<?php
// http://daveyshafik.com/archives/605-debugging-pdo-prepared-statements.html for more info

class PDOTester extends PDO {
	public function __construct($dsn, $username = null, $password = null, $driver_options = array())
	{
		parent::__construct($dsn, $username, $password, $driver_options);
		$this->setAttribute(PDO::ATTR_STATEMENT_CLASS, array("PDOStatementTester", array($this)));
	}
}

class PDOStatementTester extends PDOStatement {
	const NO_MAX_LENGTH = -1;

	protected $connection;
	protected $bound_params = array();

	protected function __construct(PDO $connection)
	{
		$this->connection = $connection;
	}

	public function bindParam($paramno, &$param, $type = PDO::PARAM_STR, $maxlen = null, $driverdata = null)
	{
		$this->bound_params[$paramno] = array(
				"value" => &$param,
				"type" => $type,
				"maxlen" => (is_null($maxlen)) ? self::NO_MAX_LENGTH : $maxlen,
				// ignore driver data
		);

		$result = parent::bindParam($paramno, $param, $type, $maxlen, $driverdata);
	}

	public function bindValue($parameter, $value, $data_type = PDO::PARAM_STR)
	{
		$this->bound_params[$parameter] = array(
				"value" => $value,
				"type" => $data_type,
				"maxlen" => self::NO_MAX_LENGTH
		);
		parent::bindValue($parameter, $value, $data_type);
	}

	public function getSQL($values = array())
	{
		$sql = $this->queryString;

		if (sizeof($values) > 0) {
			krsort($values);

			foreach ($values as $key => $value) {
				$sql = str_replace_once($key, $this->connection->quote($value), $sql);
				//preg_replace('/'.$key.'/', $this->connection->quote($value), $sql, 1); // outputs '123def abcdef abcdef'
			}
		}

		if (sizeof($this->bound_params)) {
			foreach ($this->bound_params as $key => $param) {
				$value = $param['value'];
				if (!is_null($param['type'])) {
					$value = self::cast($value, $param['type']);
				}
				if ($param['maxlen'] && $param['maxlen'] != self::NO_MAX_LENGTH) {
					$value = self::truncate($value, $param['maxlen']);
				}
				if (!is_null($value)) {
					$sql = str_replace($key, $this->connection->quote($value), $sql);
				} else {
					$sql = str_replace($key, "NULL", $sql);
				}
			}
		}
		return $sql;
	}
	
	// return error code and binded SQL for checking error
	public function getError(array $param=array()){
		
		if( preg_match('/^[0]*$/' ,$this->errorCode()) ){
			//var_dump($this->errorInfo());
			return false;
		}
		
		$error = $this->errorInfo();
		$error['sql'] = $this->getSQL($param);
		return $error;
	}

	//do something audit before SQL is being executed
	public function execute($bound_input_params = NULL){
/*		$statment = explode(' ', $this->queryString, 5);
		if(strtoupper($statment[0])=='DELETE'){
			if( strpos($statment[2], 'AUDIT')===false ){
				//echo "deleting".$statment[2];
				//echo $this->queryString."<br/>";
				//todo: write to auditlog
			}else{
				//echo "accessing audit table";
			}
		}*/
		return parent::execute($bound_input_params);

	}

	static protected function cast($value, $type)
	{
		switch ($type) {
			case PDO::PARAM_BOOL:
				return (bool) $value;
				break;
			case PDO::PARAM_NULL:
				return null;
				break;
			case PDO::PARAM_INT:
				return (int) $value;
			case PDO::PARAM_STR:
			default:
				return $value;
		}
	}

	static protected function truncate($value, $length)
	{
		return substr($value, 0, $length);
	}
}

//$dbh = new PDOTester($dsn, $user, $password);

//testPDO();

/**
 * Replaces any parameter placeholders in a query with the value of that
 * parameter. Useful for debugging. Assumes anonymous parameters from
 * $params are are in the same order as specified in $query
 *
 * @param string $query The sql query with parameter placeholders
 * @param array $params The array of substitution parameters
 * @return string The interpolated query
 */
//public static
function showSQL($query, $params) {
	$keys = array();

	# build a regular expression for each parameter
	foreach ($params as $key => $value) {
		if (is_string($key)) {
			$keys[] = '/:'.$key.'/';
		} else {
			$keys[] = '/[?]/';
		}
	}

	$query = preg_replace($keys, $params, $query, 1, $count);

	#trigger_error('replaced '.$count.' keys');

	return $query;
}

function pdo_showerror($sth, $q, $param=''){
	//global $sth;
	if(!$q && DEBUG)
	{
		print"Execute query error, because: <br/><pre>";
		print $sth->getSQL().HTML_EOL;
		var_dump( $sth->errorInfo() );
		print"</pre>";

		$dump = error_get_last();
		adderrorlog( 'SQL error', $dump['message'].PHP_EOL.$sth->getSQL( (array)$param) );
		exit;
	}

}

function str_replace_once($str_pattern, $str_replacement, $string){ 
	if (strpos($string, $str_pattern) !== false){ 
		$occurrence = strpos($string, $str_pattern); 
		return substr_replace($string, $str_replacement, strpos($string, $str_pattern), strlen($str_pattern)); 
	} 	
	return $string; 
}