Order items logic with Laravel - laravel

Question

For my Laravel-application I've implemented a sort-functionality. In the list of the options I show two buttons (up and down) which trigger the functions up and down in the OptionController (see below).
Question 1
At the moment I am justing a DECIMAL(30,15) field for the sort-column in the database. I choose this 30,15 randomly. Can you give me an advice, which DECIMAL(?,?) is best for this sort field?
Question 2
I want to move the up and down logic to a place, where I can use it in different controllers with generic models (e.g. Sort::up($models, $item). What would be the right place to place such a logic? Service? Helper-function? ...?
Question 3
When I create a new item (e.g. option in my example below) I need to set the sort automatically to the sort of the last item + 1. Of course, I could do this in the controller when storing it, but can I put this logic to the model itself? And: Where can I put this logic to use it in more than one model without repeating the code?
namespace App\Http\Controllers;
use App\Models\Option;
use App\Models\Attribute;
class OptionController extends Controller
{
public function up($id, $attributeId) {
$options = Attribute::findOrFail($attributeId)->options;
$option = Option::findOrFail($id);
foreach ($options as $index => $o) {
// Search for the current position of the
// option we have to move.
if( $option->id == $o->id ) {
// Will be first element?
if( $index == 1) {
// Set the sort to current first element sort - 1
$option->sort = $options[0]->sort-1;
} else if( $index > 1) {
// Get the previous and the pre-previous items from the options
$pre = $options[$index-1]->sort;
$prepre = $options[$index-2]->sort;
$diff = ($pre - $prepre) / 2;
$option->sort = $prepre + $diff;
}
break;
}
}
$option->save();
Session::flash('message', __(':option moved up.', [ 'option' => $option->name ]));
Session::flash('message-type', 'success');
return redirect()->back();
}
public function down($id, $attributeId) {
$options = Attribute::findOrFail($attributeId)->options;
$option = Option::findOrFail($id);
foreach ($options as $index => $o) {
// Search for the current position of the
// option we have to move.
if( $option->id == $o->id ) {
// Will be last element?
if( $index == count($options)-2 ) {
// Set the sort to current last element sort + 1
$option->sort = $options[count($options)-1]->sort+1;
} else if( $index < count($options)-2) { // ???
// Get the previous and the pre-previous items from the options
$next = $options[$index+1]->sort;
$nextnext = $options[$index+2]->sort;
$diff = ($nextnext - $next) / 2;
$option->sort = $next + $diff;
}
break;
}
}
$option->save();
Session::flash('message', __(':option moved down.', [ 'option' => $option->name ]));
Session::flash('message-type', 'success');
return redirect()->back();
}
}

Answer 1

You can use a trait for this. See link for more details.