// Copyright 2021 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

syntax = "proto3";

package google.cloud.retail.v2alpha;

import "google/api/field_behavior.proto";
import "google/api/resource.proto";
import "google/cloud/retail/v2alpha/common.proto";
import "google/cloud/retail/v2alpha/promotion.proto";
import "google/protobuf/duration.proto";
import "google/protobuf/field_mask.proto";
import "google/protobuf/timestamp.proto";
import "google/protobuf/wrappers.proto";

option csharp_namespace = "Google.Cloud.Retail.V2Alpha";
option go_package = "google.golang.org/genproto/googleapis/cloud/retail/v2alpha;retail";
option java_multiple_files = true;
option java_outer_classname = "ProductProto";
option java_package = "com.google.cloud.retail.v2alpha";
option objc_class_prefix = "RETAIL";
option php_namespace = "Google\\Cloud\\Retail\\V2alpha";
option ruby_package = "Google::Cloud::Retail::V2alpha";
option (google.api.resource_definition) = {
  type: "retail.googleapis.com/Branch"
  pattern: "projects/{project}/locations/{location}/catalogs/{catalog}/branches/{branch}"
};

// Product captures all metadata information of items to be recommended or
// searched.
message Product {
  option (google.api.resource) = {
    type: "retail.googleapis.com/Product"
    pattern: "projects/{project}/locations/{location}/catalogs/{catalog}/branches/{branch}/products/{product}"
  };

  // The type of this product.
  enum Type {
    // Default value. Default to
    // [Catalog.product_level_config.ingestion_product_type][google.cloud.retail.v2alpha.ProductLevelConfig.ingestion_product_type]
    // if unset.
    TYPE_UNSPECIFIED = 0;

    // The primary type.
    //
    // As the primary unit for predicting, indexing and search serving, a
    // [Type.PRIMARY][google.cloud.retail.v2alpha.Product.Type.PRIMARY]
    // [Product][google.cloud.retail.v2alpha.Product] is grouped with multiple
    // [Type.VARIANT][google.cloud.retail.v2alpha.Product.Type.VARIANT]
    // [Product][google.cloud.retail.v2alpha.Product]s.
    PRIMARY = 1;

    // The variant type.
    //
    // [Type.VARIANT][google.cloud.retail.v2alpha.Product.Type.VARIANT]
    // [Product][google.cloud.retail.v2alpha.Product]s usually share some common
    // attributes on the same
    // [Type.PRIMARY][google.cloud.retail.v2alpha.Product.Type.PRIMARY]
    // [Product][google.cloud.retail.v2alpha.Product]s, but they have variant
    // attributes like different colors, sizes and prices, etc.
    VARIANT = 2;

    // The collection type. Collection products are bundled
    // [Type.PRIMARY][google.cloud.retail.v2alpha.Product.Type.PRIMARY]
    // [Product][google.cloud.retail.v2alpha.Product]s or
    // [Type.VARIANT][google.cloud.retail.v2alpha.Product.Type.VARIANT]
    // [Product][google.cloud.retail.v2alpha.Product]s that are sold together,
    // such as a jewelry set with necklaces, earrings and rings, etc.
    COLLECTION = 3;
  }

  // Product availability. If this field is unspecified, the product is
  // assumed to be in stock.
  enum Availability {
    // Default product availability. Default to
    // [Availability.IN_STOCK][google.cloud.retail.v2alpha.Product.Availability.IN_STOCK]
    // if unset.
    AVAILABILITY_UNSPECIFIED = 0;

    // Product in stock.
    IN_STOCK = 1;

    // Product out of stock.
    OUT_OF_STOCK = 2;

    // Product that is in pre-order state.
    PREORDER = 3;

    // Product that is back-ordered (i.e. temporarily out of stock).
    BACKORDER = 4;
  }

  oneof expiration {
    // The timestamp when this product becomes unavailable for
    // [SearchService.Search][google.cloud.retail.v2alpha.SearchService.Search].
    //
    // If it is set, the [Product][google.cloud.retail.v2alpha.Product] is not
    // available for
    // [SearchService.Search][google.cloud.retail.v2alpha.SearchService.Search]
    // after [expire_time][google.cloud.retail.v2alpha.Product.expire_time].
    // However, the product can still be retrieved by
    // [ProductService.GetProduct][google.cloud.retail.v2alpha.ProductService.GetProduct]
    // and
    // [ProductService.ListProducts][google.cloud.retail.v2alpha.ProductService.ListProducts].
    //
    // [expire_time][google.cloud.retail.v2alpha.Product.expire_time] must be
    // later than
    // [available_time][google.cloud.retail.v2alpha.Product.available_time] and
    // [publish_time][google.cloud.retail.v2alpha.Product.publish_time],
    // otherwise an INVALID_ARGUMENT error is thrown.
    //
    // Corresponding properties: Google Merchant Center property
    // [expiration_date](https://support.google.com/merchants/answer/6324499).
    google.protobuf.Timestamp expire_time = 16;

    // Input only. The TTL (time to live) of the product.
    //
    // If it is set, it must be a non-negative value, and
    // [expire_time][google.cloud.retail.v2alpha.Product.expire_time] is set as
    // current timestamp plus [ttl][google.cloud.retail.v2alpha.Product.ttl].
    // The derived
    // [expire_time][google.cloud.retail.v2alpha.Product.expire_time] is
    // returned in the output and [ttl][google.cloud.retail.v2alpha.Product.ttl]
    // is left blank when retrieving the
    // [Product][google.cloud.retail.v2alpha.Product].
    //
    // If it is set, the product is not available for
    // [SearchService.Search][google.cloud.retail.v2alpha.SearchService.Search]
    // after current timestamp plus
    // [ttl][google.cloud.retail.v2alpha.Product.ttl]. However, the product can
    // still be retrieved by
    // [ProductService.GetProduct][google.cloud.retail.v2alpha.ProductService.GetProduct]
    // and
    // [ProductService.ListProducts][google.cloud.retail.v2alpha.ProductService.ListProducts].
    google.protobuf.Duration ttl = 17
        [(google.api.field_behavior) = INPUT_ONLY];
  }

  // Immutable. Full resource name of the product, such as
  // `projects/*/locations/global/catalogs/default_catalog/branches/default_branch/products/product_id`.
  string name = 1 [(google.api.field_behavior) = IMMUTABLE];

  // Immutable. [Product][google.cloud.retail.v2alpha.Product] identifier, which
  // is the final component of [name][google.cloud.retail.v2alpha.Product.name].
  // For example, this field is "id_1", if
  // [name][google.cloud.retail.v2alpha.Product.name] is
  // `projects/*/locations/global/catalogs/default_catalog/branches/default_branch/products/id_1`.
  //
  // This field must be a UTF-8 encoded string with a length limit of 128
  // characters. Otherwise, an INVALID_ARGUMENT error is returned.
  //
  // Corresponding properties: Google Merchant Center property
  // [id](https://support.google.com/merchants/answer/6324405). Schema.org
  // property [Product.sku](https://schema.org/sku).
  string id = 2 [(google.api.field_behavior) = IMMUTABLE];

  // Immutable. The type of the product. Default to
  // [Catalog.product_level_config.ingestion_product_type][google.cloud.retail.v2alpha.ProductLevelConfig.ingestion_product_type]
  // if unset.
  Type type = 3 [(google.api.field_behavior) = IMMUTABLE];

  // Variant group identifier. Must be an
  // [id][google.cloud.retail.v2alpha.Product.id], with the same parent branch
  // with this product. Otherwise, an error is thrown.
  //
  // For [Type.PRIMARY][google.cloud.retail.v2alpha.Product.Type.PRIMARY]
  // [Product][google.cloud.retail.v2alpha.Product]s, this field can only be
  // empty or set to the same value as
  // [id][google.cloud.retail.v2alpha.Product.id].
  //
  // For VARIANT [Product][google.cloud.retail.v2alpha.Product]s, this field
  // cannot be empty. A maximum of 2,000 products are allowed to share the same
  // [Type.PRIMARY][google.cloud.retail.v2alpha.Product.Type.PRIMARY]
  // [Product][google.cloud.retail.v2alpha.Product]. Otherwise, an
  // INVALID_ARGUMENT error is returned.
  //
  // Corresponding properties: Google Merchant Center property
  // [item_group_id](https://support.google.com/merchants/answer/6324507).
  // Schema.org property
  // [Product.inProductGroupWithID](https://schema.org/inProductGroupWithID).
  string primary_product_id = 4;

  // The [id][google.cloud.retail.v2alpha.Product.id] of the collection members
  // when [type][google.cloud.retail.v2alpha.Product.type] is
  // [Type.COLLECTION][google.cloud.retail.v2alpha.Product.Type.COLLECTION].
  //
  // Non-existent product ids are allowed.
  // The [type][google.cloud.retail.v2alpha.Product.type] of the members must be
  // either [Type.PRIMARY][google.cloud.retail.v2alpha.Product.Type.PRIMARY] or
  // [Type.VARIANT][google.cloud.retail.v2alpha.Product.Type.VARIANT] otherwise
  // and INVALID_ARGUMENT error is thrown. Should not set it for other types. A
  // maximum of 1000 values are allowed. Otherwise, an INVALID_ARGUMENT error is
  // return.
  repeated string collection_member_ids = 5;

  // The Global Trade Item Number (GTIN) of the product.
  //
  // This field must be a UTF-8 encoded string with a length limit of 128
  // characters. Otherwise, an INVALID_ARGUMENT error is returned.
  //
  // This field must be a Unigram. Otherwise, an INVALID_ARGUMENT error is
  // returned.
  //
  // Corresponding properties: Google Merchant Center property
  // [gtin](https://support.google.com/merchants/answer/6324461).
  // Schema.org property
  // [Product.isbn](https://schema.org/isbn),
  // [Product.gtin8](https://schema.org/gtin8),
  // [Product.gtin12](https://schema.org/gtin12),
  // [Product.gtin13](https://schema.org/gtin13), or
  // [Product.gtin14](https://schema.org/gtin14).
  //
  // If the value is not a valid GTIN, an INVALID_ARGUMENT error is returned.
  string gtin = 6;

  // Product categories. This field is repeated for supporting one product
  // belonging to several parallel categories. Strongly recommended using the
  // full path for better search / recommendation quality.
  //
  //
  // To represent full path of category, use '>' sign to separate different
  // hierarchies. If '>' is part of the category name, please replace it with
  // other character(s).
  //
  // For example, if a shoes product belongs to both
  // ["Shoes & Accessories" -> "Shoes"] and
  // ["Sports & Fitness" -> "Athletic Clothing" -> "Shoes"], it could be
  // represented as:
  //
  //      "categories": [
  //        "Shoes & Accessories > Shoes",
  //        "Sports & Fitness > Athletic Clothing > Shoes"
  //      ]
  //
  // Must be set for
  // [Type.PRIMARY][google.cloud.retail.v2alpha.Product.Type.PRIMARY]
  // [Product][google.cloud.retail.v2alpha.Product] otherwise an
  // INVALID_ARGUMENT error is returned.
  //
  // At most 250 values are allowed per
  // [Product][google.cloud.retail.v2alpha.Product]. Empty values are not
  // allowed. Each value must be a UTF-8 encoded string with a length limit of
  // 5,000 characters. Otherwise, an INVALID_ARGUMENT error is returned.
  //
  // Corresponding properties: Google Merchant Center property
  // [google_product_category][mc_google_product_category]. Schema.org property
  // [Product.category] (https://schema.org/category).
  //
  // [mc_google_product_category]:
  // https://support.google.com/merchants/answer/6324436
  repeated string categories = 7;

  // Required. Product title.
  //
  // This field must be a UTF-8 encoded string with a length limit of 1,000
  // characters. Otherwise, an INVALID_ARGUMENT error is returned.
  //
  // Corresponding properties: Google Merchant Center property
  // [title](https://support.google.com/merchants/answer/6324415). Schema.org
  // property [Product.name](https://schema.org/name).
  string title = 8 [(google.api.field_behavior) = REQUIRED];

  // The brands of the product.
  //
  // A maximum of 30 brands are allowed. Each brand must be a UTF-8 encoded
  // string with a length limit of 1,000 characters. Otherwise, an
  // INVALID_ARGUMENT error is returned.
  //
  // Corresponding properties: Google Merchant Center property
  // [brand](https://support.google.com/merchants/answer/6324351). Schema.org
  // property [Product.brand](https://schema.org/brand).
  repeated string brands = 9;

  // Product description.
  //
  // This field must be a UTF-8 encoded string with a length limit of 5,000
  // characters. Otherwise, an INVALID_ARGUMENT error is returned.
  //
  // Corresponding properties: Google Merchant Center property
  // [description](https://support.google.com/merchants/answer/6324468).
  // Schema.org property [Product.description](https://schema.org/description).
  string description = 10;

  // Language of the title/description and other string attributes. Use language
  // tags defined by [BCP 47](https://www.rfc-editor.org/rfc/bcp/bcp47.txt).
  //
  // For product prediction, this field is ignored and the model automatically
  // detects the text language. The
  // [Product][google.cloud.retail.v2alpha.Product] can include text in
  // different languages, but duplicating
  // [Product][google.cloud.retail.v2alpha.Product]s to provide text in multiple
  // languages can result in degraded model performance.
  //
  // For product search this field is in use. It defaults to "en-US" if unset.
  string language_code = 11;

  // Highly encouraged. Extra product attributes to be included. For example,
  // for products, this could include the store name, vendor, style, color, etc.
  // These are very strong signals for recommendation model, thus we highly
  // recommend providing the attributes here.
  //
  // Features that can take on one of a limited number of possible values. Two
  // types of features can be set are:
  //
  // Textual features. some examples would be the brand/maker of a product, or
  // country of a customer. Numerical features. Some examples would be the
  // height/weight of a product, or age of a customer.
  //
  // For example: `{ "vendor": {"text": ["vendor123", "vendor456"]},
  // "lengths_cm": {"numbers":[2.3, 15.4]}, "heights_cm": {"numbers":[8.1, 6.4]}
  // }`.
  //
  // This field needs to pass all below criteria, otherwise an INVALID_ARGUMENT
  // error is returned:
  //
  // * Max entries count: 200.
  // * The key must be a UTF-8 encoded string with a length limit of 128
  //   characters.
  // * For indexable attribute, the key must match the pattern:
  //   `[a-zA-Z0-9][a-zA-Z0-9_]*`. For example, `key0LikeThis` or
  //   `KEY_1_LIKE_THIS`.
  // * For text attributes, at most 400 values are allowed. Empty values are not
  //   allowed. Each value must be a non-empty UTF-8 encoded string with a
  //   length limit of 256 characters.
  // * For number attributes, at most 400 values are allowed.
  map<string, CustomAttribute> attributes = 12;

  // Custom tags associated with the product.
  //
  // At most 250 values are allowed per
  // [Product][google.cloud.retail.v2alpha.Product]. This value must be a UTF-8
  // encoded string with a length limit of 1,000 characters. Otherwise, an
  // INVALID_ARGUMENT error is returned.
  //
  // This tag can be used for filtering recommendation results by passing the
  // tag as part of the
  // [PredictRequest.filter][google.cloud.retail.v2alpha.PredictRequest.filter].
  //
  // Corresponding properties: Google Merchant Center property
  // [custom_label_0–4](https://support.google.com/merchants/answer/6324473).
  repeated string tags = 13;

  // Product price and cost information.
  //
  // Corresponding properties: Google Merchant Center property
  // [price](https://support.google.com/merchants/answer/6324371).
  PriceInfo price_info = 14;

  // The rating of this product.
  Rating rating = 15;

  // The timestamp when this [Product][google.cloud.retail.v2alpha.Product]
  // becomes available for
  // [SearchService.Search][google.cloud.retail.v2alpha.SearchService.Search].
  google.protobuf.Timestamp available_time = 18;

  // The online availability of the
  // [Product][google.cloud.retail.v2alpha.Product]. Default to
  // [Availability.IN_STOCK][google.cloud.retail.v2alpha.Product.Availability.IN_STOCK].
  //
  // Corresponding properties: Google Merchant Center property
  // [availability](https://support.google.com/merchants/answer/6324448).
  // Schema.org property [Offer.availability](https://schema.org/availability).
  Availability availability = 19;

  // The available quantity of the item.
  google.protobuf.Int32Value available_quantity = 20;

  // Fulfillment information, such as the store IDs for in-store pickup or
  // region IDs for different shipping methods.
  //
  // All the elements must have distinct
  // [FulfillmentInfo.type][google.cloud.retail.v2alpha.FulfillmentInfo.type].
  // Otherwise, an INVALID_ARGUMENT error is returned.
  repeated FulfillmentInfo fulfillment_info = 21;

  // Canonical URL directly linking to the product detail page.
  //
  // It is strongly recommended to provide a valid uri for the product,
  // otherwise the service performance could be significantly degraded.
  //
  // This field must be a UTF-8 encoded string with a length limit of 5,000
  // characters. Otherwise, an INVALID_ARGUMENT error is returned.
  //
  // Corresponding properties: Google Merchant Center property
  // [link](https://support.google.com/merchants/answer/6324416). Schema.org
  // property [Offer.url](https://schema.org/url).
  string uri = 22;

  // Product images for the product. We highly recommend putting the main
  // image first.
  //
  // A maximum of 300 images are allowed.
  //
  // Corresponding properties: Google Merchant Center property
  // [image_link](https://support.google.com/merchants/answer/6324350).
  // Schema.org property [Product.image](https://schema.org/image).
  repeated Image images = 23;

  // The target group associated with a given audience (e.g. male, veterans,
  // car owners, musicians, etc.) of the product.
  Audience audience = 24;

  // The color of the product.
  //
  // Corresponding properties: Google Merchant Center property
  // [color](https://support.google.com/merchants/answer/6324487). Schema.org
  // property [Product.color](https://schema.org/color).
  ColorInfo color_info = 25;

  // The size of the product. To represent different size systems or size types,
  // consider using this format: [[[size_system:]size_type:]size_value].
  //
  // For example, in "US:MENS:M", "US" represents size system; "MENS" represents
  // size type; "M" represents size value. In "GIRLS:27", size system is empty;
  // "GIRLS" represents size type; "27" represents size value. In "32 inches",
  // both size system and size type are empty, while size value is "32 inches".
  //
  // A maximum of 20 values are allowed per
  // [Product][google.cloud.retail.v2alpha.Product]. Each value must be a UTF-8
  // encoded string with a length limit of 128 characters. Otherwise, an
  // INVALID_ARGUMENT error is returned.
  //
  // Corresponding properties: Google Merchant Center property
  // [size](https://support.google.com/merchants/answer/6324492),
  // [size_type](https://support.google.com/merchants/answer/6324497), and
  // [size_system](https://support.google.com/merchants/answer/6324502).
  // Schema.org property [Product.size](https://schema.org/size).
  repeated string sizes = 26;

  // The material of the product. For example, "leather", "wooden".
  //
  // A maximum of 20 values are allowed. Each value must be a UTF-8 encoded
  // string with a length limit of 200 characters. Otherwise, an
  // INVALID_ARGUMENT error is returned.
  //
  // Corresponding properties: Google Merchant Center property
  // [material](https://support.google.com/merchants/answer/6324410). Schema.org
  // property [Product.material](https://schema.org/material).
  repeated string materials = 27;

  // The pattern or graphic print of the product. For example, "striped", "polka
  // dot", "paisley".
  //
  // A maximum of 20 values are allowed per
  // [Product][google.cloud.retail.v2alpha.Product]. Each value must be a UTF-8
  // encoded string with a length limit of 128 characters. Otherwise, an
  // INVALID_ARGUMENT error is returned.
  //
  // Corresponding properties: Google Merchant Center property
  // [pattern](https://support.google.com/merchants/answer/6324483). Schema.org
  // property [Product.pattern](https://schema.org/pattern).
  repeated string patterns = 28;

  // The condition of the product. Strongly encouraged to use the standard
  // values: "new", "refurbished", "used".
  //
  // A maximum of 1 value is allowed per
  // [Product][google.cloud.retail.v2alpha.Product]. Each value must be a UTF-8
  // encoded string with a length limit of 128 characters. Otherwise, an
  // INVALID_ARGUMENT error is returned.
  //
  // Corresponding properties: Google Merchant Center property
  // [condition](https://support.google.com/merchants/answer/6324469).
  // Schema.org property
  // [Offer.itemCondition](https://schema.org/itemCondition).
  repeated string conditions = 29;

  // The promotions applied to the product. A maximum of 10 values are allowed
  // per [Product][google.cloud.retail.v2alpha.Product]. Only
  // [Promotion.promotion_id][google.cloud.retail.v2alpha.Promotion.promotion_id]
  // will be used, other fields will be ignored if set.
  repeated Promotion promotions = 34;

  // The timestamp when the product is published by the retailer for the first
  // time, which indicates the freshness of the products. Note that this field
  // is different from
  // [available_time][google.cloud.retail.v2alpha.Product.available_time], given
  // it purely describes product freshness regardless of when it is available on
  // search and recommendation.
  google.protobuf.Timestamp publish_time = 33;

  // Indicates which fields in the
  // [Product][google.cloud.retail.v2alpha.Product]s are returned in
  // [SearchResponse][google.cloud.retail.v2alpha.SearchResponse].
  //
  // Supported fields for all [type][google.cloud.retail.v2alpha.Product.type]s:
  //
  // * [audience][google.cloud.retail.v2alpha.Product.audience]
  // * [availability][google.cloud.retail.v2alpha.Product.availability]
  // * [brands][google.cloud.retail.v2alpha.Product.brands]
  // * [color_info][google.cloud.retail.v2alpha.Product.color_info]
  // * [conditions][google.cloud.retail.v2alpha.Product.conditions]
  // * [gtin][google.cloud.retail.v2alpha.Product.gtin]
  // * [materials][google.cloud.retail.v2alpha.Product.materials]
  // * [name][google.cloud.retail.v2alpha.Product.name]
  // * [patterns][google.cloud.retail.v2alpha.Product.patterns]
  // * [price_info][google.cloud.retail.v2alpha.Product.price_info]
  // * [rating][google.cloud.retail.v2alpha.Product.rating]
  // * [sizes][google.cloud.retail.v2alpha.Product.sizes]
  // * [title][google.cloud.retail.v2alpha.Product.title]
  // * [uri][google.cloud.retail.v2alpha.Product.uri]
  //
  // Supported fields only for
  // [Type.PRIMARY][google.cloud.retail.v2alpha.Product.Type.PRIMARY] and
  // [Type.COLLECTION][google.cloud.retail.v2alpha.Product.Type.COLLECTION]:
  //
  // * [categories][google.cloud.retail.v2alpha.Product.categories]
  // * [description][google.cloud.retail.v2alpha.Product.description]
  // * [images][google.cloud.retail.v2alpha.Product.images]
  //
  // Supported fields only for
  // [Type.VARIANT][google.cloud.retail.v2alpha.Product.Type.VARIANT]:
  //
  // * Only the first image in
  // [images][google.cloud.retail.v2alpha.Product.images]
  //
  // To mark [attributes][google.cloud.retail.v2alpha.Product.attributes] as
  // retrievable, include paths of the form "attributes.key" where "key" is the
  // key of a custom attribute, as specified in
  // [attributes][google.cloud.retail.v2alpha.Product.attributes].
  //
  // For [Type.PRIMARY][google.cloud.retail.v2alpha.Product.Type.PRIMARY] and
  // [Type.COLLECTION][google.cloud.retail.v2alpha.Product.Type.COLLECTION], the
  // following fields are always returned in
  // [SearchResponse][google.cloud.retail.v2alpha.SearchResponse] by default:
  //
  // * [name][google.cloud.retail.v2alpha.Product.name]
  //
  // For [Type.VARIANT][google.cloud.retail.v2alpha.Product.Type.VARIANT], the
  // following fields are always returned in by default:
  //
  // * [name][google.cloud.retail.v2alpha.Product.name]
  // * [color_info][google.cloud.retail.v2alpha.Product.color_info]
  //
  // The maximum number of paths is 30. Otherwise, an INVALID_ARGUMENT error is
  // returned.
  //
  // Note: Returning more fields in
  // [SearchResponse][google.cloud.retail.v2alpha.SearchResponse] can increase
  // response payload size and serving latency.
  google.protobuf.FieldMask retrievable_fields = 30;

  // Output only. Product variants grouped together on primary product which
  // share similar product attributes. It's automatically grouped by
  // [primary_product_id][google.cloud.retail.v2alpha.Product.primary_product_id]
  // for all the product variants. Only populated for
  // [Type.PRIMARY][google.cloud.retail.v2alpha.Product.Type.PRIMARY]
  // [Product][google.cloud.retail.v2alpha.Product]s.
  //
  // Note: This field is OUTPUT_ONLY for
  // [ProductService.GetProduct][google.cloud.retail.v2alpha.ProductService.GetProduct].
  // Do not set this field in API requests.
  repeated Product variants = 31 [(google.api.field_behavior) = OUTPUT_ONLY];
}