application.js

define([
    'jquery',
    'underscore',
    'backbone',
    'component',
    'intent'
], function ($, _, Backbone, component, Intent) {
    'use strict';

    var definedComponents = {};

    var Application = {
        DEBUG: false,
        /**
         * Initalization functions
         * @type {Function[]}
         */
        _initCallbacks: [],

        /**
         * Components registered to trigger specific intent types
         * Intent type: Component[]
         */
        _intentHandlers: {},

        /**
         * Array of intents and callbacks that are sent when 
         * application is started
         * @type {Array}
         */
        _initIntents: [],


        extend: function (options) {
            return Object.create(Application);
        },


        /**
         * Starts application. Calls initial callbacks and send start intents
         *
         * @param {Object} [options] Options passed to all initial callbacks
         */
        start: function(options) {
            if (this.DEBUG) console.info('APP Starting application..');

            component._application = this;
            Intent._application = this;


            // Layout init function
            if (window.layoutInit) window.layoutInit.call(this);
            // Apply page specific init function if set
            if (window.pageInit) window.pageInit.call(this);

            var initCallback;
            while (this._initCallbacks.length > 0) {
                initCallback = this._initCallbacks.shift();
                initCallback(options);
            }
            // Send start intents
            var def, cmp;
            while (this._initIntents.length > 0) {
                def = this._initIntents.shift();
                cmp = this.getComponent(def.uid);
                cmp.start(Intent.create('predefined', def.data));
            }

        },


        /**
         * Defines component to be used in application
         * 
         * @param {Componen} cmp 
         */
        defineComponent: function (cmp) {
            if (this.DEBUG) console.info('APP defining ' + cmp.uid);

            var inst = this,
                intentTypes = [];

            if (!cmp.uid) throw new Error('Component UID missing');
            if (definedComponents[cmp.uid]) throw new Error('UID already in use: ' + cmp.uid);

            definedComponents[cmp.uid] = cmp;

            _.each(cmp.callbacks, function (callbacks) {
                intentTypes = _.union(_.keys(callbacks), intentTypes);
            });

            // Bind intent types to component
            _.each(intentTypes, function (intentType) {
                inst.registerIntentHandler(intentType, cmp);
            });
            
            return cmp;
        },


        /**
         * Creates intent that is sent when application starts 
         *
         */
        predefined: function(uid, data) {
            this._initIntents.push({
                uid:    uid,
                data:   data
            });
        },


        /**
         * Adds initialization callback function
         * 
         * @param {Function} initFunction
         */
        onInit: function(initFunction) {
            this._initCallbacks.push(_.bind(initFunction, this));
        },


        /**
         * Register component as intent handler
         *
         * @param {String} intentType
         * @param {Component} component
         */
        registerIntentHandler: function(intentType, component) {
            if (!this._intentHandlers[intentType]) {
                this._intentHandlers[intentType] = [];
            }
            this._intentHandlers[intentType].push(component);
        },


        /**
         * Broadcasts intent
         *
         * @param {Intent} intent
         * @return void
         */
        sendIntent: function(intent) {
            if (this._intentHandlers[intent.type]) {
                _.forEach(this._intentHandlers[intent.type], function (component) {
                    if (!intent.handled) {
                        component.start(intent);
                    }
                });
            }
        },


        /**
         * Returns component.
         * 
         * This sould be used only for debugging and in server side view
         * specific javascript.
         * @param {String} uid Component uid
         * @return {Component}
         */
        getComponent: function(uid) {
            if (!definedComponents[uid]) throw new Error('No component: ' + uid);
            return definedComponents[uid];
        }
    };


    return Application;
});