File upload, attachment not getting emailed.

file_upload.php

<?php 

$formerror = 0;
$form = "<form action='' method='post' id='upload_work' enctype='multipart/form-data'>
  <input type='file' name='upload_file'>
  <input type='submit' value='Upload' name='submit_work'>
</form>";
  
  if ($input->post->submit_work) { 
  // form has been submitted

    $page->of(false);

    // check if a valid file has been submitted
    if(file_exists($_FILES['upload_file']['tmp_name']) || is_uploaded_file($_FILES['upload_file']['tmp_name'])) {

      // instantiate the class and give it the name of the HTML field 
      $u = new WireUpload('upload_file'); 
      // tell it to only accept 1 file
      $u->setMaxFiles(1); 
      // tell it to rename rather than overwrite existing files
      $u->setOverwrite(f); 
      // have it put the files in their final destination. this should be okay since
      // the WireUpload class will only create PW compatible filenames
      $u->setDestinationPath($page->files->path); 
      // tell it what extensions to expect
      $u->setValidExtensions(array('doc', 'docx', 'txt', 'xls', 'xlsx', 'pdf', 'png', 'jpg', 'jpeg', 'gif')); 
      // execute() returns an array, so we'll foreach() it even though only 1 file
      foreach($u->execute() as $filename) $page->files->add($filename);
      $page->save();
      $page->of(true);

      $doc_type = $_FILES["upload_file"]["type"];
      $allowed_doc_types = array(
        'application/msword', 
        'application/vnd.openxmlformats-officedocument.wordprocessingml.document',
        'text/plain', 
        'image/jpeg', 
        'image/pjpeg', 
        'image/gif', 
        'application/excel',
        'application/vnd.ms-excel',
        'application/x-excel',
        'application/png',
        'application/pdf',

      );


      if (!in_array($doc_type, $allowed_doc_types)) {
        echo "<h5>Sorry, that is not a valid extension. Please ensure it is one of the following valid extensions: doc, docx, txt, xls, xlsx, pdf, png, jpg, jpeg, gif </h5>";
        echo $form;
      }

      elseif ($_FILES["upload_file"]["size"] > 500000) {
        echo "<h5>Sorry, that file is too large. Please ensure your file is 500kb or less in size.</h5>";
        echo $form;
      }

      else {

      echo "<h3>Thank you. Your file has been uploaded.</h3>";
      echo "<p>Please <a href='{$config->urls->root}students/{$page->name}'>click here</a> to return to your profile page</p>";

      require_once("./scripts/PHPMailer/class.phpmailer.php");

      $to_name = "Company Name";
      $to = "me@gmail.com";
      $subject = "Student {$page->name} has uploaded a document";
      $form_message = "
      <h4>{$page->name} has uploaded a document to their profile.<h4>
      <p>You can visit their profile <a href={$page->httpUrl}>here</a>.</p>
      <p>Alternatively, you can visit the page in the admin by clicking <a href='http://localhost/admin/page/edit/?id={$page->id}'>here</a>.</p>
      <p>http://localhost{$page->files->last()->url}</p>
      ";

      $doc_path = "http://localhost{$page->files->last()->url}";
      $doc_name = "http://localhost{$page->files->last()->filename}";
      
      
      $from = "webmaster@company.com";
      $from_name = "Webmaster - Company Name";

      $mail = new PHPMailer();

      $mail->IsSMTP();
      $mail->CharSet = 'UTF-8';
      $mail->Host = "smtp.gmail.com";
      $mail->SMTPAuth = true;
      $mail->SMTPSecure = "ssl";
      $mail->Username = "me@gmail.com";
      $mail->Password = "mypass";
      $mail->Port = "465";

      $mail->From = "$from";
      $mail->FromName = "$from_name";
      $mail->AddAddress($to, $to_name);

      $mail->WordWrap = 50;                         
      $mail->IsHTML(true);                                

      $mail->Subject = "$subject";
      $mail->Body    = "$form_message";
      $mail->AddAttachment($doc_path);

      $mail->Send();

      }

    } else { // end if file has been submitted

      // form has been submitted but something went wrong
      $formerror = 1;
      echo "<h5>Sorry there was a problem uploading your files. Please ensure they have a valid extension.</h5>";
      echo $form;

    } // end invalid file

  } // end if form has been submitted 
     
   else {
    echo "<h3>Upload documents</h3>";
    echo "<p>Please feel free to upload your document {$page->first_name} with any of the following valid file extensions - doc, docx, xls, xlsx, pdf, png, jpg, jpeg, gif. Please also ensure it is 500kb or less in size.";
    echo $form;      
   }

?>