// JavaScript Document
// DHTMLapi.js custom API for cross-platform
// object positioning by Danny Goodman (http://www.dannyg.com).
// Release 2.0. Supports NN4, IE, and W3C DOMs.

// Global variables
var isCSS, isW3C, isIE4, isNN4, isIE6CSS;
// Initialize upon load to let all browsers establish content objects
function initDHTMLAPI() {
    if (document.images) {
        isCSS = (document.body && document.body.style) ? true : false;
        isW3C = (isCSS && document.getElementById) ? true : false;
        isIE4 = (isCSS && document.all) ? true : false;
        isNN4 = (document.layers) ? true : false;
        isIE6CSS = (document.compatMode && document.compatMode.indexOf("CSS1") >= 0) ? true : false;
    }
}
// Set event handler to initialize API
window.onload = initDHTMLAPI;

// Seek nested NN4 layer from string name
function seekLayer(doc, name) {
    var theObj;
    for (var i = 0; i < doc.layers.length; i++) {
        if (doc.layers[i].name == name) {
            theObj = doc.layers[i];
            break;
        }
        // dive into nested layers if necessary
        if (doc.layers[i].document.layers.length > 0) {
            theObj = seekLayer(document.layers[i].document, name);
        }
    }
    return theObj;
}

// Convert object name string or object reference
// into a valid element object reference
function getRawObject(obj) {
    var theObj;
    if (typeof obj == "string") {
        if (isW3C) {
            theObj = document.getElementById(obj);
        } else if (isIE4) {
            theObj = document.all(obj);
        } else if (isNN4) {
            theObj = seekLayer(document, obj);
        }
    } else {
        // pass through object reference
        theObj = obj;
    }
    return theObj;
}

// Convert object name string or object reference
// into a valid style (or NN4 layer) reference
function getObject(obj) {
    var theObj = getRawObject(obj);
    if (theObj && isCSS) {
        theObj = theObj.style;
    }
    return theObj;
}

// Position an object at a specific pixel coordinate
function shiftTo(obj, x, y) {
    var theObj = getObject(obj);
    if (theObj) {
        if (isCSS) {
            // equalize incorrect numeric value type
            var units = (typeof theObj.left == "string") ? "px" : 0 
            theObj.left = x + units;
            theObj.top = y + units;
        } else if (isNN4) {
            theObj.moveTo(x,y)
        }
    }
}

// Move an object by x and/or y pixels
function shiftBy(obj, deltaX, deltaY) {
    var theObj = getObject(obj);
    if (theObj) {
        if (isCSS) {
            // equalize incorrect numeric value type
            var units = (typeof theObj.left == "string") ? "px" : 0 
            theObj.left = getObjectLeft(obj) + deltaX + units;
            theObj.top = getObjectTop(obj) + deltaY + units;
        } else if (isNN4) {
            theObj.moveBy(deltaX, deltaY);
        }
    }
}

// Set the z-order of an object
function setZIndex(obj, zOrder) {
    var theObj = getObject(obj);
    if (theObj) {
        theObj.zIndex = zOrder;
    }
}

// Set the background color of an object
function setBGColor(obj, color) {
    var theObj = getObject(obj);
    if (theObj) {
        if (isNN4) {
            theObj.bgColor = color;
        } else if (isCSS) {
            theObj.backgroundColor = color;
        }
    }
}

// Set the visibility of an object to visible
function show(obj) {
    var theObj = getObject(obj);
    if (theObj) {
        theObj.visibility = "visible";
    }
}

// Set the visibility of an object to hidden
function hide(obj) {
    var theObj = getObject(obj);
    if (theObj) {
        theObj.visibility = "hidden";
    }
}

// Retrieve the x coordinate of a positionable object
function getObjectLeft(obj)  {
    var elem = getRawObject(obj);
    var result = 0;
    if (document.defaultView) {
        var style = document.defaultView;
        var cssDecl = style.getComputedStyle(elem, "");
        result = cssDecl.getPropertyValue("left");
    } else if (elem.currentStyle) {
        result = elem.currentStyle.left;
    } else if (elem.style) {
        result = elem.style.left;
    } else if (isNN4) {
        result = elem.left;
    }
    return parseInt(result);
}

// Retrieve the y coordinate of a positionable object
function getObjectTop(obj)  {
    var elem = getRawObject(obj);
    var result = 0;
    if (document.defaultView) {
        var style = document.defaultView;
        var cssDecl = style.getComputedStyle(elem, "");
        result = cssDecl.getPropertyValue("top");
    } else if (elem.currentStyle) {
        result = elem.currentStyle.top;
    } else if (elem.style) {
        result = elem.style.top;
    } else if (isNN4) {
        result = elem.top;
    }
    return parseInt(result);
}

// Retrieve the rendered width of an element
function getObjectWidth(obj)  {
    var elem = getRawObject(obj);
    var result = 0;
    if (elem.offsetWidth) {
        result = elem.offsetWidth;
    } else if (elem.clip && elem.clip.width) {
        result = elem.clip.width;
    } else if (elem.style && elem.style.pixelWidth) {
        result = elem.style.pixelWidth;
    }
    return parseInt(result);
}

// Retrieve the rendered height of an element
function getObjectHeight(obj)  {
    var elem = getRawObject(obj);
    var result = 0;
    if (elem.offsetHeight) {
        result = elem.offsetHeight;
    } else if (elem.clip && elem.clip.height) {
        result = elem.clip.height;
    } else if (elem.style && elem.style.pixelHeight) {
        result = elem.style.pixelHeight;
    }
    return parseInt(result);
}

// Return the available content width space in browser window
function getInsideWindowWidth() {
    if (window.innerWidth) {
        return window.innerWidth;
    } else if (isIE6CSS) {
        // measure the html element's clientWidth
        return document.body.parentElement.clientWidth
    } else if (document.body && document.body.clientWidth) {
        return document.body.clientWidth;
    }
    return 0;
}

// Return the available content height space in browser window
function getInsideWindowHeight() {
    if (window.innerHeight) {
        return window.innerHeight;
    } else if (isIE6CSS) {
        // measure the html element's clientHeight
        return document.body.parentElement.clientHeight
    } else if (document.body && document.body.clientHeight) {
        return document.body.clientHeight;
    }
    return 0;
}

var scrollEngaged = false;
var scrollInterval;
var scrollBars = new Array();

function getElementStyle(elemID, IEStyleAttr, CSSStyleAttr) {
    var elem = document.getElementById(elemID);
    if (elem.currentStyle) {
        return elem.currentStyle[IEStyleAttr];
    } else if (window.getComputedStyle) {
        var compStyle = window.getComputedStyle(elem, "");
        return compStyle.getPropertyValue(CSSStyleAttr);
    }
    return "";
}

function scrollBar(ownerID, ownerContentID, upID, dnID) {
    this.ownerID = ownerID;
    this.ownerContentID = ownerContentID;
    this.index = scrollBars.length;
    this.upButton = document.getElementById(upID);
    this.dnButton = document.getElementById(dnID);
    this.upButton.index = this.index;
    this.dnButton.index = this.index;
    
    this.ownerHeight = parseInt(getElementStyle(this.ownerID, "height", "height"));

    this.contentElem = document.getElementById(ownerContentID);
    this.contentFontSize = parseInt(getElementStyle(this.ownerContentID, 
        "fontSize", "font-size"));
    this.contentScrollHeight = (this.contentElem.scrollHeight) ? 
        this.contentElem.scrollHeight : this.contentElem.offsetHeight;
    this.initScroll = initScroll;
}

function initScroll() {
    this.upButton.onmousedown = handleScrollClick;
    this.upButton.onmouseup = handleScrollStop;
    this.upButton.oncontextmenu = blockEvent;

    this.dnButton.onmousedown = handleScrollClick;
    this.dnButton.onmouseup = handleScrollStop;
    this.dnButton.oncontextmenu = blockEvent;
    
    var isIEMac = (navigator.appName.indexOf("Explorer") != -1 && navigator.userAgent.indexOf("Mac") != -1);
    if (!isIEMac) {
        document.getElementById("innerWrapper0").style.overflow = "hidden";
    }
}

function handleScrollStop() {
    scrollEngaged = false;
}

function blockEvent(evt) {
    evt = (evt) ? evt : event;
    evt.cancelBubble = true;
    return false;
}

function handleScrollClick(evt) {
    var fontSize;
    evt = (evt) ? evt : event;
    var target = (evt.target) ? evt.target : evt.srcElement;
    var index = target.index;
    fontSize = scrollBars[index].contentFontSize;
    fontSize = (target.className == "lineup") ? fontSize : -fontSize;
    scrollEngaged = true;
    scrollBy(index, parseInt(fontSize));
    scrollInterval = setInterval("scrollBy(" + index + ", " + 
        parseInt(fontSize) + ")", 100);
    evt.cancelBubble = true;
    return false;
}

function scrollBy(index, px) {
    var scroller = scrollBars[index];
    var elem = document.getElementById(scroller.ownerContentID);
    var top = parseInt(elem.style.top);
    var scrollHeight = parseInt(scroller.contentScrollHeight);
    var height = scroller.ownerHeight;
    if (scrollEngaged && top + px >= -scrollHeight + height && top + px <= 0) {
        shiftBy(elem, 0, px);
    } else {
        clearInterval(scrollInterval);
    }
}

function initScrollers() {
    scrollBars[0] = new scrollBar("outerWrapper0", "innerWrapper0", "lineup0", 
        "linedown0");
    scrollBars[0].initScroll();
}

function init2Scrollers() {
    scrollBars[0] = new scrollBar("outerWrapper0", "innerWrapper0", "lineup0", 
        "linedown0");
    scrollBars[0].initScroll();
    scrollBars[1] = new scrollBar("outerWrapper1", "innerWrapper1", "lineup1", 
        "linedown1");
    scrollBars[1].initScroll();
}

function init3Scrollers() {
    scrollBars[0] = new scrollBar("outerWrapper0", "innerWrapper0", "lineup0", 
        "linedown0");
    scrollBars[0].initScroll();
    scrollBars[1] = new scrollBar("outerWrapper1", "innerWrapper1", "lineup1", 
        "linedown1");
    scrollBars[1].initScroll();
    scrollBars[2] = new scrollBar("outerWrapper2", "innerWrapper2", "lineup2", 
        "linedown2");
    scrollBars[2].initScroll();
}