import * as plugins from './lik.plugins'
import { Objectmap } from './lik.objectmap'
import { Stringmap } from './lik.stringmap'
import { Observable } from 'rxjs/Rx'


/**
 * bundles an observable with an emitter
 */
export interface ObservableEmitterBundle {
    observable: plugins.rx.Observable<any>
    emitter: plugins.events.EventEmitter
    event: string
}

/**
 * manages observables by making sure that only one observable is regsitered per event
 */
export class Observablemap {
    ObservableEmitterBundleObjectmap = new Objectmap<ObservableEmitterBundle>()

    /**
     * creates a new observable if not yet registered for the same event.
     * In case event has been registered before the same observable is returned.
     */
    getObservableForEmitterEvent(emitterArg: plugins.events.EventEmitter, eventArg: string) {
        let existingBundle = this.ObservableEmitterBundleObjectmap.find((bundleArg) => {
            return(bundleArg.emitter === emitterArg && bundleArg.event === eventArg)
        })
        if (existingBundle) {
            return existingBundle.observable
        } else {
            let emitterObservable = plugins.rx.Observable.fromEvent(emitterArg, eventArg)
            this.ObservableEmitterBundleObjectmap.add({
                observable: emitterObservable,
                emitter: emitterArg,
                event: eventArg
            })
            return emitterObservable
        }
    }
}