/*
 * Copyright (C) 2017 Dgraph Labs, Inc. and Contributors
 *
 * 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 pb;

message KV {
  bytes key = 1;
  bytes value = 2;
  bytes user_meta = 3;
  uint64 version = 4;
  uint64 expires_at = 5;
  bytes meta = 6;

  // Stream id is used to identify which stream the KV came from.
  uint32 stream_id = 10;
  // Stream done is used to indicate end of stream.
  bool stream_done = 11;

  enum Kind {
    KEY = 0;
    DATA_KEY = 1;
    FILE = 2;
  }
  Kind kind = 12;
}

message KVList {
  repeated KV kv = 1;

  // alloc_ref used internally for memory management.
  uint64 alloc_ref = 10;
}

message ManifestChangeSet {
  // A set of changes that are applied atomically.
  repeated ManifestChange changes = 1;
}

enum EncryptionAlgorithm {
  None = 0;
  Aes = 1;
}

message Encryption {
  EncryptionAlgorithm algo = 1; // For storing type of encryption algorithm used
  bytes secret = 2; // For storing the secret key
}

message ManifestChange {
  uint64 id = 1;            // Table ID.
  enum Operation {
    CREATE = 0;
    DELETE = 1;
  }
  Operation op   = 2;
  uint32 level   = 3;       // Only used for CREATE.
  uint64 key_id  = 4;
  EncryptionAlgorithm encryption_algo = 5;
  uint32 compression = 6;   // Only used for CREATE Op.
}


// Compression specifies how a block should be compressed.
message Compression {
  // CompressionAlgorithm specifies to use which algorithm to compress a block.
  enum CompressionAlgorithm {
    // None mode indicates that a block is not compressed.
    None = 0;
    // Snappy mode indicates that a block is compressed using Snappy algorithm.
    Snappy = 1;

    // ZSTD mode indicates that a block is compressed using ZSTD algorithm.
    // ZSTD,
    Zstd = 2;

    // Lz4 mode indicates that a block is compressed using lz4 algorithm. 
    Lz4 = 3;
  }

  // compression algorithm
  CompressionAlgorithm algo = 1;
  // only for zstd, <= 0 use default(3) compression level, 1 - 21 uses the exact level of zstd compression level, >=22 use the largest compression level supported by zstd.
  int32 level = 2;
}

message Checksum {
  enum ChecksumAlgorithm {
    CRC32C = 0;
    XXHash64 = 1;
    SeaHash = 2;
  }
  ChecksumAlgorithm algo = 1; // For storing type of Checksum algorithm used
  uint64 sum = 2;
}

message DataKey {
  uint64 key_id     = 1;
  bytes  data       = 2;
  bytes  iv         = 3;
  uint64 created_at = 4;
}

message Match {
  bytes prefix = 1;
  string ignore_bytes = 2; // Comma separated with dash to represent ranges "1, 2-3, 4-7, 9"
}

message BlockOffset {
  bytes key = 1;
  uint32 offset = 2;
  uint32 len = 3;
}

message TableIndex {
  repeated BlockOffset offsets = 1;
  bytes  bloom_filter = 2;
  uint32 estimated_size = 3;
  uint64 max_version = 4;
  uint32 key_count = 5;
  uint32 uncompressed_size = 6;
  uint32 stale_data_size = 7;
}