<?php
// +----------------------------------------------------------------------
// | TOPThink [ WE CAN DO IT JUST THINK ]
// +----------------------------------------------------------------------
// | Copyright (c) 2011 http://topthink.com All rights reserved.
// +----------------------------------------------------------------------
// | Licensed ( http://www.apache.org/licenses/LICENSE-2.0 )
// +----------------------------------------------------------------------
// | Author: liu21st <liu21st@gmail.com>
// +----------------------------------------------------------------------

namespace Think\Model;

class Lite {
    // 当前数据库操作对象
    protected $db               =   null;
    // 数据库名称
    protected $dbName           =   '';
    //数据库配置
    protected $connection       =   '';
    // 数据表前缀
    protected $tablePrefix      =   '';
    // 数据表名（不包含表前缀）
    protected $tableName        =   '';
    // 实际数据表名（包含表前缀）
    protected $trueTableName    =   '';
    // 最近错误信息
    protected $error            =   '';
    // 配置参数
    protected $config =   [];

    /**
     * 架构函数
     * 取得DB类的实例对象 字段检查
     * @access public
     * @param string $name 模型名称
     * @param array $config 模型配置
     */
    public function __construct($name='',$config=[]) {
        // 传入模型参数
        if(!empty($name)){
            $this->name =   $name;
        }elseif(empty($this->name)){
            $this->name =   $this->getModelName();
        }
        if(strpos($this->name,'.')) { // 支持 数据库名.模型名的 定义
            list($this->dbName,$this->name) = explode('.',$this->name);
        }

        if(isset($config['table_prefix'])) {
            $this->tablePrefix  =   $config['table_prefix'];
        }
        if(isset($config['connection'])) {
            $this->connection   =   $config['connection'];
        }
        if(isset($config['table_name'])) {
            $this->tableName    =   $config['table_name'];
        }
        if(isset($config['true_table_name'])) {
            $this->trueTableName    =   $config['true_table_name'];
        }
        if(isset($config['db_name'])) {
            $this->dbName    =   $config['db_name'];
        }

        // 设置表前缀
        if(empty($this->tablePrefix)) {
            $this->tablePrefix  =   is_null($this->tablePrefix)?'':C('database.prefix');
        }

        // 数据库初始化操作
        // 获取数据库操作对象
        // 当前模型有独立的数据库连接信息
        $this->db(0,$this->connection);
    }

    /**
     * 得到当前的数据对象名称
     * @access public
     * @return string
     */
    public function getModelName() {
        if(empty($this->name))
            $this->name =   substr(get_class($this),0,-5);
        return $this->name;
    }

    /**
     * 得到完整的数据表名
     * @access public
     * @return string
     */
    public function getTableName() {
        if(empty($this->trueTableName)) {
            $tableName  = !empty($this->tablePrefix) ? $this->tablePrefix : '';
            if(!empty($this->tableName)) {
                $tableName .= $this->tableName;
            }else{
                $tableName .= parse_name($this->name);
            }
            $this->trueTableName    =   strtolower($tableName);
        }
        return (!empty($this->dbName)?$this->dbName.'.':'').$this->trueTableName;
    }


    /**
     * SQL查询
     * @access public
     * @param string $sql  SQL指令
     * @param array $binding  参数绑定
     * @return mixed
     */
    public function query($sql,$binding=[]) {
        $sql  =   $this->parseSql($sql);
        return $this->db->query($sql,$binding);
    }

    /**
     * 执行SQL语句
     * @access public
     * @param string $sql  SQL指令
     * @param array $binding  参数绑定
     * @return false | integer
     */
    public function execute($sql,$binding=[]) {
        $sql    =   $this->parseSql($sql);
        return $this->db->execute($sql,$binding);
    }

    /**
     * 解析SQL语句
     * @access public
     * @param string $sql  SQL指令
     * @return string
     */
    protected function parseSql($sql) {
        // 分析表达式
        $sql    =   strtr($sql,array('__TABLE__'=>$this->getTableName(),'__PREFIX__'=>$this->config['DB_PREFIX']));
        $this->db->setModel($this->name);
        return $sql;
    }

    /**
     * 切换当前的数据库连接
     * @access public
     * @param integer $linkNum  连接序号
     * @param mixed $config  数据库连接信息
     * @return Model
     */
    public function db($linkNum='',$config=''){
        if(''===$linkNum && $this->db) {
            return $this->db;
        }
        static $_linkNum    =   [];
        static $_db = [];
        if(!isset($_db[$linkNum]) || (isset($_db[$linkNum]) && $config && $_linkNum[$linkNum]!=$config) ) {
            // 创建一个新的实例
            if(!empty($config) && is_string($config) && false === strpos($config,'/')) { // 支持读取配置参数
                $config  =  Config::get($config);
            }
            $_db[$linkNum]            =    \Think\Db::instance($config,true);
        }elseif(NULL === $config){
            $_db[$linkNum]->close(); // 关闭数据库连接
            unset($_db[$linkNum]);
            return ;
        }
        // 记录连接信息
        $_linkNum[$linkNum] =   $config;
        // 切换数据库连接
        $this->db   =    $_db[$linkNum];
        return $this;
    }

    /**
     * 启动事务
     * @access public
     * @return void
     */
    public function startTrans() {
        $this->commit();
        $this->db->startTrans();
        return ;
    }

    /**
     * 提交事务
     * @access public
     * @return boolean
     */
    public function commit() {
        return $this->db->commit();
    }

    /**
     * 事务回滚
     * @access public
     * @return boolean
     */
    public function rollback() {
        return $this->db->rollback();
    }

    /**
     * 返回模型的错误信息
     * @access public
     * @return string
     */
    public function getError(){
        return $this->error;
    }

    /**
     * 返回数据库的错误信息
     * @access public
     * @return string
     */
    public function getDbError() {
        return $this->db->getError();
    }

    /**
     * 返回最后插入的ID
     * @access public
     * @return string
     */
    public function getLastInsID() {
        return $this->db->getLastInsID();
    }

    /**
     * 返回最后执行的sql语句
     * @access public
     * @return string
     */
    public function getLastSql() {
        return $this->db->getLastSql($this->name);
    }

}