// Require jQuery
// Use jQuery.cookie if you want to restore the previous expansion of the tree

jQuery.fn.tree = function (options) {

    // Setup default options
    /** Avaiable options are:
    *  - open_char: defeault character to display on open node in tree
    *  - close_char: defeault character to display on close node in tree
    *  - default_expanded_paths_string: if no cookie found the tree will be expand with this paths string
    **/
    if (options === undefined || options === null)
        options = {};
    var open_char = options.open_char;
    var close_char = options.close_char;
    var default_expanded_paths_string = options.default_expanded_paths_string;
    if (open_char === undefined || open_char === null)
        open_char = '▼';
    if (close_char === undefined || close_char === null)
        close_char = '►';
    if (default_expanded_paths_string === undefined || default_expanded_paths_string === null)
        default_expanded_paths_string = '0';

    // Get the expanded paths from the current state of tree
    jQuery.fn.save_paths = function () {
        var paths = [];
        var path = [];
        var open_nodes = jQuery(this).find('li span.open');
        var last_depth = null;
        for (var i = 0; i < open_nodes.length; i++) {
            var depth = jQuery(open_nodes[i]).parents('ul').length - 1;
            if ((last_depth == null && depth > 0) || (depth > last_depth && depth - last_depth > 1))
                continue;
            var pos = jQuery(open_nodes[i]).parent().prevAll().length;
            if (last_depth == null) {
                path = [pos];
            } else if (depth < last_depth) {
                paths.push(path.join('/'));
                var diff = last_depth - depth;
                path.splice(path.length - diff - 1, diff + 1);
                path.push(pos);
            } else if (depth == last_depth) {
                paths.push(path.join('/'));
                path.splice(path.length - 1, 1);
                path.push(pos);
            } else if (depth > last_depth) {
                path.push(pos);
            }
            last_depth = depth;
        }
        paths.push(path.join('/'));
        try { jQuery.cookie(this.attr('class'), paths.join(',')); }
        catch (e) { }
    };

    // This function expand the tree with 'path'
    jQuery.fn.restore_paths = function () {
        return;
        var paths_string = null;
        try { paths_string = jQuery.cookie(this.attr('class')); }
        catch (e) { paths_string = default_expanded_paths_string; }
        if (paths_string === null || paths_string === undefined)
            paths_string = default_expanded_paths_string;
        var paths = paths_string.split(',');
        for (var i = 0; i < paths.length; i++) {
            var path = paths[i].split('/');
            var obj = jQuery(this);
            for (var j = 0; j < path.length; j++) {
                obj = jQuery(obj.children('li')[path[j]]);
                obj.children('span').attr('class', 'open');
                obj.children('span').html(open_char);
                obj = obj.children('ul')
                obj.show();
            }
        }
    };

    for (var i = 0; i < this.length; i++) {
        if (this[i].tagName === 'UL') {
            // Make a tree
            jQuery(this[i]).find('li').has('ul').prepend('<span class="close" style="cursor:pointer;">' + close_char + '</span>');
            jQuery(this[i]).find('ul').hide();
            // Restore cookie expand path
            jQuery(this[i]).restore_paths();
            // Click event
            jQuery(this[i]).find('span').live('click', { tree: this[i] }, function (e) {
                if (jQuery(this).attr('class') == 'open') {
                    jQuery(this).parent().children('ul').hide('slow');
                    jQuery(this).attr('class', 'close');
                    jQuery(this).html(close_char);
                } else if (jQuery(this).attr('class') == 'close') {
                    jQuery(this).parent().children('ul').show('slow');
                    jQuery(this).attr('class', 'open');
                    jQuery(this).html(open_char);
                }
                jQuery(e.data.tree).save_paths();
            });
        }
    }
}