/********************************************************************
 * jQuery Dependent Select plug-in                                  *
 *                                                                  * 
 * @version     2.6                                                 *
 * @copyright   (c) Bau Alexandru 2009                              *
 * @author      Bau Alexandru                                       *
 * @email       bau.alexandru@gmail.com                             *
 *                                                                  *
 * @depends     jQuery                                              *
 *                                                                  *
 *                                                                  *
 * Do not delete or modify this header!                             *
 *                                                                  * 
 *                                                                  *
 * Plugin call example:                                             *
 *                                                                  *
 * jQuery(function($){                                              *
 *                                                                  * 
 *      SINGLE CHILD                                                *
 *      $('#child_id').dependent({                                  *
 *          parent: 'parent_id',                                    *
 *          group:  'common_class',                                 *
 *          defaultText: '-- select --' // optional                 *
 *      });                                                         *
 *                                                                  * 
 *      MULTIPLE CHILDS                                             *
 *      $('#child_id').dependent({                                  *
 *          parent: 'parent_id'                                     *
 *          defaultText: '-- select --' // optional                 *
 *      });                                                         *
 *                                                                  *
 *  });                                                             *
 *                                                                  *
 ********************************************************************/

(function($) { // create closure

    /**
     * Plug-in initialization
     * 
     * @param object
     *            plug-in options
     * @return object this
     */
    $.fn.dependent = function(settings) {
        // merge default settings with dynamic settings
        $param = $.extend( {}, $.fn.dependent.defaults, settings);

        this.each(function() { // for each element
                    $this = $(this); // current element object

                    var $parent = '#' + $param.parent;
                    var $defaultText = $param.defaultText;

                    var $child = $this;
                    var $child_id = $($child).attr('id');
                    var $child_cls = '.' + $child_id;

                    if ($param.group != '') {
                        var $group = '.' + $param.group;
                    }

                    var $index = 0;
                    var $holder = 'dpslctholder';
                    var $holder_cls = '.' + $holder;

                    _createHolder($holder, $holder_cls, $child, $child_id,
                            $child_cls);

                    // check if parent allready has an option selected
                    if ($($parent).val() != 0) {
                        $title = $($parent).find('option:selected').attr(
                                'title');
                        $($child).find('option[class!=' + $title + ']')
                                .remove();
                        $($child)
                                .prepend(
                                        '<option value="">' + $defaultText + '</option>');
                    } else {
                        // remove the child's options and add a default option
                        $($child).find('option').remove();
                        $($child)
                                .append(
                                        '<option value="">' + $defaultText + '</option>');
                    }

                    _parentChange($parent, $child, $group, $holder_cls,
                            $child_cls);

                });

        return this;
    };

    // ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

    /***************************************************************************
     * BEGIN PLUG-IN PRIVATE METHODS *
     **************************************************************************/

    /**
     * Private function description
     */

    function _createHolder($holder, $holder_cls, $child, $child_id, $child_cls) {

        // create a select to hold the options from all this child
        var $is_created = $($holder_cls + ' ' + $child_id).size();

        if ($is_created == 0) {
            $('body').append(
                    '\n\n<select class="' + $holder + ' ' + $child_id
                            + '" style="display:none">\n</select>\n');
        }

        // add options to the holder
        $($child).find('option[value!=]').each(
                function() {

                    $value = $(this).attr('value');
                    $class = $(this).attr('class');
                    $title = $(this).attr('title');
                    $text = $(this).text();

                    $($holder_cls + $child_cls).append(
                            '<option value="' + $value + '" class="' + $class
                                    + '" title="' + $title + '">' + $text
                                    + '</option>\n');
                });

    }

    function _parentChange($parent, $child, $group, $holder_cls, $child_cls) {

        // on change event
        $($parent).bind('change', function() {

            // remove all the child's options
                $($child).find('option[value!=]').remove();

                $index = $($group).index($(this));
                // set all the selects from the group to the default option
                if ($param.group != '') {
                    $($group + ':gt(' + $index + ')').find('option[value!=]')
                            .remove();
                }

                $title = $(this).find('option:selected').attr('title');
                // add options to the child mask from the holder
                $($holder_cls + $child_cls)
                        .find('option[class=' + $title + ']').each(
                                function() {

                                    $value = $(this).attr('value');
                                    $class = $(this).attr('class');
                                    $title = $(this).attr('title');
                                    $text = $(this).attr('text');

                                    $($child).append(
                                            '<option value="' + $value
                                                    + '" class="' + $class
                                                    + '" title="' + $title
                                                    + '">' + $text
                                                    + '</option>');
                                });

            });

    }

    /***************************************************************************
     * /END PLUG-IN PRIVATE METHODS *
     **************************************************************************/

    // ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
    /***************************************************************************
     * BEGIN PLUG-IN DEFAULT PARAMETERS *
     **************************************************************************/

    $.fn.dependent.defaults = {
        parent : 'parent_id',
        defaultText : ' '
    };

    /***********************************
     * /END PLUG-IN DEFAULT PARAMETERS *
     ***********************************/

})(jQuery); // end closure