Venus integration

[Havoc19]

Rebalancing Contract -

repay Function:

• The repay function is used to pay back any tokens that the portfolio borrowed.
• It does this by calling another part of the system called the BorrowManager, which handles the actual repayment.
• Sometimes, the function might take out a short-term loan (a flash loan) to help repay what was borrowed.
• After everything is repaid, the system might record the repayment, but that part isn’t shown in the code snippet.

borrow Function:

• The borrow function is used to borrow tokens from a pool, using some of the portfolio's tokens as collateral (like a security deposit).
• First, it makes sure the collateral is set up correctly by interacting with the system to "enter" the market with the token that will be used as collateral.
• Then, it actually borrows the tokens from the pool.
• Finally, it updates the list of tokens in the portfolio to make sure everything is balanced correctly after the borrowing.

Key Players:

• BorrowManager: Handles repaying borrowed tokens.
• AssetHandler: Helps with the borrowing process by connecting to the right markets.

BorrowManager Contract -

The BorrowManager contract is responsible for managing the borrowing and repayment processes within a DeFi protocol. Here’s a simple breakdown:

1. Repayment Handling:

   • The repayDeposit function handles the repayment of borrowed tokens when a user withdraws from the portfolio. It calculates the amount owed based on the user's share of the total supply and uses flash loans to repay the debt.
   • The repayVault function is specifically designed to repay the entire debt of the vault. It initiates a flash loan from a specified pool, uses the borrowed amount to repay the debt, and handles token swaps as needed.

2. Flash Loan Callback:

   • The algebraFlashCallback function is a special callback that gets triggered after receiving a flash loan. It handles the actual repayment of the debt, performs necessary token swaps, and ensures that the flash loan is repaid with the required fees.

3. Flash Loan and Debt Management:

   • The contract uses Algebra pools for flash loans, which are short-term loans that must be repaid within the same transaction. It encodes all necessary data for the flash loan process, including which tokens to borrow and repay, how much to borrow, and any associated swaps.

Key Functions:

• repayDeposit: Repays borrowed tokens when a user withdraws from the portfolio using flash loans.
• repayVault: Repays the entire vault's debt using flash loans and handles necessary swaps.
• algebraFlashCallback: Executes the repayment and swaps after receiving a flash loan and ensures the loan is repaid with fees.

Key Components:

• Flash Loans: Short-term loans used to repay debts.
• AssetHandler: Manages interactions with assets, including getting account data and processing loans.

Portfolio Contract -

_borrowManager.repayDeposit(
  _portfolioTokenAmount,
  totalSupplyPortfolio,
  repayData
);

Here, it first repays the borrowed tokens based on user's share, and then rest of the process of withdrawal goes on