/* Copyright (c) 2008 Kean Loong Tan http://www.gimiti.com/kltan
 * Licensed under the MIT (http://www.opensource.org/licenses/mit-license.php)
 * Copyright notice and license must remain intact for legal use
 * jFade
 * Version: 1.0 (Jun 30, 2008)
 * Requires: jQuery 1.2.6+
 *
 *
 * Original Code Copyright (c) 2008 by Michael Leigeber
 * Website: http://www.leigeber.com
 *
 *
 */

(function($) {

    $.fn.jFade = function(options) {
        // merge users option with default options
        var opts = $.extend({}, $.fn.jFade.defaults, options);
        var startrgb,endrgb,er,eg,eb,rint,gint,bint,step;
        var target = this;
    
        //var obj = this;
    
        var init = function() {
            var tgt = target;
            opts.steps = opts.steps || 20;
            opts.duration = opts.duration || 20;
            //clear everything + reset
            clearInterval(tgt.timer);
            endrgb = colorConv(opts.end);
            er = endrgb[0];
            eg = endrgb[1];
            eb = endrgb[2];
        
            if(!tgt.r) {
                //convert to usable rgb value
                startrgb = colorConv(opts.start);
                r = startrgb[0];
                g = startrgb[1];
                b = startrgb[2];
                tgt.r = r;
                tgt.g = g;
                tgt.b = b;
            }
            //process red
            rint = Math.round(Math.abs(tgt.r-er)/opts.steps);
            //process green
            gint = Math.round(Math.abs(tgt.g-eg)/opts.steps);
            //process blue
            bint = Math.round(Math.abs(tgt.b-eb)/opts.steps);
            if(rint == 0) { rint = 1 }
            if(gint == 0) { gint = 1 }
            if(bint == 0) { bint = 1 }
        
            tgt.step = 1;
            tgt.timer = setInterval( function() { animateColor(tgt,opts.property,opts.steps,er,eg,eb,rint,gint,bint) }, opts.duration);
        
            function animateColor(obj,property,steps,er,eg,eb,rint,gint,bint) {
                var tgt = obj;
                var color;
                if(tgt.step <= steps) { // for each loop
                    var r = tgt.r;
                    var g = tgt.g;
                    var b = tgt.b;
                    if(r >= er) {
                        r = r - rint;
                    }
                    else {
                    r = parseInt(r) + parseInt(rint);
                    }
                    if(g >= eg) {
                        g = g - gint;
                    }
                    else {
                        g = parseInt(g) + parseInt(gint);
                    }
                    if(b >= eb) {
                    b = b - bint;
                    }
                    else {
                        b = parseInt(b) + parseInt(bint);
                    }
                    color = 'rgb(' + r + ',' + g + ',' + b + ')';
                    
                    $(obj).css(property, color);
                    
                    tgt.r = r;
                    tgt.g = g;
                    tgt.b = b;
                    tgt.step = tgt.step + 1;
                }
                else {// last loop
                
                    clearInterval(tgt.timer);
                    color = 'rgb(' + er + ',' + eg + ',' + eb + ')';
                    $(obj).css(property, color);
                }
            }
            
            // convert the color to rgb from hex
            function colorConv(color) {
                //covert 0-2 position hex into decimal in rgb[0]
                //covert 2-4 position hex into decimal in rgb[1]
                //covert 4-6 position hex into decimal in rgb[2]
                var rgb = [parseInt(color.substring(0,2),16),
                parseInt(color.substring(2,4),16),
                parseInt(color.substring(4,6),16)];
                //return array containing rgb[0], rgb[1], rgb[2]
                return rgb;
            }
        };
        if (opts.trigger == "load")
            init();
        else
            $(this).bind(opts.trigger, function(){
                target = this;
                init();
            });
        
        return this;
    };

    $.fn.jFade.defaults = {
        trigger: "load",
        property: 'background',
        start: 'FFFFFF',
        end: '000000',
        steps: 5,
        duration: 30
    };
})(jQuery);