CI Upload Image skrip

//function untu handle upload image & file
    private function upload($folder = 'user', $size = 2000000){
        $data = array();
        //folder buat naruh filenya
        $folder = 'img/'.$folder.'/';
        $filename = $_FILES["userfile"]["name"];
        $file_basename = substr($filename, 0, strripos($filename, '.')); //get nama file
        $file_ext = substr($filename, strripos($filename, '.')); //get extension
        $filesize = $_FILES['username']['size'];
        $allowed_file_type = array('.jpg','.png');

        //cek apakah tipe filenya yg diizinkan dan ukuarnay sesuai dr max
        if (in_array($file_ext, $allowed_file_type)
            && ($filesize <= $size)){

            //cek dan buat directory dulu
            buatDir($folder);
            $newFile = md5($file_basename.date('YmdHis')). $file_ext;

            //cek apakah file exizt diserver atau tidak
            if (file_exists($folder.$newFile)){
                //jika exist error
                $data['result'] = false;
                $data['msg'] = "File sudah ada diserver";
            }else{
                //simpan difolder
                if (move_uploaded_file($_FILES["userfile"]["tmp_name"], $folder . $newFile)){
                    $data['result'] = true;
                    $data['namafile'] = $newFile;
                    $data['msg'] = "Upload file berhasil";
                }else{
                    //upload gagal
                    $data['result'] = false;
                    $data['msg'] = "Upload file gagal, silahkan coba lagi";
                }
            }
        }else if(empty($file_basename)){
            $data['result'] = false;
            $data['msg'] = "Silahkan pilih file untuk diupload.";
        }else if ( $filesize > $size){
            $data['result'] = false;
            $data['msg'] = "Ukuran file maksimal 2MB, silahkan coba lagi";
        }else{
            $data['result'] = false;
            $data['msg'] = "File yang diupload harus berketesi ".implode(", ", $allowed_file_type);
            //hapus filenya
            unlink($_FILES['userfile']['tmp_name']);
        }

        return $data;


    }