// Timer implementation that reduces setTimeout/clearTimeout calls.
// NOTE: something worse accuracy in not WebKit browsers (JS time accuracy).
var Timer = (function( G ) {
	
	return function Timer( g ) {
		g = g || G;
		
		var noargs = [],
			Date = g.Date,
			now = Date.now || function(){ return +new Date(); },
			timer_id,
			end_time,
			callback,
			context,
			args;
		
		function onTimeout() {
			var dt = end_time - now();
			
			if ( dt > 0 ) {
				timer_id = g.setTimeout( onTimeout, dt );
				
			} else {
				var _callback = callback,
					_context = context,
					_args = args;
					
				timer_id = callback = context = args = 0;
				_callback.apply( _context, _args || noargs );
			}
		}
		
		return {
			set: function( delay, _callback, _context, _args ) {
				var t = end_time;
				end_time = now() + delay;
				
				callback = _callback;
				context = _context;
				args = _args;
				
				if ( !timer_id || end_time < t ) {
					timer_id && g.clearTimeout( timer_id );
					timer_id = g.setTimeout( onTimeout, delay );
				}
				
				return this;
			},
			
			clear: function() {
				if ( timer_id ) {
					g.clearTimeout( timer_id );
					timer_id = callback = context = args = 0;
				}
				return this;
			}
		};
	};

})( this );