// Copyright 2025 PingCAP, Inc.
//
// 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 = "proto2";

package dtpb;

enum IndexFileKind {
    INVALID = 0;
    VECTOR_INDEX = 1;
    INVERTED_INDEX = 2;
    FULLTEXT_INDEX = 3;
}

message IndexFilePropsV2 {
    optional IndexFileKind kind = 1;
    optional int64 index_id = 2;  // For which index ID
    optional uint64 file_size = 3;

    oneof prop {
        IndexFilePropsV2Vector vector_index = 31;
        IndexFilePropsInverted inverted_index = 32;
        IndexFilePropsV2Fulltext fulltext_index = 33;
    }
}

// Note: This message is something different to VectorIndexDefinition.
// VectorIndexDefinition defines an index, comes from table DDL.
// It includes information about how index should be constructed,
// for example, it contains HNSW's 'efConstruct' parameter.
// However, IndexFilePropsV2Vector provides information for read out the index,
// for example, very basic information about what the index is, and how it is stored.
message IndexFilePropsV2Vector {
    optional uint32 format_version = 1; // Currently it must be 0.
    optional string distance_metric = 2;  // The value is tipb.VectorDistanceMetric
    optional uint64 dimensions = 3;
}

message IndexFilePropsV2Fulltext {
    optional uint32 format_version = 1; // Currently it must be 0.
}

message IndexFilePropsInverted {
    optional uint32 uncompressed_size = 1;
}