/*-
 * ============LICENSE_START=======================================================
 * SDC
 * ================================================================================
 * Copyright (C) 2017 AT&T Intellectual Property. All rights reserved.
 * ================================================================================
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * ============LICENSE_END=========================================================
 */
/**
 * Created by obarda on 7/4/2016.
 */
'use strict';
import {Dictionary} from "../utils/dictionary/dictionary";

interface IEventListenerService {

}

interface ICallbackData {
    callback:Function;
    args:any[];
}

export class EventListenerService implements IEventListenerService {

    public observerCallbacks:Dictionary<string, ICallbackData[]> = new Dictionary<string, Array<ICallbackData>>();

    //register an observer + callback
    public registerObserverCallback = (eventName:string, callback:Function, ...args) => {
        let callbackData = {
            callback: callback,
            args: args
        }

        if (this.observerCallbacks.containsKey(eventName)) {
            let callbacks = this.observerCallbacks.getValue(eventName);

            // Only insert the callback if the callback is different from existing callbacks.
            for (let i = 0; i < callbacks.length; i++) {
                if (callbacks[i].toString() === callback.toString()) {
                    return; // Do not add this callback.
                }
            }

            callbacks.push(callbackData);
            this.observerCallbacks.setValue(eventName, callbacks);
        } else {
            this.observerCallbacks.setValue(eventName, [callbackData]);
        }
    };

    //unregister an observer
    public unRegisterObserver = (eventName:string, callbackFunc?:Function) => {
        if (this.observerCallbacks.containsKey(eventName)) {

            let callbacks: ICallbackData[]  =  this.observerCallbacks.getValue(eventName);
            if(callbacks.length === 1) {
                this.observerCallbacks.remove(eventName);
            } else {
                let filterCallbacks = _.filter(callbacks, (callBackObj) => {
                    return callBackObj.callback != callbackFunc;
                });
                this.observerCallbacks.setValue(eventName, filterCallbacks);
            }

        }
    };

    public notifyObservers = function (eventName:string, ...args) {
        _.forEach(this.observerCallbacks.getValue(eventName), (callbackData:ICallbackData) => {
            callbackData.callback(...args);
        });
    };
}