Rari APY

1export const name = 'Rari APY';
2export const version = '0.1.0';
3export const license = 'MIT';
4export const description = 'Calculates the APY of the popular Rari Fuse pools, and returns the APY from the highest yield pool';
5
6const CTOKEN_ABI = [
7  'function supplyRatePerBlock() external view returns (uint)',
8  'function exchangeRateCurrent() external view returns (uint256)',
9];
10
11const blocksPerDay = 6570; // (13.15 seconds per block)
12const daysPerYear = 365;
13const MS_PER_YEAR = 365 * 24 * 60 * 60 * 1000;
14
15const markets: { [underlying: string]: string[] } = {
16  // Right now, we just check a few popular pools
17  // Would be great to check more pools, but we need to be careful to not have unbounded queries
18  // Would be amazing to have a subgraph to track this
19  '0x6b175474e89094c44da98b954eedeac495271d0f': [ // Dai
20    '0x989273ec41274C4227bCB878C2c26fdd3afbE70d', // 6
21    '0x7322b10db09687fe8889ad8e87f333f95104839f', // 7
22    '0x7e9ce3caa9910cc048590801e64174957ed41d43', // 8
23    '0x8E4E0257A4759559B4B1AC087fe8d80c63f20D19', // 18
24  ],
25  '0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48': [ // USDC
26    '0x94C49563a3950424a2a7790c3eF5458A2A359C7e', // 3
27    '0xdb55b77f5e8a1a41931684cf9e4881d24e6b6cc9', // 6
28    '0x53De5A7B03dc24Ff5d25ccF7Ad337a0425Dfd8D1', // 7
29  ],
30  '0xdac17f958d2ee523a2206206994597c13d831ec7': [ // USDT
31    '0x8691927a91a032c23b895130074669f52cf6b1e7', // 6
32    '0x6f95d4d251053483f41c8718c30f4f3c404a8cf2', // 18
33  ],
34}
35
36export function setup(sdk: Context) {
37  const getInterestRate = async (cToken: string): Promise<number> => {
38    const contract = sdk.ethers.getContract(cToken, CTOKEN_ABI);
39    const supplyRate = await contract.supplyRatePerBlock();
40
41    const mantissa = 10 ** 18 // TODO: decimals
42    const apy = (Math.pow((supplyRate.toString() / mantissa * blocksPerDay + 1), daysPerYear)) - 1;
43    return apy;
44  }
45
46  const getAPYForFuse = async (token: string) => {
47    const marketsForUndelrying = markets[token];
48    const apys = await Promise.all(marketsForUndelrying.map(getInterestRate));
49    const topAPY = apys.reduce((top: number, current: number) => Math.max(top, current), 0);
50    return topAPY;
51  };
52
53  const getInterestRateOverDateRangeForPool = async (pool: string, startDate: string, endDate: string): Promise<number> => {
54    const contract = sdk.ethers.getContract(pool, CTOKEN_ABI);
55
56    const [startPrice, endPrice] = await Promise.all([
57      contract.exchangeRateCurrent({ blockTag: startDate }),
58      contract.exchangeRateCurrent({ blockTag: endDate }),
59    ]);
60
61    const percentOfYear = MS_PER_YEAR / (new Date(endDate).getTime() - new Date(startDate).getTime());
62
63    const apy = Math.pow(endPrice / startPrice, percentOfYear) - 1;
64
65    return apy;
66  }
67
68  const getInterestRateOverDateRange = async (assetAddress: string, startDate: string, endDate: string): Promise<number> => {
69    const marketsForUndelrying = markets[assetAddress];
70    const apys = await Promise.all(marketsForUndelrying.map((pool: string) => getInterestRateOverDateRangeForPool(pool, startDate, endDate)));
71    const topAPY = apys.reduce((top: number, current: number) => Math.max(top, current), 0);
72    return topAPY;
73  }
74
75  sdk.register({
76    id: 'rari-fuse',
77    queries: {
78      apyCurrent: getAPYForFuse,
79      apyOverDateRange: getInterestRateOverDateRange,
80    },
81    metadata: {
82      name: 'Rari Capital Fuse Markets',
83      icon: sdk.ipfs.getDataURILoader('QmSoPnrN9369x4V7K6dYSVcX1NsHfdrJeVG5zaDJaskVrq', 'image/png'),
84    },
85  });
86}