query relationship dates with eloquent in laravel

A am creating a calendar application with laravel as API.

I want to be able to search through activities (Activity model) and filter the months. So I have a search term and an array of certain months to filter by. This array looks like this:

array (
  0 => 
  array (
    'first_date' => '2016-03-11',
    'last_date' => '2016-03-31',
  ),
  1 => 
  array (
    'first_date' => '2016-04-01',
    'last_date' => '2016-04-30',
  ),
  2 => 
  array (
    'first_date' => '2016-05-01',
    'last_date' => '2016-05-31',
  )
  // etc...
)   

An Activity has multiple CalendarItem(s) which represents the dates of an Activity.

Now I am not really sure what would be the best approach to get the Activity models between the dates of that array.

• I can raw query the CalendarItems and retrieve the Activities via their eloquent relationship, then I would have to sort out the duplicates.
• I can use whereHas('CalendarItem', function($q){ $q->whereBetween(etc..)})

Does anyone have a good suggestion?

via Chebli Mohamed