var HIGHLIGHT_FLAG = true;

// Flag to find whether the hit array initlized or not
var g_blnInitializedHitArr = false;

// a global array containing the html elements with class="VerityHit"
var g_objHitArr = new Array();

var currentTerm;
var currentTermIndex = -1;
var objVerityHitIndex = 0;

// it initializes the global array with the objects whose class name is "VerityHit".
function initHitList() {
	
    if (!g_blnInitializedHitArr) {
    
        var objSpanList = document.getElementsByTagName("span");
                
        for(var i=0; i < objSpanList.length; i++) {
        
            if (objSpanList[i].className == "VerityHit") {
            
                g_objHitArr[objVerityHitIndex] = objSpanList[i];
                objVerityHitIndex++;
            }
            
            
        }
                
        g_blnInitializedHitArr = true;
    }
}

// It returns the index of the next highlighted term.
function getNextHitIndex() {

    initHitList();
    currentTermIndex++;
   
    if (currentTermIndex < g_objHitArr.length) {
        // we have found the current hit.
        return currentTermIndex;
    } else {
    	currentTermIndex--;
    }
    
    return -1;
}

// It scrolls the window to the calculated y-coordinate  of the next jump term.
function scrollToNextHit() {

    
    var intCurrentHitIndex = getNextHitIndex();
            
    if (intCurrentHitIndex != -1) {
        window.scroll(0, getYCoord(g_objHitArr[intCurrentHitIndex]));
        var currentObject = g_objHitArr[intCurrentHitIndex];
        
        if (intCurrentHitIndex != 0) {
            var previousObject=g_objHitArr[intCurrentHitIndex - 1];
        	previousObject.className = "VerityHit";
        }
        
        currentObject.className = "VerityHit highlight";
        
    } else {
    	if(objVerityHitIndex != 0)
    	{
    	
        	alert("Reached the Last Term");
        }
    }
}

// It returns the index of the previous highlighted term.

function getPreviousHitIndex () {

    initHitList ();
    
    currentTermIndex--;
    
    if (currentTermIndex < 0) {
        currentTermIndex = 0;
        return -1;
    } else {
        return currentTermIndex;
    }
}

// It scrolls the window to the calculated y-coordinate  of the previous jump term.

function scrollToPreviousHit() {

    var intCurrentHitIndex = getPreviousHitIndex();
    
    //alert ("current index = " + currentTermIndex + "|" + intCurrentHitIndex);
        
    if (intCurrentHitIndex != -1) {
        window.scroll(0, getYCoord(g_objHitArr[intCurrentHitIndex]));
        
        var previousObject=g_objHitArr[intCurrentHitIndex + 1];
        var currentObject = g_objHitArr[intCurrentHitIndex];
        
        	currentObject.className = "VerityHit highlight";
        
        previousObject.className = "VerityHit";
        
    } else {
        alert("Reached the First Term");
    }
}


// It returns current y coordinate of the window.
function getYCoord(objElement) {

    var intYCoord = objElement.offsetTop;
    var objOffsetParent = objElement.offsetParent;
    
    while(objOffsetParent) {
        intYCoord += objOffsetParent.offsetTop;
        objOffsetParent = objOffsetParent.offsetParent;
    }
    
    return intYCoord;
}