Add xUSD (#1724)

* overnight-finance - add xUSD

* fix comment

* fix apy calc

Author: chpotl

src/adaptors/overnight-finance/index.js

@@ -0,0 +1,115 @@
+const sdk = require('@defillama/sdk');
+const axios = require('axios');
+const utils = require('../utils');
+const { ethers } = require('ethers');
+
+const xUSD = '0xe80772Eaf6e2E18B651F160Bc9158b2A5caFCA65';
+
+const eventAbi = [
+  {
+    anonymous: false,
+    inputs: [
+      {
+        indexed: false,
+        internalType: 'uint256',
+        name: 'profit',
+        type: 'uint256',
+      },
+      {
+        indexed: false,
+        internalType: 'uint256',
+        name: 'newLiquidityIndex',
+        type: 'uint256',
+      },
+      {
+        indexed: false,
+        internalType: 'uint256',
+        name: 'excessProfit',
+        type: 'uint256',
+      },
+      {
+        indexed: false,
+        internalType: 'uint256',
+        name: 'insurancePremium',
+        type: 'uint256',
+      },
+      {
+        indexed: false,
+        internalType: 'uint256',
+        name: 'insuranceLoss',
+        type: 'uint256',
+      },
+    ],
+    name: 'PayoutEvent',
+    type: 'event',
+  },
+];
+
+const apy = async () => {
+  const totalSupply =
+    (
+      await sdk.api.abi.call({
+        target: xUSD,
+        abi: 'erc20:totalSupply',
+        chain: 'arbitrum',
+      })
+    ).output / 1e6;
+
+  const priceKey = `arbitrum:${xUSD}`;
+  const price = (
+    await axios.get(`https://coins.llama.fi/prices/current/${priceKey}`)
+  ).data.coins[priceKey].price;
+
+  const tvlUsd = totalSupply * price;
+
+  const currentBlock = await sdk.api.util.getLatestBlock('arbitrum');
+  const toBlock = currentBlock.number;
+  const topic =
+    '0x8dd3783ac3ed2cabfce0fa4347c2cab93b8273171a7e30b28a83147b099c4038';
+  const logs = (
+    await sdk.api.util.getLogs({
+      target: '0x73cb180bf0521828d8849bc8CF2B920918e23032',
+      topic: '',
+      toBlock,
+      fromBlock: 63102109,
+      keys: [],
+      topics: [topic],
+      chain: 'arbitrum',
+    })
+  ).output.sort((a, b) => b.blockNumber - a.blockNumber);
+
+  const elapsedTime =
+    (await sdk.api.util.getTimestamp(logs[0].blockNumber, 'arbitrum')) -
+    (await sdk.api.util.getTimestamp(logs[1].blockNumber, 'arbitrum'));
+
+  const iface = new ethers.utils.Interface(eventAbi);
+  const decoded = iface.parseLog(logs[0]);
+  const rewardsReceived = parseInt(decoded.args.profit / 1e6);
+  // daily compounding
+  const apyBase = calcApy(rewardsReceived, tvlUsd, elapsedTime);
+  return [
+    {
+      pool: xUSD,
+      symbol: 'xUSD',
+      project: 'overnight-finance',
+      chain: 'arbitrum',
+      tvlUsd,
+      apyBase,
+    },
+  ];
+};
+
+function calcApy(profit, totalSupply, elapsedTime) {
+  if (profit == 0) {
+    return 0;
+  }
+  const hourlyRate = (profit / totalSupply / elapsedTime) * 3600;
+  const dailyRate = hourlyRate * 24;
+  const apy = (dailyRate + 1) ** 365 - 1;
+  return apy * 100;
+}
+
+module.exports = {
+  apy,
+  url: 'https://app.overnight.fi/',
+};