/* Based on Alex Arnell's inheritance implementation. */
var Class = {
  create: (function() {
    var extending = { };
    
    return function(parent, properties) {
      if (arguments.length == 1 && !Object.isFunction(parent))
        properties = parent, parent = null;
      
      function klass() {
        if (arguments[0] !== extending) 
          this.initialize.apply(this, arguments);
      }
    
      klass.superclass = parent;
      klass.subclasses = [];
    
      if (parent) {
        klass.prototype = new parent(extending);
        parent.subclasses.push(klass);
      }

      if (properties) Class.extend(klass, properties);
      if (!klass.prototype.initialize)
        klass.prototype.initialize = Prototype.emptyFunction;
        
      klass.prototype.constructor = klass;

      return klass;
    };
  })(),
  
  extend: function(destination, source) {
    var ancestor = destination.superclass && destination.superclass.prototype;

    for (var property in source) {
      var value = source[property];
      if (ancestor && Object.isFunction(value) &&
          value.argumentNames().first() == "$super") {
        var method = value, value = Object.extend((function(m) { 
          return function() { return ancestor[m].apply(this, arguments) };
        })(property).wrap(method), {
          valueOf:  function() { return method },
          toString: function() { return method.toString() }  
        });
      }
      destination.prototype[property] = value;
    }
    
    return destination;
  },

  mixin: function(destination, source) {
    return Object.extend(destination.prototype, source);
  }
};

var Abstract = { };

Object.extend = function(destination, source) {
  for (var property in source)
    destination[property] = source[property];
  return destination;
};

Object.extend(Object, {
  inspect: function(object) {
    try {
      if (object === undefined) return 'undefined';
      if (object === null) return 'null';
      return object.inspect ? object.inspect() : object.toString();
    } catch (e) {
      if (e instanceof RangeError) return '...';
      throw e;
    }
  },
  
  toJSON: function(object) {
    var type = typeof object;
    switch (type) {
      case 'undefined':
      case 'function':
      case 'unknown': return;
      case 'boolean': return object.toString();
    }
    
    if (object === null) return 'null';
    if (object.toJSON) return object.toJSON();
    if (Object.isElement(object)) return;
    
    var results = [];
    for (var property in object) {
      var value = Object.toJSON(object[property]);
      if (value !== undefined)
        results.push(property.toJSON() + ': ' + value);
    }
    
    return '{' + results.join(', ') + '}';
  },
  
  toHTML: function(object) {
    return object && object.toHTML ? object.toHTML() : String.interpret(object);
  },
  
  keys: function(object) {
    var keys = [];
    for (var property in object)
      keys.push(property);
    return keys;
  },
  
  values: function(object) {
    var values = [];
    for (var property in object)
      values.push(object[property]);
    return values;
  },
  
  clone: function(object) {
    return Object.extend({ }, object);
  },
  
  isElement: function(object) {
    return object && object.nodeType == 1;
  },
  
  isArray: function(object) {
    return object && object.constructor === Array;
  },
  
  isFunction: function(object) {
    return typeof object == "function";
  },
  
  isString: function(object) {
    return typeof object == "string";
  },
  
  isNumber: function(object) {
    return typeof object == "number";
  },
  
  isUndefined: function(object) {
    return typeof object == "undefined";
  }
});

Object.extend(Function.prototype, {
  argumentNames: function() {
    var names = this.toString().match(/^[\s\(]*function\s*\((.*?)\)/)[1].split(",").invoke("strip");
    return names.length == 1 && !names[0] ? [] : names;
  },
  
  bind: function() {
    if (arguments.length < 2 && arguments[0] === undefined) return this;
    var __method = this, args = $A(arguments), object = args.shift();
    return function() {
      return __method.apply(object, args.concat($A(arguments)));
    }
  },
  
  bindAsEventListener: function() {
    var __method = this, args = $A(arguments), object = args.shift();
    return function(event) {
      return __method.apply(object, [event || window.event].concat(args));
    }
  },
  
  curry: function() {
    if (!arguments.length) return this;
    var __method = this, args = $A(arguments);
    return function() {
      return __method.apply(this, args.concat($A(arguments)));
    }
  },

  delay: function() { 
    var __method = this, args = $A(arguments), timeout = args.shift() * 1000; 
    return window.setTimeout(function() {
      return __method.apply(__method, args);
    }, timeout);
  },
  
  wrap: function(wrapper) {
    var __method = this;
    return function() {
      return wrapper.apply(this, [__method.bind(this)].concat($A(arguments))); 
    }
  },
  
  methodize: function() {
    if (this._methodized) return this._methodized;
    var __method = this;
    return this._methodized = function() {
      return __method.apply(null, [this].concat($A(arguments)));
    };
  }
});

Function.prototype.defer = Function.prototype.delay.curry(0.01);

Date.prototype.toJSON = function() {
  return '"' + this.getFullYear() + '-' +
    (this.getMonth() + 1).toPaddedString(2) + '-' +
    this.getDate().toPaddedString(2) + 'T' +
    this.getHours().toPaddedString(2) + ':' +
    this.getMinutes().toPaddedString(2) + ':' +
    this.getSeconds().toPaddedString(2) + '"';
};

var Try = {
  these: function() {
    var returnValue;

    for (var i = 0, length = arguments.length; i < length; i++) {
      var lambda = arguments[i];
      try {
        returnValue = lambda();
        break;
      } catch (e) { }
    }

    return returnValue;
  }
};

RegExp.prototype.match = RegExp.prototype.test;

RegExp.escape = function(str) {
  return String(str).replace(/([.*+?^=!:${}()|[\]\/\\])/g, '\\$1');
};

/*--------------------------------------------------------------------------*/

var PeriodicalExecuter = Class.create({
  initialize: function(callback, frequency) {
    this.callback = callback;
    this.frequency = frequency;
    this.currentlyExecuting = false;

    this.registerCallback();
  },

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

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

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