<?php
/**
 * ArchiveCategroy - 文档分类类
 */

class ArchiveCategory
{
	//PDO对象
	private $db;
	
	//数据库中分类表
	public $CategoryTable;
	
	//分类左值字段名称
	private $fld_left;
	
	//分类右值字段名称
	private $fld_right;
	
	//顶级栏目标记字段
	private $fld_tid;
	
	//输出栏目中的深度信息
	public $DeepTitle;
	
	function  __construct($db){
		$this->db = $db;
		$this->CategoryTable = "ar_category";
		$this->fld_left = "lft";
		$this->fld_right = "rgt";
		$this->fld_tid = "tid";
		$this->DeepTitle = "DEEP";
	}
	
	function GetFullCategory()
	{
		return $this->GetCategory(0,'');
	}
	
	/**
     * GetTree() 获得栏目树
     * 用来获得某个栏目下或者所有栏目的树结构
	 *
	 * 典型表结构
	 * (PostgreSql)
	 * 
	 	 CREATE TABLE ar_category
		(
		  id serial NOT NULL,
		  title character varying(80),
		  tid integer NOT NULL DEFAULT 0,
		  lft integer NOT NULL DEFAULT 0,
		  rgt integer NOT NULL DEFAULT 0,
		  CONSTRAINT ar_category_pkey PRIMARY KEY (id)
		)
     *
     * @param int $tid
	 *
     * @return array;
     */
	function GetCategory($tid=0,$ptype='news'){
		
		$left = $this->fld_left;
		$right = $this->fld_right;
		$categoryTable = $this->CategoryTable;
		$tidField = $this->fld_tid;
		
		$whereSql = array();
		
		if(!empty($tid))
		{
			$sql = "SELECT $left,$right FROM $categoryTable
					WHERE id=$tid";
			$sth = $this->db->query($sql);
			$row = $sth->fetch();
			$whereSql[] = " $left BETWEEN {$row[$left]} AND {$row[$right]} ";
		}
		
		if(count($whereSql)>0)
		{
			$whereSql = " WHERE ".join(" AND ",$whereSql);
		}elseif ($ptype<>''){
			$whereSql = " where ptype='$ptype' ";
		} else 
		 $whereSql='';
		
		
		$sql = "SELECT * 
				FROM $categoryTable
				$whereSql
				ORDER BY $left ASC ";
		$sth = $this->db->query($sql);
		$rows = $sth->fetchAll();
		
		$stack = array();
		$categorys = array();
		
		foreach($rows as $k=>$v)
		{
			/*
			如果它是一个顶级栏目，则为它重置深度
			*/
			if(empty($v[$tidField]))
			{
				$stack = array();
			}else{
				if(count($stack) > 1)
				{
					/*
					在这个循环中必须追溯直至与其平级的分类
					while循环无法重写条件中已经改变的变量
					第一次max(array_keys($stack))赋值为当前深度
					循环中的第一个if里max(array_keys($stack))是重新统计，而非使用一定义的
					因为第二次循环到此时可能max(array_keys($stack))已经发生改变
					第三处max(array_keys($stack))表示第一个if中没有break掉的深度值，所以也不能使用赋过值的变量代替。
					
					加入brake 可使程序追溯至平级栏目即进行下一步操作
					必须是倒序循环，多个平级栏目时，如果是正序列循环会到第一个平级的栏目后停止循环
					*/
					for($i=max(array_keys($stack));$i>=0;$i--)
					if($v[$right]>$stack[max(array_keys($stack))])
					{
						if(count($stack)<1)
						{
							break;
						}
						if($v[$right]>$stack[max(array_keys($stack))])
						{
							array_pop($stack);
						}else{
							break;
						}
					}//end if
				}//end if
			}

			//放入输出数组
			$rows[$k][$this->DeepTitle] = count($stack);
			
			//将此节点加入栈中
			$stack[] = $v[$right];
			
		}// end foreach
		
		return $rows;
		
	}
	
	/**
     * Insert() 插入一个栏目
	 * 返回数组 left=>左值 right=>右值
	 * 
	 *
     * @param int $tid
	 *
     * @return array
     */
	function Insert($tid){
		
		$left = $this->fld_left;
		$right = $this->fld_right;
		$categoryTable = $this->CategoryTable;
		
		//分别处理有上级栏目和没上级栏目的
		if(!empty($tid))
		{
			$sql = "SELECT $right
					FROM $categoryTable 
					WHERE id=$tid";
			$sth = $this->db->query($sql);
			$row = $sth->fetch();
			$right_start = $row[$right]-1;
			
			//更新所有右值
			$sql = "UPDATE $categoryTable SET $right=$right+2 WHERE $right>$right_start";
			$this->db->exec($sql);
			
			//更新所有左值
			$sql = "UPDATE $categoryTable SET $left=$left+2 WHERE $left>$right_start";
			$this->db->exec($sql);	
			
			//返回应该插入的左右值
			$lft = $right_start + 1;
			$rgt = $lft + 1;
			return array(
				'left'=>$lft,
				'right'=>$rgt
				);
					
		}else{
			//取最大的右值
			$sql = "SELECT $right
					FROM $categoryTable
					WHERE tid=0
					ORDER BY $left DESC LIMIT 1";
					
			$sth = $this->db->query($sql);
			$row = $sth->fetch();
			$right_start = $row[$right]-1;
			
			if($right_start<1)
			{
				return array(
					'left'=>1,
					'right'=>2
					);
			}
			
			$lft = $right_start + 2;
			$rgt = $lft + 1;
			return array(
				'left'=>$lft,
				'right'=>$rgt
				);
		}

	}//Insert
	
	//获取栏目路径
	function GetRouter($lft,$rgt){
		$sql = "SELECT * FROM ".$this->CategoryTable." 
				WHERE ".$this->fld_left." < $lft AND ".$this->fld_right." > $rgt
				ORDER BY ".$this->fld_left." ASC;";
		$sth = $this->db->query($sql);
		$rows = $sth->fetchAll();
		return $rows;
	}
	
	function GetSunCount($left,$right){
		return ($right-$left-1)/2;
	}
	
	//获取一个栏目
	function GetOne($tid){
		
		$sql = "SELECT * FROM ".$this->CategoryTable." WHERE id=$tid";
		$sth = $this->db->query($sql);
		return $sth->fetch();
		
	}//GetOne
	
}