<?php
/**
 * MySQL IWP Database Backup Script
 *
 * Place in admin/temp/ and run twice.
 * The first time it will generate backup.sql.
 * The second time it will gzip backup.sql if possible.
 *
 * @author Michael Knight <michael.knight@interspire.com>
 
 * @package IWP
 * @subpackage Backup
 */

/**
 * MySQL Database Backup Class
 *
 * It uses mysqldump if possible, then falls back to a manual method.
 *
 * This class is generic and can be used to backup any MySQL database.
 *
 * @package IWP
 * @subpackage Backup
 */
class iwp_backup extends iwp_base
{
	/**
	 * @var string The name of the backup file to write to. This should include the full path to the file.
	 */
	public $backupFile = '';

	/**
	 * @var integer The current progress of the database export'
	 */
	public $progress = 0;

	/**
	* This is the JS function to call in the parent document to update the progress percentage
	*
	* @var string
	*/
	public $jsProgressFunction = "Upgrade.UpdateProgress";

	/**
	 * Instance
	 * This static variable holds the current instance of this object being loaded.
	 * So using the getInstance function anywhere will return the very same instance.
	 *
	 * @var object Instance
	 */
	public static $Instance;

	/**
	 * getInstance
	 * This is a static function that sets up the class instance and stores it to the static variable. It will then return that instantiation in the future.
	 *
	 * @return iwp_admin_home Returns the instantiated object
	 **/
	public static function getInstance(){
		if(!isset(self::$Instance)){
			self::$Instance = new self();
		}
		return self::$Instance;
	}

	/**
	 * This function writes data to the currently defined backup file. It will only ever append to the current file.
	 *
	 * @param mixed $data The data to write to the file.
	 *
	 * @return void
	 * @see $backupFile
	 */
	private function DumpSQL($data){
		file_put_contents($this->backupFile, $data, FILE_APPEND);
	}

	/**
	 * GetFields
	 *
	 * Return all the field names of the table as an array
	 *
	 * @param mixed $table
	 * @return void
	 */

	public function GetFields($table) {
		$query = "SHOW COLUMNS FROM " . $table;
		$result = $this->db->Query($query);
		$fields = array();
		while ($row = $this->db->Fetch($result)) {
			$fields[] = $row['Field'];
		}
		return $fields;
	}

	/**
	 * This function determines whether or not the current value need to be escaped or not.
	 *
	 * @param mixed $value The value to test and be escaped
	 *
	 * @return mixed Either the numeric value or an escaped string
	 */

	public function EscapeValue($value){
		if(is_numeric($value)){
			return $value;
		}
		return "'".$this->db->Quote($value)."'";
	}

	/**
	 * Returns the create table definition for a table
	 *
	 * @param mixed $table
	 * @return string
	 */
	function GetCreateTable($table) {
		$query = "SHOW CREATE TABLE ". $table;
		$result = $this->db->Query($query);
		$row = $this->db->Fetch($result);
		return $row['Create Table'] . ";\n";
	}

	/**
	 * This function makes a backup file of all the database tables with the application prefix
	 *
	 * @param boolean $outputMode Whether or not to output the progress of the export. This is used only for the upgrade wizard.
	 *
	 * @return string
	 */
	public function DumpMySQLDatabase($outputMode=false, $tables=null){
		$start_time = microtime_float();
		$encoded = $output = '';

		if(is_null($tables)) {
			$queryTables = $this->db->Query("show tables like '" . iwp_config::Get('tablePrefix') . "%'");
			$tables = array();
			while ($tableRow = $this->db->Fetch($queryTables)) {
				$tables[] = array_pop($tableRow);
			}
		}

		$count = $this->db->CountResult($queryTables);

		$percentIncrement = (100 / (max($count, 0.1)));

		foreach($tables as $table) {
			if (function_exists('gzencode')){
				$this->DumpSQL(gzencode($this->GetCreateTable($table)));
			}else{
				$this->DumpSQL($this->GetCreateTable($table));
			}

			$fields = $this->GetFields($table);

			// Fetch all the data
			$query = "SELECT * FROM " .$table;
			$result = mysql_unbuffered_query($query);

			while (($row = $this->db->Fetch($result))) {
				$line = "INSERT INTO " . $table . " (`";
				$line .= implode("`, `", $fields);
				$line .= "`) VALUES (";
				$line .= implode(", ", array_map(array($this, 'escapevalue'), $row));
				$line .= ")";
				$line .= ";\n";
				$output .= $line;
				if (strlen($output) > 2097152) { // greater than 2MB? Lets dump it to the file
					if (function_exists('gzencode')){
						$encoded = gzencode($output);
					}else{
						$encoded = $output;
					}
					$this->DumpSQL($encoded);
					unset($encoded);
					unset($output);
					$encoded = $output = '';
				}
			}

			if($outputMode){
				$this->progress = $this->progress + $percentIncrement;
				echo "<script> self.parent." . $this->jsProgressFunction . "('".(int)$this->progress."'); </script>\n\n\n";
				@ob_flush();
				@flush();
			}

			if (function_exists('gzencode')){
				$encoded = gzencode($output);
			}else{
				$encoded = $output;
			}

			$this->DumpSQL($encoded);

			unset($encoded);
			unset($output);
			$encoded = $output = '';
		}
	}
}