/**
 * 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 status = "Showing " + start + " of " + this.getProperty("size");
    YAHOO.util.Dom.get("indicator").innerHTML = status;
};

var animComplete = function(type, args) {
    var direction = args[0]; // string either: 'next' or 'prev'
    
    var status = "Showing " + this.getFirstVisible() + " of " + this.getProperty("size");
    YAHOO.util.Dom.get("indicator").innerHTML = status + " (done)";

};

/**
 * Custom load next handler. Called when the carousel loads the next
 * set of data items. Specified to the carousel as the configuration
 * parameter: loadNextHandler
 **/
var loadNextItems = function(type, args) {    

    var start = args[0];
    var last = args[1]; 
    var alreadyCached = args[2];
    
    if(!alreadyCached) {
        load(this, start, last);
    }
};

/**
 * Custom load previous handler. Called when the carousel loads the previous
 * set of data items. Specified to the carousel as the configuration
 * parameter: loadPrevHandler
 **/
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+1; i++) {
        carousel.addItem(i, fmtItem(imageList[i-1]));
    }
}

/**
 * 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 = "images/left-enabled.gif";
    } else {
        leftImage.src = "images/left-disabled.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 = "images/right-enabled.gif";
    } else {
        rightImage.src = "images/right-disabled.gif";
    }
    
};

/**
 * You must create the carousel after the page is loaded since it is
 * dependent on an HTML element (in this case 'dhtml-carousel'.) See the
 * HTML code below.
 **/