// Copyright 2022 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.documentai.v1;

option csharp_namespace = "Google.Cloud.DocumentAI.V1";
option go_package = "cloud.google.com/go/documentai/apiv1/documentaipb;documentaipb";
option java_multiple_files = true;
option java_outer_classname = "DocumentAiDocumentSchema";
option java_package = "com.google.cloud.documentai.v1";
option php_namespace = "Google\\Cloud\\DocumentAI\\V1";
option ruby_package = "Google::Cloud::DocumentAI::V1";

// The schema defines the output of the processed document by a processor.
message DocumentSchema {
  // EntityType is the wrapper of a label of the corresponding model with
  // detailed attributes and limitations for entity-based processors. Multiple
  // types can also compose a dependency tree to represent nested types.
  message EntityType {
    // Defines the a list of enum values.
    message EnumValues {
      // The individual values that this enum values type can include.
      repeated string values = 1;
    }

    // Defines properties that can be part of the entity type.
    message Property {
      // Types of occurrences of the entity type in the document.  This
      // represents the number of instances of instances of an entity, not
      // number of mentions of an entity.  For example, a bank statement may
      // only have one `account_number`, but this account number may be
      // mentioned in several places on the document.  In this case the
      // 'account_number' would be considered a `REQUIRED_ONCE` entity type. If,
      // on the other hand, we expect a bank statement to contain the status of
      // multiple different accounts for the customers, the occurrence type will
      // be set to `REQUIRED_MULTIPLE`.
      enum OccurrenceType {
        // Unspecified occurrence type.
        OCCURRENCE_TYPE_UNSPECIFIED = 0;

        // There will be zero or one instance of this entity type.  The same
        // entity instance may be mentioned multiple times.
        OPTIONAL_ONCE = 1;

        // The entity type will appear zero or multiple times.
        OPTIONAL_MULTIPLE = 2;

        // The entity type will only appear exactly once.  The same
        // entity instance may be mentioned multiple times.
        REQUIRED_ONCE = 3;

        // The entity type will appear once or more times.
        REQUIRED_MULTIPLE = 4;
      }

      // The name of the property.  Follows the same guidelines as the
      // EntityType name.
      string name = 1;

      // A reference to the value type of the property.  This type is subject
      // to the same conventions as the `Entity.base_types` field.
      string value_type = 2;

      // Occurrence type limits the number of instances an entity type appears
      // in the document.
      OccurrenceType occurrence_type = 3;
    }

    oneof value_source {
      // If specified, lists all the possible values for this entity.  This
      // should not be more than a handful of values.  If the number of values
      // is >10 or could change frequently use the `EntityType.value_ontology`
      // field and specify a list of all possible values in a value ontology
      // file.
      EnumValues enum_values = 14;
    }

    // User defined name for the type.
    string display_name = 13;

    // Name of the type. It must be unique within the schema file and
    // cannot be a 'Common Type'.  Besides that we use the following naming
    // conventions:
    //
    // - *use `snake_casing`*
    // - name matching is case-sensitive
    // - Maximum 64 characters.
    // - Must start with a letter.
    // - Allowed characters: ASCII letters `[a-z0-9_-]`.  (For backward
    //   compatibility internal infrastructure and tooling can handle any ascii
    //   character)
    // - The `/` is sometimes used to denote a property of a type.  For example
    //   `line_item/amount`.  This convention is deprecated, but will still be
    //   honored for backward compatibility.
    string name = 1;

    // The entity type that this type is derived from.  For now, one and only
    // one should be set.
    repeated string base_types = 2;

    // Description the nested structure, or composition of an entity.
    repeated Property properties = 6;
  }

  // Metadata for global schema behavior.
  message Metadata {
    // If true, a `document` entity type can be applied to subdocument (
    // splitting). Otherwise, it can only be applied to the entire document
    // (classification).
    bool document_splitter = 1;

    // If true, on a given page, there can be multiple `document` annotations
    // covering it.
    bool document_allow_multiple_labels = 2;

    // If set, all the nested entities must be prefixed with the parents.
    bool prefixed_naming_on_properties = 6;

    // If set, we will skip the naming format validation in the schema. So the
    // string values in `DocumentSchema.EntityType.name` and
    // `DocumentSchema.EntityType.Property.name` will not be checked.
    bool skip_naming_validation = 7;
  }

  // Display name to show to users.
  string display_name = 1;

  // Description of the schema.
  string description = 2;

  // Entity types of the schema.
  repeated EntityType entity_types = 3;

  // Metadata of the schema.
  Metadata metadata = 4;
}