public function chargeParams()
    {
        // Build the charge array
        $chargeDetails = [
            'name'          => $this->plan->name,
            'price'         => $this->plan->price,
            'test'          => $this->plan->isTest(),
            'trial_days'    => $this->plan->hasTrial() ? $this->plan->trial_days : 0,
            'return_url'    => URL::secure(Config::get('shopify-app.billing_redirect'), ['plan_id' => $this->plan->id]),
        ];

        // Handle capped amounts for UsageCharge API
        if (isset($this->plan->capped_amount) && $this->plan->capped_amount > 0) {
            $chargeDetails['capped_amount'] = $this->plan->capped_amount;
            $chargeDetails['terms'] = $this->plan->terms;
        }

        return $chargeDetails;
    }