<?php
/**
 * Abstract dump file: provides common interface for writing
 * data to dump files.
 */

abstract class WPR_Shuttle_Dump_File {
	/**
	 * File Handle
	 */
	protected $fh;

	/**
	 * Location of the dump file on the disk
	 */
	protected $file_location;

	abstract function write($string);
	abstract function end();

	static function create($filename) {
		if (self::is_gzip($filename)) {
			return new WPR_Shuttle_Dump_File_Gzip($filename);
		}
		return new WPR_Shuttle_Dump_File_Plaintext($filename);
	}
	function __construct($file) {
		$this->file_location = $file;
		$this->fh = $this->open();

		if (!$this->fh) {
			throw new WPR_Shuttle_Exception("Couldn't write SQL export file");
		}
	}

	public static function is_gzip($filename) {
		return preg_match('~gz$~i', $filename);
	}
}

/**
 * Plain text implementation. Uses standard file functions in PHP.
 */
class WPR_Shuttle_Dump_File_Plaintext extends WPR_Shuttle_Dump_File {
	function open() {
		return fopen($this->file_location, 'a'); //phpcs:ignore
	}
	function write($string) {
		return fwrite($this->fh, $string); //phpcs:ignore
    }
    
	function end() {
		return fclose($this->fh); //phpcs:ignore
	}
}

/**
 * Gzip implementation. Uses gz* functions.
 */
class WPR_Shuttle_Dump_File_Gzip extends WPR_Shuttle_Dump_File {
	function open() {
		return gzopen($this->file_location, 'a');
	}
	function write($string) {
		return gzwrite($this->fh, $string);
    }
	function end() {
		return gzclose($this->fh);
	}
}

/**
 * MySQL insert statement builder.
 */
class WPR_Shuttle_Insert_Statement {
	private $rows = array();
	private $length = 0;
	private $table;

	function __construct($table) {
		$this->table = $table;
	}

	function reset() {
		$this->rows = array();
		$this->length = 0;
	}

	function add_row($row) {
		$row = '(' . implode(",", $row) . ')';
		$this->rows[] = $row;
		$this->length += strlen($row);
	}

	function get_sql() {
		if (empty($this->rows)) {
			return false;
		}

		return 'INSERT INTO `' . $this->table . '` VALUES ' .
			implode(",\n", $this->rows) . ';';
	}

	function get_length() {
		return $this->length;
	}
}

/**
 * Main facade
 */
abstract class WPR_Shuttle_Dumper {
	/**
	 * Maximum length of single insert statement
	 */
	const INSERT_THRESHOLD = 838860;

	/**
	 * @var WPR_Shuttle_DBConn
	 */
	public $db;

	/**
	 * @var WPR_Shuttle_Dump_File
	 */
	public $dump_file;

	/**
	 * End of line style used in the dump
	 */
	public $eol = "\r\n";

	/**
	 * Specificed tables to include
	 */
	public $include_tables;

	/**
	 * Specified tables to exclude
	 */
	public $exclude_tables = array();

	/**
	 * Factory method for dumper on current hosts's configuration.
	 */
	static function create($db_options) {
		$db = WPR_Shuttle_DBConn::create($db_options);

		$db->connect();

		if (self::has_shell_access()
				&& self::is_shell_command_available('mysqldump')
				&& self::is_shell_command_available('gzip')
			) {
			$dumper = new WPR_Shuttle_Dumper_ShellCommand($db);
		} else {
			$dumper = new WPR_Shuttle_Dumper_Native($db);
		}

		if (isset($db_options['include_tables'])) {
			$dumper->include_tables = $db_options['include_tables'];
		}
		if (isset($db_options['exclude_tables'])) {
			$dumper->exclude_tables = $db_options['exclude_tables'];
		}

		return $dumper;
	}

	function __construct(WPR_Shuttle_DBConn $db) {
		$this->db = $db;
	}

	public static function has_shell_access() {
		if (!is_callable('shell_exec')) {
			return false;
		}
		$disabled_functions = ini_get('disable_functions');
		return stripos($disabled_functions, 'shell_exec') === false;
	}

	public static function is_shell_command_available($command) {
		if (preg_match('~win~i', PHP_OS)) {
			/*
			On Windows, the `where` command checks for availabilty in PATH. According
			to the manual(`where /?`), there is quiet mode:
			....
			    /Q       Returns only the exit code, without displaying the list
			             of matched files. (Quiet mode)
			....
			*/
			$output = array();
			exec('where /Q ' . $command, $output, $return_val);

			if (intval($return_val) === 1) {
				return false;
			} else {
				return true;
			}

		} else {
			$last_line = exec('which ' . $command);
			$last_line = trim($last_line);

			// Whenever there is at least one line in the output,
			// it should be the path to the executable
			if (empty($last_line)) {
				return false;
			} else {
				return true;
			}
		}

	}

	/**
	 * Create an export file from the tables with that prefix.
	 * @param string $export_file_location the file to put the dump to.
	 *		Note that whenever the file has .gz extension the dump will be comporessed with gzip
	 * @param string $table_prefix Allow to export only tables with particular prefix
	 * @return void
	 */
	abstract public function dump($export_file_location, $table_prefix='');

	protected function get_tables($table_prefix) {
		if (!empty($this->include_tables)) {
			return $this->include_tables;
		}


		// $tables will only include the tables and not views.
		// TODO - Handle views also, edits to be made in function 'get_create_table_sql' line 336
        if(substr($table_prefix, -1) == '_'){
          $tables = $this->db->fetch_numeric('
			SHOW FULL TABLES WHERE Table_Type = "BASE TABLE" AND `Tables_in_'.$this->db->name.'` LIKE "' . $this->db->escape_like($table_prefix) . '%"
		  ');
        } else {
          $tables = $this->db->fetch_numeric('
			SHOW FULL TABLES WHERE Table_Type = "BASE TABLE" AND `Tables_in_'.$this->db->name.'` LIKE "' . $this->db->escape_like($table_prefix) . '"
		  ');
        }

		$tables_list = array();
		foreach ($tables as $table_row) {
			$table_name = $table_row[0];
			if (!in_array($table_name, $this->exclude_tables)) {
				$tables_list[] = $table_name;
			}
		}
		return $tables_list;
	}
}

class WPR_Shuttle_Dumper_ShellCommand extends WPR_Shuttle_Dumper {
	function dump($export_file_location, $table_prefix='') {
        global $wp_reset;
        $wp_reset->log('success', 'Dump table ' . $table_prefix . ' via shell to ' . $export_file_location);
        $command = 'mysqldump --max_allowed_packet=1000000000 -h ' . escapeshellarg($this->db->host) .
            ' --port=' . escapeshellarg($this->db->port) .
			' -u ' . escapeshellarg($this->db->username) .
			' --password=' . escapeshellarg($this->db->password) .
			' ' . escapeshellarg($this->db->name);

		$include_all_tables = empty($table_prefix) &&
			empty($this->include_tables) &&
			empty($this->exclude_tables);

		if (!$include_all_tables) {
			$tables = $this->get_tables($table_prefix);
			$command .= ' ' . implode(' ', array_map('escapeshellarg', $tables));
		}

		$error_file = tempnam(sys_get_temp_dir(), 'err');

		$command .= ' 2> ' . escapeshellarg($error_file);

		if (WPR_Shuttle_Dump_File::is_gzip($export_file_location)) {
			$command .= ' | gzip';
		}

		$command .= ' >> ' . escapeshellarg($export_file_location);

		exec($command, $output, $return_val);

		if ($return_val !== 0) {
            $error_text = file_get_contents($error_file);
            $wp_reset->log('error', 'Dump error ' . $error_text);
        
			wp_delete_file($error_file);
			throw new WPR_Shuttle_Exception(esc_html('Couldn\'t export database: ' . $error_text));
		}

		wp_delete_file($error_file);
	}
}

class WPR_Shuttle_Dumper_Native extends WPR_Shuttle_Dumper {
	public function dump($export_file_location, $table_prefix='') {
		global $wp_reset;
        $eol = $this->eol;
        
        $wp_reset->log('success', 'Exporting ' . $table_prefix . ' to ' . $export_file_location . ' which has a size of ' . (file_exists($export_file_location)?filesize($export_file_location):'0'));

		$this->dump_file = WPR_Shuttle_Dump_File::create($export_file_location);

		$this->dump_file->write("-- Generation time: " . gmdate('r') . $eol); //phpcs:ignore
        $this->dump_file->write("-- Host: " . $this->db->host . $eol); //phpcs:ignore
        $this->dump_file->write("-- Port: " . $this->db->port . $eol); //phpcs:ignore
		$this->dump_file->write("-- DB name: " . $this->db->name . $eol); //phpcs:ignore
		$this->dump_file->write("-- WP Reset ver: " . $wp_reset->get_plugin_version() . $eol); //phpcs:ignore
		$this->dump_file->write("-- Table Prefix: " . $table_prefix . $eol); //phpcs:ignore
		$this->dump_file->write("/*!40030 SET NAMES UTF8 */;$eol"); 

		$this->dump_file->write("/*!40101 SET @OLD_CHARACTER_SET_CLIENT=@@CHARACTER_SET_CLIENT */;$eol");
		$this->dump_file->write("/*!40101 SET @OLD_CHARACTER_SET_RESULTS=@@CHARACTER_SET_RESULTS */;$eol");
		$this->dump_file->write("/*!40101 SET @OLD_COLLATION_CONNECTION=@@COLLATION_CONNECTION */;$eol");
		$this->dump_file->write("/*!40103 SET @OLD_TIME_ZONE=@@TIME_ZONE */;$eol");
		$this->dump_file->write("/*!40103 SET TIME_ZONE='+00:00' */;$eol");
		$this->dump_file->write("/*!40014 SET @OLD_UNIQUE_CHECKS=@@UNIQUE_CHECKS, UNIQUE_CHECKS=0 */;$eol");
		$this->dump_file->write("/*!40014 SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0 */;$eol");
		$this->dump_file->write("/*!40101 SET @OLD_SQL_MODE=@@SQL_MODE, SQL_MODE='NO_AUTO_VALUE_ON_ZERO' */;$eol");
		$this->dump_file->write("/*!40111 SET @OLD_SQL_NOTES=@@SQL_NOTES, SQL_NOTES=0 */;$eol$eol");


		$tables = $this->get_tables($table_prefix);
		foreach ($tables as $table) {
			$this->dump_table($table);
		}

		$this->dump_file->write("$eol$eol");
		$this->dump_file->write("/*!40101 SET SQL_MODE=@OLD_SQL_MODE */;$eol");
		$this->dump_file->write("/*!40014 SET FOREIGN_KEY_CHECKS=@OLD_FOREIGN_KEY_CHECKS */;$eol");
		$this->dump_file->write("/*!40014 SET UNIQUE_CHECKS=@OLD_UNIQUE_CHECKS */;$eol");
		$this->dump_file->write("/*!40101 SET CHARACTER_SET_CLIENT=@OLD_CHARACTER_SET_CLIENT */;$eol");
		$this->dump_file->write("/*!40101 SET CHARACTER_SET_RESULTS=@OLD_CHARACTER_SET_RESULTS */;$eol");
		$this->dump_file->write("/*!40101 SET COLLATION_CONNECTION=@OLD_COLLATION_CONNECTION */;$eol");
		$this->dump_file->write("/*!40111 SET SQL_NOTES=@OLD_SQL_NOTES */;$eol$eol");
        
        $this->dump_file->end();
        $wp_reset->log('success', 'Closed export of ' . $table_prefix . ' to ' . $export_file_location . ' which has a size of ' . filesize($export_file_location));
		unset($this->dump_file);
	}

	protected function dump_table($table) {
        global $wp_reset;
        $eol = $this->eol;
        $wp_reset->log('success', 'Dump table ' . $table);
		
		$this->dump_file->write("DROP TABLE IF EXISTS `$table`;$eol");

		$create_table_sql = $this->get_create_table_sql($table);
		$this->dump_file->write($create_table_sql . $eol . $eol);

		$data = $this->db->query("SELECT * FROM `$table`");

		$insert = new WPR_Shuttle_Insert_Statement($table);

		while ($row = $this->db->fetch_row($data)) {
			$row_values = array();
			foreach ($row as $value) {
				$row_values[] = $this->db->escape($value);
			}
			$insert->add_row( $row_values );

			if ($insert->get_length() > self::INSERT_THRESHOLD) {
				// The insert got too big: write the SQL and create
				// new insert statement
				$this->dump_file->write($insert->get_sql() . $eol);
				$insert->reset();
			}
		}

		$sql = $insert->get_sql();
		if ($sql) {
			$this->dump_file->write($insert->get_sql() . $eol);
		}
		$this->dump_file->write($eol . $eol);
	}

	public function get_create_table_sql($table) {
		$create_table_sql = $this->db->fetch('SHOW CREATE TABLE `' . $table . '`');
		return $create_table_sql[0]['Create Table'] . ';';
	}
}

class WPR_Shuttle_DBConn {
	public $host;
	public $port;
	public $username;
	public $password;
	public $name;

	protected $connection;

	function __construct($options) {
		$this->host = $options['host'];
		if (empty($this->host)) {
			$this->host = '127.0.0.1';
        }
        
        $this->port = $options['port'];
		if (empty($this->port)) {
			$this->port = '3306';
        }
        
		$this->username = $options['username'];
		$this->password = $options['password'];
		$this->name = $options['db_name'];
	}

	static function create($options) {
		if (class_exists('mysqli')) {
			$class_name = "WPR_Shuttle_DBConn_Mysqli";
		} else {
			$class_name = "WPR_Shuttle_DBConn_Mysql";
		}

		return new $class_name($options);
	}
}

class WPR_Shuttle_DBConn_Mysql extends WPR_Shuttle_DBConn {
	function connect() {
		$this->connection = @mysql_connect($this->host, $this->username, $this->password); //phpcs:ignore
		if (!$this->connection) {
			throw new WPR_Shuttle_Exception(esc_html("Couldn't connect to the database: " . mysql_error())); //phpcs:ignore
		}

		$select_db_res = mysql_select_db($this->name, $this->connection); //phpcs:ignore
		if (!$select_db_res) {
			throw new WPR_Shuttle_Exception(esc_html("Couldn't select database: " . mysql_error($this->connection))); //phpcs:ignore
		}

		return true;
	}

	function query($q) {
		if (!$this->connection) {
			$this->connect();
		}
		$res = mysql_query($q); //phpcs:ignore
		if (!$res) {
			throw new WPR_Shuttle_Exception(esc_html("SQL error: " . mysql_error($this->connection))); //phpcs:ignore
		}
		return $res;
	}

	function fetch_numeric($query) {
		return $this->fetch($query, MYSQL_NUM);
	}

	function fetch($query, $result_type=MYSQL_ASSOC) {
		$result = $this->query($query, $this->connection);
		$return = array();
		while ( $row = mysql_fetch_array($result, $result_type) ) { //phpcs:ignore
			$return[] = $row;
		}
		return $return;
	}

	function escape($value) {
		if (is_null($value)) {
			return "NULL";
		}
		return "'" . mysql_real_escape_string($value) . "'"; //phpcs:ignore
	}

	function escape_like($search) {
		return str_replace(array('_', '%'), array('\_', '\%'), $search);
	}

	function get_var($sql) {
		$result = $this->query($sql);
		$row = mysql_fetch_array($result); //phpcs:ignore
		return $row[0];
	}

	function fetch_row($data) {
		return mysql_fetch_assoc($data); //phpcs:ignore
	}
}


class WPR_Shuttle_DBConn_Mysqli extends WPR_Shuttle_DBConn {
	function connect() {
		$this->connection = @new MySQLi($this->host, $this->username, $this->password, $this->name); //phpcs:ignore

		if ($this->connection->connect_error) {
			throw new WPR_Shuttle_Exception(esc_html("Couldn't connect to the database: " . $this->connection->connect_error));
		}

		return true;
	}

	function query($q) {
		if (!$this->connection) {
			$this->connect();
		}
		$res = $this->connection->query($q);

		if (!$res) {
			throw new WPR_Shuttle_Exception(esc_html("SQL error: " . $this->connection->error));
		}

		return $res;
	}

	function fetch_numeric($query) {
		return $this->fetch($query, MYSQLI_NUM);
	}

	function fetch($query, $result_type=MYSQLI_ASSOC) {
		$result = $this->query($query, $this->connection);
		$return = array();
		while ( $row = $result->fetch_array($result_type) ) {
			$return[] = $row;
		}
		return $return;
	}

	function escape($value) {
		if (is_null($value)) {
			return "NULL";
		}
		return "'" . $this->connection->real_escape_string($value) . "'";
	}

	function escape_like($search) {
		return str_replace(array('_', '%'), array('\_', '\%'), $search);
	}

	function get_var($sql) {
		$result = $this->query($sql);
		$row = $result->fetch_array($result, MYSQLI_NUM);
		return $row[0];
	}

	function fetch_row($data) {
		return $data->fetch_array(MYSQLI_ASSOC);
	}
}

class WPR_Shuttle_Exception extends Exception {};
