BeNext token contracts

This repository contains the smart contracts for the BNXT ERC20 token. Built on Solidity ^0.8.20, it utilizes OpenZeppelin's libraries to provide advanced functionalities like upgradeability, access control, and token burning.

Functions

• ERC-20 Compatibility: Fully compatible with the ERC-20 standard.
• Upgradeability: Utilizes UUPS (Universal Upgradeable Proxy Standard) for easy upgrades.
• Fee Management: Supports setting and adjusting token transfer fees in various modes (none, fixed, percentage).
• Access Control: Restricts critical functionalities to users with specific roles.
• Burnability: Tokens can be burned to reduce the total supply.
• Batch Transfers: Allows batch processing of multiple transfers simultaneously.
• Permit: ERC-20 tokens can be spent by another address on behalf of the token owner without needing a transaction from the owner's address (via ERC-20 Permit).

Prerequisites

Before setting up the BNext smart contract, ensure that you have the following prerequisites installed:

• Node.js and npm

• Hardhat (should be installed globally)

  npm install --global hardhat-shorthand

Installation

1. Install dependencies:

   npm install

2. Configure .env file Setup following variables in .env file which is located in root directory of the project:

    POLYGONSCAN_API_KEY= // API token fetched from https://polygonscan.com/ in order to verify smart contracts
    POLYGON_MAINNET_RPC= // RPC url
    PRIVATE_KEY= // private key which is owner of smart contract
    POLYGON_TESTNET_RPC= // RPC url of the testnet if you are deploying it to amoy

3. Compile the smart contract:

   npx hardhat compile

Testing

In order to run unit tests use npx hardhat test command.

If you want to test the uniswap v3 integration, then edit the hardhat.config.ts file. Make the hardhat network be forking a real network like polygon and then run npx hardhat run scripts/testMintingLiquidityPositionUniswapV3.ts to mint the liquidity on a localhost fork.

Deployment

Edit values in deploymentConfig.ts file to configure the deployment.

Run npx hardhat deploy --network natworkName to deploy the contracts to the desired network.

Deployed contracts:

• Amoy (Polygon Testnet): 0xc6c28445a8650F970EC278C969BcE933FcE92BB5

Verify smart contract

To verify smart contract, ensure you've set POLYGONSCAN_API_KEY in .env and smart contract is deployed to the selected network. Then run following command:

npx hardhat verify --network polygon YOUR_CONTRACT_ADDRESS

NOTE: currently hardhat verify does not support amoy network

Features

Fee

In the smart contract, fee management is a key feature that allows the contract administrator to impose transaction fees on token transfers, which can be configured in different modes according to the business needs.

Fee Management

Struct Definition (FeeMode):

• feeType: Determines the type of fee applied. It can be either none, fixed, or percentage.
  • None: No fees are applied to the transactions.
  • Fixed: A fixed amount of tokens is deducted as a fee.
  • Percentage: A percentage of the transaction amount is deducted as a fee.
• feePercentageInBasisPoints: If the fee type is percentage, this value determines the fee rate. For example, 100 basis points equals 1%.
• fixedFeeAmount: If the fee type is fixed, this value is the fixed amount of tokens that will be deducted from each transaction as a fee.

Fee Application:

• The fee settings are managed by an address with the FEE_MANAGER_ROLE, which typically would be assigned to the contract administrator or a designated fee manager.

Fee Setting Functions

• setFeeMode(FeeMode memory feeMode): This function sets the fee mode. It updates the fee structure according to the input parameters (either none, fixed, or percentage).
• setFeeTreasuryAddress(address feeTreasuryAddress): Sets the treasury address where collected fees are sent.

Fee Logic in Token Transfers

• When a token transfer occurs (e.g., in the batchTransfer function), the contract checks the current fee settings.
• If the feeType is NONE, the transfer proceeds normally without any deductions.
• For a FIXED fee type, the specified fixedFeeAmount is deducted from the transferred amount and sent to the treasury address.
• For a PERCENTAGE fee type, the fee is calculated as a percentage of the transferred amount based on feePercentageInBasisPoints. This calculated fee is then deducted from the transferred amount and sent to the treasury address.

Fee Exemption:

• The contract allows for certain addresses to be exempt from fees. This is managed through the setExcludedFromFees(address account, bool isExcluded) function, which updates a mapping in the contract's storage to track which addresses are exempt.

Event Emissions:

• The BNext__AddressExcludedFromFees event is emitted whenever an address is set to be exempt from fees, providing transparency and traceability.