<?php
/**
 * Hierarchy - Output lists hierarchicaly
 *
 * This class can be used to output lists hierarchicaly, like a
 * directory. It uses CSS to create the layout that can be
 * configured with other names (see contants section).
 * If browser do not suport CSS, a simple HTML list is returned
 * hierarchicaly, without styles.
 *
 * This class do not control which item of list will be shown opened
 * or closed, but you can extends this class to provide this.
 * An example is made with a simple function to expose a strategy
 * of how to do this.
 *
 * @author Rubens Takiguti Ribeiro
 * @date 2008-07-16
 * @version 1.0.1 2008-12-19
 * @license http://www.gnu.org/licenses/lgpl-3.0.html LGPLv3 (LICENSE.TXT)
 * @copyright Copyright (C) 2008  Rubens Takiguti Ribeiro
 */
class hierarchy {


/// # CONSTANTS

    /**
     * CSS class names
     */
    const CSS_HIERARCHY        = 'hierarchy';
    const CSS_LEFT_LINE        = 'h_left';
    const CSS_LEFT_BOTTOM_LINE = 'h_left_bottom';
    const CSS_VALUE            = 'h_value';
    const CSS_CLEAR            = 'h_clear';
    const CSS_BUTTON_OPEN      = 'bt_open';


/// # METHODS


    /**
     * This class is not instantiable (use static methods only)
     */
    private function __construct() {}


    /**
     * Prints data hierarchicaly.
     * You should pass an array indexed by the content of items and
     * points to a boolean or an array value that indicates a sub-list.
     *
     * @param array[string => (bool || type)] $list List of data
     * @return string List disposed hierarchicaly
     */
    static public function print_list($list) {
        return self::print_list_recursion($list, true);
    }


    /**
     * Recursion of print_list method.
     *
     * @param array[string => (bool || type)] $list List of data
     * @param bool $first_call True if called by print_list, false oderwise
     */
    static private function print_list_recursion($list, $first_call = false) {
        $return = '';
        if (is_array($list)) {
            $length       = count($list);
            $arr_contents = array_keys($list);
            $arr_sublist  = array_values($list);
            unset($list);

            $class = $first_call ? ' class="'.self::CSS_HIERARCHY.'"' : '';
            $return = "<ul{$class}>\n";
            for ($i = 0; $i < $length; $i++) {
                $content = &$arr_contents[$i];
                $sublist = &$arr_sublist[$i];

                $class = ($i < ($length - 1)) ? ' class="'.self::CSS_LEFT_LINE.'"' : '';

                $return .= '<li>';
                $return .= '<span class="'.self::CSS_LEFT_BOTTOM_LINE.'">&nbsp;</span>';
                $return .= '<span'.$class.'>';
                $return .= '<span class="'.self::CSS_VALUE.'">';
                $return .= $content;
                if (is_array($sublist)) {
                    $return .= self::print_list_recursion($sublist);
                }
                $return .= '</span>';
                $return .= '</span>';
                $return .= "</li>\n";
            }
            $return .= "</ul>\n";
        }
        if ($first_call) {
            $return .= "<br class=\"".self::CSS_CLEAR."\" />\n";
        }
        return $return;
    }

}//class