Merge pull request #7 from Onyx-Protocol/feat/nft-price-adapter

Nft price adapter

contracts/ChainlinkOracle/INFTOracle.sol

@@ -0,0 +1,12 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.5.16;
+
+// Interface for BendDAO NFT Oracle
+// https://etherscan.io/address/0x7c2a19e54e48718f6c60908a9cff3396e4ea1eba
+
+interface INFTOracle {
+
+    // get asset price
+    function getAssetPrice(address _nftContract) external view returns (uint256);
+}

contracts/ChainlinkOracle/NFTPriceAdapter.sol

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+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.5.16;
+
+import "../SafeMath.sol";
+import "./AggregatorV2V3Interface.sol";
+import "./INFTOracle.sol";
+
+contract NFTPriceAdapter {
+    using SafeMath for uint256;
+
+    AggregatorV2V3Interface public ETH_PRICE_FEED;
+    INFTOracle public NFT_PRICE_ORACLE;
+    address public NFT_CONTRACT;
+
+    uint8 public constant DECIMALS = 18;
+
+    constructor(address _ethPriceFeed, address _nftOracle, address _nftContract) public {
+        ETH_PRICE_FEED = AggregatorV2V3Interface(_ethPriceFeed);
+        NFT_PRICE_ORACLE = INFTOracle(_nftOracle);
+        NFT_CONTRACT = _nftContract;
+    }
+
+    function decimals() external view returns (uint8) {
+        return DECIMALS;
+    }
+
+    function latestRoundData() external view returns (uint80, int256, uint256, uint256, uint80) {
+        (, int256 ethPrice, , , ) = ETH_PRICE_FEED.latestRoundData();
+        uint8 ethDecimals = ETH_PRICE_FEED.decimals();
+        uint256 assetPrice = NFT_PRICE_ORACLE.getAssetPrice(NFT_CONTRACT);
+        int256 price = int256(assetPrice.mul(uint256(ethPrice)).div(10 ** ethDecimals));
+
+        return (
+            1,
+            price,
+            block.timestamp,
+            block.timestamp,
+            1
+        );
+    }
+}