public function form(Inventory $inventory, $variant = false)
    {
        return $this->form->of('inventory', function (FormGrid $form) use ($inventory, $variant) {
            if ($inventory->exists) {
                if ($variant === true) {
                    // If the inventory item exists and we're looking to create a form
                    // for a variant, we'll set the forms options accordingly.
                    $method = 'POST';
                    $url = route('maintenance.inventory.variants.store', [$inventory->getKey()]);
                    $form->submit = 'Create';
                } else {
                    // Otherwise we'll set the options to update the specified inventory item.
                    $method = 'PATCH';
                    $url = route('maintenance.inventory.update', [$inventory->getKey()]);
                    $form->submit = 'Save';
                }
            } else {
                $method = 'POST';
                $url = route('maintenance.inventory.store');
                $form->submit = 'Create';
            }

            $form->with($inventory);

            $form->attributes(compact('method', 'url'));

            $categories = Category::getSelectHierarchy('inventories');

            $metrics = Metric::all()->pluck('name', 'id');
            $metrics->put(0, 'None');

            $form->fieldset(function (Fieldset $fieldset) use ($categories, $metrics) {
                $fieldset
                    ->control('select', 'category')
                    ->value(function (Inventory $item) {
                        return $item->category_id;
                    })
                    ->options($categories);

                $fieldset
                    ->control('select', 'metric')
                    ->value(function (Inventory $item) {
                        return $item->metric_id;
                    })
                    ->options($metrics);

                $fieldset
                    ->control('input:text', 'name')
                    ->attributes([
                        'placeholder' => 'ex. Nails',
                    ]);

                $fieldset->control('input:textarea', 'description');
            });
        });
    }