Codeigniter HMVC asset managment

I am trying to give a shot to HMVC in Codeigniter. Here is my folder structure.

-ROOT
--APPLICATION
---MODULES
----Module_Email
-----Controllers
-----Models
-----Views
-----Assets
------JS
------CSS
------IMG

To render the Module i have to use

Module::run('Module_Email');

This method will output the rendered output, an example is given below

<script type="text/javascript" src="PATH/TO/EMAIL_MODULE/JS/JS_FILE.JS"></script>
<div data-module-name="Module_Email" class="Email_wrapper">

  //RENDERED HTML CONTENT 

</div>

Now here my problem start. Normally i would like to put all my resources to header. So when i call any module, its dependence need to be added in header instead of from where its get called.

I searched a lot but i couldn't find any good methods.

Please help.

Update

Currently i have a function on my header called get_assets() which will output predefined resources to header. But i cant say which modules is going to use in pages, so the system need to check which modules are used in this page, and if its used then its dependencies need to be added on header.

Solution

I added an array to the Module class to store the assets and two functions to store/retrieve the items. Here is the source (updated Modules.php)

        # Register your assets
        public static function register_asset( $asset )
        {
           if( in_array($asset,self::$assets) === FALSE )
           {
              self::$assets[] = $asset;
           }
        }

       public static function assets()
       {
             return self::$assets;
       }

and now you can register your assets like this inside your module

Modules::register_asset('myslider.js');

You can retrieve all your assets using

Modules:assets();

Which will return an array of assets that can be processed depending up on the situation.