<?php
interface DatabaseInterface {
	public function get_sql($name);
	public function connectDatabase($hostname,$username,$password,$database,$port,$socket,$charset);
	public function query($sql,$params);
	public function fetch_assoc($result);
	public function fetch_row($result);
	public function insert_id($result);
	public function affected_rows($result);
	public function close($result);
	public function fetch_fields($result);
	public function add_limit_to_sql($sql,$limit,$offset);
	public function likeEscape($string);
	public function is_binary_type($field);
	public function base64_encode($string);
	public function getDefaultCharset();
}

class MySQL implements DatabaseInterface {

	protected $db;
	protected $queries;

	public function __construct() {
		$this->queries = array(
			'reflect_table'=>'SELECT
					"TABLE_NAME"
				FROM
					"INFORMATION_SCHEMA"."TABLES"
				WHERE
					"TABLE_NAME" COLLATE \'utf8_bin\' = ? AND
					"TABLE_SCHEMA" = ?',
			'reflect_pk'=>'SELECT
					"COLUMN_NAME"
				FROM
					"INFORMATION_SCHEMA"."COLUMNS"
				WHERE
					"COLUMN_KEY" = \'PRI\' AND
					"TABLE_NAME" = ? AND
					"TABLE_SCHEMA" = ?',
			'reflect_belongs_to'=>'SELECT
					"TABLE_NAME","COLUMN_NAME",
					"REFERENCED_TABLE_NAME","REFERENCED_COLUMN_NAME"
				FROM
					"INFORMATION_SCHEMA"."KEY_COLUMN_USAGE"
				WHERE
					"TABLE_NAME" COLLATE \'utf8_bin\' = ? AND
					"REFERENCED_TABLE_NAME" COLLATE \'utf8_bin\' IN ? AND
					"TABLE_SCHEMA" = ? AND
					"REFERENCED_TABLE_SCHEMA" = ?',
			'reflect_has_many'=>'SELECT
					"TABLE_NAME","COLUMN_NAME",
					"REFERENCED_TABLE_NAME","REFERENCED_COLUMN_NAME"
				FROM
					"INFORMATION_SCHEMA"."KEY_COLUMN_USAGE"
				WHERE
					"TABLE_NAME" COLLATE \'utf8_bin\' IN ? AND
					"REFERENCED_TABLE_NAME" COLLATE \'utf8_bin\' = ? AND
					"TABLE_SCHEMA" = ? AND
					"REFERENCED_TABLE_SCHEMA" = ?',
			'reflect_habtm'=>'SELECT
					k1."TABLE_NAME", k1."COLUMN_NAME",
					k1."REFERENCED_TABLE_NAME", k1."REFERENCED_COLUMN_NAME",
					k2."TABLE_NAME", k2."COLUMN_NAME",
					k2."REFERENCED_TABLE_NAME", k2."REFERENCED_COLUMN_NAME"
				FROM
					"INFORMATION_SCHEMA"."KEY_COLUMN_USAGE" k1,
					"INFORMATION_SCHEMA"."KEY_COLUMN_USAGE" k2
				WHERE
					k1."TABLE_SCHEMA" = ? AND
					k2."TABLE_SCHEMA" = ? AND
					k1."REFERENCED_TABLE_SCHEMA" = ? AND
					k2."REFERENCED_TABLE_SCHEMA" = ? AND
					k1."TABLE_NAME" COLLATE \'utf8_bin\' = k2."TABLE_NAME" COLLATE \'utf8_bin\' AND
					k1."REFERENCED_TABLE_NAME" COLLATE \'utf8_bin\' = ? AND
					k2."REFERENCED_TABLE_NAME" COLLATE \'utf8_bin\' IN ?'
		);
	}

	public function get_sql($name) {
		return isset($this->queries[$name])?$this->queries[$name]:false;
	}

	public function connectDatabase($hostname,$username,$password,$database,$port,$socket,$charset) {
		$db = mysqli_connect($hostname,$username,$password,$database,$port,$socket);
		if (mysqli_connect_errno()) {
			throw new \Exception('Connect failed. '.mysqli_connect_error());
		}
		if (!mysqli_set_charset($db,$charset)) {
			throw new \Exception('Error setting charset. '.mysqli_error($db));
		}
		if (!mysqli_query($db,'SET SESSION sql_mode = \'ANSI_QUOTES\';')) {
			throw new \Exception('Error setting ANSI quotes. '.mysqli_error($db));
		}
		$this->db = $db;
	}

	public function query($sql,$params) {
		$db = $this->db;
		$sql = preg_replace_callback('/\!|\?/', function ($matches) use (&$db,&$params) {
			$param = array_shift($params);
			if ($matches[0]=='!') return preg_replace('/[^a-zA-Z0-9\-_=<>]/','',$param);
			if (is_array($param)) return '('.implode(',',array_map(function($v) use (&$db) {
				return "'".mysqli_real_escape_string($db,$v)."'";
			},$param)).')';
			if (is_object($param) && $param->type=='base64') {
				return "x'".bin2hex(base64_decode($param->data))."'";
			}
			if ($param===null) return 'NULL';
			return "'".mysqli_real_escape_string($db,$param)."'";
		}, $sql);
		//if (!strpos($sql,'INFORMATION_SCHEMA')) echo "\n$sql\n";
		return mysqli_query($db,$sql);
	}

	public function fetch_assoc($result) {
		return mysqli_fetch_assoc($result);
	}

	public function fetch_row($result) {
		return mysqli_fetch_row($result);
	}

	public function insert_id($result) {
		return mysqli_insert_id($this->db);
	}

	public function affected_rows($result) {
		return mysqli_affected_rows($this->db);
	}

	public function close($result) {
		return mysqli_free_result($result);
	}

	public function fetch_fields($result) {
		return mysqli_fetch_fields($result);
	}

	public function add_limit_to_sql($sql,$limit,$offset) {
		return "$sql LIMIT $limit OFFSET $offset";
	}

	public function likeEscape($string) {
		return addcslashes($string,'%_');
	}

	public function is_binary_type($field) {
		//echo "$field->name: $field->type ($field->flags)\n";
		return (($field->flags & 128) && ($field->type>=249) && ($field->type<=252));
	}

	public function base64_encode($string) {
		return base64_encode($string);
	}

	public function getDefaultCharset() {
		return 'utf8';
	}

}

class PostgreSQL implements DatabaseInterface {

	protected $db;
	protected $queries;

	public function __construct() {
		$this->queries = array(
			'reflect_table'=>'select
					"table_name"
				from
					"information_schema"."tables"
				where
					"table_name" like ? and
					"table_catalog" = ?',
			'reflect_pk'=>'select
					"column_name"
				from
					"information_schema"."table_constraints" tc,
					"information_schema"."key_column_usage" ku
				where
					tc."constraint_type" = \'PRIMARY KEY\' and
					tc."constraint_name" = ku."constraint_name" and
					ku."table_name" = ? and
					ku."table_catalog" = ?',
			'reflect_belongs_to'=>'select
					cu1."table_name",cu1."column_name",
					cu2."table_name",cu2."column_name"
				from
					"information_schema".referential_constraints rc,
					"information_schema".key_column_usage cu1,
					"information_schema".key_column_usage cu2
				where
					cu1."constraint_name" = rc."constraint_name" and
					cu2."constraint_name" = rc."unique_constraint_name" and
					cu1."table_name" = ? and
					cu2."table_name" in ? and
					cu1."table_catalog" = ? and
					cu2."table_catalog" = ?',
			'reflect_has_many'=>'select
					cu1."table_name",cu1."column_name",
					cu2."table_name",cu2."column_name"
				from
					"information_schema".referential_constraints rc,
					"information_schema".key_column_usage cu1,
					"information_schema".key_column_usage cu2
				where
					cu1."constraint_name" = rc."constraint_name" and
					cu2."constraint_name" = rc."unique_constraint_name" and
					cu1."table_name" in ? and
					cu2."table_name" = ? and
					cu1."table_catalog" = ? and
					cu2."table_catalog" = ?',
			'reflect_habtm'=>'select
					cua1."table_name",cua1."column_name",
					cua2."table_name",cua2."column_name",
					cub1."table_name",cub1."column_name",
					cub2."table_name",cub2."column_name"
				from
					"information_schema".referential_constraints rca,
					"information_schema".referential_constraints rcb,
					"information_schema".key_column_usage cua1,
					"information_schema".key_column_usage cua2,
					"information_schema".key_column_usage cub1,
					"information_schema".key_column_usage cub2
				where
					cua1."constraint_name" = rca."constraint_name" and
					cua2."constraint_name" = rca."unique_constraint_name" and
					cub1."constraint_name" = rcb."constraint_name" and
					cub2."constraint_name" = rcb."unique_constraint_name" and
					cua1."table_catalog" = ? and
					cub1."table_catalog" = ? and
					cua2."table_catalog" = ? and
					cub2."table_catalog" = ? and
					cua1."table_name" = cub1."table_name" and
					cua2."table_name" = ? and
					cub2."table_name" in ?'
		);
	}

	public function get_sql($name) {
		return isset($this->queries[$name])?$this->queries[$name]:false;
	}

	public function connectDatabase($hostname,$username,$password,$database,$port,$socket,$charset) {
		$e = function ($v) { return str_replace(array('\'','\\'),array('\\\'','\\\\'),$v); };
		$conn_string = '';
		if ($hostname || $socket) {
			if ($socket) $hostname = $e($socket);
			else $hostname = $e($hostname);
			$conn_string.= " host='$hostname'";
		}
		if ($port) {
			$port = ($port+0);
			$conn_string.= " port='$port'";
		}
		if ($database) {
			$database = $e($database);
			$conn_string.= " dbname='$database'";
		}
		if ($username) {
			$username = $e($username);
			$conn_string.= " user='$username'";
		}
		if ($password) {
			$password = $e($password);
			$conn_string.= " password='$password'";
		}
		if ($charset) {
			$charset = $e($charset);
			$conn_string.= " options='--client_encoding=$charset'";
		}
		$db = pg_connect($conn_string);
		$this->db = $db;
	}

	public function query($sql,$params) {
		$db = $this->db;
		$sql = preg_replace_callback('/\!|\?/', function ($matches) use (&$db,&$params) {
			$param = array_shift($params);
			if ($matches[0]=='!') return preg_replace('/[^a-zA-Z0-9\-_=<>]/','',$param);
			if (is_array($param)) return '('.implode(',',array_map(function($v) use (&$db) {
				return "'".pg_escape_string($db,$v)."'";
			},$param)).')';
			if (is_object($param) && $param->type=='base64') {
				return "'\x".bin2hex(base64_decode($param->data))."'";
			}
			if ($param===null) return 'NULL';
			return "'".pg_escape_string($db,$param)."'";
		}, $sql);
		if (strtoupper(substr($sql,0,6))=='INSERT') {
			$sql .= ' RETURNING id;';
		}
		//echo "\n$sql\n";
		return @pg_query($db,$sql);
	}

	public function fetch_assoc($result) {
		return pg_fetch_assoc($result);
	}

	public function fetch_row($result) {
		return pg_fetch_row($result);
	}

	public function insert_id($result) {
		list($id) = pg_fetch_row($result);
		return (int)$id;
	}

	public function affected_rows($result) {
		return pg_affected_rows($result);
	}

	public function close($result) {
		return pg_free_result($result);
	}

	public function fetch_fields($result) {
		$keys = array();
		for($i=0;$i<pg_num_fields($result);$i++) {
			$field = array();
			$field['name'] = pg_field_name($result,$i);
			$field['type'] = pg_field_type($result,$i);
			$keys[$i] = (object)$field;
		}
		return $keys;
	}

	public function add_limit_to_sql($sql,$limit,$offset) {
		return "$sql LIMIT $limit OFFSET $offset";
	}

	public function likeEscape($string) {
		return addcslashes($string,'%_');
	}

	public function is_binary_type($field) {
		return $field->type == 'bytea';
	}

	public function base64_encode($string) {
		return base64_encode(hex2bin(substr($string,2)));
	}

	public function getDefaultCharset() {
		return 'UTF8';
	}

}

class SQLServer implements DatabaseInterface {

	protected $db;
	protected $queries;

	public function __construct() {
		$this->queries = array(
			'reflect_table'=>'SELECT
					"TABLE_NAME"
				FROM
					"INFORMATION_SCHEMA"."TABLES"
				WHERE
					"TABLE_NAME" LIKE ? AND
					"TABLE_CATALOG" = ?',
			'reflect_pk'=>'SELECT
					"COLUMN_NAME"
				FROM
					"INFORMATION_SCHEMA"."TABLE_CONSTRAINTS" tc,
					"INFORMATION_SCHEMA"."KEY_COLUMN_USAGE" ku
				WHERE
					tc."CONSTRAINT_TYPE" = \'PRIMARY KEY\' AND
					tc."CONSTRAINT_NAME" = ku."CONSTRAINT_NAME" AND
					ku."TABLE_NAME" = ? AND
					ku."TABLE_CATALOG" = ?',
			'reflect_belongs_to'=>'SELECT
					cu1."TABLE_NAME",cu1."COLUMN_NAME",
					cu2."TABLE_NAME",cu2."COLUMN_NAME"
				FROM
					"INFORMATION_SCHEMA".REFERENTIAL_CONSTRAINTS rc,
					"INFORMATION_SCHEMA".CONSTRAINT_COLUMN_USAGE cu1,
					"INFORMATION_SCHEMA".CONSTRAINT_COLUMN_USAGE cu2
				WHERE
					cu1."CONSTRAINT_NAME" = rc."CONSTRAINT_NAME" AND
					cu2."CONSTRAINT_NAME" = rc."UNIQUE_CONSTRAINT_NAME" AND
					cu1."TABLE_NAME" = ? AND
					cu2."TABLE_NAME" IN ? AND
					cu1."TABLE_CATALOG" = ? AND
					cu2."TABLE_CATALOG" = ?',
			'reflect_has_many'=>'SELECT
					cu1."TABLE_NAME",cu1."COLUMN_NAME",
					cu2."TABLE_NAME",cu2."COLUMN_NAME"
				FROM
					"INFORMATION_SCHEMA".REFERENTIAL_CONSTRAINTS rc,
					"INFORMATION_SCHEMA".CONSTRAINT_COLUMN_USAGE cu1,
					"INFORMATION_SCHEMA".CONSTRAINT_COLUMN_USAGE cu2
				WHERE
					cu1."CONSTRAINT_NAME" = rc."CONSTRAINT_NAME" AND
					cu2."CONSTRAINT_NAME" = rc."UNIQUE_CONSTRAINT_NAME" AND
					cu1."TABLE_NAME" IN ? AND
					cu2."TABLE_NAME" = ? AND
					cu1."TABLE_CATALOG" = ? AND
					cu2."TABLE_CATALOG" = ?',
			'reflect_habtm'=>'SELECT
					cua1."TABLE_NAME",cua1."COLUMN_NAME",
					cua2."TABLE_NAME",cua2."COLUMN_NAME",
					cub1."TABLE_NAME",cub1."COLUMN_NAME",
					cub2."TABLE_NAME",cub2."COLUMN_NAME"
				FROM
					"INFORMATION_SCHEMA".REFERENTIAL_CONSTRAINTS rca,
					"INFORMATION_SCHEMA".REFERENTIAL_CONSTRAINTS rcb,
					"INFORMATION_SCHEMA".CONSTRAINT_COLUMN_USAGE cua1,
					"INFORMATION_SCHEMA".CONSTRAINT_COLUMN_USAGE cua2,
					"INFORMATION_SCHEMA".CONSTRAINT_COLUMN_USAGE cub1,
					"INFORMATION_SCHEMA".CONSTRAINT_COLUMN_USAGE cub2
				WHERE
					cua1."CONSTRAINT_NAME" = rca."CONSTRAINT_NAME" AND
					cua2."CONSTRAINT_NAME" = rca."UNIQUE_CONSTRAINT_NAME" AND
					cub1."CONSTRAINT_NAME" = rcb."CONSTRAINT_NAME" AND
					cub2."CONSTRAINT_NAME" = rcb."UNIQUE_CONSTRAINT_NAME" AND
					cua1."TABLE_CATALOG" = ? AND
					cub1."TABLE_CATALOG" = ? AND
					cua2."TABLE_CATALOG" = ? AND
					cub2."TABLE_CATALOG" = ? AND
					cua1."TABLE_NAME" = cub1."TABLE_NAME" AND
					cua2."TABLE_NAME" = ? AND
					cub2."TABLE_NAME" IN ?'
		);
	}

	public function get_sql($name) {
		return isset($this->queries[$name])?$this->queries[$name]:false;
	}

	public function connectDatabase($hostname,$username,$password,$database,$port,$socket,$charset) {
		$connectionInfo = array();
		if ($port) $hostname.=','.$port;
		if ($username) $connectionInfo['UID']=$username;
		if ($password) $connectionInfo['PWD']=$password;
		if ($database) $connectionInfo['Database']=$database;
		if ($charset) $connectionInfo['CharacterSet']=$charset;
		$connectionInfo['QuotedId']=1;
		$connectionInfo['ReturnDatesAsStrings']=1;

		$db = sqlsrv_connect($hostname, $connectionInfo);
		if (!$db) {
			throw new \Exception('Connect failed. '.print_r( sqlsrv_errors(), true));
		}
		if ($socket) {
			throw new \Exception('Socket connection is not supported.');
		}
		$this->db = $db;
	}

	public function query($sql,$params) {
		$args = array();
		$db = $this->db;
		$sql = preg_replace_callback('/\!|\?/', function ($matches) use (&$db,&$params,&$args) {
			static $i=-1;
			$i++;
			$param = $params[$i];
			if ($matches[0]=='!') {
				return preg_replace('/[^a-zA-Z0-9\-_=<>]/','',$param);
			}
			// This is workaround because SQLSRV cannot accept NULL in a param
			if ($matches[0]=='?' && is_null($param)) {
				return 'NULL';
			}
			if (is_array($param)) {
				$args = array_merge($args,$param);
				return '('.implode(',',str_split(str_repeat('?',count($param)))).')';
			}
			if (is_object($param)) {
				switch($param->type) {
					case 'base64':
						$args[] = bin2hex(base64_decode($param->data));
						return 'CONVERT(VARBINARY(MAX),?,2)';
				}
			}
			$args[] = $param;
			return '?';
		}, $sql);
		//var_dump($params);
		//echo "\n$sql\n";
		//var_dump($args);
		if (strtoupper(substr($sql,0,6))=='INSERT') {
			$sql .= ';SELECT SCOPE_IDENTITY()';
		}
		return sqlsrv_query($db,$sql,$args)?:null;
	}

	public function fetch_assoc($result) {
		$values = sqlsrv_fetch_array($result, SQLSRV_FETCH_ASSOC);
		if ($values) $values = array_map(function($v){ return is_null($v)?null:(string)$v; },$values);
		return $values;
	}

	public function fetch_row($result) {
		$values = sqlsrv_fetch_array($result, SQLSRV_FETCH_NUMERIC);
		if ($values) $values = array_map(function($v){ return is_null($v)?null:(string)$v; },$values);
		return $values;
	}

	public function insert_id($result) {
		sqlsrv_next_result($result);
		sqlsrv_fetch($result);
		return (int)sqlsrv_get_field($result, 0);
	}

	public function affected_rows($result) {
		return sqlsrv_rows_affected($result);
	}

	public function close($result) {
		return sqlsrv_free_stmt($result);
	}

	public function fetch_fields($result) {
		//var_dump(sqlsrv_field_metadata($result));
		return array_map(function($a){
			$p = array();
			foreach ($a as $k=>$v) {
				$p[strtolower($k)] = $v;
			}
			return (object)$p;
		},sqlsrv_field_metadata($result));
	}

	public function add_limit_to_sql($sql,$limit,$offset) {
		return "$sql OFFSET $offset ROWS FETCH NEXT $limit ROWS ONLY";
	}

	public function likeEscape($string) {
		return str_replace(array('%','_'),array('[%]','[_]'),$string);
	}

	public function is_binary_type($field) {
		return ($field->type>=-4 && $field->type<=-2);
	}

	public function base64_encode($string) {
		return base64_encode($string);
	}

	public function getDefaultCharset() {
		return 'UTF-8';
	}
}

class PHP_CRUD_API {

	protected $db;
	protected $settings;

	protected function mapMethodToAction($method,$key) {
		switch ($method) {
			case 'OPTIONS': return 'headers';
			case 'GET': return $key?'read':'list';
			case 'PUT': return 'update';
			case 'POST': return 'create';
			case 'DELETE': return 'delete';
			default: $this->exitWith404('method');
		}
		return false;
	}

	protected function parseRequestParameter(&$request,$characters) {
		if (!$request) return false;
		$pos = strpos($request,'/');
		$value = $pos?substr($request,0,$pos):$request;
		$request = $pos?substr($request,$pos+1):'';
		if (!$characters) return $value;
		return preg_replace("/[^$characters]/",'',$value);
	}

	protected function parseGetParameter($get,$name,$characters) {
		$value = isset($get[$name])?$get[$name]:false;
		return $characters?preg_replace("/[^$characters]/",'',$value):$value;
	}

	protected function parseGetParameterArray($get,$name,$characters) {
		$values = isset($get[$name])?$get[$name]:false;
		if (!is_array($values)) $values = array($values);
		if ($characters) {
			foreach ($values as &$value) {
				$value = preg_replace("/[^$characters]/",'',$value);
			}
		}
		return $values;
	}

	protected function applyTableAuthorizer($callback,$action,$database,&$tables) {
		if (is_callable($callback,true)) foreach ($tables as $i=>$table) {
			if (!$callback($action,$database,$table)) {
				if ($i) unset($tables[$i]);
				else $this->exitWith404('entity');
			}
		}
	}

	protected function applyRecordFilter($callback,$action,$database,$tables,&$filters) {
		if (is_callable($callback,true)) foreach ($tables as $i=>$table) {
			$f = $this->convertFilters($callback($action,$database,$table));
			if ($f) {
				if (!isset($filters[$table])) $filters[$table] = array();
				if (!isset($filters[$table]['and'])) $filters[$table]['and'] = array();
				$filters[$table]['and'] = array_merge($filters[$table]['and'],$f);
			}
		}
	}

	protected function applyTenancyFunction($callback,$action,$database,$fields,&$filters) {
		if (is_callable($callback,true)) foreach ($fields as $table=>$keys) {
			foreach ($keys as $field) {
				$v = $callback($action,$database,$table,$field->name);
				if ($v!==null) {
					if (!isset($filters[$table])) $filters[$table] = array();
					if (!isset($filters[$table]['and'])) $filters[$table]['and'] = array();
					$filters[$table]['and'][] = array($field->name,is_array($v)?'IN':'=',$v);
				}
			}
		}
	}

	protected function applyColumnAuthorizer($callback,$action,$database,&$fields) {
		if (is_callable($callback,true)) foreach ($fields as $table=>$keys) {
			foreach ($keys as $field) {
				if (!$callback($action,$database,$table,$field->name)) {
					unset($fields[$table][$field->name]);
				}
			}
		}
	}

	protected function applyInputTenancy($callback,$action,$database,$table,&$input,$keys) {
		if (is_callable($callback,true)) foreach ((array)$input as $key=>$value) {
			if (isset($keys[$key])) {
				$v = $callback($action,$database,$table,$key);
				if ($v!==null) {
					if (is_array($v)) {
						if (in_array($input->$key,$v)) {
							$v = $input->$key;
						} else {
							$v = null;
						}
					}
					$input->$key = $v;
				}
			}
		}
	}

	protected function applyInputSanitizer($callback,$action,$database,$table,&$input,$keys) {
		if (is_callable($callback,true)) foreach ((array)$input as $key=>$value) {
			if (isset($keys[$key])) {
				$input->$key = $callback($action,$database,$table,$key,$keys[$key]->type,$value);
			}
		}
	}

	protected function applyInputValidator($callback,$action,$database,$table,$input,$keys,$context) {
		$errors = array();
		if (is_callable($callback,true)) foreach ((array)$input as $key=>$value) {
			if (isset($keys[$key])) {
				$error = $callback($action,$database,$table,$key,$keys[$key]->type,$value,$context);
				if ($error!==true && $error!==null) $errors[$key] = $error;
			}
		}
		if (!empty($errors)) $this->exitWith422($errors);
	}

	protected function processTablesParameter($database,$tables,$action) {
		$blacklist = array('information_schema','mysql','sys','pg_catalog');
		if (in_array(strtolower($database), $blacklist)) return array();
		$table_array = explode(',',$tables);
		$table_list = array();
		foreach ($table_array as $table) {
			if ($result = $this->db->query($this->db->get_sql('reflect_table'),array($table,$database))) {
				while ($row = $this->db->fetch_row($result)) $table_list[] = $row[0];
				$this->db->close($result);
				if ($action!='list') break;
			}
		}
		if (empty($table_list)) $this->exitWith404('entity');
		return $table_list;
	}

	protected function exitWith404($type) {
		if (isset($_SERVER['REQUEST_METHOD'])) {
			header('Content-Type:',true,404);
			die("Not found ($type)");
		} else {
			throw new \Exception("Not found ($type)");
		}
	}

	protected function exitWith422($object) {
		if (isset($_SERVER['REQUEST_METHOD'])) {
			header('Content-Type:',true,422);
			die(json_encode($object));
		} else {
			throw new \Exception(json_encode($object));
		}
	}

	protected function headersCommand($parameters) {
		$headers = array();
		$headers[]='Access-Control-Allow-Headers: Content-Type';
		$headers[]='Access-Control-Allow-Methods: OPTIONS, GET, PUT, POST, DELETE';
		$headers[]='Access-Control-Max-Age: 1728000';
		if (isset($_SERVER['REQUEST_METHOD'])) {
			foreach ($headers as $header) header($header);
		} else {
			echo json_encode($headers);
		}
	}

	protected function startOutput($callback) {
		if ($callback) {
			if (isset($_SERVER['REQUEST_METHOD'])) {
				header('Content-Type: application/javascript');
			}
			echo $callback.'(';
		} else {
			if (isset($_SERVER['REQUEST_METHOD'])) {
				header('Content-Type: application/json');
			}
		}
	}

	protected function endOutput($callback) {
		if ($callback) {
			echo ');';
		}
	}

	protected function processKeyParameter($key,$tables,$database) {
		if (!$key) return false;
		$count = 0;
		$field = false;
		if ($result = $this->db->query($this->db->get_sql('reflect_pk'),array($tables[0],$database))) {
			while ($row = $this->db->fetch_row($result)) {
				$count++;
				$field = $row[0];
			}
			$this->db->close($result);
		}
		if ($count!=1 || $field==false) $this->exitWith404('1pk');
		return array($key,$field);
	}

	protected function processOrderParameter($order) {
		if (!$order) return false;
		$order = explode(',',$order,2);
		if (count($order)<2) $order[1]='ASC';
		if (!strlen($order[0])) return false;
		$order[1] = strtoupper($order[1])=='DESC'?'DESC':'ASC';
		return $order;
	}

	protected function convertFilter($field, $comparator, $value) {
		switch (strtolower($comparator)) {
			case 'cs': $comparator = 'LIKE'; $value = '%'.$this->db->likeEscape($value).'%'; break;
			case 'sw': $comparator = 'LIKE'; $value = $this->db->likeEscape($value).'%'; break;
			case 'ew': $comparator = 'LIKE'; $value = '%'.$this->db->likeEscape($value); break;
			case 'eq': $comparator = '='; break;
			case 'ne': $comparator = '<>'; break;
			case 'lt': $comparator = '<'; break;
			case 'le': $comparator = '<='; break;
			case 'ge': $comparator = '>='; break;
			case 'gt': $comparator = '>'; break;
			case 'in': $comparator = 'IN'; $value = explode(',',$value); break;
		}
		return array($field, $comparator, $value);
	}

	protected function convertFilters($filters) {
		$result = array();
		if ($filters) {
			for ($i=0;$i<count($filters);$i++) {
				$filter = explode(',',$filters[$i],3);
				if (count($filter)==3) {
					$result[] = $this->convertFilter($filter[0],$filter[1],$filter[2]);
				}
			}
		}
		return $result;
	}

	protected function processFiltersParameter($tables,$satisfy,$filters) {
		$result = $this->convertFilters($filters);
		if (!$result) return array();
		$and = ($satisfy && strtolower($satisfy)=='any')?'or':'and';
		return array($tables[0]=>array($and=>$result));
	}

	protected function processPageParameter($page) {
		if (!$page) return false;
		$page = explode(',',$page,2);
		if (count($page)<2) $page[1]=20;
		$page[0] = ($page[0]-1)*$page[1];
		return $page;
	}

	protected function retrieveObject($key,$fields,$filters,$tables) {
		if (!$key) return false;
		$table = $tables[0];
		$sql = 'SELECT ';
		$sql .= '"'.implode('","',array_keys($fields[$table])).'"';
		$sql .= ' FROM "!"';
		$params = array($table);
		if (!isset($filters[$table])) $filters[$table] = array();
		if (!isset($filters[$table]['or'])) $filters[$table]['or'] = array();
		$filters[$table]['or'][] = array($key[1],'=',$key[0]);
		$this->addWhereFromFilters($filters[$table],$sql,$params);
		if ($result = $this->db->query($sql,$params)) {
			$object = $this->db->fetch_assoc($result);
			foreach ($fields[$table] as $field) {
				if ($this->db->is_binary_type($field) && $object[$field->name]) {
					$object[$field->name] = $this->db->base64_encode($object[$field->name]);
				}
			}
			$this->db->close($result);
		}
		return $object;
	}

	protected function createObject($input,$tables) {
		if (!$input) return false;
		$input = (array)$input;
		$keys = implode('","',str_split(str_repeat('!', count($input))));
		$values = implode(',',str_split(str_repeat('?', count($input))));
		$params = array_merge(array_keys($input),array_values($input));
		array_unshift($params, $tables[0]);
		$result = $this->db->query('INSERT INTO "!" ("'.$keys.'") VALUES ('.$values.')',$params);
		if (!$result) return null;
		return $this->db->insert_id($result);
	}

	protected function updateObject($key,$input,$filters,$tables) {
		if (!$input) return false;
		$input = (array)$input;
		$table = $tables[0];
		$sql = 'UPDATE "!" SET ';
		$params = array($table);
		foreach (array_keys($input) as $i=>$k) {
			if ($i) $sql .= ',';
			$v = $input[$k];
			$sql .= '"!"=?';
			$params[] = $k;
			$params[] = $v;
		}
		if (!isset($filters[$table])) $filters[$table] = array();
		if (!isset($filters[$table]['or'])) $filters[$table]['or'] = array();
		$filters[$table]['or'][] = array($key[1],'=',$key[0]);
		$this->addWhereFromFilters($filters[$table],$sql,$params);
		$result = $this->db->query($sql,$params);
		return $this->db->affected_rows($result);
	}

	protected function deleteObject($key,$filters,$tables) {
		$table = $tables[0];
		$sql = 'DELETE FROM "!"';
		$params = array($table);
		if (!isset($filters[$table])) $filters[$table] = array();
		if (!isset($filters[$table]['or'])) $filters[$table]['or'] = array();
		$filters[$table]['or'][] = array($key[1],'=',$key[0]);
		$this->addWhereFromFilters($filters[$table],$sql,$params);
		$result = $this->db->query($sql,$params);
		return $this->db->affected_rows($result);
	}

	protected function findRelations($tables,$database) {
		$tableset = array();
		$collect = array();
		$select = array();

		while (count($tables)>1) {
			$table0 = array_shift($tables);
			$tableset[] = $table0;

			$result = $this->db->query($this->db->get_sql('reflect_belongs_to'),array($table0,$tables,$database,$database));
			while ($row = $this->db->fetch_row($result)) {
				$collect[$row[0]][$row[1]]=array();
				$select[$row[2]][$row[3]]=array($row[0],$row[1]);
				if (!in_array($row[0],$tableset)) $tableset[] = $row[0];
			}
			$result = $this->db->query($this->db->get_sql('reflect_has_many'),array($tables,$table0,$database,$database));
			while ($row = $this->db->fetch_row($result)) {
				$collect[$row[2]][$row[3]]=array();
				$select[$row[0]][$row[1]]=array($row[2],$row[3]);
				if (!in_array($row[2],$tableset)) $tableset[] = $row[2];
			}
			$result = $this->db->query($this->db->get_sql('reflect_habtm'),array($database,$database,$database,$database,$table0,$tables));
			while ($row = $this->db->fetch_row($result)) {
				$collect[$row[2]][$row[3]]=array();
				$select[$row[0]][$row[1]]=array($row[2],$row[3]);
				$collect[$row[4]][$row[5]]=array();
				$select[$row[6]][$row[7]]=array($row[4],$row[5]);
				if (!in_array($row[2],$tableset)) $tableset[] = $row[2];
				if (!in_array($row[4],$tableset)) $tableset[] = $row[4];
			}
		}
		$tableset[] = array_shift($tables);
		return array($tableset,$collect,$select);
	}

	protected function retrieveInput($post) {
		$input = (object)array();
		$data = trim(file_get_contents($post));
		if (strlen($data)>0) {
			if ($data[0]=='{') {
				$input = json_decode($data);
			} else {
				parse_str($data, $input);
				foreach ($input as $key => $value) {
					if (substr($key,-9)=='__is_null') {
						$input[substr($key,0,-9)] = null;
						unset($input[$key]);
					}
				}
				$input = (object)$input;
			}
		}
		return $input;
	}

	protected function findFields($tables,$columns,$database) {
		$fields = array();
		foreach ($tables as $i=>$table) {
			$fields[$table] = $this->findTableFields($table,$database);
			if ($i==0) $fields[$table] = $this->filterFieldsByColumns($fields[$table],$columns);
		}
		return $fields;
	}

	protected function filterFieldsByColumns($fields,$columns) {
		if ($columns) {
			$columns = explode(',',$columns);
			foreach (array_keys($fields) as $key) {
				if (!in_array($key, $columns)) {
					unset($fields[$key]);
				}
			}
		}
		return $fields;
	}

	protected function findTableFields($table,$database) {
		$fields = array();
		$result = $this->db->query('SELECT * FROM "!" WHERE 1=2;',array($table));
		foreach ($this->db->fetch_fields($result) as $field) {
			$fields[$field->name] = $field;
		}
		return $fields;
	}

	protected function filterInputByFields($input,$fields) {
		if ($fields) foreach (array_keys((array)$input) as $key) {
			if (!isset($fields[$key])) {
				unset($input->$key);
			}
		}
		return $input;
	}

	protected function convertBinary(&$input,$keys) {
		foreach ($keys as $key=>$field) {
			if (isset($input->$key) && $input->$key && $this->db->is_binary_type($field)) {
				$data = $input->$key;
				$data = str_pad(strtr($data, '-_', '+/'), strlen($data) % 4, '=', STR_PAD_RIGHT);
				$input->$key = (object)array('type'=>'base64','data'=>$data);
			}
		}
	}

	protected function getParameters($settings) {
		extract($settings);

		$tables    = $this->parseRequestParameter($request, 'a-zA-Z0-9\-_,');
		$key       = $this->parseRequestParameter($request, 'a-zA-Z0-9\-_,'); // auto-increment or uuid
		$action    = $this->mapMethodToAction($method,$key);
		$callback  = $this->parseGetParameter($get, 'callback', 'a-zA-Z0-9\-_');
		$page      = $this->parseGetParameter($get, 'page', '0-9,');
		$filters   = $this->parseGetParameterArray($get, 'filter', false);
		$satisfy   = $this->parseGetParameter($get, 'satisfy', 'a-zA-Z');
		$columns   = $this->parseGetParameter($get, 'columns', 'a-zA-Z0-9\-_,');
		$order     = $this->parseGetParameter($get, 'order', 'a-zA-Z0-9\-_,');
		$transform = $this->parseGetParameter($get, 'transform', '1');

		$tables    = $this->processTablesParameter($database,$tables,$action);
		$key       = $this->processKeyParameter($key,$tables,$database);
		$filters   = $this->processFiltersParameter($tables,$satisfy,$filters);
		$page      = $this->processPageParameter($page);
		$order     = $this->processOrderParameter($order);

		// reflection
		list($tables,$collect,$select) = $this->findRelations($tables,$database);
		$fields = $this->findFields($tables,$columns,$database);

		// permissions
		if ($table_authorizer) $this->applyTableAuthorizer($table_authorizer,$action,$database,$tables);
		if ($record_filter) $this->applyRecordFilter($record_filter,$action,$database,$tables,$filters);
		if ($column_authorizer) $this->applyColumnAuthorizer($column_authorizer,$action,$database,$fields);
		if ($tenancy_function) $this->applyTenancyFunction($tenancy_function,$action,$database,$fields,$filters);

		if ($post) {
			// input
			$context = $this->retrieveInput($post);
			$input = $this->filterInputByFields($context,$fields[$tables[0]]);

			if ($tenancy_function) $this->applyInputTenancy($tenancy_function,$action,$database,$tables[0],$input,$fields[$tables[0]]);
			if ($input_sanitizer) $this->applyInputSanitizer($input_sanitizer,$action,$database,$tables[0],$input,$fields[$tables[0]]);
			if ($input_validator) $this->applyInputValidator($input_validator,$action,$database,$tables[0],$input,$fields[$tables[0]],$context);

			$this->convertBinary($input,$fields[$tables[0]]);
		}

		return compact('action','database','tables','key','callback','page','filters','fields','order','transform','input','collect','select');
	}

	protected function addWhereFromFilters($filters,&$sql,&$params) {
		$first = true;
		if (isset($filters['or'])) {
			$first = false;
			$sql .= ' WHERE (';
			foreach ($filters['or'] as $i=>$filter) {
				$sql .= $i==0?'':' OR ';
				$sql .= '"!" ! ?';
				$params[] = $filter[0];
				$params[] = $filter[1];
				$params[] = $filter[2];
			}
			$sql .= ')';
		}
		if (isset($filters['and'])) {
			foreach ($filters['and'] as $i=>$filter) {
				$sql .= $first?' WHERE ':' AND ';
				$sql .= '"!" ! ?';
				$params[] = $filter[0];
				$params[] = $filter[1];
				$params[] = $filter[2];
				$first = false;
			}
		}
	}

	protected function listCommandInternal($parameters) {
		extract($parameters);
		echo '{';
		$table = array_shift($tables);
		// first table
		$count = false;
		echo '"'.$table.'":{';
		if (is_array($order) && is_array($page)) {
			$params = array();
			$sql = 'SELECT COUNT(*) FROM "!"';
			$params[] = $table;
			if (isset($filters[$table])) {
					$this->addWhereFromFilters($filters[$table],$sql,$params);
			}
			if ($result = $this->db->query($sql,$params)) {
				while ($pages = $this->db->fetch_row($result)) {
					$count = $pages[0];
				}
			}
		}
		$params = array();
		$sql = 'SELECT ';
		$sql .= '"'.implode('","',array_keys($fields[$table])).'"';
		$sql .= ' FROM "!"';
		$params[] = $table;
		if (isset($filters[$table])) {
				$this->addWhereFromFilters($filters[$table],$sql,$params);
		}
		if (is_array($order)) {
			$sql .= ' ORDER BY "!" !';
			$params[] = $order[0];
			$params[] = $order[1];
		}
		if (is_array($order) && is_array($page)) {
			$sql = $this->db->add_limit_to_sql($sql,$page[1],$page[0]);
		}
		if ($result = $this->db->query($sql,$params)) {
			echo '"columns":';
			$keys = array();
			$base64 = array();
			foreach ($fields[$table] as $field) {
				$base64[] = $this->db->is_binary_type($field);
				$keys[] = $field->name;
			}
			echo json_encode($keys);
			$keys = array_flip($keys);
			echo ',"records":[';
			$first_row = true;
			while ($row = $this->db->fetch_row($result)) {
				if ($first_row) $first_row = false;
				else echo ',';
				if (isset($collect[$table])) {
					foreach (array_keys($collect[$table]) as $field) {
						$collect[$table][$field][] = $row[$keys[$field]];
					}
				}
				foreach ($base64 as $k=>$v) {
					if ($v && $row[$k]) {
						$row[$k] = $this->db->base64_encode($row[$k]);
					}
				}
				echo json_encode($row);
			}
			$this->db->close($result);
			echo ']';
			if ($count) echo ',';
		}
		if ($count) echo '"results":'.$count;
		echo '}';
		// other tables
		foreach ($tables as $t=>$table) {
			echo ',';
			echo '"'.$table.'":{';
			$params = array();
			$sql = 'SELECT ';
			$sql .= '"'.implode('","',array_keys($fields[$table])).'"';
			$sql .= ' FROM "!"';
			$params[] = $table;
			if (isset($select[$table])) {
				echo '"relations":{';
				$first_row = true;
				foreach ($select[$table] as $field => $path) {
					$values = $collect[$path[0]][$path[1]];
					if (!isset($filters[$table])) $filters[$table] = array();
					if (!isset($filters[$table]['or'])) $filters[$table]['or'] = array();
					$filters[$table]['or'][] = array($field,'IN',$values);
					if ($first_row) $first_row = false;
					else echo ',';
					echo '"'.$field.'":"'.implode('.',$path).'"';
				}
				echo '}';
				$this->addWhereFromFilters($filters[$table],$sql,$params);
			}
			if ($result = $this->db->query($sql,$params)) {
				if (isset($select[$table])) echo ',';
				echo '"columns":';
				$keys = array();
				$base64 = array();
				foreach ($fields[$table] as $field) {
					$base64[] = $this->db->is_binary_type($field);
					$keys[] = $field->name;
				}
				echo json_encode($keys);
				$keys = array_flip($keys);
				echo ',"records":[';
				$first_row = true;
				while ($row = $this->db->fetch_row($result)) {
					if ($first_row) $first_row = false;
					else echo ',';
					if (isset($collect[$table])) {
						foreach (array_keys($collect[$table]) as $field) {
							$collect[$table][$field][]=$row[$keys[$field]];
						}
					}
					foreach ($base64 as $k=>$v) {
						if ($v && $row[$k]) {
							$row[$k] = $this->db->base64_encode($row[$k]);
						}
					}
					echo json_encode($row);
				}
				$this->db->close($result);
				echo ']';
			}
			echo '}';
		}
		echo '}';
	}

	protected function readCommand($parameters) {
		extract($parameters);
		$object = $this->retrieveObject($key,$fields,$filters,$tables);
		if (!$object) $this->exitWith404('object');
		$this->startOutput($callback);
		echo json_encode($object);
		$this->endOutput($callback);
	}

	protected function createCommand($parameters) {
		extract($parameters);
		if (!$input) $this->exitWith404('input');
		$this->startOutput($callback);
		echo json_encode($this->createObject($input,$tables));
		$this->endOutput($callback);
	}

	protected function updateCommand($parameters) {
		extract($parameters);
		if (!$input) $this->exitWith404('subject');
		$this->startOutput($callback);
		echo json_encode($this->updateObject($key,$input,$filters,$tables));
		$this->endOutput($callback);
	}

	protected function deleteCommand($parameters) {
		extract($parameters);
		$this->startOutput($callback);
		echo json_encode($this->deleteObject($key,$filters,$tables));
		$this->endOutput($callback);
	}

	protected function listCommand($parameters) {
		extract($parameters);
		$this->startOutput($callback);
		if ($transform) {
			ob_start();
		}
		$this->listCommandInternal($parameters);
		if ($transform) {
			$content = ob_get_contents();
			ob_end_clean();
			$data = json_decode($content,true);
			echo json_encode(self::php_crud_api_transform($data));
		}
		$this->endOutput($callback);
	}

	public function __construct($config) {
		extract($config);

		// initialize
		$hostname = isset($hostname)?$hostname:null;
		$username = isset($username)?$username:null;
		$password = isset($password)?$password:null;
		$database = isset($database)?$database:null;
		$port = isset($port)?$port:null;
		$socket = isset($socket)?$socket:null;
		$charset = isset($charset)?$charset:null;

		$table_authorizer = isset($table_authorizer)?$table_authorizer:null;
		$record_filter = isset($record_filter)?$record_filter:null;
		$column_authorizer = isset($column_authorizer)?$column_authorizer:null;
		$tenancy_function = isset($tenancy_function)?$tenancy_function:null;
		$input_sanitizer = isset($input_sanitizer)?$input_sanitizer:null;
		$input_validator = isset($input_validator)?$input_validator:null;

		$dbengine = isset($dbengine)?$dbengine:null;
		$db = isset($db)?$db:null;
		$method = isset($method)?$method:null;
		$request = isset($request)?$request:null;
		$get = isset($get)?$get:null;
		$post = isset($post)?$post:null;

		// defaults
		if (!$dbengine) {
			$dbengine = 'MySQL';
		}
		if (!$method) {
			$method = $_SERVER['REQUEST_METHOD'];
		}
		if (!$request) {
			$request = isset($_SERVER['PATH_INFO'])?$_SERVER['PATH_INFO']:'';
		}
		if (!$get) {
			$get = $_GET;
		}
		if (!$post) {
			$post = 'php://input';
		}

		// connect
		$request = trim($request,'/');
		if (!$database) {
			$database  = $this->parseRequestParameter($request, 'a-zA-Z0-9\-_');
		}
		if (!$db) {
			$db = new $dbengine();
			if (!$charset) {
				$charset = $db->getDefaultCharset();
			}
			$db->connectDatabase($hostname,$username,$password,$database,$port,$socket,$charset);
		}

		$this->db = $db;
		$this->settings = compact('method', 'request', 'get', 'post', 'database', 'table_authorizer', 'record_filter', 'column_authorizer', 'tenancy_function', 'input_sanitizer', 'input_validator');
	}

	public static function php_crud_api_transform(&$tables) {
		$get_objects = function (&$tables,$table_name,$where_index=false,$match_value=false) use (&$get_objects) {
			$objects = array();
			foreach ($tables[$table_name]['records'] as $record) {
				if ($where_index===false || $record[$where_index]==$match_value) {
					$object = array();
					foreach ($tables[$table_name]['columns'] as $index=>$column) {
						$object[$column] = $record[$index];
						foreach ($tables as $relation=>$reltable) {
							if (isset($reltable['relations'])) {
								foreach ($reltable['relations'] as $key=>$target) {
									if ($target == "$table_name.$column") {
										$column_indices = array_flip($reltable['columns']);
										$object[$relation] = $get_objects($tables,$relation,$column_indices[$key],$record[$index]);
									}
								}
							}
						}
					}
					$objects[] = $object;
				}
			}
			return $objects;
		};
		$tree = array();
		foreach ($tables as $name=>$table) {
			if (!isset($table['relations'])) {
				$tree[$name] = $get_objects($tables,$name);
				if (isset($table['results'])) {
					$tree['_results'] = $table['results'];
				}
			}
		}
		return $tree;
	}

	public function executeCommand() {
		if (isset($_SERVER['REQUEST_METHOD'])) {
			header('Access-Control-Allow-Origin: *');
		}
		$parameters = $this->getParameters($this->settings);

		switch($parameters['action']){
			case 'list': $this->listCommand($parameters); break;
			case 'read': $this->readCommand($parameters); break;
			case 'create': $this->createCommand($parameters); break;
			case 'update': $this->updateCommand($parameters); break;
			case 'delete': $this->deleteCommand($parameters); break;
			case 'headers': $this->headersCommand($parameters); break;
		}
	}

}

// uncomment the lines below when running in stand-alone mode:

// $api = new PHP_CRUD_API(array(
// 	'hostname'=>'localhost',
//	'username'=>'xxx',
//	'password'=>'xxx',
//	'database'=>'xxx',
// 	'charset'=>'utf8'
// ));
// $api->executeCommand();

// For Microsoft SQL Server use:

// $api = new PHP_CRUD_API(array(
// 	'hostname'=>'(local)',
// 	'username'=>'',
// 	'password'=>'',
// 	'database'=>'xxx',
// 	'charset'=>'UTF-8'
// ));
// $api->executeCommand();

// For PostgreSQL use:

// $api = new PHP_CRUD_API(array(
// 	'hostname'=>'localhost',
// 	'username'=>'xxx',
// 	'password'=>'xxx',
// 	'database'=>'xxx',
// 	'charset'=>'UTF8'
// ));
// $api->executeCommand();