/*
Photo Viewer JavaScript
*/


// Parameters

var showIndex = new Boolean(true);                   // Enable index display
var indexSeparator = ' ';                            // String between index items
var showCaption = new Boolean(true);                 // Enable caption display
var preCache = new Boolean(true);                    // Activates pre-caching of next photo
var pictureID = 'photo';                             // SPAN ID for photo
var captionID = 'caption';                           // SPAN ID for caption
var indexID = 'index';                               // SPAN ID for index
var wrapOn = new Boolean(true);                      // Wrapping from last photo to first and vice-versa
var slideMode = new Boolean(false);                  // Enables slideshow mode
var slideDelay = 8;                                  // Default delay between slides inseconds
var clickMode = new Boolean(true);                   // Disable image clicking to advance
var imageALT = new Boolean(true);                    // Disable caption as image ALT tag text


function createRequestObject() 
{

FORM_DATA = new Object();                            // Object array where data will be stored.
 
separator = ',';                                     // The token used to separate data from multi-select inputs

query = '' + this.location;
query = query.substring((query.indexOf('?')) + 1);
 
if (query.length < 1) { return false; }              // Error handling for bad data

keypairs = new Object();
numKP = 1;

while (query.indexOf('&') > -1) 
{
  keypairs[numKP] = query.substring(0,query.indexOf('&'));
  query = query.substring((query.indexOf('&')) + 1);
  numKP++;
}
 
keypairs[numKP] = query;
 
for (i in keypairs) 
{
  keyName = keypairs[i].substring(0,keypairs[i].indexOf('='));         // Left of '=' is name.
  keyValue = keypairs[i].substring((keypairs[i].indexOf('=')) + 1);    // Right of '=' is value.
  
  while (keyValue.indexOf('+') > -1) 
  {
      // Replace each '+' in data string with a space.
      keyValue = keyValue.substring(0,keyValue.indexOf('+')) + ' ' +     keyValue.substring(keyValue.indexOf('+') + 1);
      
  }

  keyValue = unescape(keyValue);                      // Unescape non-alphanumerics

  if (FORM_DATA[keyName]) 
  {
       FORM_DATA[keyName] = FORM_DATA[keyName] + separator + keyValue;
  } else 
  {
       FORM_DATA[keyName] = keyValue;
  }
}

return FORM_DATA;
}

FORM_DATA = createRequestObject();

var glbCacheTimer;
var glbSlideTimer;

// Contains index of the current photo, initialized to the first photo (1)
var glbCurrentPhoto = 1;

// Array holding photo filenames
var photos = new Array ();

// Array holding photo captions
var captions = new Array ();

// Array holding link names
var linkNames = new Array ();

function getObjectByID(id) 
{
  // Cross-browser function to return the object with the specific id

  if (document.all) 
  { // IE
    return document.all[id];
  } else { // Netscape
    return document.getElementById(id);
  }
}


function showPhoto(index) 
{
  // Shows the photo with identified index
  var theURL = "" + this.location;

  // Strip parameters, if any present, from end of URL.
  if (theURL.indexOf("?")>0) 
  {
    theURL = theURL.substring(0,theURL.indexOf("?"));
  }

  // Append the new photo index as a parameter.
  theURL += "?photo=" + index;

  // Append the slideshow mode as a parameter.
  if (slideMode == true) 
  {
    theURL += "&slideMode=true";
    theURL += "&slideDelay=" + slideDelay;
  }

  // Go to the constructed URL which has the new
  // photo's index as a parameter.
  this.location = theURL;
}

function showNext() 
{
  if (glbCurrentPhoto >= photos.length) 
  {
    if (wrapOn == true) 
    {
      glbCurrentPhoto = 1;
      showPhoto (glbCurrentPhoto);
    }
  } else {
    glbCurrentPhoto += 1;
    showPhoto (glbCurrentPhoto);
  }
}

function showPrevious() 
{
  if (glbCurrentPhoto <= 1) 
  {
    if (wrapOn == true) 
    {
      glbCurrentPhoto = photos.length;
      showPhoto (glbCurrentPhoto);
    }
  } else {
    glbCurrentPhoto += -1;
    showPhoto (glbCurrentPhoto);
  }
}

function showFirst() 
{
	glbCurrentPhoto = 1;
	showPhoto (glbCurrentPhoto);
}

function showLast() 
{
	glbCurrentPhoto = photos.length;
	showPhoto (glbCurrentPhoto);
}

function initPhoto() 
{
  // Display the photo
  var photoLocation = getObjectByID(pictureID);
  var imgString = '';

  if (clickMode == true) {imgString += "<a href='javascript:void(showNext());'>";}
  imgString += "<img border='0' id='mainImage' src='"+ photos[glbCurrentPhoto-1] +"'";
  if (imageALT == true) {imgString += ' alt="'+captions[glbCurrentPhoto-1].replace(/"/g,"'").replace(/<[^>]*>/g,"")+'"';}

  imgString += ">";
  if (clickMode == true) {imgString += "</a>";}
  photoLocation.innerHTML = imgString;

  // Create caption if enabled.
  if (showCaption == true) 
  {
    var photoCaption = getObjectByID(captionID);
    photoCaption.innerHTML = captions[glbCurrentPhoto-1];
  }

  // Build the index if enabled.
  if (showIndex == true) {buildIndex();}

  // Pre-cache if enabled.
  if ((preCache == true) && (glbCurrentPhoto < photos.length)) 
  {
    // Start timer for cache loader routine to check if main image is loaded
    glbCacheTimer = setTimeout('cache(' + glbCurrentPhoto + ');', 500);
  }

  // Slideshow mode, if enabled.
  if (slideMode == true) 
  {
    glbSlideTimer = setTimeout('showNext();', (slideDelay * 1000));
  }
}

function cache(photoID) 
{
  // Check to see if main image has loaded
  if (getObjectByID('mainImage').complete) 
  {
    // Clear the timer
    clearTimeout(glbCacheTimer);
    // Load the next image.
    getObjectByID('cache').src= photos[photoID];
  } else {
    // Not loaded, so reset timer
    glbCacheTimer = setTimeout('cache(' + glbCurrentPhoto + ');', 500);
  }
}

function addPhoto(filename, caption, linkName) 
{
  // Add filenames and captions to their respective arrays.
  var len = photos.length;
  photos[len] = filename;
  captions[len] = caption;
  if (typeof linkName == "undefined") 
  {
	linkNames[len] = len + 1;
  } else {
	linkNames[len] = linkName;
  }
}

function buildIndex() 
{
  // Creates a clickable list of image numbers.
  var indexString = '';
  var i;

  for (i = 1; i < photos.length+1; i++) 
  {
    // If not the first photo, add separator
    if (i>1) {indexString += indexSeparator}
    // Make current photo # bold and don't make it a link
    if (i == glbCurrentPhoto) {
      indexString += '<b>' + linkNames[i-1] + '</b>';
    } else { // Make all other numbers links
      indexString += '<a href="javascript:void(showPhoto(' + i + '));">' + linkNames[i-1] + '</a>';
    }
  }
  // Display the index
  getObjectByID(indexID).innerHTML = indexString;
}

function enableSlideMode (newDelay) 
{
  // Turns slide mode on
  slideMode=Boolean(true);
  if (newDelay > 0) 
  {
    slideDelay = newDelay;
  }
  showPhoto(glbCurrentPhoto); //necessary to reset URL parameters.
//  glbSlideTimer=setTimeout('showNext();',(slideDelay*1000));
}

function disableSlideMode() 
{
  slideMode = Boolean(false);
  clearTimeout (glbSlideTimer);
  showPhoto(glbCurrentPhoto); //necessary to reset URL parameters.
}

// Get photo index from URL, if there is one, otherwise start at 1
if (FORM_DATA["photo"]>0) 
{
  glbCurrentPhoto = Number(FORM_DATA["photo"]);
} else {
  glbCurrentPhoto = 1;
}

// Get slide mode from URL, if there is one
if (FORM_DATA["slideMode"] == "true") 
{
  slideMode = Boolean(true);
  slideDelay = FORM_DATA["slideDelay"];
}