/*
 * Autotab - jQuery plugin 1.0
 * http://dev.lousyllama.com/auto-tab
 * 
 * Copyright (c) 2008 Matthew Miller
 * 
 * Dual licensed under the MIT and GPL licenses:
 *   http://www.opensource.org/licenses/mit-license.php
 *   http://www.gnu.org/licenses/gpl.html
 * 
 * Revised: 2008/05/22 01:23:25
 */
(function($) {
$.fn.autotab = function(options) {
    var defaults = {
        format: 'all',            // text, numeric, alphanumeric, all
        maxlength: 2147483647,    // Defaults to maxlength value
        uppercase: false,        // Converts a string to UPPERCASE
        lowercase: false,        // Converts a string to lowecase
        nospace: false,        // Remove spaces in the user input
        target: null,            // Where to auto tab to
        previous: null            // Backwards auto tab when all data is backspaced
    };
    $.extend(defaults, options);
    var check_element = function(name) {
        var val = null;
        var check_id = $('#' + name)[0];
        var check_name = $('input[name=' + name + ']')[0];
        if(check_id != undefined)
            val = $(check_id);
        else if(check_name != undefined)
            val = $(check_name);
        return val;
    };
    var key = function(e) {
        if(!e)
            e = window.event;
        return e.keyCode;
    };
    // Sets targets to element based on the name or ID passed
    if(typeof defaults.target == 'string')
        defaults.target = check_element(defaults.target);
    if(typeof defaults.previous == 'string')
        defaults.previous = check_element(defaults.previous);
    var maxlength = $(this).attr('maxlength');
    // Each text field has a maximum character limit of 2147483647
    // defaults.maxlength has not changed and maxlength was specified
    if(defaults.maxlength == 2147483647 && maxlength != 2147483647)
        defaults.maxlength = maxlength;
    // defaults.maxlength overrides maxlength
    else if(defaults.maxlength > 0)
        $(this).attr('maxlength', defaults.maxlength)
    // defaults.maxlength and maxlength have not been specified
    // A target cannot be used since there is no defined maxlength
    else
        defaults.target = null;
    // IE does not recognize the backspace key
    // with keypress in a blank input box
    if($.browser.msie)
    {
        this.keydown(function(e) {
            if(key(e) == 8)
            {
                var val = this.value;
                if(val.length == 0 && defaults.previous)
                    defaults.previous.focus();
            }
        });
    }
    return this.keypress(function(e) {
        if(key(e) == 8)
        {
            var val = this.value;
            if(val.length == 0 && defaults.previous)
                defaults.previous.focus();
        }
    }).keyup(function(e) {
        var val = this.value;
        switch(defaults.format)
        {
            case 'text':
                var pattern = new RegExp('[0-9]+', 'g');
                var val = val.replace(pattern, '');
                break;
            case 'alpha':
                var pattern = new RegExp('[^a-zA-Z]+', 'g');
                var val = val.replace(pattern, '');
                break;
            case 'number':
            case 'numeric':
                var pattern = new RegExp('[^0-9]+', 'g');
                var val = val.replace(pattern, '');
                break;
            case 'alphanumeric':
                var pattern = new RegExp('[^0-9a-zA-Z]+', 'g');
                var val = val.replace(pattern, '');
                break;
            case 'all':
            default:
                break;
        }
        if(defaults.nospace)
        {
            pattern = new RegExp('[ ]+', 'g');
            val = val.replace(pattern, '');
        }
        if(defaults.uppercase)
            val = val.toUpperCase();
        if(defaults.lowercase)
            val = val.toLowerCase();
        this.value = val;
        /**
         * Do not auto tab when the following keys are pressed
         * 8:    Backspace
         * 9:    Tab
         * 16:    Shift
         * 17:    Ctrl
         * 18:    Alt
         * 19:    Pause Break
         * 20:    Caps Lock
         * 27:    Esc
         * 33:    Page Up
         * 34:    Page Down
         * 35:    End
         * 36:    Home
         * 37:    Left Arrow
         * 38:    Up Arrow
         * 39:    Right Arrow
         * 40:    Down Arroww
         * 45:    Insert
         * 46:    Delete
         * 144:    Num Lock
         * 145:    Scroll Lock
         */
        var keys = [8, 9, 16, 17, 18, 19, 20, 27, 33, 34, 35, 36, 37, 38, 39, 40, 45, 46, 144, 145];
        var string = keys.toString();
        if(string.indexOf(key(e)) == -1 && val.length == defaults.maxlength && defaults.target)
            defaults.target.focus();
    });
};
})(jQuery);