How to access a model assigned by the controller from an action

gistfile1.js

import Ember from "ember";

export default Ember.Route.extend({
  setupController:function(controller){
    if(sessionStorage.user){
      var user = JSON.parse(sessionStorage.user);
      if(!user){
        this.transitionTo('login');
      }else{
        //way to go
        controller.set('user', user);
        controller.set('categories', this.store.find('category'));
        controller.set('events', this.store.find('event'));
        controller.set('newCatForm',this.store.createRecord('category'));
      }
    }else{
      this.transitionTo('login');
    }
  },
  actions:{
    newCat:function(category){
      category.save();
      this.get('controller').set('newCatForm',this.store.createRecord('category'));
    },
    editCat:function(id){
      //Not working code:
      //need to get one of the records stored in categories and set it as editCatForm..
      var cat = this.controller.get('categories')[id];
      console.log(cat);
      this.get('controller').set('editCatForm',cat);
      $('#modEditCat').modal('show');

    }
  }
});