var imageTag = "image=";
var categoryTag = "category=";
var autoTag = "auto=";

function getVariable(defaultVal, tagStr)
{
  var searchStr = window.location.search;
  var index = searchStr.indexOf(tagStr);
  if (index >= 0)
  {
    return searchStr.substring(index+tagStr.length);
  }
  else return(defaultVal);
}

function getImageNumber(defaultVal)
{
  return(parseInt(getVariable(defaultVal, imageTag)));
}

function getCategoryNumber(defaultVal)
{
  return(parseInt(getVariable(defaultVal, categoryTag)));
}

function getAutoNumber(defaultVal)
{
  return(parseInt(getVariable(defaultVal, autoTag)));
}

function buildURL(href, imageNumber, categoryNumber)
{
  var URL;
  
  URL = href + "?" + imageTag + imageNumber;
  if (categoryNumber > 0)
    URL = URL + "&" + categoryTag + categoryNumber;
  var autoTime = getAutoNumber(0);
  if (autoTime > 0)
    URL = URL +  "&" + autoTag + autoTime;
  return(URL);
}
    
function getNextUrl()
{
  var newURL = "";
  var categoryNumber = getCategoryNumber(0);
  var imageNumber = getImageNumber(0);
  
  imageNumber = getNextImageNumber(categoryNumber, imageNumber);
  if (imageNumber > 0)
    newURL = buildURL("slide.html", imageNumber, categoryNumber);
  return(newURL);
}

function doArrow(arrowImageNumber, arrowCategoryNumber, arrow)
{
  if (arrowImageNumber > 0)
  {
    document.write("<TD><a href=");
    document.write(buildURL("slide.html", arrowImageNumber, arrowCategoryNumber));
    document.write(">");
    document.write("<IMG WIDTH=31 HEIGHT=31 SRC = '" + arrow + "'</a></TD>");
  }
  else 
    document.write("<TD WIDTH=36></TD>");
}
    
function showThumbnail(thumbnailFilename, categoryNumber, categoryName, numberPhotos)
{
  makeTooltip(categoryName, "Currently&nbsp;" + numberPhotos + "&nbsp;images"); 
  document.write("<TD>");
  document.write("<TABLE BORDER=0 CELLPADDING=4 CELLSPACING=1>");
  document.write("<TR>");
  document.write("<TD ALIGN=CENTER><a href = slide.html?" + categoryTag + categoryNumber);
  setTooltip(categoryName);
  document.write("><IMG SRC='" + thumbnailFilename + ".jpg' BORDER=0></TD>");
  document.write("</TR>");
  document.write("<TR>");
  document.write("<TD ALIGN=CENTER><a href = slide.html?" + categoryTag + categoryNumber);
  setTooltip(categoryName);
  document.write(">" + categoryName + "</a></TD>");
  document.write("</TR>");
  document.write("</TABLE>");
  document.write("</TD>");
}
    
function showFooter(url, urlDescription)
{
  document.write("<HR><BR>");

  document.write("<TD>");
  document.write("<CENTER>");
  document.write("<TABLE>");
  document.write("<TD ALIGN=CENTER WIDTH=400>");
  document.write("<a href=" + url + "><B>" + urlDescription + "</B></a>");
  document.write("</TD>");
  document.write("<TD ALIGN=CENTER WIDTH=400>");
  showCopyright();
  document.write("</TD>");
  document.write("<TD ALIGN=CENTER WIDTH=400>");
  document.write("<a href = mailto:photo@dan-stone.com>email</a>");
  document.write("</TD>");
  document.write("</TABLE>");
  document.write("</CENTER>");
  document.write("</TD>");

  document.write("<BR><HR>");
}

function showCopyright()
{
  document.write("All photographs Copyright &copy 2008 Dan Stone ");
}