// 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.storage.v1;

import "google/api/field_behavior.proto";
import "google/api/resource.proto";
import "google/cloud/bigquery/storage/v1/arrow.proto";
import "google/cloud/bigquery/storage/v1/avro.proto";
import "google/protobuf/timestamp.proto";

option csharp_namespace = "Google.Cloud.BigQuery.Storage.V1";
option go_package = "google.golang.org/genproto/googleapis/cloud/bigquery/storage/v1;storage";
option java_multiple_files = true;
option java_outer_classname = "StreamProto";
option java_package = "com.google.cloud.bigquery.storage.v1";
option php_namespace = "Google\\Cloud\\BigQuery\\Storage\\V1";

// Data format for input or output data.
enum DataFormat {
  DATA_FORMAT_UNSPECIFIED = 0;

  // Avro is a standard open source row based file format.
  // See https://avro.apache.org/ for more details.
  AVRO = 1;

  // Arrow is a standard open source column-based message format.
  // See https://arrow.apache.org/ for more details.
  ARROW = 2;
}

// Information about the ReadSession.
message ReadSession {
  option (google.api.resource) = {
    type: "bigquerystorage.googleapis.com/ReadSession"
    pattern: "projects/{project}/locations/{location}/sessions/{session}"
  };

  // Additional attributes when reading a table.
  message TableModifiers {
    // The snapshot time of the table. If not set, interpreted as now.
    google.protobuf.Timestamp snapshot_time = 1;
  }

  // Options dictating how we read a table.
  message TableReadOptions {
    // Names of the fields in the table that should be read. If empty, all
    // fields will be read. If the specified field is a nested field, all
    // the sub-fields in the field will be selected. The output field order is
    // unrelated to the order of fields in selected_fields.
    repeated string selected_fields = 1;

    // SQL text filtering statement, similar to a WHERE clause in a query.
    // Aggregates are not supported.
    //
    // Examples: "int_field > 5"
    //           "date_field = CAST('2014-9-27' as DATE)"
    //           "nullable_field is not NULL"
    //           "st_equals(geo_field, st_geofromtext("POINT(2, 2)"))"
    //           "numeric_field BETWEEN 1.0 AND 5.0"
    string row_restriction = 2;
  }

  // Output only. Unique identifier for the session, in the form
  // `projects/{project_id}/locations/{location}/sessions/{session_id}`.
  string name = 1 [(google.api.field_behavior) = OUTPUT_ONLY];

  // Output only. Time at which the session becomes invalid. After this time, subsequent
  // requests to read this Session will return errors. The expire_time is
  // automatically assigned and currently cannot be specified or updated.
  google.protobuf.Timestamp expire_time = 2 [(google.api.field_behavior) = OUTPUT_ONLY];

  // Immutable. Data format of the output data.
  DataFormat data_format = 3 [(google.api.field_behavior) = IMMUTABLE];

  // The schema for the read. If read_options.selected_fields is set, the
  // schema may be different from the table schema as it will only contain
  // the selected fields.
  oneof schema {
    // Output only. Avro schema.
    AvroSchema avro_schema = 4 [(google.api.field_behavior) = OUTPUT_ONLY];

    // Output only. Arrow schema.
    ArrowSchema arrow_schema = 5 [(google.api.field_behavior) = OUTPUT_ONLY];
  }

  // Immutable. Table that this ReadSession is reading from, in the form
  // `projects/{project_id}/datasets/{dataset_id}/tables/{table_id}`
  string table = 6 [
    (google.api.field_behavior) = IMMUTABLE,
    (google.api.resource_reference) = {
      type: "bigquery.googleapis.com/Table"
    }
  ];

  // Optional. Any modifiers which are applied when reading from the specified table.
  TableModifiers table_modifiers = 7 [(google.api.field_behavior) = OPTIONAL];

  // Optional. Read options for this session (e.g. column selection, filters).
  TableReadOptions read_options = 8 [(google.api.field_behavior) = OPTIONAL];

  // Output only. A list of streams created with the session.
  //
  // At least one stream is created with the session. In the future, larger
  // request_stream_count values *may* result in this list being unpopulated,
  // in that case, the user will need to use a List method to get the streams
  // instead, which is not yet available.
  repeated ReadStream streams = 10 [(google.api.field_behavior) = OUTPUT_ONLY];
}

// Information about a single stream that gets data out of the storage system.
// Most of the information about `ReadStream` instances is aggregated, making
// `ReadStream` lightweight.
message ReadStream {
  option (google.api.resource) = {
    type: "bigquerystorage.googleapis.com/ReadStream"
    pattern: "projects/{project}/locations/{location}/sessions/{session}/streams/{stream}"
  };

  // Output only. Name of the stream, in the form
  // `projects/{project_id}/locations/{location}/sessions/{session_id}/streams/{stream_id}`.
  string name = 1 [(google.api.field_behavior) = OUTPUT_ONLY];
}