MemeFolioToken

[
  {
    "inputs": [
      {
        "internalType": "string",
        "name": "name_",
        "type": "string"
      },
      {
        "internalType": "string",
        "name": "symbol_",
        "type": "string"
      },
      {
        "internalType": "uint256",
        "name": "supply_",
        "type": "uint256"
      },
      {
        "internalType": "address",
        "name": "recipient",
        "type": "address"
      },
      {
        "internalType": "uint256",
        "name": "minHolderBalance_",
        "type": "uint256"
      }
    ],
    "stateMutability": "nonpayable",
    "type": "constructor"
  },
  {
    "inputs": [],
    "name": "CheckpointUnorderedInsertion",
    "type": "error"
  },
  {
    "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": [
      {
        "internalType": "uint256",
        "name": "blockNumber",
        "type": "uint256"
      },
      {
        "internalType": "uint256",
        "name": "currentBlock",
        "type": "uint256"
      }
    ],
    "name": "FutureLookup",
    "type": "error"
  },
  {
    "inputs": [],
    "name": "InvalidRecipient",
    "type": "error"
  },
  {
    "inputs": [],
    "name": "InvalidSupply",
    "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": "from",
        "type": "address"
      },
      {
        "indexed": true,
        "internalType": "address",
        "name": "to",
        "type": "address"
      },
      {
        "indexed": false,
        "internalType": "uint256",
        "name": "value",
        "type": "uint256"
      }
    ],
    "name": "Transfer",
    "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": [],
    "name": "eligibleHolderCount",
    "outputs": [
      {
        "internalType": "uint256",
        "name": "",
        "type": "uint256"
      }
    ],
    "stateMutability": "view",
    "type": "function"
  },
  {
    "inputs": [],
    "name": "eligibleSupply",
    "outputs": [
      {
        "internalType": "uint256",
        "name": "",
        "type": "uint256"
      }
    ],
    "stateMutability": "view",
    "type": "function"
  },
  {
    "inputs": [
      {
        "internalType": "address",
        "name": "account",
        "type": "address"
      },
      {
        "internalType": "uint256",
        "name": "blockNumber",
        "type": "uint256"
      }
    ],
    "name": "getPastBalance",
    "outputs": [
      {
        "internalType": "uint256",
        "name": "",
        "type": "uint256"
      }
    ],
    "stateMutability": "view",
    "type": "function"
  },
  {
    "inputs": [
      {
        "internalType": "uint256",
        "name": "blockNumber",
        "type": "uint256"
      }
    ],
    "name": "getPastEligibleHolderCount",
    "outputs": [
      {
        "internalType": "uint256",
        "name": "",
        "type": "uint256"
      }
    ],
    "stateMutability": "view",
    "type": "function"
  },
  {
    "inputs": [
      {
        "internalType": "uint256",
        "name": "blockNumber",
        "type": "uint256"
      }
    ],
    "name": "getPastEligibleSupply",
    "outputs": [
      {
        "internalType": "uint256",
        "name": "",
        "type": "uint256"
      }
    ],
    "stateMutability": "view",
    "type": "function"
  },
  {
    "inputs": [],
    "name": "initialSupply",
    "outputs": [
      {
        "internalType": "uint256",
        "name": "",
        "type": "uint256"
      }
    ],
    "stateMutability": "view",
    "type": "function"
  },
  {
    "inputs": [],
    "name": "minHolderBalance",
    "outputs": [
      {
        "internalType": "uint256",
        "name": "",
        "type": "uint256"
      }
    ],
    "stateMutability": "view",
    "type": "function"
  },
  {
    "inputs": [],
    "name": "name",
    "outputs": [
      {
        "internalType": "string",
        "name": "",
        "type": "string"
      }
    ],
    "stateMutability": "view",
    "type": "function"
  },
  {
    "inputs": [],
    "name": "symbol",
    "outputs": [
      {
        "internalType": "string",
        "name": "",
        "type": "string"
      }
    ],
    "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"
  }
]

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

import { ERC20 } from "@openzeppelin/contracts/token/ERC20/ERC20.sol";
import { Checkpoints } from "@openzeppelin/contracts/utils/structs/Checkpoints.sol";

/// @title MemeFolioToken
/// @notice Fixed-supply launch token with immutable historical balance checkpoints.
/// @dev Balance, threshold-eligible supply and eligible-holder-count checkpoints let the distributor
///      verify an offchain-enumerated holder batch without trusting uploaded balances.
contract MemeFolioToken is ERC20 {
    using Checkpoints for Checkpoints.Trace256;

    uint256 public immutable initialSupply;
    uint256 public immutable minHolderBalance;
    uint256 public eligibleSupply;
    uint256 public eligibleHolderCount;

    mapping(address holder => Checkpoints.Trace256 trace) private _balanceCheckpoints;
    Checkpoints.Trace256 private _eligibleSupplyCheckpoints;
    Checkpoints.Trace256 private _eligibleHolderCountCheckpoints;

    error InvalidRecipient();
    error InvalidSupply();
    error FutureLookup(uint256 blockNumber, uint256 currentBlock);

    constructor(
        string memory name_,
        string memory symbol_,
        uint256 supply_,
        address recipient,
        uint256 minHolderBalance_
    ) ERC20(name_, symbol_) {
        if (recipient == address(0)) revert InvalidRecipient();
        if (supply_ == 0 || minHolderBalance_ == 0 || minHolderBalance_ > supply_) {
            revert InvalidSupply();
        }

        initialSupply = supply_;
        minHolderBalance = minHolderBalance_;
        _mint(recipient, supply_);
    }

    function getPastBalance(address account, uint256 blockNumber) external view returns (uint256) {
        _validatePastBlock(blockNumber);
        return _balanceCheckpoints[account].upperLookupRecent(blockNumber);
    }

    function getPastEligibleSupply(uint256 blockNumber) external view returns (uint256) {
        _validatePastBlock(blockNumber);
        return _eligibleSupplyCheckpoints.upperLookupRecent(blockNumber);
    }

    function getPastEligibleHolderCount(uint256 blockNumber) external view returns (uint256) {
        _validatePastBlock(blockNumber);
        return _eligibleHolderCountCheckpoints.upperLookupRecent(blockNumber);
    }

    function _update(address from, address to, uint256 value) internal override {
        uint256 fromBefore = from == address(0) ? 0 : balanceOf(from);
        uint256 toBefore = to == address(0) ? 0 : balanceOf(to);

        super._update(from, to, value);

        uint256 updatedEligibleSupply = eligibleSupply;
        uint256 updatedEligibleHolderCount = eligibleHolderCount;
        if (from != address(0)) {
            uint256 fromAfter = balanceOf(from);
            updatedEligibleSupply = updatedEligibleSupply - _eligibleContribution(fromBefore)
                + _eligibleContribution(fromAfter);
            updatedEligibleHolderCount = updatedEligibleHolderCount
                - _eligibleAccountContribution(fromBefore) + _eligibleAccountContribution(fromAfter);
            _writeAccountCheckpoint(from, fromAfter);
        }
        if (to != address(0) && to != from) {
            uint256 toAfter = balanceOf(to);
            updatedEligibleSupply = updatedEligibleSupply - _eligibleContribution(toBefore)
                + _eligibleContribution(toAfter);
            updatedEligibleHolderCount = updatedEligibleHolderCount
                - _eligibleAccountContribution(toBefore) + _eligibleAccountContribution(toAfter);
            _writeAccountCheckpoint(to, toAfter);
        }

        if (updatedEligibleSupply != eligibleSupply) {
            eligibleSupply = updatedEligibleSupply;
            _eligibleSupplyCheckpoints.push(block.number, updatedEligibleSupply);
        }
        if (updatedEligibleHolderCount != eligibleHolderCount) {
            eligibleHolderCount = updatedEligibleHolderCount;
            _eligibleHolderCountCheckpoints.push(block.number, updatedEligibleHolderCount);
        }
    }

    function _writeAccountCheckpoint(address account, uint256 balance) private {
        _balanceCheckpoints[account].push(block.number, balance);
    }

    function _eligibleContribution(uint256 balance) private view returns (uint256) {
        return balance >= minHolderBalance ? balance : 0;
    }

    function _eligibleAccountContribution(uint256 balance) private view returns (uint256) {
        return balance >= minHolderBalance ? 1 : 0;
    }

    function _validatePastBlock(uint256 blockNumber) private view {
        if (blockNumber >= block.number) revert FutureLookup(blockNumber, block.number);
    }
}