RatchetToken

[
  {
    "inputs": [
      {
        "internalType": "address",
        "name": "_hook",
        "type": "address"
      },
      {
        "internalType": "address",
        "name": "_poolManager",
        "type": "address"
      },
      {
        "internalType": "address",
        "name": "_owner",
        "type": "address"
      },
      {
        "internalType": "string",
        "name": "name_",
        "type": "string"
      },
      {
        "internalType": "string",
        "name": "symbol_",
        "type": "string"
      }
    ],
    "stateMutability": "nonpayable",
    "type": "constructor"
  },
  {
    "inputs": [
      {
        "internalType": "address",
        "name": "spender",
        "type": "address"
      },
      {
        "internalType": "uint256",
        "name": "allowance",
        "type": "uint256"
      },
      {
        "internalType": "uint256",
        "name": "needed",
        "type": "uint256"
      }
    ],
    "name": "ERC20InsufficientAllowance",
    "type": "error"
  },
  {
    "inputs": [
      {
        "internalType": "address",
        "name": "sender",
        "type": "address"
      },
      {
        "internalType": "uint256",
        "name": "balance",
        "type": "uint256"
      },
      {
        "internalType": "uint256",
        "name": "needed",
        "type": "uint256"
      }
    ],
    "name": "ERC20InsufficientBalance",
    "type": "error"
  },
  {
    "inputs": [
      {
        "internalType": "address",
        "name": "approver",
        "type": "address"
      }
    ],
    "name": "ERC20InvalidApprover",
    "type": "error"
  },
  {
    "inputs": [
      {
        "internalType": "address",
        "name": "receiver",
        "type": "address"
      }
    ],
    "name": "ERC20InvalidReceiver",
    "type": "error"
  },
  {
    "inputs": [
      {
        "internalType": "address",
        "name": "sender",
        "type": "address"
      }
    ],
    "name": "ERC20InvalidSender",
    "type": "error"
  },
  {
    "inputs": [
      {
        "internalType": "address",
        "name": "spender",
        "type": "address"
      }
    ],
    "name": "ERC20InvalidSpender",
    "type": "error"
  },
  {
    "inputs": [],
    "name": "OnlyHook",
    "type": "error"
  },
  {
    "inputs": [
      {
        "internalType": "address",
        "name": "owner",
        "type": "address"
      }
    ],
    "name": "OwnableInvalidOwner",
    "type": "error"
  },
  {
    "inputs": [
      {
        "internalType": "address",
        "name": "account",
        "type": "address"
      }
    ],
    "name": "OwnableUnauthorizedAccount",
    "type": "error"
  },
  {
    "inputs": [],
    "name": "Reentrancy",
    "type": "error"
  },
  {
    "anonymous": false,
    "inputs": [
      {
        "indexed": true,
        "internalType": "address",
        "name": "owner",
        "type": "address"
      },
      {
        "indexed": true,
        "internalType": "address",
        "name": "spender",
        "type": "address"
      },
      {
        "indexed": false,
        "internalType": "uint256",
        "name": "value",
        "type": "uint256"
      }
    ],
    "name": "Approval",
    "type": "event"
  },
  {
    "anonymous": false,
    "inputs": [
      {
        "indexed": true,
        "internalType": "address",
        "name": "previousOwner",
        "type": "address"
      },
      {
        "indexed": true,
        "internalType": "address",
        "name": "newOwner",
        "type": "address"
      }
    ],
    "name": "OwnershipTransferred",
    "type": "event"
  },
  {
    "anonymous": false,
    "inputs": [
      {
        "indexed": true,
        "internalType": "address",
        "name": "account",
        "type": "address"
      },
      {
        "indexed": false,
        "internalType": "bool",
        "name": "exempt",
        "type": "bool"
      }
    ],
    "name": "TaxExemptUpdated",
    "type": "event"
  },
  {
    "anonymous": false,
    "inputs": [
      {
        "indexed": true,
        "internalType": "address",
        "name": "from",
        "type": "address"
      },
      {
        "indexed": true,
        "internalType": "address",
        "name": "to",
        "type": "address"
      },
      {
        "indexed": false,
        "internalType": "uint256",
        "name": "value",
        "type": "uint256"
      }
    ],
    "name": "Transfer",
    "type": "event"
  },
  {
    "anonymous": false,
    "inputs": [
      {
        "indexed": true,
        "internalType": "address",
        "name": "from",
        "type": "address"
      },
      {
        "indexed": true,
        "internalType": "address",
        "name": "to",
        "type": "address"
      },
      {
        "indexed": false,
        "internalType": "uint256",
        "name": "taxAmount",
        "type": "uint256"
      },
      {
        "indexed": false,
        "internalType": "uint256",
        "name": "taxBps",
        "type": "uint256"
      }
    ],
    "name": "TransferTax",
    "type": "event"
  },
  {
    "inputs": [
      {
        "internalType": "address",
        "name": "owner",
        "type": "address"
      },
      {
        "internalType": "address",
        "name": "spender",
        "type": "address"
      }
    ],
    "name": "allowance",
    "outputs": [
      {
        "internalType": "uint256",
        "name": "",
        "type": "uint256"
      }
    ],
    "stateMutability": "view",
    "type": "function"
  },
  {
    "inputs": [
      {
        "internalType": "address",
        "name": "spender",
        "type": "address"
      },
      {
        "internalType": "uint256",
        "name": "value",
        "type": "uint256"
      }
    ],
    "name": "approve",
    "outputs": [
      {
        "internalType": "bool",
        "name": "",
        "type": "bool"
      }
    ],
    "stateMutability": "nonpayable",
    "type": "function"
  },
  {
    "inputs": [
      {
        "internalType": "address",
        "name": "account",
        "type": "address"
      }
    ],
    "name": "balanceOf",
    "outputs": [
      {
        "internalType": "uint256",
        "name": "",
        "type": "uint256"
      }
    ],
    "stateMutability": "view",
    "type": "function"
  },
  {
    "inputs": [],
    "name": "decimals",
    "outputs": [
      {
        "internalType": "uint8",
        "name": "",
        "type": "uint8"
      }
    ],
    "stateMutability": "view",
    "type": "function"
  },
  {
    "inputs": [
      {
        "internalType": "uint256",
        "name": "amount",
        "type": "uint256"
      }
    ],
    "name": "estimateNetTransfer",
    "outputs": [
      {
        "internalType": "uint256",
        "name": "net",
        "type": "uint256"
      },
      {
        "internalType": "uint256",
        "name": "tax",
        "type": "uint256"
      }
    ],
    "stateMutability": "view",
    "type": "function"
  },
  {
    "inputs": [],
    "name": "hook",
    "outputs": [
      {
        "internalType": "address",
        "name": "",
        "type": "address"
      }
    ],
    "stateMutability": "view",
    "type": "function"
  },
  {
    "inputs": [
      {
        "internalType": "address",
        "name": "from",
        "type": "address"
      },
      {
        "internalType": "uint256",
        "name": "amount",
        "type": "uint256"
      }
    ],
    "name": "hookBurn",
    "outputs": [],
    "stateMutability": "nonpayable",
    "type": "function"
  },
  {
    "inputs": [
      {
        "internalType": "address",
        "name": "",
        "type": "address"
      }
    ],
    "name": "isTaxExempt",
    "outputs": [
      {
        "internalType": "bool",
        "name": "",
        "type": "bool"
      }
    ],
    "stateMutability": "view",
    "type": "function"
  },
  {
    "inputs": [
      {
        "internalType": "address",
        "name": "to",
        "type": "address"
      },
      {
        "internalType": "uint256",
        "name": "amount",
        "type": "uint256"
      }
    ],
    "name": "mint",
    "outputs": [],
    "stateMutability": "nonpayable",
    "type": "function"
  },
  {
    "inputs": [],
    "name": "name",
    "outputs": [
      {
        "internalType": "string",
        "name": "",
        "type": "string"
      }
    ],
    "stateMutability": "view",
    "type": "function"
  },
  {
    "inputs": [],
    "name": "owner",
    "outputs": [
      {
        "internalType": "address",
        "name": "",
        "type": "address"
      }
    ],
    "stateMutability": "view",
    "type": "function"
  },
  {
    "inputs": [],
    "name": "poolManager",
    "outputs": [
      {
        "internalType": "address",
        "name": "",
        "type": "address"
      }
    ],
    "stateMutability": "view",
    "type": "function"
  },
  {
    "inputs": [],
    "name": "renounceOwnership",
    "outputs": [],
    "stateMutability": "nonpayable",
    "type": "function"
  },
  {
    "inputs": [
      {
        "internalType": "address",
        "name": "account",
        "type": "address"
      },
      {
        "internalType": "bool",
        "name": "exempt",
        "type": "bool"
      }
    ],
    "name": "setTaxExempt",
    "outputs": [],
    "stateMutability": "nonpayable",
    "type": "function"
  },
  {
    "inputs": [],
    "name": "symbol",
    "outputs": [
      {
        "internalType": "string",
        "name": "",
        "type": "string"
      }
    ],
    "stateMutability": "view",
    "type": "function"
  },
  {
    "inputs": [],
    "name": "taxModule",
    "outputs": [
      {
        "internalType": "contract IRatchetTaxModule",
        "name": "",
        "type": "address"
      }
    ],
    "stateMutability": "view",
    "type": "function"
  },
  {
    "inputs": [],
    "name": "totalSupply",
    "outputs": [
      {
        "internalType": "uint256",
        "name": "",
        "type": "uint256"
      }
    ],
    "stateMutability": "view",
    "type": "function"
  },
  {
    "inputs": [
      {
        "internalType": "address",
        "name": "to",
        "type": "address"
      },
      {
        "internalType": "uint256",
        "name": "value",
        "type": "uint256"
      }
    ],
    "name": "transfer",
    "outputs": [
      {
        "internalType": "bool",
        "name": "",
        "type": "bool"
      }
    ],
    "stateMutability": "nonpayable",
    "type": "function"
  },
  {
    "inputs": [
      {
        "internalType": "address",
        "name": "from",
        "type": "address"
      },
      {
        "internalType": "address",
        "name": "to",
        "type": "address"
      },
      {
        "internalType": "uint256",
        "name": "value",
        "type": "uint256"
      }
    ],
    "name": "transferFrom",
    "outputs": [
      {
        "internalType": "bool",
        "name": "",
        "type": "bool"
      }
    ],
    "stateMutability": "nonpayable",
    "type": "function"
  },
  {
    "inputs": [
      {
        "internalType": "address",
        "name": "newOwner",
        "type": "address"
      }
    ],
    "name": "transferOwnership",
    "outputs": [],
    "stateMutability": "nonpayable",
    "type": "function"
  }
]

// SPDX-License-Identifier: MIT
pragma solidity 0.8.26;

import { ERC20 } from "@openzeppelin/contracts/token/ERC20/ERC20.sol";
import { Ownable } from "@openzeppelin/contracts/access/Ownable.sol";
import { IRatchetTaxModule } from "./interfaces/IRatchetTaxModule.sol";

contract RatchetToken is ERC20, Ownable {
	/// @notice The sole minting and burn authority (RatchetHook proxy).
	address public immutable hook;
	/// @notice Uniswap v4 PoolManager used by the official Hook.
	address public immutable poolManager;

	/// @notice Tax module, equal to the Hook in production.
	IRatchetTaxModule public immutable taxModule;

	/// @notice Addresses exempt from transfer tax; a transfer is exempt when either endpoint is exempt.
	mapping(address => bool) public isTaxExempt;

	uint256 private _taxLock;

	/// @notice Emitted when an account's tax exemption changes.
	/// @param account Updated account.
	/// @param exempt Whether the account is exempt.
	event TaxExemptUpdated(address indexed account, bool exempt);
	/// @notice Emitted when transfer tax is burned and liquidated.
	/// @param from Taxed sender.
	/// @param to Transfer recipient.
	/// @param taxAmount Burned tax amount.
	/// @param taxBps Applied tax rate in basis points.
	event TransferTax(address indexed from, address indexed to, uint256 taxAmount, uint256 taxBps);

	/// @notice Reverts when the caller is not the Hook.
	error OnlyHook();
	/// @notice Reverts on reentry into tax liquidation.
	error Reentrancy();

	/// @notice Creates the token and binds its Hook, PoolManager and owner.
	/// @param _hook Hook proxy address (mint/burn authority and tax module)
	/// @param _poolManager Uniswap v4 PoolManager used by the official Hook
	/// @param _owner Owner for `setTaxExempt` (typically the Hook deployer).
	/// @param name_ Token name, configured at deployment.
	/// @param symbol_ Token symbol, configured at deployment.
	constructor(
		address _hook,
		address _poolManager,
		address _owner,
		string memory name_,
		string memory symbol_
	) ERC20(name_, symbol_) Ownable(_owner) {
		hook = _hook;
		poolManager = _poolManager;
		taxModule = IRatchetTaxModule(_hook);
		isTaxExempt[_hook] = true;
		emit TaxExemptUpdated(_hook, true);
	}

	modifier onlyHook() {
		if (msg.sender != hook) revert OnlyHook();
		_;
	}

	/// @notice Allows the owner to add or remove a transfer-tax exemption.
	/// @param account Account to update.
	/// @param exempt Whether the account should be exempt.
	function setTaxExempt(address account, bool exempt) external onlyOwner {
		isTaxExempt[account] = exempt;
		emit TaxExemptUpdated(account, exempt);
	}

	/// @notice Mints tokens to a recipient; callable only by the Hook.
	/// @param to Token recipient.
	/// @param amount Amount to mint.
	function mint(address to, uint256 amount) external onlyHook {
		_mint(to, amount);
	}

	/// @notice Burns tokens from an address; callable only by the Hook.
	/// @param from Account whose tokens are burned.
	/// @param amount Amount to burn.
	function hookBurn(address from, uint256 amount) external onlyHook {
		_burn(from, amount);
	}

	/// @notice Estimate net amount received and tax for a non-exempt transfer of `amount`.
	/// @param amount Gross transfer amount.
	/// @return net Estimated recipient amount.
	/// @return tax Estimated tax amount.
	function estimateNetTransfer(uint256 amount) external view returns (uint256 net, uint256 tax) {
		if (amount == 0) return (0, 0);
		uint256 bps = taxModule.transferTaxBps();
		if (bps == 0) return (amount, 0);
		tax = (amount * bps) / 10_000;
		if (tax == 0) return (amount, 0);
		if (!taxModule.canLiquidateTax(tax)) return (amount, 0);
		return (amount - tax, tax);
	}

	function _update(address from, address to, uint256 value) internal override {
		if (from == address(0) || to == address(0)) {
			super._update(from, to, value);
			return;
		}

		if (value == 0 || (from.code.length == 0 && to.code.length == 0) || isTaxExempt[from] || isTaxExempt[to]) {
			super._update(from, to, value);
			return;
		}

		uint256 bps = taxModule.transferTaxBps();
		if (bps == 0) {
			super._update(from, to, value);
			return;
		}

		uint256 tax = (value * bps) / 10_000;
		if (tax == 0) {
			super._update(from, to, value);
			return;
		}

		if (!taxModule.canLiquidateTax(tax)) {
			super._update(from, to, value);
			return;
		}

		if (_taxLock != 0) revert Reentrancy();
		_taxLock = 1;

		uint256 net = value - tax;
		super._update(from, to, net);
		super._update(from, address(0), tax);
		taxModule.liquidateTax(tax);
		emit TransferTax(from, to, tax, bps);

		_taxLock = 0;
	}
}