'use strict';

var EventEmitter = require('events').EventEmitter,
	globalChannel = new EventEmitter(),
	Rx = require('rx'),
	nutrients = require('./food-objects/nutrients'),
	nutrients,
	
	defaultHandlers = {
        onError: function (err) {
            console.log('Error: ' + err);
        },
        
        onComplete: function () {
            console.log('Completed');
        }
    },
    
    globalChannelDestroyEvent = Rx.Observable.fromEvent( globalChannel, 'destroy').take(1),

    // declaration
    //-----------------------------------------
    frenchFryNutrition = Object.create( nutrients ); // using delegation pattern 

// lazy instantiation
//-----------------------------------------
frenchFryNutrition.initNutrition({
	state: {
		salt: 100,
		sugar: 95,
		calories: 50
	},
	
	init: function() {
		console.log('init was called on this stateContainer');
	}
});

// events
//-----------------------------------------

// create observables
Rx.Observable.fromEvent( globalChannel, 'nutrientRequest',
	function( eventArgs ) {
		return frenchFryNutrition.getState()[ eventArgs[0] ];
	}).
takeUntil(globalChannelDestroyEvent).
subscribe(
    function( response ) { globalChannel.emit( 'nutrientResponse', response ); },
    defaultHandlers.onError,
    defaultHandlers.onComplete
);

Rx.Observable.fromEvent( globalChannel, 'nutrientResponse' ).
takeUntil(globalChannelDestroyEvent).
subscribe(
    function( response ) { console.log( response ); },
    defaultHandlers.onError,
    defaultHandlers.onComplete
);


//-----------------------------------------
// main
//-----------------------------------------
console.log(frenchFryNutrition.getNutrients()); // { salt: 100, sugar: 95, calories: 50 }
// test that we got a value not reference
nutrients = frenchFryNutrition.getNutrients();
nutrients.salt = 25; // this does not work because getNutrients() returns a shallow copy not a reference
console.log(frenchFryNutrition.getNutrients()); // { salt: 100, sugar: 95, calories: 50 }
// test modification of ingredient
frenchFryNutrition.setNutrients({ salt: 5 });
console.log(frenchFryNutrition.getNutrients()); // { salt: 5, sugar: 95, calories: 50 }

// test events
globalChannel.emit('nutrientRequest', 'salt'); // 5
globalChannel.emit('nutrientRequest', 'sugar'); // 95
globalChannel.emit('nutrientRequest', 'calories'); // 50
globalChannel.emit('destroy'); // Completed\nCompleted

// output
//-----------------------------------------
// $ node index.js 
// init was called on this stateContainer
// { salt: 100, sugar: 95, calories: 50 }
// { salt: 100, sugar: 95, calories: 50 }
// { salt: 5, sugar: 95, calories: 50 }
// 5
// 95
// 50
// Completed
// Completed