<?php
declare (strict_types = 1);
namespace backup;
use think\facade\Db;
use think\facade\Config;
class Backup
{
    /**
     * 文件指针
     * @var resource
     */
    private $fp;
    
    /**
     * 备份文件信息 part - 卷号，name - 文件名
     * @var array
     */
    private $file;

    /**
     * 当前打开文件大小
     * @var integer
     */
    private $size = 0;
    /**
     * 数据库配置
     * @var integer
     */
    private $dbconfig=array();

    /**
     * 备份配置
     * @var integer
     */
    private $config=array(
        'path'     => './backup/',//数据库备份路径
        'part'     => 20971520,//数据库备份卷大小
        'compress' => 0,//数据库备份文件是否启用压缩 0不压缩 1 压缩
        'level'    => 9 //数据库备份文件压缩级别 1普通 4 一般  9最高
    );
    /**
     * 数据库备份构造方法
     * @param array  $file   备份或还原的文件信息
     * @param array  $config 备份配置信息
     */
    public function __construct($config=[]){
        $this->config = array_merge($this->config, $config);
        //初始化文件名
        $this->setFile();
        //初始化数据库连接参数
        $this->setDbConn();
        //检查文件是否可写
        if(!$this->checkPath($this->config['path'])){
            throw new \Exception("The current directory is not writable");
        }
    }

    /**
     * 设置数据库连接必备参数
     * @param array  $dbconfig   数据库连接配置信息
     * @return object 
     */
    public function setDbConn($dbconfig=[])
    {
        if (empty($dbconfig)) {
            $this->dbconfig = Config::get('database'); 
        }else{
            $this->dbconfig=$dbconfig;
        }
        return $this;
    }
    /**
     * 设置备份文件名
     * @param String  $file  文件名字
     * @return object 
     */
    public function setFile($file=null)
    {
        if(is_null($file)){
            $this->file=['name'=>date('Ymd-His'),'part'=>1];
        }else{
            if(!array_key_exists("name",$file) && !array_key_exists("part",$file)){
                $this->file=$file['1'];
            }else{
                $this->file=$file;
            }
           
        }
        return $this;
    }
    //数据类连接
    public static function connect()
    {
       return  Db::connect();
    }

    //数据库备份文件列表
    public function fileList()
    {
       if(!is_dir($this->config['path'])){
        mkdir($this->config['path'], 0755, true);
       }
       $path = realpath($this->config['path']);
       $flag = \FilesystemIterator::KEY_AS_FILENAME;
       $glob = new \FilesystemIterator($path,  $flag);
       $list = array();
       foreach ($glob as $name => $file) {
            if(preg_match('/^\d{8,8}-\d{6,6}-\d+\.sql(?:\.gz)?$/', $name)){
                $name = sscanf($name, '%4s%2s%2s-%2s%2s%2s-%d');

                $date = "{$name[0]}-{$name[1]}-{$name[2]}";
                $time = "{$name[3]}:{$name[4]}:{$name[5]}";
                $part = $name[6];

                if(isset($list["{$date} {$time}"])){
                    $info = $list["{$date} {$time}"];
                    $info['part'] = max($info['part'], $part);
                    $info['size'] = $info['size'] + $file->getSize();
                } else {
                    $info['part'] = $part;
                    $info['size'] = $file->getSize();
                }
                $extension        = strtoupper(pathinfo($file->getFilename(), PATHINFO_EXTENSION));
                $info['compress'] = ($extension === 'SQL') ? '-' : $extension;
                $info['time']     = strtotime("{$date} {$time}");

                $list["{$date} {$time}"] = $info;
            }
        }

       return $list;
    }
    public function getFile($type='',$time=0)
    {          //
        if(!is_numeric($time) ){
            throw new \Exception("{$time} Illegal data type");
        }
        switch ($type)
        {
            case 'time':
                $name  = date('Ymd-His', $time) . '-*.sql*';
                $path  = realpath($this->config['path']) . DIRECTORY_SEPARATOR . $name;
                return glob($path);
                break;
            case 'timeverif':
                $name  = date('Ymd-His', $time) . '-*.sql*';
                $path  = realpath($this->config['path']) . DIRECTORY_SEPARATOR . $name;
                $files = glob($path);
                $list  = array();
                foreach($files as $name){
                    $basename = basename($name);
                    $match    = sscanf($basename, '%4s%2s%2s-%2s%2s%2s-%d');
                    $gz       = preg_match('/^\d{8,8}-\d{6,6}-\d+\.sql.gz$/', $basename);
                    $list[$match[6]] = array($match[6], $name, $gz);
                }
                $last = end($list);
                if(count($list) === $last[0]){
                    return $list;
                } else {
                    throw new \Exception("File {$files['0']} may be damaged, please check again");
                }
               
                break;
            case 'pathname':
                return "{$this->config['path']}{$this->file['name']}-{$this->file['part']}.sql";
                break; 
            case 'filename':
                return "{$this->file['name']}-{$this->file['part']}.sql";
                break; 
            case 'filepath':
                return $this->config['path'];
                break;
            default:
                $arr=array(
                    'pathname'=>"{$this->config['path']}{$this->file['name']}-{$this->file['part']}.sql",
                    'filename'=>"{$this->file['name']}-{$this->file['part']}.sql",
                    'filepath'=>$this->config['path'],
                    'file'=>$this->file
                );
            return $arr;
        }
    }

    //删除备份文件
    public function delFile($time)
    {
        if($time){
            $file=$this->getFile('time',$time);
            array_map("unlink", $this->getFile('time',$time));
            if(count( $this->getFile('time',$time) )){
                throw new \Exception("File {$path} deleted failed");
            } else {
               return $time;
            }
        } else {
            throw new \Exception("{$time} Time parameter is incorrect");
        }
    }
    public function import($start){
        //还原数据
        $db =  self::connect();

        if($this->config['compress']){
            $gz   = gzopen($this->file[1], 'r');
            $size = 0;
        } else {
            $size = filesize($this->file[1]);
            $gz   = fopen($this->file[1], 'r');
        }

        $sql  = '';
        if($start){
            $this->config['compress'] ? gzseek($gz, $start) : fseek($gz, $start);
        }
        for($i = 0; $i < 1000; $i++){
            $sql .= $this->config['compress'] ? gzgets($gz) : fgets($gz); 
            if(preg_match('/.*;$/', trim($sql))){
                if(false !== $db->execute($sql)){
                    $start += strlen($sql);
                } else {
                    return false;
                }
                $sql = '';
            } elseif ($this->config['compress'] ? gzeof($gz) : feof($gz)) {
                return 0;
            }
        }

        return array($start, $size);
    }


    //数据库表列表
    public function dataList($table=null)
    {
        $db = self::connect();
        
        if(is_null($table)){
            $list = $db->query("SHOW TABLE STATUS");
        }else{
            $list = $db->query("show columns from {$table}");
        }
        return  array_map('array_change_key_case', $list);//$list;
    }
    /**
     * 写入初始数据
     * @return boolean true - 写入成功，false - 写入失败
     */
    public function Backup_Init(){
        $sql  = "-- -----------------------------\n";
        $sql .= "-- Think MySQL Data Transfer \n";
        $sql .= "-- \n";
        $sql .= "-- Host     : " .$this->dbconfig['hostname']. "\n";
        $sql .= "-- Port     : " .$this->dbconfig['hostport']. "\n";
        $sql .= "-- Database : " .$this->dbconfig['database']. "\n";
        $sql .= "-- \n";
        $sql .= "-- Part : #{$this->file['part']}\n";
        $sql .= "-- Date : " . date("Y-m-d H:i:s") . "\n";
        $sql .= "-- -----------------------------\n\n";
        $sql .= "SET FOREIGN_KEY_CHECKS = 0;\n\n";
        return  $this->write($sql);
    }

    /**
     * 备份表结构
     * @param  string  $table 表名
     * @param  integer $start 起始行数
     * @return boolean        false - 备份失败
     */
    public function backup($table, $start){

        $db = self::connect();
        // 备份表结构
        if(0 == $start){
            $result = $db->query("SHOW CREATE TABLE `{$table}`");
            $sql  = "\n";
            $sql .= "-- -----------------------------\n";
            $sql .= "-- Table structure for `{$table}`\n";
            $sql .= "-- -----------------------------\n";
            $sql .= "DROP TABLE IF EXISTS `{$table}`;\n";

            $sql .= trim($result[0]['Create Table']) . ";\n\n";

            if(false === $this->write($sql)){
                return false;
            }
        }

        //数据总数
        $result = $db->query("SELECT COUNT(*) AS count FROM `{$table}`");
       
        $count  = $result['0']['count'];
            
        //备份表数据
        if($count){
            //写入数据注释
            if(0 == $start){
                $sql  = "-- -----------------------------\n";
                $sql .= "-- Records of `{$table}`\n";
                $sql .= "-- -----------------------------\n";
                $this->write($sql);
            }

            //备份数据记录
            $result = $db->query("SELECT * FROM `{$table}` LIMIT {$start}, 1000");
            foreach ($result as $row) {
                $row = array_map('addslashes', $row);
                $sql = "INSERT INTO `{$table}` VALUES ('" . str_replace(array("\r","\n"),array('\r','\n'),implode("', '", $row)) . "');\n";
                if(false === $this->write($sql)){
                    return false;
                }
            }

            //还有更多数据
            if($count > $start + 1000){
                return array($start + 1000, $count);
            }
        }
        //备份下一表
        return 0;
    }
    /**
     * 优化表
     * @param  String $tables 表名
     * @return String $tables  
     */
    public function optimize($tables = null){
        if($tables) {
            $db = self::connect();
            if(is_array($tables)){
                $tables = implode('`,`', $tables);
                $list = $db->query("OPTIMIZE TABLE `{$tables}`");
            } else {
                $list = $db->query("OPTIMIZE TABLE `{$tables}`");
            }
            if($list){
                return $tables;
            } else {
                throw new \Exception("data sheet'{$tables}'Repair mistakes please try again!");
            }
        } else {
            throw new \Exception("Please specify the table to be repaired!");
        }
    }
    /**
     * 修复表
     * @param  String $tables 表名
     * @return String $tables  
     */
    public function repair($tables = null){
        if($tables) {
            $db = self::connect();
            if(is_array($tables)){
                $tables = implode('`,`', $tables);
                $list = $db->query("REPAIR TABLE `{$tables}`");
            } else {
                $list =  $db->query("REPAIR TABLE `{$tables}`");
            }
            if($list){
                return $list;
            } else {
                throw new \Exception("data sheet'{$tables}'Repair mistakes please try again!");
            }
        } else {
            throw new \Exception("Please specify the table to be repaired!");
        }
    }

    /**
     * 写入SQL语句
     * @param  string $sql 要写入的SQL语句
     * @return boolean     true - 写入成功，false - 写入失败！
     */
    private function write($sql){
        $size = strlen($sql);
        //由于压缩原因，无法计算出压缩后的长度，这里假设压缩率为50%，
        //一般情况压缩率都会高于50%；
        $size = $this->config['compress'] ? $size / 2 : $size;
        $this->open($size); 
        return $this->config['compress'] ? @gzwrite($this->fp, $sql) : @fwrite($this->fp, $sql);
    }
    /**
     * 打开一个卷，用于写入数据
     * @param  integer $size 写入数据的大小
     */
    private function open($size){
        if($this->fp){
            $this->size += $size;
            if($this->size > $this->config['part']){
                $this->config['compress'] ? @gzclose($this->fp) : @fclose($this->fp);
                $this->fp = null;
                $this->file['part']++;
                session('backup_file', $this->file);
                $this->create();
            }
        } else {
            $backuppath = $this->config['path'];
            $filename   = "{$backuppath}{$this->file['name']}-{$this->file['part']}.sql";
            if($this->config['compress']){
                $filename = "{$filename}.gz";
                $this->fp = @gzopen($filename, "a{$this->config['level']}");
            } else {
                $this->fp = @fopen($filename, 'a');
            }
            $this->size = filesize($filename) + $size;
        }
    }
    /**
     * 检查目录是否可写
     * @param  string   $path    目录
     * @return boolean
     */
    protected function checkPath($path)
    {
        if (is_dir($path)) {
            return true;
        }
        if (mkdir($path, 0755, true)) {
            return true;
        } else {
            return false;
        }
    }
    /**
     * 析构方法，用于关闭文件资源
     */
    public function __destruct(){
        if($this->fp){
            $this->config['compress'] ? @gzclose($this->fp) : @fclose($this->fp);
        }        
    }

}