//
// +----------------------------------------------------------------------+
// | PHP2Go Web Development Framework                                     |
// +----------------------------------------------------------------------+
// | Copyright (c) 2002-2006 Marcos Pont                                  |
// +----------------------------------------------------------------------+
// | This library is free software; you can redistribute it and/or        |
// | modify it under the terms of the GNU Lesser General Public           |
// | License as published by the Free Software Foundation; either         |
// | version 2.1 of the License, or (at your option) any later version.   |
// | 																	  |
// | This library is distributed in the hope that it will be useful,      |
// | but WITHOUT ANY WARRANTY; without even the implied warranty of       |
// | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU    |
// | Lesser General Public License for more details.                      |
// | 																	  |
// | You should have received a copy of the GNU Lesser General Public     |
// | License along with this library; if not, write to the Free Software  |
// | Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA             |
// | 02111-1307  USA                                                      |
// +----------------------------------------------------------------------+
//
// $Header: /www/cvsroot/php2go/resources/javascript/form/memofield.js,v 1.2 2006/07/22 13:12:38 mpont Exp $
// $Date: 2006/07/22 13:12:38 $
// $Revision: 1.2 $

/**
 * @fileoverview
 * This file contains the MemoField form component class
 */

/**
 * The MemoField form component is used in form components
 * built using the "memofield" tag in the XML specification
 * @class MemoField
 * @base ComponentField
 * @param {Object} id Textarea field ID
 * @param {Number} maxlength Max length
 */
function MemoField(id, maxlength) {
	this.ComponentField($(id), 'MemoField');
	/**
	 * Control field used to display characters left
	 * @type Object
	 */
	this.count = $(this.id + "_count");
	/**
	 * Max chars allowed
	 * @type Number
	 */
	this.maxlength = maxlength;
	this.setup();
}
MemoField.extend(ComponentField);

/**
 * Initializes the component's properties and event handlers
 * @type void
 */
MemoField.prototype.setup = function() {
	this.fld.component = this;
	this.count.auxiliary = true;
	Event.addListener(this.fld, 'keydown', this.keyHandler.bind(this));
	Event.addListener(this.fld, 'keyup', this.keyHandler.bind(this));
};

/**
 * Clears the textarea value
 * @type void
 */
MemoField.prototype.clear = function() {
	this.fld.value = '';
	this.count.value = this.maxlength;
};

/**
 * Checks whether the textarea value is an empty string
 * @type Boolean
 */
MemoField.prototype.isEmpty = function() {
	return (this.fld.value.trim() == '');
};

/**
 * Handles onKeyUp and onKeyDown events in the textarea,
 * updating the aux control field with the number of chars left
 * @param {Event} event
 * @type void
 */
MemoField.prototype.keyHandler = function(event) {
	var len = this.fld.value.length;
	if (len >= this.maxlength) {
		this.fld.value = this.fld.value.substring(0, this.maxlength);
		this.count.value = 0;
	} else {
		this.count.value = this.maxlength - len;
	}
};