */

/* global window */
import {isNode} from './isNode';

/**
 *
 * The internal isomorphic event emitter
 * @internal
 ** @module monitor
 */
export class EventEmitter {
    private readonly _emitter: any;

    constructor() {
        if (isNode()) {
            // @ts-ignore
            const Events = require('events');
            this._emitter = new Events();
        } else {
            this._emitter = {
                on: (name: string | symbol, cb: Function) => {
                    // @ts-ignore
                    window.addEventListener(name, e => cb(e.detail));
                },
                once: (name: string | symbol, cb: Function) => {
                    const singleCallback = (data) => {
                        cb(data);
                    };
                    // @ts-ignore
                    window.addEventListener(name, (e) => {
                        // @ts-ignore
                        singleCallback(e.detail);
                        // @ts-ignore
                        window.removeEventListener(name, singleCallback);
                    });
                },
                off: (name: string | symbol, cb: Function) => {
                    // @ts-ignore
                    window.removeEventListener(name, cb);
                },
                emit: (name: string | symbol, payload?: unknown) => {
                    // @ts-ignore
                    window.dispatchEvent(new window.CustomEvent(name, {
                        detail: payload
                    }));
                },
            };
        }
    }

    public off(eventName: string | symbol, fn: Function): void {
        this._emitter.off(eventName, fn);
    }

    public on(eventName: string | symbol, fn: Function): void {
        this._emitter.on(eventName, fn);
    }

    public once(eventName: string | symbol, fn: Function): void {
        this._emitter.once(eventName, fn);
    }

    public emit(eventName: string | symbol, payload?: unknown) {
        this._emitter.emit(eventName, payload);
    }
}