// SPDX-License-Identifier: MIT
pragma solidity 0.8.30;
interface IERC20 { function balanceOf(address account) external view returns (uint256); }
library ExactToken {
    function invoke(address token, bytes memory data) private {
        require(token.code.length > 0, "TOKEN_NOT_CONTRACT");
        (bool success, bytes memory result) = token.call(data);
        require(success && (result.length == 0 || abi.decode(result, (bool))), "TOKEN_CALL_FAILED");
    }
    function pull(address token, address from, uint256 amount) internal {
        uint256 beforeSender = IERC20(token).balanceOf(from);
        uint256 beforeReceiver = IERC20(token).balanceOf(address(this));
        invoke(token, abi.encodeWithSignature("transferFrom(address,address,uint256)", from, address(this), amount));
        uint256 afterSender = IERC20(token).balanceOf(from);
        uint256 afterReceiver = IERC20(token).balanceOf(address(this));
        require(beforeSender >= amount && afterSender == beforeSender - amount, "NON_STANDARD_SENDER_BALANCE");
        require(afterReceiver >= beforeReceiver && afterReceiver - beforeReceiver == amount, "TRANSFER_TAX_NOT_SUPPORTED");
    }
    function pay(address token, address recipient, uint256 amount) internal {
        uint256 beforeSender = IERC20(token).balanceOf(address(this));
        uint256 beforeReceiver = IERC20(token).balanceOf(recipient);
        invoke(token, abi.encodeWithSignature("transfer(address,uint256)", recipient, amount));
        uint256 afterSender = IERC20(token).balanceOf(address(this));
        uint256 afterReceiver = IERC20(token).balanceOf(recipient);
        require(beforeSender >= amount && afterSender == beforeSender - amount, "NON_STANDARD_SENDER_BALANCE");
        require(afterReceiver >= beforeReceiver && afterReceiver - beforeReceiver == amount, "TRANSFER_TAX_NOT_SUPPORTED");
    }
}
contract RewardCampaign {
    address public owner;
    address public token;
    uint256 public deadline;
    uint256 public total;
    uint256 public paid;
    uint256 public recipientCount;
    bool public direct;
    bool public funded;
    bool public reclaimed;
    bytes32 public manifestHash;
    mapping(address => uint256) public allocation;
    mapping(address => uint256) public owed;
    uint256 private entered = 1;
    event Registered(address indexed recipient, uint256 amount);
    event Funded(uint256 amount);
    event RewardPaid(address indexed recipient, uint256 amount);
    event Recovered(uint256 amount);
    modifier onlyOwner() { require(msg.sender == owner, "OWNER_ONLY"); _; }
    modifier nonReentrant() { require(entered == 1, "REENTRANCY"); entered = 2; _; entered = 1; }
    modifier live() {
        require(funded, "NOT_FUNDED");
        require(!reclaimed, "RECLAIMED");
        require(block.timestamp < deadline, "CAMPAIGN_EXPIRED"); _;
    }
    constructor(address rewardToken, uint256 expiresAt, bool directDistribution, bytes32 campaignManifestHash) {
        require(rewardToken.code.length > 0, "TOKEN_NOT_CONTRACT");
        require(expiresAt > block.timestamp && expiresAt <= block.timestamp + 366 days, "INVALID_DEADLINE");
        owner = msg.sender; token = rewardToken; deadline = expiresAt;
        direct = directDistribution; manifestHash = campaignManifestHash;
    }
    function register(address[] calldata recipients, uint256[] calldata amounts) external onlyOwner nonReentrant {
        require(!funded, "ALREADY_FUNDED");
        require(block.timestamp < deadline, "CAMPAIGN_EXPIRED");
        require(recipients.length > 0 && recipients.length <= 100 && recipients.length == amounts.length, "INVALID_BATCH");
        for (uint256 i = 0; i < recipients.length; i++) {
            address recipient = recipients[i]; uint256 amount = amounts[i];
            require(recipient != address(0) && recipient != address(this) && recipient != owner && recipient != token && recipient != address(0xdead), "INVALID_RECIPIENT");
            require(amount > 0, "ZERO_AMOUNT");
            if (allocation[recipient] != 0) { require(allocation[recipient] == amount, "ALLOCATION_MISMATCH"); continue; }
            allocation[recipient] = amount; owed[recipient] = amount; total += amount; recipientCount++;
            emit Registered(recipient, amount);
        }
    }
    function fund() external onlyOwner nonReentrant {
        require(!funded, "ALREADY_FUNDED"); require(!reclaimed, "RECLAIMED");
        require(block.timestamp < deadline, "CAMPAIGN_EXPIRED"); require(total > 0, "EMPTY_CAMPAIGN");
        funded = true; ExactToken.pull(token, owner, total); emit Funded(total);
    }
    function pendingIn(address[] calldata recipients) external view returns (uint256 amount) {
        for (uint256 i = 0; i < recipients.length; i++) amount += owed[recipients[i]];
    }
    function distribute(address[] calldata recipients) external onlyOwner nonReentrant live {
        require(direct, "CLAIM_MODE"); require(recipients.length > 0 && recipients.length <= 100, "INVALID_BATCH");
        for (uint256 i = 0; i < recipients.length; i++) {
            address recipient = recipients[i]; uint256 amount = owed[recipient]; if (amount == 0) continue;
            owed[recipient] = 0; paid += amount; ExactToken.pay(token, recipient, amount); emit RewardPaid(recipient, amount);
        }
    }
    function claim() external nonReentrant live {
        require(!direct, "DIRECT_MODE"); uint256 amount = owed[msg.sender]; require(amount > 0, "NO_REWARD");
        owed[msg.sender] = 0; paid += amount; ExactToken.pay(token, msg.sender, amount); emit RewardPaid(msg.sender, amount);
    }
    function recover() external onlyOwner nonReentrant {
        require(block.timestamp >= deadline, "NOT_EXPIRED"); require(!reclaimed, "ALREADY_RECOVERED"); reclaimed = true;
        uint256 balance = IERC20(token).balanceOf(address(this));
        if (balance > 0) ExactToken.pay(token, owner, balance); emit Recovered(balance);
    }
}