!function ($) {
    
    "use strict";
    
    function ninjaSelect(element, options) {
        this.$element = $(element);
        this.options = $.extend({}, $.fn.ninjaSelect.defaults, options);
        this.page = 1;
        
        this.init();                
    }
    
    ninjaSelect.prototype = {
        
        constructor: ninjaSelect,
        
        init: function() {
            var self = this, allow = true;
            
            self.$div = $('<div>', {'id': 'ninja_' + this.$element.attr('id'), 'class': 'ninjaSelect'}),
            self.$input = $('<input>'),
            self.$list = $('<div>', {'class': 'ninjaSelect_wrapper'}).hide();
            self.$selected = $('<div>', {'class': 'ninjaSelect_selected'});
            self.$ul = $('<ul>', {'class': 'ninjaSelect_list'});
            
            self.$element.hide().after(
                self.$div.append(
                    self.$input, self.$selected, self.$list.append(
                        self.$ul
                    )
                )
            );
            
            self.$input.on('keyup', function(e) {                
                self.loadData($(this).val());
            });
            
            self.$ul.delegate('li', 'click', function(e) {
                var id = $(this).data().id, allow = true;
                
                self.$selected.show().find('.ninjaSelect_item').each(function() {
                    if ($(this).data().id == id) {
                        allow = false;
                    }
                });
                
                if (!self.options.multiple && $('.ninjaSelect_item').length == 1) {
                    allow = false;
                }
                
                if (allow) {
                    $(this).addClass('active');
                    
                    self.$selected.append(
                        $('<div>', {'class': 'ninjaSelect_item'}).data({'id': id, 'index': $(this).index()}).text($(this).text()).click(function() {
                            self.$ul.find('li').eq($(this).data().index).removeClass('active');
                            $(this).next().remove().end().remove();
                            
                            if (!self.$selected.find('.ninjaSelect_item').length) {
                                self.$selected.hide()
                            }
                        }),
                        $('<input>', {'type': 'hidden', 'name': $(this).text() + '_' + id}).val($(this).text())
                    )
                }
            });
            
            self.$list.mousewheel(function(e, delta) {
                if (delta < 0) {
                    if ($(this).scrollTop() + $(this).innerHeight() >= self.$ul.innerHeight() && allow) {
                        allow = false;
                        
                        self.loadData(self.$input.val(), function() {
                            allow = true;
                        })
                    }
                }
            });
            
            $(document).delegate('body', 'click', function(e) {
                if ($(e.target).closest('.ninjaSelect_list').length == 0) {
                    self.$list.hide();
                    self.$ul.empty();
                }
            })
        },
        
        loadData: function(val, callback) {
            var self = this, len = val.length;
            
            if (len >= self.options.minLength) {
                $.get(self.options.url, {offset: self.page, count: self.options.itemsPerPage, value: val, data: self.options.data}, function(json) {
                    if (json.length) {
                        if (json.length >= self.options.itemsPerPage) {
                            self.page++;
                        } 
                        
                        self.$list.show();                        
                        
                        json.forEach(function(item, i, arr) {
                            self.$ul.append(
                                $('<li>').text(item.text).data('id', item.id)
                            )
                        })
                        
                        
                        if (self.page == 1) {
                            self.$list.animate({scrollTop: 0}, 0);
                        } else {
                            self.$list.css({scrollTop: self.$list.scrollTop()}, 0);
                        }

                        if (callback) {
                            callback();
                        }
                    } else {
                        self.$list.hide();
                        self.$ul.empty();
                    }
                }, 'json');
            } else {
                self.$list.hide();
                self.$ul.empty();
            }
        }
        
    }
    
    $.fn.ninjaSelect = function(options) {
        return this.each(function() {
            var $this = $(this), data = $this.data('ninjaSelect');
            
            if (!data) {
                $this.data('ninjaSelect', (data = new ninjaSelect(this, options)))
            }
        })
    }
    
    $.fn.ninjaSelect.defaults = {
        url: '/ajax.php',
        data: {},
        minLength: 2,
        itemsPerPage: 3,
        multiple: true
    }
    
}(jQuery);