/* Copyright 2009-2010 Taco Software. All rights reserved.
 * http://tacosw.com
 *
 * This file is part of the Component Library included in Taco HTML Edit.
 * Licensed users of Taco HTML Edit may modify and use this source code 
 * for their web development (including commercial projects), as long as 
 * this copyright notice is retained.
 *
 * The contents of this file may not be published in a format intended
 * for access by other humans, so you may not put code examples on a
 * web site with all or part of the contents of this file, and you may
 * not publish the contents of this file in a printed format.
 */

function tswImageScrollRight(id)
{
    tswImageScrollGetForId(id).scrollRight();
}

function tswImageScrollLeft(id)
{
    tswImageScrollGetForId(id).scrollLeft();
}

function tswImageSelectPage(id, page)
{
    tswImageScrollGetForId(id).selectPage(page);
}

var tswImageScrollMap = new Object(); //maps image scroll id to TSWImageScroll object;

//Returns the TSWImageScroll object for an id, creating the object
//if necessary.
function tswImageScrollGetForId(id)
{
    var imageScroll = tswImageScrollMap[id];
    if(imageScroll == null)
    {
        imageScroll = new TSWImageScroll(id);
        tswImageScrollMap[id] = imageScroll;
    }
    return imageScroll;
}

//Invoked from setInterval to animate the scroll operation
function _tswImageScrollAnimate(id)
{
    tswImageScrollGetForId(id).animate();
}

//TSWImageScroll is a javascript object that represents
//the image scroll component in the HTML document. The
//constructor takes the id of the object.
function TSWImageScroll(id)
{
    this.id = id;
    this.selectedPage = 0; //The page that is currently selected
    
    //The total number of pages (before copying first page)
    this.numPages = TSWDomUtils.getChildrenWithTagName(this.getImageScrollContentElement(), 'div').length; 
    
    //Copy the first page to the end so that we can do wrap-around scrolling
    if(this.numPages > 0)
    {
        var content = this.getImageScrollContentElement();
        content.appendChild(TSWDomUtils.getChildrenWithTagName(content, 'div')[0].cloneNode(true));
    }
    
    //variables used in animation
    this.initialXOffset = 0; //The x offset of the scroll content when animation started
    this.targetXOffset = 0; //The targeted x offset for the animation
    
    this.animationStartDate; //date when the animation began
    this.animationIntervalId = null; //Identifies the interval timer being used for the animation
};
    
TSWImageScroll.prototype.selectPage = function(page)
{
    this.unselectPageMarker(this.selectedPage);
    var scrollRight = page > this.selectedPage;
    this.selectedPage = page;
    this.selectPageMarker(this.selectedPage);
    
    this._setupAnimation(scrollRight);
};
    
TSWImageScroll.prototype.scrollRight = function()
{
    this.unselectPageMarker(this.selectedPage);
    this.selectedPage = (this.selectedPage + 1) % this.numPages;
    this.selectPageMarker(this.selectedPage);
    
    this._setupAnimation(true);
};
    
TSWImageScroll.prototype.scrollLeft = function()
{
    this.unselectPageMarker(this.selectedPage);
    this.selectedPage = this.selectedPage > 0 ? (this.selectedPage - 1) : (this.numPages - 1);
    this.selectPageMarker(this.selectedPage);
    
    this._setupAnimation(false);
};
    
TSWImageScroll.prototype._setupAnimation = function(scrollRight)
{
    var scrollContent = this.getImageScrollContentElement();
    
    if(scrollContent.style.left != null && scrollContent.style.left != '')
    {
        this.initialXOffset = tswUtilsGetPixelsAsInteger(scrollContent.style.left);
    }
    this.animationStartDate = new Date();
    var pageWidth = this.getPageWidth();
    this.targetXOffset = -this.selectedPage*pageWidth;
    
    if(scrollRight)
    {
        //target must be less than initial
        if(this.targetXOffset > this.initialXOffset)
        {
            this.targetXOffset -= this.numPages*pageWidth
        }
    }
    else
    {
        //target must be greater than initial
        if(this.targetXOffset < this.initialXOffset)
        {
            this.targetXOffset += this.numPages*pageWidth
        }
    }
    
    if(this.animationIntervalId == null)
    {
        this.animationIntervalId = setInterval("_tswImageScrollAnimate('"+this.id+"')", 25);
    }
};

TSWImageScroll.prototype.unselectPageMarker = function(page)
{
    var pageMarker = this.getPageMarker(page);
    if(pageMarker != null)
    {
        pageMarker.className = 'tswImageScrollPageMarkerUnselected';
    }
}

TSWImageScroll.prototype.selectPageMarker = function(page)
{
    var pageMarker = this.getPageMarker(page);
    if(pageMarker != null)
    {
        pageMarker.className = 'tswImageScrollPageMarkerSelected';
    }
}

TSWImageScroll.prototype.getPageMarker = function(page)
{
    var pageMarkersElement = TSWDomUtils.getChildWithClassName(this.getImageScrollElement(), 'tswImageScrollPageMarkers');
    if(pageMarkersElement != null && pageMarkersElement.className == 'tswImageScrollPageMarkers')
    {
        var pageMarkersContainer = TSWDomUtils.getChildWithClassName(pageMarkersElement, 'tswImageScrollPageMarkersContainer');
        var images = TSWDomUtils.getChildrenWithTagName(pageMarkersContainer, 'div');
        if(page >= 0 && page < images.length)
        {
            return images[page];
        }
    }
    return null;
};

TSWImageScroll.prototype.getImageScrollElement = function()
{
    return document.getElementById(this.id);
};

TSWImageScroll.prototype.getImageScrollContentElement = function()
{
    return TSWDomUtils.getChildWithClassName(this.getImageScrollElement(), 'tswImageScrollContent');
};

TSWImageScroll.prototype.getPageWidth = function()
{
    return this.getImageScrollElement().offsetWidth;
};

TSWImageScroll.prototype.animate = function()
{
    var currentDate = new Date();
    var delta = (currentDate.getTime() - this.animationStartDate.getTime()) / 600.0;
    var pageWidth = this.getPageWidth();
    
    if(delta >= 1.0)
    {
        //complete the animation
        clearInterval(this.animationIntervalId);
        this.animationIntervalId = null;
        this.getImageScrollContentElement().style.left = String(-this.selectedPage*pageWidth) + 'px';
    }
    else
    {
        //continue animation
        var minXOffset = -(this.numPages)*pageWidth;
        
        var movementProgress = Math.sin(delta*Math.PI/2.0);
        var nextXOffset = movementProgress*this.targetXOffset + (1 - movementProgress)*this.initialXOffset;
        
        if(nextXOffset > 0.0)
        {
            nextXOffset -= this.numPages*pageWidth;
            this.initialXOffset -= this.numPages*pageWidth;
            this.targetXOffset -= this.numPages*pageWidth;
        }
        else if(nextXOffset < minXOffset)
        {
            nextXOffset += this.numPages*pageWidth;
            this.initialXOffset += this.numPages*pageWidth;
            this.targetXOffset += this.numPages*pageWidth;
        }
        
        this.getImageScrollContentElement().style.left = String(nextXOffset) + 'px';
    }
};

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   to detect if a component file has been modified.
   TacoHTMLEditChecksum: 7483ED80 */