// Copyright 2020 The Exonum Team
//
// 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";

import "exonum/crypto/types.proto";

package exonum.proof;

option java_package = "com.exonum.messages.proof";

// Subset of ProofList elements coupled with a proof. ListProof` can assert existence of
// certain elements and that the list is shorter than the requested range of indexes.
message ListProof {
  // Array of { ProofListKey, Hash } objects.
  repeated HashedEntry proof = 1;
  // Array with list elements and their indexes.
  repeated ListProofEntry entries = 2;
  // Length of the underlying `ProofListIndex`.
  uint64 length = 3;
}

// Represents list key and corresponding hash value.
message HashedEntry {
  // Location of the node within the Merkle tree.
  ProofListKey key = 1;
  // Hash associated with the node.
  exonum.crypto.Hash hash = 2;
}

// Index of the list element and its value.
message ListProofEntry {
  // Zero-based index of the element.
  uint64 index = 1;
  // Value serialized per `BinaryValue` implementation (usually as
  // a Protobuf message, except for primitive types).
  bytes value = 2;
}

// Node position in the Merkle tree.
message ProofListKey {
  // Zero-based index of the node on the level.
  uint64 index = 1;
  // Height of the element. Should always be greater than 0.
  // 1 corresponds to the hashes of single elements, 2 to hashes
  // obtained by hashing together pairs of hashes at height 1, etc.
  uint32 height = 2;
}