Add rari-fuse strategy [rari-fuse]

src/strategies/index.ts

@@ -334,6 +334,7 @@ import * as solvVoucherClaimable from './solv-voucher-claimable';
 import * as h2o from './h2o';
 import * as dopamine from './dopamine';
 import * as lrcL2SubgraphBalanceOf from './lrc-l2-subgraph-balance-of';
+import * as rariFuse from './rari-fuse';
 
 const strategies = {
   'forta-shares': fortaShares,
@@ -671,7 +672,8 @@ const strategies = {
   apeswap,
   h2o,
   dopamine,
-  'lrc-l2-subgraph-balance-of': lrcL2SubgraphBalanceOf
+  'lrc-l2-subgraph-balance-of': lrcL2SubgraphBalanceOf,
+  'rari-fuse': rariFuse
 };
 
 Object.keys(strategies).forEach(function (strategyName) {

src/strategies/rari-fuse/README.md

@@ -0,0 +1,22 @@
+# rari-fuse
+
+Returns the voter's underlying collateral balances in a given Rari Fuse market (fToken).
+
+Here is an example of parameters:
+
+- `symbol` - (**Optional**, `string`) Symbol of the underlying ERC20 token
+- `token` - (**Required**, `string`) Address of the underlying token.
+- `fToken` - (**Required**, `string`) Address of the fToken (Rari Fuse market)
+
+```json
+{
+  "symbol": "BANK",
+  "token": "0x2d94AA3e47d9D5024503Ca8491fcE9A2fB4DA198",
+  "fToken": "0x250316B3E46600417654b13bEa68b5f64D61E609"
+}
+```
+
+## Reference
+
+For details about exchange rate between fTokens and underlying tokens, see
+https://docs.rari.capital/fuse/#interpreting-exchange-rates

src/strategies/rari-fuse/examples.json

@@ -0,0 +1,22 @@
+[
+  {
+    "name": "Example query",
+    "strategy": {
+      "name": "rari-fuse",
+      "params": {
+        "symbol": "BANK",
+        "token": "0x2d94AA3e47d9D5024503Ca8491fcE9A2fB4DA198",
+        "fToken": "0x250316B3E46600417654b13bEa68b5f64D61E609"
+      }
+    },
+    "network": "1",
+    "addresses": [
+      "0x3839AcF1ee7699D1F46b1BE840D8aD8317FDf757",
+      "0x0cf861f96378dbd5194d74cbe6b0424fafaed940",
+      "0x0f1d41cc51e97dc9d0cad80dc681777eed3675e3",
+      "0xb6ac0341fcf3fb507a8208d34a97f13779e1393d",
+      "0x173ff4db38c3fcde0584f8ea7930c44969a29ba4"
+    ],
+    "snapshot": 14482171
+  }
+]

src/strategies/rari-fuse/index.ts

@@ -0,0 +1,62 @@
+import { BigNumber } from '@ethersproject/bignumber';
+import { formatUnits } from '@ethersproject/units';
+import { Multicaller } from '../../utils';
+
+export const author = 'MantisClone';
+export const version = '0.1.0';
+
+const abi = [
+  'function underlying() public view returns (address)',
+  'function decimals() public view returns (uint8)',
+  'function exchangeRateStored() public view returns (uint256)',
+  'function balanceOf(address owner) external returns (uint256)'
+];
+
+export async function strategy(
+  space,
+  network,
+  provider,
+  addresses,
+  options,
+  snapshot
+): Promise<Record<string, number>> {
+  const blockTag = typeof snapshot === 'number' ? snapshot : 'latest';
+
+  const multi = new Multicaller(network, provider, abi, { blockTag });
+  multi.call('underlying', options.fToken, 'underlying', []);
+  multi.call('tokenDecimals', options.token, 'decimals', []);
+  multi.call('fTokenDecimals', options.fToken, 'decimals', []);
+  multi.call('exchangeRate', options.fToken, 'exchangeRateStored', []);
+  addresses.forEach((address) =>
+    multi.call(`fTokenBalances.${address}`, options.fToken, 'balanceOf', [
+      address
+    ])
+  );
+  const result = await multi.execute();
+
+  const underlying: string = result.underlying;
+  const tokenDecimals: BigNumber = result.tokenDecimals;
+  const fTokenDecimals: BigNumber = result.fTokenDecimals;
+  const exchangeRate: BigNumber = result.exchangeRate;
+  const fTokenBalances: Record<string, BigNumber> = result.fTokenBalances;
+
+  if (options.token !== underlying) {
+    throw new Error(
+      `token parameter doesn't match fToken.underlying(). token=${options.token}, underlying=${underlying}`
+    );
+  }
+
+  const mantissa: BigNumber = BigNumber.from(18)
+    .add(tokenDecimals)
+    .sub(fTokenDecimals);
+  const divisor: BigNumber = BigNumber.from(10).pow(mantissa);
+
+  return Object.fromEntries(
+    Object.entries(fTokenBalances).map(([address, balance]) => [
+      address,
+      parseFloat(
+        formatUnits(balance.mul(exchangeRate).div(divisor), fTokenDecimals)
+      )
+    ])
+  );
+}

src/strategies/rari-fuse/schema.json

@@ -0,0 +1,36 @@
+{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "$ref": "#/definitions/Strategy",
+  "definitions": {
+    "Strategy": {
+      "title": "Strategy",
+      "type": "object",
+      "properties": {
+        "symbol": {
+          "type": "string",
+          "title": "symbol",
+          "examples": ["e.g. BANK"],
+          "maxLength": 16
+        },
+        "token": {
+          "type": "string",
+          "title": "token",
+          "examples": ["e.g. 0x2d94AA3e47d9D5024503Ca8491fcE9A2fB4DA198"],
+          "pattern": "^0x[a-fA-F0-9]{40}$",
+          "minLength": 42,
+          "maxLength": 42
+        },
+        "fToken": {
+          "type": "string",
+          "title": "fToken",
+          "examples": ["e.g. 0x250316B3E46600417654b13bEa68b5f64D61E609"],
+          "pattern": "^0x[a-fA-F0-9]{40}$",
+          "minLength": 42,
+          "maxLength": 42
+        }
+      },
+      "required": ["token", "fToken"],
+      "additionalProperties": false
+    }
+  }
+}