Rex-bank

This is Ricochet project for managing fixed-rate collateral-backed lending on with interest paid in real-time via Superfluid stream. This repository contains the core smart contracts and the tests written in Typescript using the framework hardhat and the ethers library.

Smart Contract Summary

On deployment, the bank deployer specifies the following parameters via constructor:

Host: Superfluid host contract - https://docs.superfluid.finance/superfluid/protocol-developers/networks
CFA: Constant Flow Agreement Resolver - https://docs.superfluid.finance/superfluid/protocol-developers/networks
Registration Key: - Key issued by Superfluid to allow mainnet deployment. Can be blank for test/testnets
Owner: - Owner with DEFAULT_ADMIN_ROLE permissions (doesn't have to be deployer)
Interest Rate: - The annual interest rate the bank charges borrowers
Collateralization Ratio: - The loan-to-value amount borrowers must maintain to avoid a liquidation
Liquidation Penalty: - The fixed fee charged to borrowers who get liquidated
Oracle Contract: - The Tellor oracle contract from which price data will be pulled for RIC and USDC tokens

Rinkeby Testnet Basic Usage

Current Testnet Deployment: 0xEa3e612ab0f415c87740b140C21B5d7153f4FAC8

Before doing anything

Mint yourself some collateral tokens (RIC) here
Mint yourself some debt tokens (fUSDC) here
Upgrade your debt tokens to super debt tokens here
Approve rexBank for spending of collateral token
Approve rexBank for spending of super debt token (this is important because you could unintentionally face liquidation if this is not done)

1. Depositing collateral token

With enough balance and allowance for collateral token, call the below with desired amount

vaultDeposit(uint256 amount)

2. Borrow super debt token

Get correct flow rate that will yield desired borrow amount with below Borrow Amount Formula

Borrow Amount Formula:

Desired Borrow Amount * Interest Rate (APR) = Payment Flow Rate (as a yearly rate)

Example:

1000 USDCx * 2% = 20 USDCx/year

Head to Superfluid Dashboard and start a flow to the rexBank in the proper rate

3. Partial Repay / Additional Borrow

Update flow to a higher or lower rate to borrow more or partially repay loan. Use Borrow Amount Formula to reassess targeted new debt amount.

4. Full Repay / Self-Liquidate

Cancel your stream to the bank. This will attempt to pull the super debt tokens out of your wallet to repay the loan in full.

If you:

Do not have enough super debt tokens in your wallet to repay the loan in full
or have not approved the rexBank to spend your super debt tokens

You will be liquidated. Otherwise, you will have repaid the loan.

Working with the Tellor Oracle on Localhost (deprecated)

Initialize the oracle objects and get accounts:

let oracle = await TellorMaster.deployed()
let oracleAddress = (web3.utils.toChecksumAddress(oracle.address))
let oracle2 = await new web3.eth.Contract(Tellor.abi, oracleAddress)
let accounts = await web3.eth.getAccounts()

Then make a request to the oracle:

await web3.eth.sendTransaction({to: oracleAddress, from: accounts[0], gas: 4000000, data: oracle2.methods.requestData("USDT","USDT/USD",1000,0).encodeABI()})

Next, submit 5 values through mining:

await web3.eth.sendTransaction({to: oracle.address, from: accounts[1],gas:4000000, data: oracle2.methods.submitMiningSolution("nonce", 1, 1000000).encodeABI()})
await web3.eth.sendTransaction({to: oracle.address, from: accounts[2],gas:4000000, data: oracle2.methods.submitMiningSolution("nonce", 1, 1000000).encodeABI()})
await web3.eth.sendTransaction({to: oracle.address, from: accounts[3],gas:4000000, data: oracle2.methods.submitMiningSolution("nonce", 1, 1000000).encodeABI()})
await web3.eth.sendTransaction({to: oracle.address, from: accounts[4],gas:4000000, data: oracle2.methods.submitMiningSolution("nonce", 1, 1000000).encodeABI()})
await web3.eth.sendTransaction({to: oracle.address, from: accounts[5],gas:4000000, data: oracle2.methods.submitMiningSolution("nonce", 1, 1000000).encodeABI()})

Because the Bank contract is UsingTellor, you can get the current data from the oracle using:

let vars = await bank.getCurrentValue.call(1)

And the price will be contained in vars[1].

And you can update the price with:

await bank.updatePrice({from: accounts[0]})

Smoke Testing After Deployment

In addition to the unit tests, you can run these tests manually after the contract has been deployed to confirm everything works correctly through the DApp:

Update the debt and collateral token prices
As the owner, deposit debt tokens
As a borrower, deposit collateral and withdraw some debt
- Borrow and repay debt
- Add and remove collateral
- Repay all the debt and withdraw all collateral
With a borrower undercollateralized, liquidate the borrower
As the owner, withdraw collateral and debt

sade-ce / rex-bank-temp