<?php
/**
 * @author: 郭永磊 
 * @description: 数据库接口基类
 * @create date: 2015-8-13
 */

class DbBase{
	public $server;
	public $db;
	
	public $usedPrefix = false;
	
	private $_defaultServer;
	private $_defaultDb;
		
	private $_conn;
	private $_useDefaultServer = false;
	
	private $_queryString;
	
	public $dbTable = array();
	public $mappingName = "default"; //默认映射

	function __construct(){
		$this->_defaultServer = Yii::app()->params["default_server"];
		$this->_defaultDb = Yii::app()->params["default_db"];
		
		$this->_resetServer();
		
		$this->dbTable["default"] = " school_id = ".$this->_getSchoolId();
		
		$params = func_get_args();
		if($params){
			if(!empty($params[0]) && isset($params[1])){
				$this->db["name"] = $params[0];
				$this->_useDefaultServer = true;
				
				if(!empty($params[1]))
					$this->db["t_pre"] = $params[1];
			}
			else if(!empty($params[0]))
				$this->mappingName = $params[0];
		}
		else if($this->_getSchoolId() === false){
			$this->_useDefaultServer = true;
		}
		
		$this->_condition = $this->dbTable[$this->mappingName];
	}
	
	private function _getSchoolId(){
		return !empty(Yii::app()->session["school_id"]) ? Yii::app()->session["school_id"] : false;
	}
	
	private function _resetServer(){
		$this->server = $this->_defaultServer;
		$this->db = $this->_defaultDb;
	}
	
	private function _connect(){
		$dsn = "mysql:host={$this->server["addr"]};dbname={$this->db["name"]}";
		$this->_conn = new PDO($dsn, $this->server["username"], $this->server["password"]);
	}
	
	private function _connTrigger(){
		if(!is_object($this->_conn))
			$this->connect();
	}
	
	private function _connectTarget(){
		$this->_resetServer();
		$this->_connect();
		$sql = "select * from `{$this->_defaultDb["t_pre"]}{$this->_defaultDb["t_servers"]}` 
			where{$this->_condition}";
		$rs = $this->getRow($sql);
		
		if($rs){
			$this->server = array(
				"addr" => $rs["database_host"],
				"username" => $rs["database_user"],
				"password" => $rs["database_password"],
			);
			$this->db = array(
				"name" => $rs["database_name"],
				"t_pre" => isset($rs["t_pre"]) ? $rs["t_pre"] : "",
			);
			
			$this->_connect();
		}
	}
	
	
	public function connect(){
		if($this->_useDefaultServer)
			$this->_connect();
		else
			$this->_connectTarget();
	}
	
	private function _getSqlType($sql){
		$arr = explode(" ", trim(str_replace("　", " ", $sql)), 2);
		return strtolower($arr[0]);
	}
	
	private function _limit($offset, $limit){
		return $limit > 0 ? " limit {$offset}, {$limit}" : "";
	}
	
	private function _query($sql, $fetch = null, $offset = 0, $limit = -1){
		$this->_connTrigger();
		
		if(is_object($this->_conn) && $fetch){
			$sqlType = $this->_getSqlType($sql);
			
			if($this->usedPrefix)
				$sql = preg_replace("/{{(.*?)}}/", "{$this->db["t_pre"]}$1", $sql);
			
			if($sqlType === "select" || $sqlType === "show"){
				if($fetch === "ALL" && $limit > 0){
					$sql = preg_replace("/\s*limit[^\)]*$/i", "", $sql);
					$sql .= $this->_limit($offset, $limit);
				}
				
				$handle = $this->_conn->prepare($sql);
				$handle->execute();
				
				switch($fetch){
					case "ALL":
						$rs = $handle->fetchAll(PDO::FETCH_ASSOC);
					break;
					
					case "ROW":
						$rs = $handle->fetch(PDO::FETCH_ASSOC);
					break;
					
					case "COUNT":
						$rs = $handle->rowCount();
					break;
					
					case "HANDLE":
						$rs = $handle;
					break;
					
					default:
						$rs = false;
					break;
				}
			}
			else
				$rs = $this->_conn->exec($sql);
				
			return $rs;
		}
		
		return false;
	}
	
	public function getConn(){
		$this->_connTrigger();
		return $this->_conn;
	}
	
	public function exec($sql){
		$this->_connTrigger();
		return $this->_conn->exec($sql);
	}
	
	public function getHandle($sql){
		return $this->_query($sql, "HANDLE");
	}
	
	public function getRs($sql, $offset = 0, $limit = -1){
		return $this->_query($sql, "ALL", $offset, $limit);
	}
	
	public function getRow($sql){
		return $this->_query($sql, "ROW");
	}
	
	public function countRs($sql){
		return $this->_query($sql, "COUNT");
	}
	
	public function insert($tableName, $data){
		if($tableName && $data){
			$dimension = Arr::countDimension($data);
			
			if($dimension === 1){
				$fields = "";
				$values = "";
			
				foreach($data as $field => $val){
					$fields .= ",`{$field}`";
					$values .= ",'{$val}'";
				}
				$fields = substr($fields, 1);
				$values = substr($values, 1);
			
				$sql = "insert into `{$tableName}`({$fields}) values({$values})";
			}
			else if($dimension === 2){
				
			}
			
			return $this->exec($sql);
		}
		
		return false;
	}
}