/*
Script: PeriodicalExecuter.js
    port of the Prototype.js timer to Mootools

    License: MIT-style license.
    Copyright: Copyright (c) 2007 Thierry bela <bntfr at yahoo dot fr>

    License:
        MIT-style license.

    Authors:
        Thierry Bela

    TODO: possibility to stop the timer when the window is idle ?
*/          
    var PeriodicalExecuter = new Class({
        // name: 'PeriodicalExecuter',
        initialize: function(callback, frequency) {
        
            this.callback = callback;
            this.frequency = frequency;
            this.currentlyExecuting = false;

            this.registerCallback()
        },

        registerCallback: function() {
        
            this.stop();
            this.timer = setInterval(this.onTimerEvent.bind(this), this.frequency * 1000);
            return this
        },

        execute: function() {
        
            this.callback(this);
            return this
        },

        stop: function() {
        
            if (!this.timer) return this;
            clearInterval(this.timer);
            this.timer = null;
            return this
        },

        onTimerEvent: function() {
        
            if (!this.currentlyExecuting) {
            
                try {
                
                    this.currentlyExecuting = true;
                    this.execute();
                } finally {
                
                    this.currentlyExecuting = false;
                }
            }
                
            return this
        }
    });