//Functions for navigating views
//Sean Power
//26 Nov 2007

var vPosition = 1; //the position in the view to retrieve from
var entryCountDocument = 10; //number of entries to retireve & display - documents
var entryCountCategory = 30; //number of entries to retireve & display - Categories
var previousPageScript = "";	//the script to call from a back button to get back to a page - this could be a cat page or a search or something
var currentPageURL = ""; //the current page url, this will allow us to determine if we're using categories or anything else
var viewName = ""; //current view to lookup
var categoryView = ""; //used for the view we want to lookup the categories from

//Sets the start position in the view to the next page
function setPositionDown (type) {
	var countNum = entryCountDocument;
	if (type == "C") {
		countNum = entryCountCategory;
	}
	vPosition = vPosition + countNum;
} //end setPositionDown

//Sets the start postion in the view to the previous page
function setPositionUp (type){
	var countNum = entryCountDocument;
	if (type == "C") {
		countNum = entryCountCategory;
	}
	vPosition = vPosition - countNum;
	if (vPosition < 1) {
		vPosition = 1;
	}
} //end setPositionUp

//retrieves the documents from the view
function retrieveViewCategories (requestStr)
{
	var xmlhttp = new XMLHttpRequest ();	
	if (!requestStr) requestStr = categoryView + "?ReadViewEntries&CollapseView&Start=" + vPosition + "&Count=" + entryCountCategory;	
	
	currentPageURL = requestStr;
	previousPageScript = "vPosition="+ vPosition +";viewName=\"" + viewName + "\"; categoryView=\"" + categoryView + "\";retrieveViewCategories (\"" + requestStr +"\")";
	xmlhttp.open ("POST", requestStr, true) //open the view ready to send the request
	
	//Add a listener so we know when the agent has finished retrieving information
	function viewCategoryHandler ()
	{
		//only process if we get a ready state of 4
		if (xmlhttp.readyState == 4)
		{
			//Process the returned XML - i.e. Put it into a html table/div and shove it into the screen
			var luVals;
			//if we have a category element then get them
			 if (xmlhttp.responseXML.getElementsByTagName ("viewentry").length >0 )
	 		{
		 		luVals = xmlhttp.responseXML.getElementsByTagName ("viewentry");
		 		parseCategories (luVals, xmlhttp.responseXML);
			}
			
			hideLoading ();
		}
	}
	//tell the http request what to run when we're ready
	xmlhttp.onreadystatechange = viewCategoryHandler;
	
	//Draw the loading DIV so the user knows we're doing something
	showLoading ();

     xmlhttp.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
    	xmlhttp.send(null);
	
} //end RetrieveViewDocuments


//retrieves the documents from the view
function retrieveViewDocuments (category)
{
	var xmlhttp = new XMLHttpRequest ();	
	var requestStr = viewName + "?ReadViewEntries&Start=" + vPosition + "&Count=" + entryCountDocument;
	
	//if we have category then we need to lookup by that too
	if (category)
	{
		requestStr += "&RestrictToCategory="+ category;
	}

	//if we have a currenturl then set it to previous, other wise just set this to current
	if (currentPageURL) previousPageURL = currentPageURL;
	currentPageURL = requestStr;
	
	xmlhttp.open ("POST", requestStr, true) //open the view ready to send the request
	
	//Add a listener so we know when the agent has finished retrieving information
	function viewRequestHandler ()
	{
		//only process if we get a ready state of 4
		if (xmlhttp.readyState == 4)
		{
			//Process the returned XML - i.e. Put it into a html table/div and shove it into the screen
			var luVals;
			//if we have a category element then get them
			 if (xmlhttp.responseXML.getElementsByTagName ("viewentry").length >0 )
	 		{
		 		luVals = xmlhttp.responseXML.getElementsByTagName ("viewentry");
		 		parseEntryDocuments (luVals, xmlhttp.responseXML);
			} else
			{
				var viewData = document.getElementById ("ViewData");
				if (vPosition > 1) viewData.innerHTML =  "No more documents for that selection."; else viewData.innerHTML = "No documents for that selection";
			}
			hideLoading ();
		}
	}
	//tell the http request what to run when we're ready
	xmlhttp.onreadystatechange = viewRequestHandler;
	
	//Draw the loading DIV so the user knows we're doing something
	showLoading ();

     xmlhttp.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
    	xmlhttp.send(null);
	
} //end RetrieveViewDocuments


function parseCategories (luVals, oDomDoc)
{

		//workout the html to put in it
	var viewData = document.getElementById ("ViewData");
	var viewNav = createViewBreadCrumbHTML (oDomDoc, "C");
	var cCat;
	var catHTML = "<div class='ViewHeader'>Select Category</div>" ;
	var elData;
	
	//do some columns - if we've got less than 10 items then done worry about it
	var colLen = luVals.length/2;
	if (colLen < 10) colLen = luVals.length;
	
	catHTML += htmlStartTag ("table", "ViewCategories", "", "") + "<tr><td>";
	for (var i=0; i< colLen; i++)
	{
			elData = luVals[i].getElementsByTagName ("entrydata");
			if (elData[0].lastChild && elData[0].lastChild.firstChild)
			{
				catHTML += "<a href='#' onclick='vPosition=1;retrieveViewDocuments(\"" + elData[0].lastChild.firstChild.nodeValue.replace (/'/g, "&#39;")  + "\"); return false;'>" + elData[0].lastChild.firstChild.nodeValue + "</a><br>"
			}
	}
	catHTML += ce;
	if (colLen != luVals.length)
	{
	catHTML += "<td>";
	for (var i=Math.round (colLen); i< luVals.length; i++)
	{
			elData = luVals[i].getElementsByTagName ("entrydata");
			if (elData[0].lastChild && elData[0].lastChild.firstChild)
			{
					catHTML += "<a href='#' onclick='vPosition=1;retrieveViewDocuments(\"" + elData[0].lastChild.firstChild.nodeValue.replace (/'/g, "&#39;")  + "\"); return false;'>" + elData[0].lastChild.firstChild.nodeValue + "</a><br>"
			}
	}
	}
	catHTML += re + te;
	
	viewData.innerHTML  = catHTML + viewNav;
	resetScreen ();
}

function parseEntryDocuments (luVals, oDomDoc, searchResults)
{
	//will have a list of the documents and then the view navigator (ie, next previous), this could go at the top too if wanted
	var viewData = document.getElementById ("ViewData");
	var html = "";
	var docObj;
	documentList = new Array ();
	var docCount = 0;
	var viewNav ="";
	
	if (searchResults != true)
	{
		viewNav = createViewBreadCrumbHTML (oDomDoc, "D");
	}
	for (var i=0; i < luVals.length; i++){
		docObj = new BookDetails ();
		docObj.initialise (luVals [i]);
		documentList [docCount] = docObj;
		docObj.listNumber = docCount;
		docCount ++;
	
		html += docObj.generateViewHTML (i+vPosition);
		html += "<div class='RowSpacer'>"+ sp + "</div>";
	}
	
	viewData.innerHTML  = html+ viewNav;
	resetScreen ();
}

//formulate the bottom section of the view
function createViewBreadCrumbHTML (oDomDoc, type)
{
	var bLink = ""; //back link if we're coming from a search or category or something
	
	var pageArray = new Array (); //an array of pages - this is of the vPositions for the pages - i dont want it to grow to big so i'm limiting it to the first, 3 b4 and after current and last
	var lastLink = ""; //a link to go to the last page
	var firstLink = ""; //a link to the first page
	var cPageHTML = "";	//if we're on page one and there is only one page then dont display anything
	
	//links for 3up and 3 down from current position
	var up1Link = "";
	var up2Link = "";
	var up3Link = "";
	var down1Link = "";
	var down2Link = "";
	var down3Link = "";
	
	var entryNum = entryCountDocument;
	if (type == "C") entryNum = entryCountCategory;
	
	var numEntries = oDomDoc.getElementsByTagName("viewentries")[0].getAttribute("toplevelentries"); 
	var pageCount = numEntries/entryNum;
	var currentPage = vPosition/entryNum;

	//work out the page array
	pageArray[0] = 1 //start
	pageArray[1] = vPosition - (entryNum*3)
	pageArray[2] = vPosition - (entryNum*2)
	pageArray[3] = vPosition - (entryNum)
	pageArray[4] = vPosition
	pageArray[5] = vPosition + (entryNum) 
	pageArray[6] = vPosition + (entryNum*2) 
	pageArray[7] = vPosition + (entryNum*3)
	//find the last
	for (var i = 1; i<=numEntries; i+=entryNum)
	{
			if (i+entryNum >= numEntries) pageArray[8] = i;			
	}		

	var functionToCall = "";
	if (type == "D")
	{

		//if we've got a previousPageScript then we set the back link
		if (previousPageScript) bLink = "<a href='#' onclick='" + previousPageScript + "; return false;'> RETURN TO CATEGORIES </a>";

		//need to determin if we were using a category.
		if (currentPageURL.match("RestrictToCategory"))
		{
			//we had a category so we need to retrieve it
			var splitString = currentPageURL.substring (currentPageURL.indexOf ("Category=") + 9);
			functionToCall = "retrieveViewDocuments (\"" + splitString + "\")";	
		}else
		{
			functionToCall = "retrieveViewDocuments ()";	
		}
	}else
	{
		functionToCall = "retrieveViewCategories ()";	
	}
	
	var tCounter = Math.round (pageCount);
	if (pageCount <= tCounter)
	{
		pageCount = tCounter;
	}else
	{
		pageCount = tCounter+ 1;
	}

	tCounter = Math.round (currentPage)
	if (currentPage < tCounter)
	{
		currentPage = tCounter;
	}else
	{
		currentPage = tCounter+ 1;
	}
	
	var html = "";
	//lets do the 1 up link
	if (currentPage < pageCount) up1Link = "<a href='#' onclick='vPosition="+ pageArray[5]+";" + functionToCall + " ; return false;'> " + (currentPage + 1) + "</a>";
	//lets do the 2 up link
	if (currentPage+1 < pageCount) up2Link = "<a href='#' onclick='vPosition="+ pageArray[6]+";" + functionToCall + " ; return false;'> " + (currentPage + 2) + "</a>";
	//lets do the 3 up link
	if (currentPage+2 < pageCount) up3Link = "<a href='#' onclick='vPosition="+ pageArray[7]+";" + functionToCall + " ; return false;'> " + (currentPage + 3) + " </a>";

	//we need a last page work out start
	if (currentPage+3 < pageCount) lastLink = "<a href='#' onclick='vPosition="+pageArray[8]+";" + functionToCall + " ; return false;'> LAST</a>";
	
	//lets do the 1 down link
	if (currentPage > 1) down1Link = "<a href='#' onclick='vPosition="+ pageArray[3]+"; " + functionToCall + "; return false;'> " + (currentPage - 1) + "</a>";
	//lets do the 2 down link
	if (currentPage > 2) down2Link = "<a href='#' onclick='vPosition="+ pageArray[2]+"; " + functionToCall + "; return false;'> " + (currentPage - 2) + "</a>";
	//lets do the 3 down link
	if (currentPage > 3) down3Link = "<a href='#' onclick='vPosition="+ pageArray[1]+"; " + functionToCall + "; return false;'> " + (currentPage - 3) + "</a>";

	//if we have so many pages that it gets over 4 digits we're going to run into space problems so we'll cut it down to 2 buttons each way
	if (currentPage+3 >=1000) up3Link = "";
	if (currentPage-3 >=1000) down3Link = "";
	
	//first page
	if (currentPage-3 > 1) 	firstLink = "<a href='#' onclick='vPosition="+pageArray[0]+";" + functionToCall + " ; return false;'> FIRST</a>";

	if (currentPage != 1 || pageCount != 1)  cPageHTML = "<span class='currentpage'>" + currentPage + "</span>";

	html += htmlStartTag ("div", "pageswitcher FloatLeft","","") + bLink + de;
 	html += htmlStartTag ("div", "ralign pageswitcher","","");
	html += firstLink + down3Link + down2Link + down1Link + cPageHTML + up1Link + up2Link + up3Link + lastLink;	
	html += de;
	return html;	
}