PaymentForwarder

{{
  "language": "Solidity",
  "sources": {
    "contract.sol": {
      "content": "// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

import "@openzeppelin/contracts/utils/ReentrancyGuard.sol";
import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/utils/Pausable.sol";

/**
 * @title PaymentForwarder
 * @dev Secure payment forwarder contract for real estate investments
 * 
 * This contract receives ETH payments and immediately forwards them to a designated
 * receiver wallet. All transactions are logged with events for transparency and
 * audit purposes.
 * 
 * Security Features:
 * - Reentrancy protection
 * - Pausable functionality for emergency stops
 * - Owner-only administrative functions
 * - Comprehensive event logging
 * - Gas-efficient forwarding mechanism
 */
contract PaymentForwarder is ReentrancyGuard, Ownable, Pausable {
    
    // The wallet that receives all forwarded funds
    address payable public receiverWallet;
    
    // Minimum investment amount (0.01 ETH)
    uint256 public constant MIN_INVESTMENT = 0.0001 ether;
    
    // Maximum investment amount (100 ETH)
    uint256 public constant MAX_INVESTMENT = 100 ether;
    
    // Total amount forwarded through this contract
    uint256 public totalForwarded;
    
    // Number of successful investments
    uint256 public investmentCount;
    
    // Events for transparency and off-chain tracking
    event InvestmentReceived(
        address indexed investor,
        uint256 amount,
        uint256 timestamp,
        uint256 investmentId
    );
    
    event FundsForwarded(
        address indexed receiver,
        uint256 amount,
        uint256 timestamp
    );
    
    event ReceiverWalletUpdated(
        address indexed oldReceiver,
        address indexed newReceiver,
        uint256 timestamp
    );
    
    event EmergencyWithdrawal(
        address indexed admin,
        uint256 amount,
        uint256 timestamp
    );
    
    /**
     * @dev Constructor sets the initial receiver wallet
     * @param _receiverWallet Address that will receive all forwarded funds
     */
    constructor(address payable _receiverWallet) Ownable(msg.sender) {
        require(_receiverWallet != address(0), "Invalid receiver wallet");
        receiverWallet = _receiverWallet;
        
        emit ReceiverWalletUpdated(address(0), _receiverWallet, block.timestamp);
    }
    
    /**
     * @dev Main investment function - receives ETH and forwards to receiver wallet
     * Can be called directly or through other functions
     */
    function invest() external payable nonReentrant whenNotPaused {
        require(msg.value >= MIN_INVESTMENT, "Investment below minimum");
        require(msg.value <= MAX_INVESTMENT, "Investment above maximum");
        require(receiverWallet != address(0), "Receiver wallet not set");
        
        uint256 amount = msg.value;
        uint256 currentInvestmentId = investmentCount + 1;
        
        // Update state before external call
        totalForwarded += amount;
        investmentCount = currentInvestmentId;
        
        // Emit investment received event
        emit InvestmentReceived(
            msg.sender,
            amount,
            block.timestamp,
            currentInvestmentId
        );
        
        // Forward funds to receiver wallet
        (bool success, ) = receiverWallet.call{value: amount}("");
        require(success, "Failed to forward funds");
        
        // Emit forwarding confirmation
        emit FundsForwarded(receiverWallet, amount, block.timestamp);
    }
    
    /**
     * @dev Internal investment function for receive/fallback
     */
    function _processInvestment() internal nonReentrant whenNotPaused {
        require(msg.value >= MIN_INVESTMENT, "Investment below minimum");
        require(msg.value <= MAX_INVESTMENT, "Investment above maximum");
        require(receiverWallet != address(0), "Receiver wallet not set");
        
        uint256 amount = msg.value;
        uint256 currentInvestmentId = investmentCount + 1;
        
        // Update state before external call
        totalForwarded += amount;
        investmentCount = currentInvestmentId;
        
        // Emit investment received event
        emit InvestmentReceived(
            msg.sender,
            amount,
            block.timestamp,
            currentInvestmentId
        );
        
        // Forward funds to receiver wallet
        (bool success, ) = receiverWallet.call{value: amount}("");
        require(success, "Failed to forward funds");
        
        // Emit forwarding confirmation
        emit FundsForwarded(receiverWallet, amount, block.timestamp);
    }
    
    /**
     * @dev Fallback function to handle direct ETH transfers
     */
    receive() external payable {
        _processInvestment();
    }
    
    /**
     * @dev Fallback function for any other calls
     */
    fallback() external payable {
        _processInvestment();
    }
    
    /**
     * @dev Update the receiver wallet address (owner only)
     * @param _newReceiver New receiver wallet address
     */
    function updateReceiverWallet(address payable _newReceiver) external onlyOwner {
        require(_newReceiver != address(0), "Invalid receiver wallet");
        require(_newReceiver != receiverWallet, "Same as current receiver");
        
        address oldReceiver = receiverWallet;
        receiverWallet = _newReceiver;
        
        emit ReceiverWalletUpdated(oldReceiver, _newReceiver, block.timestamp);
    }
    
    /**
     * @dev Pause the contract (owner only)
     * Prevents new investments while allowing administrative functions
     */
    function pause() external onlyOwner {
        _pause();
    }
    
    /**
     * @dev Unpause the contract (owner only)
     */
    function unpause() external onlyOwner {
        _unpause();
    }
    
    /**
     * @dev Emergency withdrawal function (owner only)
     * Should only be used in extreme circumstances
     * @param _amount Amount to withdraw (0 for full balance)
     */
    function emergencyWithdraw(uint256 _amount) external onlyOwner {
        uint256 balance = address(this).balance;
        require(balance > 0, "No funds to withdraw");
        
        uint256 withdrawAmount = _amount == 0 ? balance : _amount;
        require(withdrawAmount <= balance, "Insufficient balance");
        
        (bool success, ) = payable(owner()).call{value: withdrawAmount}("");
        require(success, "Emergency withdrawal failed");
        
        emit EmergencyWithdrawal(owner(), withdrawAmount, block.timestamp);
    }
    
    /**
     * @dev Get contract information
     * @return receiver Current receiver wallet address
     * @return forwarded Total amount forwarded
     * @return count Number of investments processed
     * @return balance Current contract balance
     * @return isPaused Whether contract is paused
     */
    function getContractInfo() external view returns (
        address receiver,
        uint256 forwarded,
        uint256 count,
        uint256 balance,
        bool isPaused
    ) {
        return (
            receiverWallet,
            totalForwarded,
            investmentCount,
            address(this).balance,
            super.paused()
        );
    }
    
    /**
     * @dev Check if an investment amount is valid
     * @param _amount Amount to check
     * @return valid Whether the amount is within valid range
     */
    function isValidInvestmentAmount(uint256 _amount) external pure returns (bool valid) {
        return _amount >= MIN_INVESTMENT && _amount <= MAX_INVESTMENT;
    }
}"
    },
    "@openzeppelin/contracts/utils/Pausable.sol": {
      "content": "// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.3.0) (utils/Pausable.sol)

pragma solidity ^0.8.20;

import {Context} from "../utils/Context.sol";

/**
 * @dev Contract module which allows children to implement an emergency stop
 * mechanism that can be triggered by an authorized account.
 *
 * This module is used through inheritance. It will make available the
 * modifiers `whenNotPaused` and `whenPaused`, which can be applied to
 * the functions of your contract. Note that they will not be pausable by
 * simply including this module, only once the modifiers are put in place.
 */
abstract contract Pausable is Context {
    bool private _paused;

    /**
     * @dev Emitted when the pause is triggered by `account`.
     */
    event Paused(address account);

    /**
     * @dev Emitted when the pause is lifted by `account`.
     */
    event Unpaused(address account);

    /**
     * @dev The operation failed because the contract is paused.
     */
    error EnforcedPause();

    /**
     * @dev The operation failed because the contract is not paused.
     */
    error ExpectedPause();

    /**
     * @dev Modifier to make a function callable only when the contract is not paused.
     *
     * Requirements:
     *
     * - The contract must not be paused.
     */
    modifier whenNotPaused() {
        _requireNotPaused();
        _;
    }

    /**
     * @dev Modifier to make a function callable only when the contract is paused.
     *
     * Requirements:
     *
     * - The contract must be paused.
     */
    modifier whenPaused() {
        _requirePaused();
        _;
    }

    /**
     * @dev Returns true if the contract is paused, and false otherwise.
     */
    function paused() public view virtual returns (bool) {
        return _paused;
    }

    /**
     * @dev Throws if the contract is paused.
     */
    function _requireNotPaused() internal view virtual {
        if (paused()) {
            revert EnforcedPause();
        }
    }

    /**
     * @dev Throws if the contract is not paused.
     */
    function _requirePaused() internal view virtual {
        if (!paused()) {
            revert ExpectedPause();
        }
    }

    /**
     * @dev Triggers stopped state.
     *
     * Requirements:
     *
     * - The contract must not be paused.
     */
    function _pause() internal virtual whenNotPaused {
        _paused = true;
        emit Paused(_msgSender());
    }

    /**
     * @dev Returns to normal state.
     *
     * Requirements:
     *
     * - The contract must be paused.
     */
    function _unpause() internal virtual whenPaused {
        _paused = false;
        emit Unpaused(_msgSender());
    }
}
"
    },
    "@openzeppelin/contracts/access/Ownable.sol": {
      "content": "// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (access/Ownable.sol)

pragma solidity ^0.8.20;

import {Context} from "../utils/Context.sol";

/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * The initial owner is set to the address provided by the deployer. This can
 * later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract contract Ownable is Context {
    address private _owner;

    /**
     * @dev The caller account is not authorized to perform an operation.
     */
    error OwnableUnauthorizedAccount(address account);

    /**
     * @dev The owner is not a valid owner account. (eg. `address(0)`)
     */
    error OwnableInvalidOwner(address owner);

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the address provided by the deployer as the initial owner.
     */
    constructor(address initialOwner) {
        if (initialOwner == address(0)) {
            revert OwnableInvalidOwner(address(0));
        }
        _transferOwnership(initialOwner);
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        _checkOwner();
        _;
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if the sender is not the owner.
     */
    function _checkOwner() internal view virtual {
        if (owner() != _msgSender()) {
            revert OwnableUnauthorizedAccount(_msgSender());
        }
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby disabling any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        _transferOwnership(address(0));
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        if (newOwner == address(0)) {
            revert OwnableInvalidOwner(address(0));
        }
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Internal function without access restriction.
     */
    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}
"
    },
    "@openzeppelin/contracts/utils/ReentrancyGuard.sol": {
      "content": "// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.1.0) (utils/ReentrancyGuard.sol)

pragma solidity ^0.8.20;

/**
 * @dev Contract module that helps prevent reentrant calls to a function.
 *
 * Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier
 * available, which can be applied to functions to make sure there are no nested
 * (reentrant) calls to them.
 *
 * Note that because there is a single `nonReentrant` guard, functions marked as
 * `nonReentrant` may not call one another. This can be worked around by making
 * those functions `private`, and then adding `external` `nonReentrant` entry
 * points to them.
 *
 * TIP: If EIP-1153 (transient storage) is available on the chain you're deploying at,
 * consider using {ReentrancyGuardTransient} instead.
 *
 * TIP: If you would like to learn more about reentrancy and alternative ways
 * to protect against it, check out our blog post
 * https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].
 */
abstract contract ReentrancyGuard {
    // Booleans are more expensive than uint256 or any type that takes up a full
    // word because each write operation emits an extra SLOAD to first read the
    // slot's contents, replace the bits taken up by the boolean, and then write
    // back. This is the compiler's defense against contract upgrades and
    // pointer aliasing, and it cannot be disabled.

    // The values being non-zero value makes deployment a bit more expensive,
    // but in exchange the refund on every call to nonReentrant will be lower in
    // amount. Since refunds are capped to a percentage of the total
    // transaction's gas, it is best to keep them low in cases like this one, to
    // increase the likelihood of the full refund coming into effect.
    uint256 private constant NOT_ENTERED = 1;
    uint256 private constant ENTERED = 2;

    uint256 private _status;

    /**
     * @dev Unauthorized reentrant call.
     */
    error ReentrancyGuardReentrantCall();

    constructor() {
        _status = NOT_ENTERED;
    }

    /**
     * @dev Prevents a contract from calling itself, directly or indirectly.
     * Calling a `nonReentrant` function from another `nonReentrant`
     * function is not supported. It is possible to prevent this from happening
     * by making the `nonReentrant` function external, and making it call a
     * `private` function that does the actual work.
     */
    modifier nonReentrant() {
        _nonReentrantBefore();
        _;
        _nonReentrantAfter();
    }

    function _nonReentrantBefore() private {
        // On the first call to nonReentrant, _status will be NOT_ENTERED
        if (_status == ENTERED) {
            revert ReentrancyGuardReentrantCall();
        }

        // Any calls to nonReentrant after this point will fail
        _status = ENTERED;
    }

    function _nonReentrantAfter() private {
        // By storing the original value once again, a refund is triggered (see
        // https://eips.ethereum.org/EIPS/eip-2200)
        _status = NOT_ENTERED;
    }

    /**
     * @dev Returns true if the reentrancy guard is currently set to "entered", which indicates there is a
     * `nonReentrant` function in the call stack.
     */
    function _reentrancyGuardEntered() internal view returns (bool) {
        return _status == ENTERED;
    }
}
"
    },
    "@openzeppelin/contracts/utils/Context.sol": {
      "content": "// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.1) (utils/Context.sol)

pragma solidity ^0.8.20;

/**
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }

    function _contextSuffixLength() internal view virtual returns (uint256) {
        return 0;
    }
}
"
    }
  },
  "settings": {
    "optimizer": {
      "enabled": false,
      "runs": 200
    },
    "outputSelection": {
      "*": {
        "*": [
          "evm.bytecode",
          "evm.deployedBytecode",
          "devdoc",
          "userdoc",
          "metadata",
          "abi"
        ]
      }
    },
    "remappings": []
  }
}}