Doctrine query with relationships and count - php

Question

I am trying to do a complex query in Doctrine but had no luck so far.
I had an Entity called Category.
Category has reports (1 to many)
Category has subcategories (1 to many self referencing)
class Category extends
{
/**
* #var integer
*
* #ORM\Column(name="id", type="integer")
* #ORM\Id
* #ORM\GeneratedValue(strategy="AUTO")
* #Expose
*/
private $id;
/**
* #var string
*
* #ORM\Column(name="name", type="string", length=255)
* #Expose
*/
private $name;
/**
* #ORM\OneToMany(targetEntity=".....\Category", mappedBy="parentCategory", cascade={"persist"})
*
* #MaxDepth(1)
*
* #Expose
*
**/
private $subcategories;
/**
* #ORM\ManyToOne(targetEntity="....\Category", inversedBy="subcategories", cascade={"persist"})
* #ORM\JoinColumn(name="idparent", referencedColumnName="id", nullable=true)
*
* #Expose
*/
private $parentCategory;
/**
* #ORM\OneToMany(targetEntity="....\Report", mappedBy="category")
*/
private $reports;
I use these entities in a rest API set up in symfony with FosRestBundle and HATEOASBundle.
So my objective is to return the following:
All parent categories (categories with idparent=null, meaning they are roots) with total_count reports and total_sum_reports of their subcategpories, with their subcategories with total_count reports and total_sum_reports.
Something like that:
name: parentCategory1
total_reports: 20
total_amount 100
subcategories: [
[name: child 1, total_reports: 15, total_amount 80],
[name: child 2, total_reports: 5, total_amount 20],
]
Unfortunately haven't figured this out.
How to take all info in need into a single json object?
Is it possible with Doctrine take all this into a big object or need to create this manually?