(function($) {
// Look for an element based on ID or name
var check_element = function(name) {
	var obj = null;
	var check_id = $('#' + name);
	var check_name = $('input[name=' + name + ']');

	if(check_id != undefined)
		obj = check_id;
	else if(check_name != undefined)
		obj = check_name;

	return obj;
};

$.fn.autotab_magic = function(focus) {
	for(var i = 0; i < this.length; i++)
	{
		var n = i + 1;
		var p = i - 1;

		if(i > 0 && n < this.length)
			$(this[i]).autotab({ target: $(this[n]), previous: $(this[p]) });
		else if(i > 0)
			$(this[i]).autotab({ previous: $(this[p]) });
		else
			$(this[i]).autotab({ target: $(this[n]) });

		// Set the focus on the specified element
		if(focus != null && (isNaN(focus) && focus == $(this[i]).attr('id')) || (!isNaN(focus) && focus == i))
			$(this[i]).focus();
	}
};

$.fn.autotab_filter = function(options) {
	var defaults = {
		format: 'all',
		uppercase: false,
		lowercase: false,
		nospace: false,
		pattern: null
	};

	if(typeof options == 'string' || typeof options == 'function')
		defaults.format = options;
	else
		$.extend(defaults, options);

	for(var i = 0; i < this.length; i++)
	{
		$(this[i]).bind('keyup', function(e) {
			var val = this.value;

			switch(defaults.format)
			{
				case 'text':
					var pattern = new RegExp('[0-9]+', 'g');
					val = val.replace(pattern, '');
					break;

				case 'alpha':
					var pattern = new RegExp('[^a-zA-Z]+', 'g');
					val = val.replace(pattern, '');
					break;

				case 'number':
				case 'numeric':
					var pattern = new RegExp('[^0-9]+', 'g');
					val = val.replace(pattern, '');
					break;

				case 'alphanumeric':
					var pattern = new RegExp('[^0-9a-zA-Z]+', 'g');
					val = val.replace(pattern, '');
					break;

				case 'custom':
					var pattern = new RegExp(defaults.pattern, 'g');
					var val = val.replace(pattern, '');
					break;

				case 'all':
				default:
					if(typeof defaults.format == 'function')
						var val = defaults.format(val);

					break;
			}

			if(defaults.nospace)
			{
				var pattern = new RegExp('[ ]+', 'g');
				val = val.replace(pattern, '');
			}

			if(defaults.uppercase)
				val = val.toUpperCase();

			if(defaults.lowercase)
				val = val.toLowerCase();

			if(val != this.value)
				this.value = val;
		});
	}
};

$.fn.autotab = function(options) {
	var defaults = {
		format: 'all',
		maxlength: 2147483647,
		uppercase: false,
		lowercase: false,
		nospace: false,
		target: null,
		previous: null,
		pattern: null
	};

	$.extend(defaults, options);

	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');

	if(defaults.maxlength == 2147483647 && maxlength != 2147483647)
		defaults.maxlength = maxlength;
	else if(defaults.maxlength > 0)
		$(this).attr('maxlength', defaults.maxlength)
	else
		defaults.target = null;

	if(defaults.format != 'all')
		$(this).autotab_filter(defaults);

	// Go to the previous element when backspace
	// is pressed in an empty input field
	return $(this).bind('keydown', function(e) {
		if(e.which == 8 && this.value.length == 0 && defaults.previous)
			defaults.previous.focus().val(defaults.previous.val());
	}).bind('keyup', function(e) {
		var keys = [8, 9, 16, 17, 18, 19, 20, 27, 33, 34, 35, 36, 37, 38, 39, 40, 45, 46, 144, 145];

		if(e.which != 8)
		{
			var val = $(this).val();

			if($.inArray(e.which, keys) == -1 && val.length == defaults.maxlength && defaults.target)
				defaults.target.focus();
		}
	});
};

})(jQuery);