/**
 * jquery.scrollFollow.js
 * Copyright (c) 2008 Net Perspective (http://kitchen.net-perspective.com/)
 * Licensed under the MIT License (http://www.opensource.org/licenses/mit-license.php)
 * 
 * @author R.A. Ray
 *
 * @projectDescription	jQuery plugin for allowing an element to animate down as the user scrolls the page.
 * 
 * @version 0.4.0
 * 
 * @requires jquery.js (tested with 1.2.6)
 * @requires ui.core.js (tested with 1.5.2)
 * 
 * @optional jquery.cookie.js (http://www.stilbuero.de/2006/09/17/cookie-plugin-for-jquery/)
 * @optional jquery.easing.js (http://gsgd.co.uk/sandbox/jquery/easing/ - tested with 1.3)
 * 
 * @param speed		int - Duration of animation (in milliseconds)
 * 								default: 500
 * @param offset			int - Number of pixels box should remain from top of viewport
 * 								default: 0
 * @param easing		string - Any one of the easing options from the easing plugin - Requires jQuery Easing Plugin < http://gsgd.co.uk/sandbox/jquery/easing/ >
 * 								default: 'linear'
 * @param container	string - ID of the containing div
 * 								default: box's immediate parent
 * @param killSwitch	string - ID of the On/Off toggle element
 * 								default: 'killSwitch'
 * @param onText		string - killSwitch text to be displayed if sliding is enabled
 * 								default: 'Turn Slide Off'
 * @param offText		string - killSwitch text to be displayed if sliding is disabled
 * 								default: 'Turn Slide On'
 * @param relativeTo	string - Scroll animation can be relative to either the 'top' or 'bottom' of the viewport
 * 								default: 'top'
 * @param delay			int - Time between the end of the scroll and the beginning of the animation in milliseconds
 * 								default: 0
 */

( function( j$ ) {
	
	j$.scrollFollow = function ( box, options )
	{ 
		// Convert box into a jQuery object
		box = j$( box );
		
		// 'box' is the object to be animated
		var position = box.css( 'position' );
		
		function ani()
		{		
			// The script runs on every scroll which really means many times during a scroll.
			// We don't want multiple slides to queue up.
			box.queue( [ ] );
		
			// A bunch of values we need to determine where to animate to
			var viewportHeight = parseInt( j$( window ).height() );	
			var pageScroll =  parseInt( j$( document ).scrollTop() );
			var parentTop =  parseInt( box.cont.offset().top );
			var parentHeight = parseInt( box.cont.attr( 'offsetHeight' ) );
			var boxHeight = parseInt( box.attr( 'offsetHeight' ) + ( parseInt( box.css( 'marginTop' ) ) || 0 ) + ( parseInt( box.css( 'marginBottom' ) ) || 0 ) );
			var aniTop;
			
			// Make sure the user wants the animation to happen
			if ( isActive )
			{
				// If the box should animate relative to the top of the window
				if ( options.relativeTo == 'top' )
				{
					// Don't animate until the top of the window is close enough to the top of the box
					if ( box.initialOffsetTop >= ( pageScroll + options.offset ) )
					{
						aniTop = box.initialTop;
					}
					else
					{
						aniTop = Math.min( ( Math.max( ( -parentTop ), ( pageScroll - box.initialOffsetTop + box.initialTop ) ) + options.offset ), ( parentHeight - boxHeight - box.paddingAdjustment ) );
					}
				}
				// If the box should animate relative to the bottom of the window
				else if ( options.relativeTo == 'bottom' )
				{
					// Don't animate until the bottom of the window is close enough to the bottom of the box
					if ( ( box.initialOffsetTop + boxHeight ) >= ( pageScroll + options.offset + viewportHeight ) )
					{
						aniTop = box.initialTop;
					}
					else
					{
						aniTop = Math.min( ( pageScroll + viewportHeight - boxHeight - options.offset ), ( parentHeight - boxHeight ) );
					}
				}
				
				// Checks to see if the relevant scroll was the last one
				// "-20" is to account for inaccuracy in the timeout
				if ( ( new Date().getTime() - box.lastScroll ) >= ( options.delay - 20 ) )
				{
					box.animate(
						{
							top: aniTop
						}, options.speed, options.easing
					);
				}
			}
		};
		
		// For user-initiated stopping of the slide
		var isActive = true;
		
		if ( j$.cookie != undefined )
		{
			if( j$.cookie( 'scrollFollowSetting' + box.attr( 'id' ) ) == 'false' )
			{
				var isActive = false;
				
				j$( '#' + options.killSwitch ).text( options.offText )
					.toggle( 
						function ()
						{
							isActive = true;
							
							j$( this ).text( options.onText );
							
							j$.cookie( 'scrollFollowSetting' + box.attr( 'id' ), true, { expires: 365, path: '/'} );
							
							ani();
						},
						function ()
						{
							isActive = false;
							
							j$( this ).text( options.offText );
							
							box.animate(
								{
									top: box.initialTop
								}, options.speed, options.easing
							);	
							
							j$.cookie( 'scrollFollowSetting' + box.attr( 'id' ), false, { expires: 365, path: '/'} );
						}
					);
			}
			else
			{
				j$( '#' + options.killSwitch ).text( options.onText )
					.toggle( 
						function ()
						{
							isActive = false;
							
							j$( this ).text( options.offText );
							
							box.animate(
								{
									top: box.initialTop
								}, 0
							);	
							
							j$.cookie( 'scrollFollowSetting' + box.attr( 'id' ), false, { expires: 365, path: '/'} );
						},
						function ()
						{
							isActive = true;
							
							j$( this ).text( options.onText );
							
							j$.cookie( 'scrollFollowSetting' + box.attr( 'id' ), true, { expires: 365, path: '/'} );
							
							ani();
						}
					);
			}
		}
		
		// If no parent ID was specified, and the immediate parent does not have an ID
		// options.container will be undefined. So we need to figure out the parent element.
		if ( options.container == '')
		{
			box.cont = box.parent();
		}
		else
		{
			box.cont = j$( '#' + options.container );
		}
		
		// Finds the default positioning of the box.
		box.initialOffsetTop =  parseInt( box.offset().top );
		box.initialTop = parseInt( box.css( 'top' ) ) || 0;
		
		// Hack to fix different treatment of boxes positioned 'absolute' and 'relative'
		if ( box.css( 'position' ) == 'relative' )
		{
			box.paddingAdjustment = parseInt( box.cont.css( 'paddingTop' ) ) + parseInt( box.cont.css( 'paddingBottom' ) );
		}
		else
		{
			box.paddingAdjustment = 0;
		}
		
		// Animate the box when the page is scrolled
		j$( window ).scroll( function ()
			{
				// Sets up the delay of the animation
				j$.fn.scrollFollow.interval = setTimeout( function(){ ani();} , options.delay );
				
				// To check against right before setting the animation
				box.lastScroll = new Date().getTime();
			}
		);
		
		// Animate the box when the page is resized
		j$( window ).resize( function ()
			{
				// Sets up the delay of the animation
				j$.fn.scrollFollow.interval = setTimeout( function(){ ani();} , options.delay );
				
				// To check against right before setting the animation
				box.lastScroll = new Date().getTime();
			}
		);

		// Run an initial animation on page load
		box.lastScroll = 0;
		
		ani();
	};
	
	j$.fn.scrollFollow = function ( options )
	{
		options = options || {};
		options.relativeTo = options.relativeTo || 'top';
		options.speed = options.speed || 500;
		options.offset = options.offset || 0;
		options.easing = options.easing || 'swing';
		options.container = options.container || this.parent().attr( 'id' );
		options.killSwitch = options.killSwitch || 'killSwitch';
		options.onText = options.onText || 'Turn Slide Off';
		options.offText = options.offText || 'Turn Slide On';
		options.delay = options.delay || 0;
		
		this.each( function() 
			{
				new j$.scrollFollow( this, options );
			}
		);
		
		return this;
	};
})( jQuery );

jQuery( document ).ready( function (){
	jQuery('#pagetop').scrollFollow({});
});

jQuery(document).ready(function() {
	var pageTopScroller = function() {
		jQuery( '#pagetop' ).scrollFollow( {
			speed: 500,
			offset: 431,
			killSwitch: 'exampleLink',
			onText: 'Disable Follow',
			offText: 'Enable Follow'
		});
	}
	pageTopScroller();
});



/* Smooth scrolling ===============================================================================
   Changes links that link to other parts of this page to scroll
   smoothly to those links rather than jump to them directly, which
   can be a little disorienting.
   
   sil, http://www.kryogenix.org/
   
   v1.0 2003-11-11
   v1.1 2005-06-16 wrap it up in an object
*/

var ss = {
  fixAllLinks: function() {
    // Get a list of all links in the page
    var allLinks = document.getElementsByTagName('a');
    // Walk through the list
    for (var i=0;i<allLinks.length;i++) {
      var lnk = allLinks[i];
      if ((lnk.href && lnk.href.indexOf('#') != -1) && 
          ( (lnk.pathname == location.pathname) ||
	    ('/'+lnk.pathname == location.pathname) ) && 
          (lnk.search == location.search)) {
        // If the link is internal to the page (begins in #)
        // then attach the smoothScroll function as an onclick
        // event handler
        ss.addEvent(lnk,'click',ss.smoothScroll);
      }
    }
  },

  smoothScroll: function(e) {
    // This is an event handler; get the clicked on element,
    // in a cross-browser fashion
    if (window.event) {
      target = window.event.srcElement;
    } else if (e) {
      target = e.target;
    } else return;

    // Make sure that the target is an element, not a text node
    // within an element
    if (target.nodeName.toLowerCase() != 'a') {
      target = target.parentNode;
    }
  
    // Paranoia; check this is an A tag
    if (target.nodeName.toLowerCase() != 'a') return;
  
    // Find the <a name> tag corresponding to this href
    // First strip off the hash (first character)
    anchor = target.hash.substr(1);
    // Now loop all A tags until we find one with that name
    var allLinks = document.getElementsByTagName('a');
    var destinationLink = null;
    for (var i=0;i<allLinks.length;i++) {
      var lnk = allLinks[i];
      if (lnk.name && (lnk.name == anchor)) {
        destinationLink = lnk;
        break;
      }
    }
    if (!destinationLink) destinationLink = document.getElementById(anchor);

    // If we didn't find a destination, give up and let the browser do
    // its thing
    if (!destinationLink) return true;
  
    // Find the destination's position
    var destx = destinationLink.offsetLeft; 
    var desty = destinationLink.offsetTop;
    var thisNode = destinationLink;
    while (thisNode.offsetParent && 
          (thisNode.offsetParent != document.body)) {
      thisNode = thisNode.offsetParent;
      destx += thisNode.offsetLeft;
      desty += thisNode.offsetTop;
    }
  
    // Stop any current scrolling
    clearInterval(ss.INTERVAL);
  
    cypos = ss.getCurrentYPos();
  
    ss_stepsize = parseInt((desty-cypos)/ss.STEPS);
    ss.INTERVAL =
setInterval('ss.scrollWindow('+ss_stepsize+','+desty+',"'+anchor+'")',10);
  
    // And stop the actual click happening
    if (window.event) {
      window.event.cancelBubble = true;
      window.event.returnValue = false;
    }
    if (e && e.preventDefault && e.stopPropagation) {
      e.preventDefault();
      e.stopPropagation();
    }
  },

  scrollWindow: function(scramount,dest,anchor) {
    wascypos = ss.getCurrentYPos();
    isAbove = (wascypos < dest);
    window.scrollTo(0,wascypos + scramount);
    iscypos = ss.getCurrentYPos();
    isAboveNow = (iscypos < dest);
    if ((isAbove != isAboveNow) || (wascypos == iscypos)) {
      // if we've just scrolled past the destination, or
      // we haven't moved from the last scroll (i.e., we're at the
      // bottom of the page) then scroll exactly to the link
      window.scrollTo(0,dest);
      // cancel the repeating timer
      clearInterval(ss.INTERVAL);
      // and jump to the link directly so the URL's right
      location.hash = anchor;
    }
  },

  getCurrentYPos: function() {
    if (document.body && document.body.scrollTop)
      return document.body.scrollTop;
    if (document.documentElement && document.documentElement.scrollTop)
      return document.documentElement.scrollTop;
    if (window.pageYOffset)
      return window.pageYOffset;
    return 0;
  },

  addEvent: function(elm, evType, fn, useCapture) {
    // addEvent and removeEvent
    // cross-browser event handling for IE5+,  NS6 and Mozilla
    // By Scott Andrew
    if (elm.addEventListener){
      elm.addEventListener(evType, fn, useCapture);
      return true;
    } else if (elm.attachEvent){
      var r = elm.attachEvent("on"+evType, fn);
      return r;
    } else {
      alert("Handler could not be removed");
    }
  } 
}

ss.STEPS = 25;

ss.addEvent(window,"load",ss.fixAllLinks);