KT.auto_complete_box = function(params) {

    var settings = {
        values: undefined, //either a url, an array, or a callback of items for auto_completion
        default_text: undefined, //default text to go into the search box if desired
        comma_separated_input: false,
        input_id: undefined,
        input: undefined,
        selected_input_id: undefined,
        selected_input: undefined,
        form_id: undefined,
        add_btn_id: undefined,
        add_btn: undefined,
        add_text: katelloI18n.add_plus,
        require_select: false, //disable the add button if proper autocompleted item isn't selected
        add_cb: function(item, item_id, cb){cb();}
    };
    $.extend( settings, params );

    var add_item_from_input = function(e) {
        var item = get_input().attr("value"),
            item_id = get_selected_input().val();


        e.preventDefault();
        if (item.length === 0 || item === settings.default_text){
                return;
        }
            get_add_btn().addClass("working");
        add_item_base(item, item_id, true);
    },
    get_input = function(){
        return settings.input || $("#" + settings.input_id);
    },
    get_selected_input = function(){
        return settings.selected_input || $("#" + settings.selected_input_id);
    },
    get_add_btn = function(){
        return settings.add_btn || $("#" + settings.add_btn_id);
    },
    add_item_base = function(item, item_id, focus) {
        var input = get_input(),
            add_btn = get_add_btn();

        input.removeClass("input_error");
        add_btn.addClass("working");
        add_btn.html("<img src='" + KT.common.spinner_path() + "'>");
        input.attr("disabled", "disabled");
        input.autocomplete('disable');
        input.autocomplete('close');

        if (settings.comma_separated_input) {
            // convert the item string to an array
            item = split(item);
        }
        settings.add_cb(item, item_id, function(){
            reset_input();
            if (focus) {
                get_input().focus();
            }
        });
    },
    reset_input = function() {
        //re-lookup all items, since a redraw may have happened
        var input = get_input(),
            add_btn = get_add_btn();
        add_btn.removeClass('working');
        if (add_btn.text() === "") {
            add_btn.html(settings.add_text);
        }
        input.removeAttr('disabled');
        input.autocomplete('enable');
        input.val('');
    },
    manually_add = function(item, item_id) {
        add_item_base(item, item_id, false);
    },
    error = function() {
        var input = get_input();
        input.addClass("input_error");
    },
    split = function(val) {
        return val.split(/,\s*/);
    },
    extractLast = function(term) {
        return split(term).pop();
    };

    //initialization
    var input = get_input(),
        form = $("#" + settings.form_id),
        add_btn = get_add_btn();

    if (settings.default_text) {
        input.val(settings.default_text);
        input.focus(function() {
            if (input.val() === settings.default_text) {
                input.val("");
            }
        });
        input.blur(function() {
            if(input.val() === "") {
                input.val(settings.default_text);
            }
        });
    }

    if (!settings.comma_separated_input) {
        input.autocomplete({
            source: function (request, response) {
                $.ajax({
                    url: settings.values,
                    data: request,
                    dataType: 'json',
                    success: function (data) {
                        response(data);
                        KT.utils.each(data, function(item){
                            if(request.term === item.value ||
                               request.term === item.label)
                            {
                                get_selected_input().val(item.id);
                                add_btn.removeAttr("disabled");
                            }
                        });
                    },
                    error: function () {
                        response([]);
                    }
                });
            },
            search: function(){
                get_selected_input().val('');
                if(settings.require_select){
                    add_btn.attr("disabled", "disabled");
                }
            },
            select: function (event, ui) {
                get_input().val(ui.item.value);
                get_selected_input().val(ui.item.id);
                add_btn.removeAttr("disabled");
                return false;
            }
        });
    } else {
        input.autocomplete({
            source: function(request, response) {
                $.getJSON( settings.values, {
                    term: extractLast(request.term)
                }, response);
            },
            search: function () {
                // custom minLength
                var term = extractLast(this.value);
                if (term.length < 1) {
                    return false;
                }
            },
            focus: function () {
                // prevent value inserted on focus
                return false;
            },
            select: function (event, ui) {
                var terms = split(this.value);
                // remove the current input
                terms.pop();
                // add the selected item
                terms.push(ui.item.value);
                // add placeholder to get the comma-and-space at the end
                terms.push("");
                this.value = terms.join(", ");
                return false;
            }
        });
    }
    add_btn.bind('click', add_item_from_input);
    form.submit(add_item_from_input);

    return {
        manually_add: manually_add,
        error: error,
        reset_input: reset_input
    };
};