From d2944b8e72f0b7050ae03425619f8e3b0b61f49e Mon Sep 17 00:00:00 2001
From: Danil Kovtonyuk <danx.kov@gmail.com>
Date: Fri, 26 Feb 2021 19:52:15 +1000
Subject: [PATCH] update price oracle

---
 abis/MultiCall.abi.json      | 22 +++++++++++++++++++
 abis/OffchainOracle.abi.json | 12 +++++++++++
 abis/PriceOracle.abi.json    | 28 ------------------------
 src/config.js                |  3 ++-
 src/priceWatcher.js          | 42 +++++++++++++++++++++++++++++-------
 5 files changed, 70 insertions(+), 37 deletions(-)
 create mode 100644 abis/MultiCall.abi.json
 create mode 100644 abis/OffchainOracle.abi.json
 delete mode 100644 abis/PriceOracle.abi.json

diff --git a/abis/MultiCall.abi.json b/abis/MultiCall.abi.json
new file mode 100644
index 0000000..fa6dc92
--- /dev/null
+++ b/abis/MultiCall.abi.json
@@ -0,0 +1,22 @@
+[
+  {
+    "inputs": [
+      {
+        "components": [
+          { "internalType": "address", "name": "to", "type": "address" },
+          { "internalType": "bytes", "name": "data", "type": "bytes" }
+        ],
+        "internalType": "struct MultiCall.Call[]",
+        "name": "calls",
+        "type": "tuple[]"
+      }
+    ],
+    "name": "multicall",
+    "outputs": [
+      { "internalType": "bytes[]", "name": "results", "type": "bytes[]" },
+      { "internalType": "bool[]", "name": "success", "type": "bool[]" }
+    ],
+    "stateMutability": "view",
+    "type": "function"
+  }
+]
diff --git a/abis/OffchainOracle.abi.json b/abis/OffchainOracle.abi.json
new file mode 100644
index 0000000..e5b971d
--- /dev/null
+++ b/abis/OffchainOracle.abi.json
@@ -0,0 +1,12 @@
+[
+  {
+    "inputs": [
+      { "internalType": "contract IERC20", "name": "srcToken", "type": "address" },
+      { "internalType": "contract IERC20", "name": "dstToken", "type": "address" }
+    ],
+    "name": "getRate",
+    "outputs": [{ "internalType": "uint256", "name": "weightedRate", "type": "uint256" }],
+    "stateMutability": "view",
+    "type": "function"
+  }
+]
diff --git a/abis/PriceOracle.abi.json b/abis/PriceOracle.abi.json
deleted file mode 100644
index 76c5c60..0000000
--- a/abis/PriceOracle.abi.json
+++ /dev/null
@@ -1,28 +0,0 @@
-[
-  {
-    "constant": true,
-    "inputs": [
-      {
-        "internalType": "contract IERC20[]",
-        "name": "fromTokens",
-        "type": "address[]"
-      },
-      {
-        "internalType": "uint256[]",
-        "name": "oneUnitAmounts",
-        "type": "uint256[]"
-      }
-    ],
-    "name": "getPricesInETH",
-    "outputs": [
-      {
-        "internalType": "uint256[]",
-        "name": "prices",
-        "type": "uint256[]"
-      }
-    ],
-    "payable": false,
-    "stateMutability": "view",
-    "type": "function"
-  }
-]
diff --git a/src/config.js b/src/config.js
index 4393e02..be0c5a4 100644
--- a/src/config.js
+++ b/src/config.js
@@ -8,7 +8,8 @@ module.exports = {
   httpRpcUrl: process.env.HTTP_RPC_URL,
   wsRpcUrl: process.env.WS_RPC_URL,
   oracleRpcUrl: process.env.ORACLE_RPC_URL || 'https://mainnet.infura.io/',
-  oracleAddress: '0xA2b8E7ee7c8a18ea561A5CF7C9C365592026E374',
+  offchainOracleAddress: '0x080ab73787a8b13ec7f40bd7d00d6cc07f9b24d0',
+  multiCallAddress: '0xda3c19c6fe954576707fa24695efb830d9cca1ca',
   aggregatorAddress: process.env.AGGREGATOR,
   minerMerkleTreeHeight: 20,
   privateKey: process.env.PRIVATE_KEY,
diff --git a/src/priceWatcher.js b/src/priceWatcher.js
index a0c1630..4f187f9 100644
--- a/src/priceWatcher.js
+++ b/src/priceWatcher.js
@@ -1,20 +1,46 @@
 const Redis = require('ioredis')
-const { redisUrl, oracleAddress, oracleRpcUrl } = require('./config')
+const { redisUrl, offchainOracleAddress, multiCallAddress, oracleRpcUrl } = require('./config')
 const { getArgsForOracle, setSafeInterval } = require('./utils')
 const redis = new Redis(redisUrl)
 const Web3 = require('web3')
 const web3 = new Web3(oracleRpcUrl)
 
-const priceOracleABI = require('../abis/PriceOracle.abi.json')
-const oracle = new web3.eth.Contract(priceOracleABI, oracleAddress)
+const multiCallABI = require('../abis/MultiCall.abi.json')
+const offchainOracleABI = require('../abis/OffchainOracle.abi.json')
+
+const offchainOracle = new web3.eth.Contract(offchainOracleABI)
+const multiCall = new web3.eth.Contract(multiCallABI, multiCallAddress)
 const { tokenAddresses, oneUintAmount, currencyLookup } = getArgsForOracle()
 
+const { toBN } = require('web3-utils')
+
 async function main() {
-  const prices = await oracle.methods.getPricesInETH(tokenAddresses, oneUintAmount).call()
-  const ethPrices = prices.reduce((acc, price, i) => {
-    acc[currencyLookup[tokenAddresses[i]]] = price
-    return acc
-  }, {})
+  const callData = tokenAddresses.map(address => ({
+    to: offchainOracleAddress,
+    data: offchainOracle.methods
+      .getRate(
+        address,
+        '0x0000000000000000000000000000000000000000', // rate to ETH
+      )
+      .encodeABI(),
+  }))
+
+  const { results, success } = await multiCall.methods.multicall(callData).call()
+
+  const ethPrices = {}
+  for (let i = 0; i < results.length; i++) {
+    if (!success[i]) {
+      continue
+    }
+
+    const decodedRate = web3.eth.abi.decodeParameter('uint256', results[i]).toString()
+    const numerator = toBN(oneUintAmount[i])
+    const denominator = toBN(10).pow(toBN(18)) // eth decimals
+    const price = toBN(decodedRate).mul(numerator).div(denominator)
+
+    ethPrices[currencyLookup[tokenAddresses[i]]] = price.toString()
+  }
+
   await redis.hmset('prices', ethPrices)
   console.log('Wrote following prices to redis', ethPrices)
 }