Cannot set new image name in codeigniter - image

Question

I'm uploading multiple image in codeigniter, But when i set new name using this code $_FILES['attachment']['name']= $filename;
I'm getting
The filetype you are attempting to upload is not allowed.
Please suggest solution to solve this issue.
public function do_upload()
{
if (($_SERVER['REQUEST_METHOD']) == "POST") {
$count = count($_FILES['attach_file']['name']);
$files = $_FILES;
for($i=0; $i<$count; $i++){
$filename = $_FILES['attach_file']['name'][$i];
$filename = strstr($filename, '.', true);
$email = $this->session->userdata('email');
$filename = strstr($email, '#', true)."_".$filename;
$filename = strtolower($filename);
$_FILES['attachment']['name']= $filename;
$_FILES['attachment']['type']= $_FILES['attach_file']['type'][$i];
$_FILES['attachment']['tmp_name']= $_FILES['attach_file']['tmp_name'][$i];
$_FILES['attachment']['error']= $_FILES['attach_file']['error'][$i];
$_FILES['attachment']['size']= $_FILES['attach_file']['size'][$i];
$config['upload_path'] = FCPATH .'./assets/attachments/new/';
$config['allowed_types'] = 'pdf|doc|docx|bmp|gif|jpg|jpeg|jpe|png';
$config['max_size'] = 0;
$config['max_width'] = 0;
$config['max_height'] = 0;
$config['encrypt_name'] = true;
$config['file_ext_tolower'] = true;
$config['overwrite'] = false;
$this->load->library('upload', $config);
if (!$this->upload->do_upload('attachment')) {
$data['exception'] = $this->upload->display_errors();
$data['status'] = false;
echo json_encode($data);
} else {
$upload = $this->upload->data();
$data['message'] = 'upload_successfully';
$data['filepath'] = './assets/attachments/'.$upload['file_name'];
$data['status'] = true;
echo json_encode($data);
}
}
}
}

Answer 1

Note:- You are assign same variable name again & again $filename
Please Change this:-
$filename = $_FILES['attach_file']['name'][$i];
$filename = strstr($filename, '.', true);
$email = $this->session->userdata('email');
$filename = strstr($email, '#', true)."_".$filename;
$filename = strtolower($filename);
$_FILES['attachment']['name']= $filename;
to :-
$filename = $_FILES['attach_file']['name'][$i];
$filename1 = strstr($filename, '.', true);
$email = $this->session->userdata('email');
$filename2 = strstr($email, '#', true)."_".$filename1;
$filename3 = strtolower($filename2);