Technical Aspects

Contract Modules

• ERC20CollateralPool.sol: Main contract.
• ERC20CollateralPool.interface.sol: Interface for contract structures and events.
• ERC20CollateralPool.storage.sol: Storage contract for state management.
• AggregatorV3Interface.sol: Interface for Chainlink price feeds.

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Key Components

Constants

• LIQUIDATION_PROTOCOL_FEE: A fixed fee charged by the contract during liquidation.
• LIQUIDATION_FEE: A fee awarded to the liquidator as an incentive for carrying out liquidations.
• LIQUIDATION_MARGIN_FACTOR: Factor that determines whether the position is liquidatable.
• MAX_LTV_PERCENTAGE: The highest loan-to-value (LTV) ratio that can be set for a pool.
• ONE_YEAR: One year in seconds.
• BPS_DIVIDER: Basis point divider.

Initialization

• __ERC20CollateralPool_init: Initialize the contract with admin, USDC token, and pools.

Pool Management

• addPool: Add a new pool.
• announceEditPool: Announce upcoming pool edits.
• commitEditPool: Commit announced pool edits.
• cancelEditPool: Cancel announced pool edits.

Contract Control

• pause / unpause: Pause or unpause contract operations.
• withdrawProtocolRewards: Allows admin to withdraw protocol fees.

User Interactions

• lend: Supply USDC to a pool.
• borrow: Borrow USDC against collateral.
• repay: Repay borrowed USDC with interest.
• claim: Withdraw supplied USDC with rewards.
• changeCollateralAmount: Change the collateral amount of a borrow position.
• liquidate: Liquidate borrow positions that are liquidatable.
• claimCollateral: Allow to withdraw supply positions, receiving their rewards in collateral tokens by liquidate borrow positions.

Calculation Utilities

• calculateRepayInterest: Calculate repayment interest.
• calculateCollateralTokenAmount: Calculate required collateral token amount.
• isPositionLiquidatable: Calculate is a borrow position is liquidatable.

View Functions

• getPools: Get details of all pools.
• getPool: Get details of one pool.
• getLendPosition: Get details of one supply.
• getAllLendPositions: Get all user supply position in the given pool.
• getBorrowPosition: Get details of one borrow.
• getAllBorrowPositions: Get all user borrow position in the given pool.
• getCollateralTokens: Get the list of all collateral tokens.
• getCollateralTokenProtocolFee: Get protocol fees for collateral token.
• getAvailableAmountsInPool: Get available USDC and collateral token amount in a given pool.

Error Handling

Defined errors for exceptional scenarios, like PoolEndsAtIsInThePast and AdminMustNotBeZeroAddress.

Event Logging

Events like newLend, newBorrow, Repaid, RewardsClaimed, AddedCollateral, RemovedCollateral, and UserPositionLiquidated for activity tracking.

Security Features

• Pausable: Stop activities in emergencies.
• Access Control: Restricted functions for specific roles.
• Chainlink Integration: For accurate price information.

Dependencies

Uses OpenZeppelin's SafeERC20Upgradeable, AccessControlUpgradeable, PausableUpgradeable, and math utilities.

Upgradeability

Designed with OpenZeppelin's upgradeable contracts framework.

Important Considerations

• Precision and Rounding: While mathematical calculations are handled accurately, slight discrepancies may arise due to rounding and the use of different timestamps for calculating suppliers' and borrowers' rewards.
• Time Dependencies: Time-sensitive functions need careful handling.
• Security: Regular audits and reviews are recommended.