/**
 *  plugin name: jquery totop for smoothly scroll back to top
 *  plugin url: https://github.com/mmkjony/jquery.totop
 *  version: 1.1
 *  author: mmk jony
 *  author url: https://github.com/mmkjony
 *  license: licensed under mit
 **/

(function( $ ){
    'use strict';
    
    $.fn.totop = function(opt){
        
        //variables
        var elem = this;
        var win = $(window);
        var doc = $('html, body');
        
        //extended options
        var options = $.extend({
            autohide: true,
            offset: 420,
            speed: 500,
            position: true,
            right: 15,
            bottom: 30
        }, opt);
        
        elem.css({
            'cursor': 'pointer'
        });
        
        if(options.autohide){
            elem.css('display', 'none');
        }
        
        if(options.position){
            elem.css({
                'position': 'fixed',
                'right': options.right,
                'bottom': options.bottom,
            });
        }
        
        elem.click(function(){
            doc.animate({scrolltop: 0}, options.speed);
        });
        
        win.scroll(function(){
            var scrolling = win.scrolltop();
            
            if(options.autohide){
                if(scrolling > options.offset){
                    elem.fadein(options.speed);
                }
                else elem.fadeout(options.speed);
            }
            
        });
        
    };
    
}( jquery ));