// Common JavaScript Functions
// Date: 08-15-2011
//

// Global Variables
var displayFlag = true;

// switchDiv() Switches division layers
function switchDiv(hideDivName, showDivName) {
    var hideDiv = document.getElementById(hideDivName);
    if (hideDiv) {
        hideDiv.style.display = 'none';
    }

    var showDiv = document.getElementById(showDivName);
    if (showDiv) {
        showDiv.style.display = 'block';
    }
} // End switchDiv()


// Slideshow Services Global Variables
var interval = 3500;
var random_display = 0;
var imageDir = "/core_images/";
var imageNum = -1;
var slideCount = 4;
var slideCtr = 0;
var timerID;
var place;

// Get Image Item
function imageItem(url){
    this.img = new Image();
    this.img.src = url;
    this.url = url;
} //imageItem()

var imageArray = [
    new imageItem(imageDir + "main_image[1].jpg"),
    new imageItem(imageDir + "main_image[2].jpg"),
    new imageItem(imageDir + "main_image[3].jpg"),   
    new imageItem(imageDir + "main_image[4].jpg")
];

// Generate Random Number
function randNum(x, y) {
    var range = y - x + 1;
    return Math.floor(Math.random() * range) + x;
}

// Get Next Image
function getNextImage() {
    imageNum = (random_display) ? randNum(0, imageArray.length-1) : ((imageNum+1) % imageArray.length);
    return imageArray[imageNum];
}

// Get Previous Image
function getPrevImage() {
    imageNum = (imageNum-1 >= 0) ? (imageNum-1) : (imageArray.length-1);
    return imageArray[imageNum];
}

// Previous Image Service
function prevImage() {
    var image_item = getPrevImage();
    place.src = place.alt = image_item.url;
}

// Next Image Service
function nextImage() {
    var image_item = getNextImage();
    place.src = place.alt = image_item.url;
}

// Play Slide Show Service
function playSlideshow() {
    slideCtr = ++slideCtr;
    if (slideCtr > 4) {
        clearTimeout(timerID);
        switchDiv('slideShow', 'videoDiv');
        return;
    }
    place = document.getElementById('imageHolder');
    if (place) {
        nextImage();
        timerID = setTimeout("playSlideshow()", interval);
    }

}