/**
 * Custom button state handler for enabling/disabling button state. 
 * Called when the carousel has determined that the previous button
 * state should be changed.
 * Specified to the carousel as the configuration
 * parameter: prevButtonStateHandler
 **/
var handlePrevButtonState = function(type, args) {

	var enabling = args[0];
	var leftImage = args[1];
	if(enabling) {
		leftImage.src = "/img/b-arrowleft-on.gif";
	} else {
		leftImage.src = "/img/b-arrowleft-off.gif";
	}
	
};

/**
 * Custom button state handler for enabling/disabling button state. 
 * Called when the carousel has determined that the next button
 * state should be changed.
 * Specified to the carousel as the configuration
 * parameter: nextButtonStateHandler
 **/
var handleNextButtonState = function(type, args) {

	var enabling = args[0];
	var rightImage = args[1];
	if(enabling) {
		rightImage.src = "/img/b-arrowright-on.gif";
	} else {
		rightImage.src = "/img/b-arrowright-off.gif";
	}
};

/**
 * Custom inital load handler. Called when the carousel loads the initial
 * set of data items. Specified to the carousel as the configuration
 * parameter: loadInitHandler
 **/
var loadInitialItems = function(type, args) {
    var start = args[0];
    var last = args[1]; 

    load(this, start, last);    
};	

var loadNextItems = function(type, args) {	

	var start = args[0];
	var last = args[1]; 
	var alreadyCached = args[2];

	if(!alreadyCached) {
		load(this, start, last);
	}
}

var loadPrevItems = function(type, args) {
	var start = args[0];
	var last = args[1]; 
	var alreadyCached = args[2];

	if(!alreadyCached) {
		load(this, start, last);
	}
}	

var load = function(carousel, start, last) {

	for(var i=start; i<=last; i++) {
		carousel.addItem(i, lineList[i-1], "#", "Number "+i);
	}
}