<?php
/**
 +------------------------------------------------------------------------------
 * Tree 构建tree状数据
 +------------------------------------------------------------------------------
 * @author    [email protected]
 * @version   v1.1
 +------------------------------------------------------------------------------
 */
class Tree
{
    /**
     * 主键名称
     * @var string
     */
    private static $primary = 'id';

    /**
     * 父键名称
     * @var string
     */
    private static $parentId = 'parent_id';

    /**
     * 子节点名称
     * @var string
     */
    private static $child    = 'child';

    /**
     * 修改主键名称、父键名称、子节点名称
     * @param string $primary
     * @param string $parentId
     * @param string $child
     */
    public static function setConfig($primary = '', $parentId = '', $child = ''){
        if(!empty($primary))  self::$primary  = $primary;
        if(!empty($parentId)) self::$parentId = $parentId;
        if(!empty($child))    self::$child    = $child;
    }

    /**
     * 生成Tree
     * @param array $data
     * @param number $index
     * @return array
     */
    public static  function  makeTree(&$data, $index = 0)
    {
        $childs = self::findChild($data, $index);
        if(empty($childs))
        {
            return $childs;
        }
        foreach($childs as $k => &$v)
        {
            if(empty($data)) break;
            $child = self::makeTree($data, $v[self::$primary]);
            if(!empty($child))
            {
                $v[self::$child] = $child;
            }
        }
        unset($v);
        return $childs;
    }

    /**
     * 查找子类
     * @param array $data
     * @param number $index
     * @return array
     */
    public static function findChild(&$data, $index)
    {
        $childs = [];
		foreach ($data as $k => $v){
			if($v[self::$parentId] == $index){
				$childs[]  = $v;
                unset($v);
			}
		}
		return $childs;
    }
}