class GroupItem
{
    /**
     * Creates a new combo group item and returns it
     *
     * @author Evan D Shaw <evandanielshaw@gmail.com>
     * @param array $args
     * @param array $payload
     * @return GenericError|GroupItemType
     */
    public function create(array $args, array $payload) {
        $requiredFields = ['welitemSkuMetaId'];
        foreach ($requiredFields as $field) {
            if (empty($payload[$field])) {
                return Master::getErrorStore()->getErrorResponse(ErrorStore::REQUIRED_FIELDS_MISSING, [$field]);
            }
        }

        $groupId = (int)$args['groupId'];
        $welitemSkuMetaId = (int)$payload['welitemSkuMetaId'];
        $priceModifier = !empty($payload['priceModifier']) ? (float)$payload['priceModifier'] : 0;
        $itemLabel = !empty($payload['itemLabel']) ? (string)$payload['itemLabel'] : '';
        $itemQuantity = !empty($payload['itemQuantity']) ? (int)$payload['itemQuantity'] : 1;
        $itemQuantity = $itemQuantity < 1 ? 1 : $itemQuantity;
        $position = !empty($payload['position']) ? (int)$payload['position'] : 0;

        return API\GroupItem::createGroupItem(
            $groupId,
            $welitemSkuMetaId,
            $priceModifier,
            $itemLabel,
            $itemQuantity,
            $position
        );
    }

    /**
     * Gets a group item by id or returns all group items
     *
     * @author Evan D Shaw <evandanielshaw@gmail.com>
     * @param array $args
     * @param array $payload
     * @return GenericError|GroupItemType|GroupItemType[]
     */
    public function get(array $args, array $payload) {
        $groupId = (int)$args['groupId'];
        $id = !empty($payload['itemId']) ? (int)$payload['itemId'] : null;
        if (!empty($id)) {
            return API\GroupItem::getGroupItemById($id);
        }

        return API\GroupItem::getAllGroupItemsByComboGroupId($groupId);
    }

    /**
     * Updates a combo group item and returns it
     *
     * @author Evan D Shaw <evandanielshaw@gmail.com>
     * @param array $args
     * @param array $payload
     * @return GenericError|GroupItemType
     */
    public function update(array $args, array $payload) {
        $itemId = (int)$args['itemId'];
        $priceModifier = !empty($payload['priceModifier']) ? (float)$payload['priceModifier'] : 0;
        $itemLabel = !empty($payload['itemLabel']) ? (string)$payload['itemLabel'] : '';
        $itemQuantity = !empty($payload['itemQuantity']) ? (int)$payload['itemQuantity'] : 1;
        $itemQuantity = $itemQuantity < 1 ? 1 : $itemQuantity;

        return API\GroupItem::updateGroupItem($itemId, $priceModifier, $itemLabel, $itemQuantity);
    }

    /**
     * Deletes a combo group item
     *
     * @author Evan D Shaw <evandanielshaw@gmail.com>
     * @param array $args
     * @return GenericError|string `success` on success
     */
    public function delete(array $args) {
        $itemId = (int)$args['itemId'];
        $res = API\GroupItem::deleteGroupItem($itemId);
        if ($res instanceof GenericError) {
            return $res;
        }

        return 'success';
    }

    /**
     * Re-orders all items in a group
     *
     * @author Evan D Shaw <evandanielshaw@gmail.com>
     * @param array $args
     * @param array $payload
     * @return GenericError|GroupItemType[]
     */
    public function reorder(array $args, array $payload) {
        $groupId = (int)$args['groupId'];
        $itemIds = (array)$payload['itemIds'];
        $res = API\GroupItem::reorderGroupItems($groupId, $itemIds);
        if ($res instanceof GenericError) {
            return $res;
        }

        return API\GroupItem::getAllGroupItemsByComboGroupId($groupId);
    }
}