/**
 * simple event aggregator for sending messages between components/attributes etc
 *
 */
export class EventAggregator {

    private channels: any;

    constructor() {
        this.channels = {};
    }


    // todo, do we want a async option ?
    // todo, do we want to upper/lower case all channels? less chance for typos..

    /**
     * publish to channel
     *
     */
    public publish(channel: string, ...args: any[]): void {
        if (Array.isArray(this.channels[channel])) {
            for (let i = 0, len = this.channels[channel].length; i < len; i++) {
                this.channels[channel][i].apply(this, args);
            }
        } else {
            // if no one is listening then do we really need to do anything ?
        }
    }



    /**
     * unsubscribes to channel
     *
     */
    public unsubscribe(channel: string, func: Function): void {
        if (Array.isArray(this.channels[channel])) {
            for (let i = 0, len = this.channels[channel].length; i < len; i++) {
                if (this.channels[channel][i] === func) {
                    this.channels[channel].splice(i, 1);
                }
            }
        } else {
            // channel does not exist, great!
        }

    }


    /**
     * subscribes to channel
     *
     */
    public subscribe(channel: string, func: Function): void {
        if (!Array.isArray(this.channels[channel])) {
            this.channels[channel] = [];
        }
        this.channels[channel].push(func);
    }
}