/**
* jQuery fontscale - A plugin to alter the font size of DOM elements 
* Copyright (c) 2010 Ben Byrne - ben(at)fireflypartners(dot)com | http://www.fireflypartners.com
* Dual licensed under MIT and GPL.
* http://www.opensource.org/licenses/mit-license.php
* http://www.gnu.org/licenses/gpl.html
* Date: 07/21/2010
* @author Ben Byrne
* @version 0.2
*
*/

/**
* For complete documentation, visit http://byrnecreative.com/blog/fontscale
* @example $("#fontgrow").fontscale("p","+");
* @desc Bind scaling up the font size of all P elements to the element #fontgrow with default settings.
* @example $("#fontshrink").fontscale("p","-",{unit:"percent",increment:25,useCookie:false,adjustLeading:true});
* @desc Bind scaling down the font size of all P elements to the element #fontshrink with custom settings.
* @example $("#reset").fontscale("p","reset");
* @desc Eliminate all fontscale resizing 
*/

(function ($) {
    $.fn.fontscale = function (selectors, adjustment, parameters) {

        var settings = $.extend($.fn.fontscale.defaults, parameters);

        //only use cookies if we can
        if (!$.isFunction($.cookie)) settings.useCookie = false;

        // if the cookie exists, we're supposed to use it, and we haven't before, then load it 
        if (!settings.cookieLoaded && $.cookie(settings.cookieName) && settings.useCookie) {
            cookieSettings = $.fn.fontscale.readcookie(settings.cookieName);
            //only actually apply the data from the cookie if its unit settings match!
            if (cookieSettings.unit == settings.unit && !settings.cookieLoaded) $.fn.fontscale.scale(selectors, cookieSettings.delta, settings, true);
        }

        this.each(function () {

            // bind to elements
            $(this).bind(settings.event, function () {
                $.fn.fontscale.scale(selectors, adjustment, settings, false);
                if ($.isFunction(settings.onAfter)) settings.onAfter(selectors, adjustment, settings); //is this okay?				
            });
        });

        return this;

    };

    $.fn.fontscale.reset = function (object, settings) {

        //remove any scaling done inline (assumed to be from this plugin)
        $(object).each(function (i) {
            $(this).css('font-size', '');
            if (settings.adjustLeading) $(this).css('line-height', '');
        });

        //if we're using a cookie, reset it too
        if (settings.useCookie) {
            $.fn.fontscale.savecookie("delete", settings);
        }
    }

    $.fn.fontscale.scale = function (object, adj, settings, fromcookie) {

        //make delta an int that changes nothing to start
        var delta = 0;

        if (adj == "+" || adj == "up") {
            //set the delta as an increase
            delta = settings.increment;
        } else if (adj == "-" || adj == "down") {
            //set the delta as a decrease
            delta = settings.increment * -1;
        } else if (adj == "reset") {
            //remove applied changes and do nothing else
            return $.fn.fontscale.reset(object, settings);
        } else if (fromcookie) {
            //get a pre-calibrated delta from the cookie if 
            delta = parseFloat(adj);
            settings.cookieLoaded = true;
        }

        //change the value into a percent if we have to
        if (settings.unit == "percent" && !fromcookie) {
            delta = 1 + (delta / 100);
        }

        $(object).each(function (i) {

            var currentSize = parseInt($(this).css("font-size"));
            var currentLeading = parseInt($(this).css("line-height"));

            if (settings.unit == "percent") {
                $(this).css("font-size", Math.round(currentSize * delta));
                if (settings.adjustLeading) $(this).css("line-height", Math.round(currentLeading * delta));
            } else {
                $(this).css("font-size", currentSize + delta);
                if (settings.adjustLeading) $(this).css("line-height", currentLeading + delta);
            }

        });

        if (settings.useCookie && !fromcookie) $.fn.fontscale.savecookie(delta, settings);

        return;

    };

    $.fn.fontscale.savecookie = function (delta, settings) {

        //delete the cookie if we're performing a reset, do nothing else
        if (delta == "delete") {
            $.cookie(settings.cookieName, null, settings.cookieParams);
            return true;
        }

        if ($.cookie(settings.cookieName)) {
            properties = $.fn.fontscale.readcookie(settings.cookieName);
        } else {
            properties = { "delta": 0 }
        }

        //if we have a cookie that matches, just change the delta
        if (settings.unit == properties.unit) {

            if (settings.unit == "percent") {
                properties.delta = (delta) ? properties.delta * delta : 1;
            } else {
                properties.delta = parseInt(properties.delta) + delta;
            }

            return $.cookie(settings.cookieName, "delta=" + properties.delta + "&unit=" + properties.unit, settings.cookieParams);

            //no cookie that matches, create a new     
        } else {
            $.cookie(settings.cookieName, "delta=" + delta + "&unit=" + settings.unit, settings.cookieParams);
            return true;
        }

    };

    $.fn.fontscale.readcookie = function (the_cookie) {

        val_string = $.cookie(the_cookie);

        var objResult = {};
        $.each(val_string.split("&"), function () {
            var prm = this.split("=");
            objResult[prm[0]] = prm[1];
        });
        return objResult;
    };

})(jQuery);

$.fn.fontscale.defaults = {
    useCookie: true,
    cookieName: 'fontscale',
    cookieParams: {
        expires: 30,
        path: "/"
    },
    increment: 2,
    unit: "px",
    adjustLeading: false,
    event: "click",
    cookieLoaded: false
};