Add StakingNodeInfo for MerkleStakingInfo (#277)

add staking node info

services/state/token/staking_node_info.proto

@@ -0,0 +1,91 @@
+syntax = "proto3";
+
+package proto;
+
+/*-
+ * ‌
+ * Hedera Network Services Protobuf
+ * ​
+ * Copyright (C) 2018 - 2023 Hedera Hashgraph, 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.
+ * ‍
+ */
+
+import "state/common.proto";
+import "basic_types.proto";
+
+option java_package = "com.hederahashgraph.api.proto.java";
+// <<<pbj.java_package = "com.hedera.hapi.node.state.token">>> This comment is special code for setting PBJ Compiler java package
+option java_multiple_files = true;
+
+/**
+ * First-draft representation of a Hedera Token Service staking info entity in the network Merkle tree.
+ *
+ * As with all network entities, staking info is per node and has an unique entity number represented as shard.realm.X.
+ */
+message StakingNodeInfo {
+    /**
+     * The unique entity number of the node. The shard and realm numbers are implied, based on the network
+     * this entity came from.
+     */
+    int64 node_number = 1;
+    /**
+     * The minimum stake on this node that is required for this node to have a non-zero weight to
+     * participate in the network consensus.
+     */
+    int64 min_stake = 2;
+    /**
+     * The maximum stake on this node that is considered to calculate its weight to participate in the network consensus.
+     */
+    int64 max_stake = 3;
+    /**
+     * The sum of balances of all accounts staked to this node who have opted to receive rewards.
+     */
+    int64 stake_to_reward = 4;
+    /**
+     * The sum of balances of all accounts staked to this node who have opted to decline rewards.
+     */
+    int64 stake_to_not_reward = 5;
+    /**
+     * The snapshot of stake_to_reward value at the beginning of the current staking period.
+     * This is needed for calculating rewards for current staking period without considering changes to
+     * stake_to_reward in the current staking period. It is reset at the beginning of every period.
+     */
+    int64 stake_reward_start = 6;
+    /**
+     * Tracks how much stake from stakeRewardStart will have unclaimed rewards due to accounts changing their staking
+     * metadata in a way that disqualifies them for the current period; It is reset at the beginning of every period
+     */
+    int64 unclaimed_stake_reward_start = 7;
+    /**
+     * The total amount of effective hbar staked to this node. This is sum of stake_to_reward and stake_to_not_reward.
+     * If the sum is greater than max_stake, then the effective stake is max_stake.
+     * If the sum is less than min_stake, then the effective stake is 0.
+     */
+    int64 stake = 8;
+    /**
+     * An running sum of reward rates per hbar for the last 365+1 staking periods. The first element is the
+     * is the reward up to and including the last full period that finished before the present. Second element is
+     * the reward up to and including the period before that
+     */
+    repeated int64 reward_sum_history = 9;
+    /**
+     * The consensus weight of this node in the network. This is computed based on the stake of this node
+     * at midnight UTC of the current day. If the stake of this node is less than minStake, then the weight is 0.
+     * Sum of all weights of nodes in the network should be less than 500.
+     * If the stake of this node A is greater than minStake, then the weight of this node A is calculated as:
+     * (node A stake * 500/ total stake of all nodes)
+     */
+    int32 weight = 10;
+}