/*
important utility functions in this file includes:
(helper functions not directly used in the project are not listed here)
1. trim(str, chars)
2. BrowserDetect
3. blendimage(divid, imageid, imagefile, millisec)
4. stopAnimation(tos)
*/

//trim function uses the following 3 methods
function trim(str, chars) {
    return ltrim(rtrim(str, chars), chars);
}
function ltrim(str, chars) {
    chars = chars || "\\s";
    return str.replace(new RegExp("^[" + chars + "]+", "g"), "");
}
function rtrim(str, chars) {
    chars = chars || "\\s";
    return str.replace(new RegExp("[" + chars + "]+$", "g"), "");
}

//javascript browswer detection
var BrowserDetect = {
    init: function() {
        this.browser = this.searchString(this.dataBrowser) || "An unknown browser";
        this.version = this.searchVersion(navigator.userAgent)
			|| this.searchVersion(navigator.appVersion)
			|| "an unknown version";
        this.OS = this.searchString(this.dataOS) || "an unknown OS";
    },
    searchString: function(data) {
        for (var i = 0; i < data.length; i++) {
            var dataString = data[i].string;
            var dataProp = data[i].prop;
            this.versionSearchString = data[i].versionSearch || data[i].identity;
            if (dataString) {
                if (dataString.indexOf(data[i].subString) != -1)
                    return data[i].identity;
            }
            else if (dataProp)
                return data[i].identity;
        }
    },
    searchVersion: function(dataString) {
        var index = dataString.indexOf(this.versionSearchString);
        if (index == -1) return;
        return parseFloat(dataString.substring(index + this.versionSearchString.length + 1));
    },
    dataBrowser: [
		{
		    string: navigator.userAgent,
		    subString: "Chrome",
		    identity: "Chrome"
		},
		{ string: navigator.userAgent,
		    subString: "OmniWeb",
		    versionSearch: "OmniWeb/",
		    identity: "OmniWeb"
		},
		{
		    string: navigator.vendor,
		    subString: "Apple",
		    identity: "Safari",
		    versionSearch: "Version"
		},
		{
		    prop: window.opera,
		    identity: "Opera"
		},
		{
		    string: navigator.vendor,
		    subString: "iCab",
		    identity: "iCab"
		},
		{
		    string: navigator.vendor,
		    subString: "KDE",
		    identity: "Konqueror"
		},
		{
		    string: navigator.userAgent,
		    subString: "Firefox",
		    identity: "Firefox"
		},
		{
		    string: navigator.vendor,
		    subString: "Camino",
		    identity: "Camino"
		},
		{		// for newer Netscapes (6+)
		    string: navigator.userAgent,
		    subString: "Netscape",
		    identity: "Netscape"
		},
		{
		    string: navigator.userAgent,
		    subString: "MSIE",
		    identity: "Explorer",
		    versionSearch: "MSIE"
		},
		{
		    string: navigator.userAgent,
		    subString: "Gecko",
		    identity: "Mozilla",
		    versionSearch: "rv"
		},
		{ 		// for older Netscapes (4-)
		    string: navigator.userAgent,
		    subString: "Mozilla",
		    identity: "Netscape",
		    versionSearch: "Mozilla"
		}
	],
    dataOS: [
		{
		    string: navigator.platform,
		    subString: "Win",
		    identity: "Windows"
		},
		{
		    string: navigator.platform,
		    subString: "Mac",
		    identity: "Mac"
		},
		{
		    string: navigator.userAgent,
		    subString: "iPhone",
		    identity: "iPhone/iPod"
		},
		{
		    string: navigator.platform,
		    subString: "Linux",
		    identity: "Linux"
		}
	]

};
BrowserDetect.init();

function opacity(id, opacStart, opacEnd, millisec) {
    //speed for each frame
    var speed = Math.round(millisec / 100);
    var timer = 0;

    //determine the direction for the blending, if start and end are the same nothing happens
    var tos = new Array();
    if (opacStart > opacEnd) {
        for (i = opacStart; i >= opacEnd; i--) {
            tos[i] = setTimeout("changeOpac(" + i + ",'" + id + "')", (timer * speed));
            timer++;
        }
    } else if (opacStart < opacEnd) {
        for (i = opacStart; i <= opacEnd; i++) {
            tos[i] = setTimeout("changeOpac(" + i + ",'" + id + "')", (timer * speed));
            timer++;
        }
    }
    return tos;
}

//change the opacity for different browsers
function changeOpac(opacity, id) {
    var object = $(id).style;
    object.opacity = (opacity / 100);
    object.MozOpacity = (opacity / 100);
    object.KhtmlOpacity = (opacity / 100);
    object.filter = "alpha(opacity=" + opacity + ")";
}

function shiftOpacity(id, millisec) {
    //if an element is invisible, make it visible, else make it ivisible
    if ($(id).style.opacity == 0) {
        return opacity(id, 0, 100, millisec);
    } else {
        return opacity(id, 100, 0, millisec);
    }
}

function blendimage(divid, imageid, imagefile, millisec) {
    var speed = Math.round(millisec / 100);
    var timer = 0;
    var image = $$("#" + imageid + " img")[0];
    //set the current image as background
    $(divid).setStyle({ backgroundImage: "url(" + image.readAttribute("src") + ")" });
    //make image transparent
    changeOpac(0, imageid);
    //make new image
    image.setAttribute("src", imagefile);
    //fade in image
    var tos = new Array();
    for (i = 0; i <= 100; i++) {
        tos[i] = setTimeout("changeOpac(" + i + ",'" + imageid + "')", (timer * speed));
        timer++;
    }
    return tos;
}

function currentOpac(id, opacEnd, millisec) {
    //standard opacity is 100
    var currentOpac = 100;
    //if the element has an opacity set, get it
    if ($(id).style.opacity < 100) {
        currentOpac = $(id).style.opacity * 100;
    }
    //call for the function that changes the opacity
    opacity(id, currentOpac, opacEnd, millisec)
}

//clear timeouts in the tos array to stop animation
function stopAnimation(tos) {
    for (i = 0; i <= 100; i++) {
        if (tos[i] != null) {
            clearTimeout(tos[i]);
        }
    }
}