From a0ae0e7a8913f41a33cc06939b8c51b813e5bcb6 Mon Sep 17 00:00:00 2001
From: Vadim Arasev <varasev@gmail.com>
Date: Fri, 18 May 2018 10:54:38 +0300
Subject: [PATCH] (Feature) BlockReward contract

Relates to https://github.com/poanetwork/RFC/issues/14
---
 contracts/BlockReward.sol             | 77 +++++++++++++++++++++++++++
 contracts/interfaces/IBlockReward.sol |  8 +++
 2 files changed, 85 insertions(+)
 create mode 100644 contracts/BlockReward.sol
 create mode 100644 contracts/interfaces/IBlockReward.sol

diff --git a/contracts/BlockReward.sol b/contracts/BlockReward.sol
new file mode 100644
index 0000000..f75ab24
--- /dev/null
+++ b/contracts/BlockReward.sol
@@ -0,0 +1,77 @@
+pragma solidity ^0.4.23;
+
+import "./interfaces/IBlockReward.sol";
+import "./interfaces/IKeysManager.sol";
+import "./interfaces/IProxyStorage.sol";
+
+
+contract BlockReward is IBlockReward {
+    address constant SYSTEM_ADDRESS = 0xffffFFFfFFffffffffffffffFfFFFfffFFFfFFfE;
+    
+    IProxyStorage public proxyStorage;
+    address public emissionFunds;
+    uint256 public blockRewardAmount;
+    uint256 public emissionFundsAmount;
+
+    modifier onlySystem {
+        require(msg.sender == SYSTEM_ADDRESS);
+        _;
+    }
+
+    constructor(
+        address _proxyStorage,
+        address _emissionFunds,
+        uint256 _blockRewardAmount,
+        uint256 _emissionFundsAmount
+    ) public {
+        require(_proxyStorage != address(0));
+        require(_blockRewardAmount != 0);
+        proxyStorage = IProxyStorage(_proxyStorage);
+        emissionFunds = _emissionFunds;
+        blockRewardAmount = _blockRewardAmount;
+        emissionFundsAmount = _emissionFundsAmount;
+    }
+
+    function reward(address[] benefactors, uint16[] kind)
+        external
+        onlySystem
+        returns (address[], uint256[])
+    {
+        require(benefactors.length == kind.length);
+        require(benefactors.length == 1);
+        require(kind[0] == 0);
+
+        address miningKey = benefactors[0];
+        address payoutKey = _getPayoutByMining(miningKey);
+
+        require(payoutKey != address(0));
+
+        uint256 receiversLength = 2;
+
+        if (emissionFunds == address(0) || emissionFundsAmount == 0) {
+            receiversLength = 1;
+        }
+
+        address[] memory receivers = new address[](receiversLength);
+        uint256[] memory rewards = new uint256[](receiversLength);
+
+        receivers[0] = payoutKey;
+        rewards[0] = blockRewardAmount;
+
+        if (receiversLength == 2) {
+            receivers[1] = emissionFunds;
+            rewards[1] = emissionFundsAmount;
+        }
+    
+        return (receivers, rewards);
+    }
+
+    function _getPayoutByMining(address _miningKey)
+    	private
+    	view
+    	returns (address)
+    {
+    	IKeysManager keysManager = IKeysManager(proxyStorage.getKeysManager());
+    	return keysManager.getPayoutByMining(_miningKey);
+    }
+}
diff --git a/contracts/interfaces/IBlockReward.sol b/contracts/interfaces/IBlockReward.sol
new file mode 100644
index 0000000..6747c81
--- /dev/null
+++ b/contracts/interfaces/IBlockReward.sol
@@ -0,0 +1,8 @@
+pragma solidity ^0.4.23;
+
+
+interface IBlockReward {
+    // Produce rewards for the given benefactors, with corresponding reward codes.
+    // Only callable by `SYSTEM_ADDRESS`
+    function reward(address[], uint16[]) external returns (address[], uint256[]);
+}