// Copyright 2019 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.bigquery.v2;

import "google/cloud/bigquery/v2/model_reference.proto";
import "google/cloud/bigquery/v2/standard_sql.proto";
import "google/protobuf/empty.proto";
import "google/protobuf/timestamp.proto";
import "google/protobuf/wrappers.proto";
import "google/api/annotations.proto";

option go_package = "google.golang.org/genproto/googleapis/cloud/bigquery/v2;bigquery";
option java_outer_classname = "ModelProto";
option java_package = "com.google.cloud.bigquery.v2";


service ModelService {
  // Gets the specified model resource by model ID.
  rpc GetModel(GetModelRequest) returns (Model) {
  }

  // Lists all models in the specified dataset. Requires the READER dataset
  // role.
  rpc ListModels(ListModelsRequest) returns (ListModelsResponse) {
  }

  // Patch specific fields in the specified model.
  rpc PatchModel(PatchModelRequest) returns (Model) {
  }

  // Deletes the model specified by modelId from the dataset.
  rpc DeleteModel(DeleteModelRequest) returns (google.protobuf.Empty) {
  }
}

message Model {
  // Evaluation metrics for regression models.
  message RegressionMetrics {
    // Mean absolute error.
    google.protobuf.DoubleValue mean_absolute_error = 1;

    // Mean squared error.
    google.protobuf.DoubleValue mean_squared_error = 2;

    // Mean squared log error.
    google.protobuf.DoubleValue mean_squared_log_error = 3;

    // Median absolute error.
    google.protobuf.DoubleValue median_absolute_error = 4;

    // R^2 score.
    google.protobuf.DoubleValue r_squared = 5;
  }

  // Aggregate metrics for classification models. For multi-class models,
  // the metrics are either macro-averaged: metrics are calculated for each
  // label and then an unweighted average is taken of those values or
  // micro-averaged: the metric is calculated globally by counting the total
  // number of correctly predicted rows.
  message AggregateClassificationMetrics {
    // Precision is the fraction of actual positive predictions that had
    // positive actual labels. For multiclass this is a macro-averaged
    // metric treating each class as a binary classifier.
    google.protobuf.DoubleValue precision = 1;

    // Recall is the fraction of actual positive labels that were given a
    // positive prediction. For multiclass this is a macro-averaged metric.
    google.protobuf.DoubleValue recall = 2;

    // Accuracy is the fraction of predictions given the correct label. For
    // multiclass this is a micro-averaged metric.
    google.protobuf.DoubleValue accuracy = 3;

    // Threshold at which the metrics are computed. For binary
    // classification models this is the positive class threshold.
    // For multi-class classfication models this is the confidence
    // threshold.
    google.protobuf.DoubleValue threshold = 4;

    // The F1 score is an average of recall and precision. For multiclass
    // this is a macro-averaged metric.
    google.protobuf.DoubleValue f1_score = 5;

    // Logarithmic Loss. For multiclass this is a macro-averaged metric.
    google.protobuf.DoubleValue log_loss = 6;

    // Area Under a ROC Curve. For multiclass this is a macro-averaged
    // metric.
    google.protobuf.DoubleValue roc_auc = 7;
  }

  // Evaluation metrics for binary classification models.
  message BinaryClassificationMetrics {
    // Confusion matrix for binary classification models.
    message BinaryConfusionMatrix {
      // Threshold value used when computing each of the following metric.
      google.protobuf.DoubleValue positive_class_threshold = 1;

      // Number of true samples predicted as true.
      google.protobuf.Int64Value true_positives = 2;

      // Number of false samples predicted as true.
      google.protobuf.Int64Value false_positives = 3;

      // Number of true samples predicted as false.
      google.protobuf.Int64Value true_negatives = 4;

      // Number of false samples predicted as false.
      google.protobuf.Int64Value false_negatives = 5;

      // Aggregate precision.
      google.protobuf.DoubleValue precision = 6;

      // Aggregate recall.
      google.protobuf.DoubleValue recall = 7;
    }

    // Aggregate classification metrics.
    AggregateClassificationMetrics aggregate_classification_metrics = 1;

    // Binary confusion matrix at multiple thresholds.
    repeated BinaryConfusionMatrix binary_confusion_matrix_list = 2;
  }

  // Evaluation metrics for multi-class classification models.
  message MultiClassClassificationMetrics {
    // Confusion matrix for multi-class classification models.
    message ConfusionMatrix {
      // A single entry in the confusion matrix.
      message Entry {
        // The predicted label. For confidence_threshold > 0, we will
        // also add an entry indicating the number of items under the
        // confidence threshold.
        string predicted_label = 1;

        // Number of items being predicted as this label.
        google.protobuf.Int64Value item_count = 2;
      }

      // A single row in the confusion matrix.
      message Row {
        // The original label of this row.
        string actual_label = 1;

        // Info describing predicted label distribution.
        repeated Entry entries = 2;
      }

      // Confidence threshold used when computing the entries of the
      // confusion matrix.
      google.protobuf.DoubleValue confidence_threshold = 1;

      // One row per actual label.
      repeated Row rows = 2;
    }

    // Aggregate classification metrics.
    AggregateClassificationMetrics aggregate_classification_metrics = 1;

    // Confusion matrix at different thresholds.
    repeated ConfusionMatrix confusion_matrix_list = 2;
  }

  // Evaluation metrics for clustering models.
  message ClusteringMetrics {
    // Davies-Bouldin index.
    google.protobuf.DoubleValue davies_bouldin_index = 1;

    // Mean of squared distances between each sample to its cluster centroid.
    google.protobuf.DoubleValue mean_squared_distance = 2;
  }

  // Evaluation metrics of a model. These are either computed on all
  // training data or just the eval data based on whether eval data was used
  // during training.
  message EvaluationMetrics {
    oneof metrics {
      // Populated for regression models.
      RegressionMetrics regression_metrics = 1;

      // Populated for binary classification models.
      BinaryClassificationMetrics binary_classification_metrics = 2;

      // Populated for multi-class classification models.
      MultiClassClassificationMetrics multi_class_classification_metrics = 3;

      // [Beta] Populated for clustering models.
      ClusteringMetrics clustering_metrics = 4;
    }
  }

  // Information about a single training query run for the model.
  message TrainingRun {
    message TrainingOptions {
      // The maximum number of iterations in training.
      int64 max_iterations = 1;

      // Type of loss function used during training run.
      LossType loss_type = 2;

      // Learning rate in training.
      double learn_rate = 3;

      // L1 regularization coefficient.
      google.protobuf.DoubleValue l1_regularization = 4;

      // L2 regularization coefficient.
      google.protobuf.DoubleValue l2_regularization = 5;

      // When early_stop is true, stops training when accuracy improvement is
      // less than 'min_relative_progress'.
      google.protobuf.DoubleValue min_relative_progress = 6;

      // Whether to train a model from the last checkpoint.
      google.protobuf.BoolValue warm_start = 7;

      // Whether to stop early when the loss doesn't improve significantly
      // any more (compared to min_relative_progress).
      google.protobuf.BoolValue early_stop = 8;

      // Name of input label columns in training data.
      repeated string input_label_columns = 9;

      // The data split type for training and evaluation, e.g. RANDOM.
      DataSplitMethod data_split_method = 10;

      // The fraction of evaluation data over the whole input data. The rest
      // of data will be used as training data. The format should be double.
      // Accurate to two decimal places.
      // Default value is 0.2.
      double data_split_eval_fraction = 11;

      // The column to split data with. This column won't be used as a
      // feature.
      // 1. When data_split_method is CUSTOM, the corresponding column should
      // be boolean. The rows with true value tag are eval data, and the false
      // are training data.
      // 2. When data_split_method is SEQ, the first DATA_SPLIT_EVAL_FRACTION
      // rows (from smallest to largest) in the corresponding column are used
      // as training data, and the rest are eval data. It respects the order
      // in Orderable data types:
      // https://cloud.google.com/bigquery/docs/reference/standard-sql/data-types#data-type-properties
      string data_split_column = 12;

      // The strategy to determine learning rate.
      LearnRateStrategy learn_rate_strategy = 13;

      // Specifies the initial learning rate for line search to start at.
      double initial_learn_rate = 16;

      // Weights associated with each label class, for rebalancing the
      // training data.
      map<string, double> label_class_weights = 17;

      // [Beta] Distance type for clustering models.
      DistanceType distance_type = 20;

      // [Beta] Number of clusters for clustering models.
      int64 num_clusters = 21;
    }

    // Information about a single iteration of the training run.
    message IterationResult {
      // Information about a single cluster for clustering model.
      message ClusterInfo {
        // Centroid id.
        int64 centroid_id = 1;

        // Cluster radius, the average distance from centroid
        // to each point assigned to the cluster.
        google.protobuf.DoubleValue cluster_radius = 2;

        // Cluster size, the total number of points assigned to the cluster.
        google.protobuf.Int64Value cluster_size = 3;
      }

      // Index of the iteration, 0 based.
      google.protobuf.Int32Value index = 1;

      // Time taken to run the iteration in milliseconds.
      google.protobuf.Int64Value duration_ms = 4;

      // Loss computed on the training data at the end of iteration.
      google.protobuf.DoubleValue training_loss = 5;

      // Loss computed on the eval data at the end of iteration.
      google.protobuf.DoubleValue eval_loss = 6;

      // Learn rate used for this iteration.
      double learn_rate = 7;

      // [Beta] Information about top clusters for clustering models.
      repeated ClusterInfo cluster_infos = 8;
    }

    // Options that were used for this training run, includes
    // user specified and default options that were used.
    TrainingOptions training_options = 1;

    // The start time of this training run.
    google.protobuf.Timestamp start_time = 8;

    // Output of each iteration run, results.size() <= max_iterations.
    repeated IterationResult results = 6;

    // The evaluation metrics over training/eval data that were computed at the
    // end of training.
    EvaluationMetrics evaluation_metrics = 7;
  }

  // Indicates the type of the Model.
  enum ModelType {
    MODEL_TYPE_UNSPECIFIED = 0;

    // Linear regression model.
    LINEAR_REGRESSION = 1;

    // Logistic regression model.
    LOGISTIC_REGRESSION = 2;

    // [Beta] K-means clustering model.
    KMEANS = 3;
  }

  // Loss metric to evaluate model training performance.
  enum LossType {
    LOSS_TYPE_UNSPECIFIED = 0;

    // Mean squared loss, used for linear regression.
    MEAN_SQUARED_LOSS = 1;

    // Mean log loss, used for logistic regression.
    MEAN_LOG_LOSS = 2;
  }

  // Distance metric used to compute the distance between two points.
  enum DistanceType {
    DISTANCE_TYPE_UNSPECIFIED = 0;

    // Eculidean distance.
    EUCLIDEAN = 1;

    // Cosine distance.
    COSINE = 2;
  }

  // Indicates the method to split input data into multiple tables.
  enum DataSplitMethod {
    DATA_SPLIT_METHOD_UNSPECIFIED = 0;

    // Splits data randomly.
    RANDOM = 1;

    // Splits data with the user provided tags.
    CUSTOM = 2;

    // Splits data sequentially.
    SEQUENTIAL = 3;

    // Data split will be skipped.
    NO_SPLIT = 4;

    // Splits data automatically: Uses NO_SPLIT if the data size is small.
    // Otherwise uses RANDOM.
    AUTO_SPLIT = 5;
  }

  // Indicates the learning rate optimization strategy to use.
  enum LearnRateStrategy {
    LEARN_RATE_STRATEGY_UNSPECIFIED = 0;

    // Use line search to determine learning rate.
    LINE_SEARCH = 1;

    // Use a constant learning rate.
    CONSTANT = 2;
  }

  // Output only. A hash of this resource.
  string etag = 1;

  // Required. Unique identifier for this model.
  ModelReference model_reference = 2;

  // Output only. The time when this model was created, in millisecs since the
  // epoch.
  int64 creation_time = 5;

  // Output only. The time when this model was last modified, in millisecs
  // since the epoch.
  int64 last_modified_time = 6;

  // [Optional] A user-friendly description of this model.
  // @mutable bigquery.models.patch
  string description = 12;

  // [Optional] A descriptive name for this model.
  // @mutable bigquery.models.patch
  string friendly_name = 14;

  // [Optional] The labels associated with this model. You can use these to
  // organize and group your models. Label keys and values can be no longer
  // than 63 characters, can only contain lowercase letters, numeric
  // characters, underscores and dashes. International characters are allowed.
  // Label values are optional. Label keys must start with a letter and each
  // label in the list must have a different key.
  // @mutable bigquery.models.patch
  map<string, string> labels = 15;

  // [Optional] The time when this model expires, in milliseconds since the
  // epoch. If not present, the model will persist indefinitely. Expired models
  // will be deleted and their storage reclaimed.  The defaultTableExpirationMs
  // property of the encapsulating dataset can be used to set a default
  // expirationTime on newly created models.
  // @mutable bigquery.models.patch
  int64 expiration_time = 16;

  // Output only. The geographic location where the model resides. This value
  // is inherited from the dataset.
  string location = 13;

  // Output only. Type of the model resource.
  ModelType model_type = 7;

  // Output only. Information for all training runs in increasing order of
  // start_time.
  repeated TrainingRun training_runs = 9;

  // Output only. Input feature columns that were used to train this model.
  repeated StandardSqlField feature_columns = 10;

  // Output only. Label columns that were used to train this model.
  // The output of the model will have a “predicted_” prefix to these columns.
  repeated StandardSqlField label_columns = 11;
}

message GetModelRequest {
  // Project ID of the requested model.
  string project_id = 1;

  // Dataset ID of the requested model.
  string dataset_id = 2;

  // Model ID of the requested model.
  string model_id = 3;
}

message PatchModelRequest {
  // Project ID of the model to patch.
  string project_id = 1;

  // Dataset ID of the model to patch.
  string dataset_id = 2;

  // Model ID of the model to patch.
  string model_id = 3;

  // Patched model.
  // Follows patch semantics. Missing fields are not updated. To clear a field,
  // explicitly set to default value.
  Model model = 4;
}

message DeleteModelRequest {
  // Project ID of the model to delete.
  string project_id = 1;

  // Dataset ID of the model to delete.
  string dataset_id = 2;

  // Model ID of the model to delete.
  string model_id = 3;
}

message ListModelsRequest {
  // Project ID of the models to list.
  string project_id = 1;

  // Dataset ID of the models to list.
  string dataset_id = 2;

  // The maximum number of results per page.
  google.protobuf.UInt32Value max_results = 3;

  // Page token, returned by a previous call to request the next page of
  // results
  string page_token = 4;
}

message ListModelsResponse {
  // Models in the requested dataset. Only the following fields are populated:
  // model_reference, model_type, creation_time, last_modified_time and
  // labels.
  repeated Model models = 1;

  // A token to request the next page of results.
  string next_page_token = 2;
}
