var alwaysOnTop = {

    dsettings: {
        targetid: '',
        orientation: 2,
        position: [10, 30],
        externalsource: '',
        frequency: 1,
        hideafter: 0,
        fadeduration: [500, 500],
        display: 0 //internal setting on whether to display target element at all (based on frequency setting)
    },

    settingscache: {},

    positiontarget: function($target, settings) {
        var fixedsupport = !document.all || document.all && document.compatMode == "CSS1Compat" && window.XMLHttpRequest //not IE or IE7+ browsers in standards mode
        var posoptions = { position: fixedsupport ? 'fixed' : 'absolute', visibility: 'visible' }
        if (settings.fadeduration[0] > 0) //if fade in
            posoptions.opacity = 0
        posoptions[(/^[13]$/.test(settings.orientation)) ? 'left' : 'right'] = settings.position[0]
        posoptions[(/^[12]$/.test(settings.orientation)) ? 'top' : 'bottom'] = settings.position[1]
        if (document.all && !window.XMLHttpRequest) //loose check for IE6 and below
            posoptions.width = $target.width() //IE6- seems to require an explicit width on a DIV
        $target.css(posoptions)
        if (!fixedsupport) {
            this.keepfixed($target, settings)
            var evtstr = 'scroll.' + settings.targetid + ' resize.' + settings.targetid
            jQuery(window).bind(evtstr, function() { alwaysOnTop.keepfixed($target, settings) })
        }
        this.revealdiv($target, settings, fixedsupport)
        if (settings.hideafter > 0) { //if hide timer enabled
            setTimeout(function() {
                alwaysOnTop.hidediv(settings.targetid)
            }, settings.hideafter + settings.fadeduration[0])
        }
    },

    keepfixed: function($target, settings) {
        var $window = jQuery(window)
        var is1or3 = /^[13]$/.test(settings.orientation)
        var is1or2 = /^[12]$/.test(settings.orientation)
        var x = $window.scrollLeft() + (is1or3 ? settings.position[0] : $window.width() - $target.outerWidth() - settings.position[0])
        var y = $window.scrollTop() + (is1or2 ? settings.position[1] : $window.height() - $target.outerHeight() - settings.position[1])
        $target.css({ left: x + 'px', top: y + 'px' })
    },

    revealdiv: function($target, settings) {
        if (settings.fadeduration[0] > 0) //if fade in
            $target.show().animate({ opacity: 1 }, settings.fadeduration[0])
        else
            $target.show()
        if (settings.frequency == "session") //set session only cookie (name: 'sots' + targetid)? 
            this.setCookie('sots' + settings.targetid, 'shown')
        else if (/^\d+ day/i.test(settings.frequency)) { //set persistent cookie (name: 'sotp' + targetid)? 
            var persistdays = parseInt(settings.frequency)
            this.setCookie('sotp' + settings.targetid, persistdays, persistdays)
        }
    },

    hidediv: function(targetid) { //public function
        var $target = jQuery('#' + targetid)
        if ($target.css('display') == 'none') //if target hidden already
            return
        var settings = this.settingscache[targetid]
        if (settings.fadeduration[1] > 0) //if fade out
            $target.animate({ opacity: 0 }, settings.fadeduration[1], function() { $target.hide() })
        else
            $target.hide()
        var evtstr = 'scroll.' + settings.targetid + ' resize.' + settings.targetid
        jQuery(window).unbind(evtstr)
    },

    loadajaxcontent: function($, settings) {
        $.ajax({
            url: settings.externalsource,
            error: function(ajaxrequest) {
                alert('Error fetching Ajax content.\nServer Response: ' + ajaxrequest.responseText)
            },
            success: function(content) {
                var $target = $(content)
                if ($target.get(0).id == settings.targetid)
                    alwaysOnTop.positiontarget($target.appendTo('body'), settings)
                else
                    alert('Error: The value you have entered for "targetid" (' + settings.targetid + ') '
						+ 'doesn\'t match the ID of your remote content\'s DIV container (' + $target.get(0).id + '). This must be corrected'
					)
            }
        })
    },

    init: function(options) {
        var settings = {}
        settings = jQuery.extend(settings, this.dsettings, options)
        this.settingscache[settings.targetid] = settings
        if (typeof settings.frequency == "number") //value of 1=show, 0=hide
            settings.display = (settings.frequency > Math.random()) ? 1 : 0
        else if (settings.frequency == "session")
            settings.display = (this.getCookie('sots' + settings.targetid) == 'shown') ? 0 : 1 //session cookie name: 'sots' + targetid
        else if (/^\d+ day/i.test(settings.frequency)) { //match 'xx days'
            //If admin has changed number of days to persist from current cookie records, reset persistence by deleting cookie
            if (parseInt(this.getCookie('sotp' + settings.targetid)) != parseInt(settings.frequency))
                this.setCookie('sotp' + settings.targetid, '', -1)
            settings.display = (this.getCookie('sotp' + settings.targetid) != null) ? 0 : 1 //persistent cookie name: 'sotp' + targetid
        }
        jQuery(document).ready(function($) {
            if (settings.externalsource != '' && settings.display) { //if ajax content
                alwaysOnTop.loadajaxcontent($, settings)
            }
            else if (settings.externalsource == '') { //inline content
                var $target = $('#' + settings.targetid)
                if (!settings.display) { //if hide content (based on frequency setting)
                    $target.hide()
                    return false
                }
                else {
                    alwaysOnTop.positiontarget($target, settings)
                }
            }
        }) //end ready
    },

    getCookie: function(Name) {
        var re = new RegExp(Name + "=[^;]*", "i"); //construct RE to search for target name/value pair
        if (document.cookie.match(re)) //if cookie found
            return document.cookie.match(re)[0].split("=")[1] //return its value
        return null
    },

    setCookie: function(name, value, days) {
        if (typeof days != "undefined") { //if set persistent cookie
            var expireDate = new Date()
            var expstring = expireDate.setDate(expireDate.getDate() + days)
            document.cookie = name + "=" + value + "; expires=" + expireDate.toGMTString()
        }
        else
            document.cookie = name + "=" + value + "; path=/"
    }
}