prestashop file upload won't work - php

Question

I am trying to implement file upload in Order Detail page.
Created form
<form action="" method="post" id="uploadForm" enctype="multipart/form-data">
  <label for="fileUpload">{l s='File to upload:'}</label>
  <input type="hidden" name="MAX_FILE_SIZE" value="2000000" />
  <input type="file" name="fileUpload" id="fileUpload" />
<div class="submit">
<input type="hidden" name="id_order" value="{$order->id|intval}" />
<input type="submit" class="unvisible" name="submitMessage" value="{l s='Send'}"/>
<button type="submit" name="submitMessage" class="button btn btn-default button-medium"><span>{l s='Send'}<i class="icon-chevron-right right"></i></span></button>
</div>
</form>
and added this to OrderDetailController.php
if (Tools::isSubmit('submitMessage')) {
$idOrder = (int)Tools::getValue('id_order');
$msgText = Tools::getValue('msgText');
if (isset($_FILES['fileUpload']['name']) && !empty($_FILES['fileUpload']['name']) && !empty($_FILES['fileUpload']['tmp_name']))
{
$this->errors[] = Tools::displayError('Works');
}
...
Now when i submit form - it saves message and completely ignores file.
Does anyone know why?

Answer 1

Solved myself. Answered here
It was ajax issue not sending $_FILES[] data

Answer 2

I'm assuming you placed this into order-detail.tpl of default template.
You put your file input into a separate form that doesn't do anything since it does not have a submit button. The comments form on that page is a completely different one that's why your input is ignored.
What you want to do is place your html code without <form> tags into a proper form that submits message. The form is at the bottom of order-detail.tpl.
<form action="{$link->getPageLink('order-detail', true)|escape:'html':'UTF-8'}" method="post" class="std" id="sendOrderMessage">
<h3 class="page-heading bottom-indent">{l s='Add a message'}</h3>
<p>{l s='If you would like to add a comment about your order, please write it in the field below.'}</p>
<p class="form-group">
<label for="id_product">{l s='Product'}</label>
<select name="id_product" class="form-control">
<option value="0">{l s='-- Choose --'}</option>
{foreach from=$products item=product name=products}
<option value="{$product.product_id}">{$product.product_name}</option>
{/foreach}
</select>
</p>
<p class="form-group">
<textarea class="form-control" cols="67" rows="3" name="msgText"></textarea>
</p>
<!-- Your html snippet -->
<p class="form-group">
<label for="fileUpload">{l s='File to upload:'}</label>
<input type="hidden" name="MAX_FILE_SIZE" value="2000000" />
<input type="file" name="fileUpload" id="fileUpload" />
</p>
<div class="submit">
<input type="hidden" name="id_order" value="{$order->id|intval}" />
<input type="submit" class="unvisible" name="submitMessage" value="{l s='Send'}"/>
<button type="submit" name="submitMessage" class="button btn btn-default button-medium"><span>{l s='Send'}<i class="icon-chevron-right right"></i></span></button>
</div>
</form>