type Mutation {
    redeemLoyaltyReward(
        input: RedeemLoyaltyRewardInput!
    ): RedeemLoyaltyRewardOutput
        @resolver(class: "Mironsoft\\Loyalty\\Model\\Resolver\\RedeemLoyaltyReward")
        @doc(description: "Redeems a loyalty reward for the current customer")
}

input RedeemLoyaltyRewardInput @doc(description: "Input for redeemLoyaltyReward") {
    reward_id: Int!
}

type RedeemLoyaltyRewardOutput @doc(description: "Result of redeemLoyaltyReward") {
    reward_id: Int!
    points_spent: Int!
    points_balance_after: Int!
    redeemed_at: String!
}

<?php

declare(strict_types=1);

namespace Mironsoft\Loyalty\Model\Resolver;

use Magento\Framework\Exception\LocalizedException;
use Magento\Framework\Exception\NoSuchEntityException;
use Magento\Framework\GraphQl\Config\Element\Field;
use Magento\Framework\GraphQl\Exception\GraphQlAuthorizationException;
use Magento\Framework\GraphQl\Exception\GraphQlInputException;
use Magento\Framework\GraphQl\Exception\GraphQlNoSuchEntityException;
use Magento\Framework\GraphQl\Query\ResolverInterface;
use Magento\Framework\GraphQl\Schema\Type\ResolveInfo;
use Mironsoft\Loyalty\Api\RewardRedemptionManagementInterface;

/**
 * Resolves the redeemLoyaltyReward mutation field. Deliberately does not
 * reimplement any redemption logic - it injects the exact same
 * RewardRedemptionManagementInterface the REST endpoint in chapter 81 uses,
 * and only translates GraphQL input/context into that service contract's
 * call and its exceptions into GraphQL-flavored ones.
 */
class RedeemLoyaltyReward implements ResolverInterface
{
    /**
     * @param RewardRedemptionManagementInterface $redemptionManagement Shared redemption business logic (chapter 81).
     */
    public function __construct(
        private readonly RewardRedemptionManagementInterface $redemptionManagement,
    ) {
    }

    /**
     * @param Field $field Resolved GraphQL field configuration.
     * @param mixed $context Resolver context, carries the customer ID.
     * @param ResolveInfo $info GraphQL resolve tree info.
     * @param array|null $value Parent resolver's value, unused for a top-level field.
     * @param array|null $args Arguments passed to the redeemLoyaltyReward field (input.reward_id).
     * @return array<string, mixed>
     * @throws GraphQlAuthorizationException
     * @throws GraphQlInputException
     * @throws GraphQlNoSuchEntityException
     */
    public function resolve(
        Field $field,
        $context,
        ResolveInfo $info,
        ?array $value = null,
        ?array $args = null
    ): array {
        if (!$context->getExtensionAttributes()->getIsCustomer()) {
            throw new GraphQlAuthorizationException(
                __('The current customer isn\'t authorized.')
            );
        }

        $rewardId = (int) ($args['input']['reward_id'] ?? 0);
        $customerId = (int) $context->getUserId();

        try {
            $result = $this->redemptionManagement->redeem($rewardId, $customerId);
        } catch (NoSuchEntityException $exception) {
            throw new GraphQlNoSuchEntityException(__($exception->getMessage()), $exception);
        } catch (LocalizedException $exception) {
            // Covers the "not enough points" / "reward inactive" business rules from
            // RewardRedemptionManagement::redeem() - the same exception class chapter 81's
            // REST endpoint lets bubble up unchanged, remapped here to the GraphQL family.
            throw new GraphQlInputException(__($exception->getMessage()), $exception);
        }

        return [
            'reward_id' => $result->getRewardId(),
            'points_spent' => $result->getPointsSpent(),
            'points_balance_after' => $result->getPointsBalanceAfter(),
            'redeemed_at' => $result->getRedeemedAt(),
        ];
    }
}