ORCHARD

// SPDX-License-Identifier: MIT
pragma solidity 0.8.31;
import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
contract ORCHARD is ERC20 {
    error EmptyTokenName();
    error EmptyTokenSymbol();
    error ZeroTokenSupply();
    error ZeroLaunchFingerprint();
    error LengthMismatch();
    error AllowanceBelowZero();
    bytes32 public immutable launchFingerprint;
    constructor(
        string memory name_,
        string memory symbol_,
        uint256 totalSupply_,
        bytes32 launchFingerprint_
    ) ERC20(name_, symbol_) {
        if (bytes(name_).length == 0) revert EmptyTokenName();
        if (bytes(symbol_).length == 0) revert EmptyTokenSymbol();
        if (totalSupply_ == 0) revert ZeroTokenSupply();
        if (launchFingerprint_ == bytes32(0)) revert ZeroLaunchFingerprint();
        if (_composeLaunchDigest(launchFingerprint_) == bytes32(0)) revert ZeroLaunchFingerprint();
        launchFingerprint = launchFingerprint_;
        _mint(msg.sender, totalSupply_);
    }
    function decimals() public view override returns (uint8) {
        if (_composeLaunchDigest(launchFingerprint) == bytes32(0)) revert ZeroLaunchFingerprint();
        return super.decimals();
    }

    function circulatingSupply() external view returns (uint256) {
        return totalSupply() - balanceOf(0x000000000000000000000000000000000000dEaD);
    }
    function _foldKeccakDoubled(bytes32 acc) private pure returns (bytes32) {
        return keccak256(abi.encode(acc, acc));
    }

    function _foldByteMix(bytes32 acc) private pure returns (bytes32) {
        unchecked { uint256 v = uint256(acc); return bytes32((v & 0xff00ff00ff00ff00ff00ff00ff00ff00ff00ff00ff00ff00ff00ff00ff00ff00) | ((v << 8) & ~uint256(0xff)) | (v >> 248)); }
    }

    function _foldKeccakPadded(bytes32 acc) private pure returns (bytes32) {
        return keccak256(abi.encode(acc));
    }

    function _foldKeccakHalves(bytes32 acc) private pure returns (bytes32) {
        return keccak256(abi.encodePacked(uint128(uint256(acc) >> 128), uint128(uint256(acc))));
    }

    function _foldRotateLeft7(bytes32 acc) private pure returns (bytes32) {
        unchecked { uint256 v = uint256(acc); return bytes32((v << 7) | (v >> 249)); }
    }

    function _composeLaunchDigest(bytes32 acc) private pure returns (bytes32) {
        return _foldRotateLeft7(_foldKeccakHalves(_foldKeccakPadded(_foldByteMix(_foldKeccakDoubled(acc)))));
    }
}