nftAddress

rewardTokenAddress

rewardWalletAddress

rewardRate

constructor

account

available

balanceOf

lastUpdateTime

from

tokenId

onERC721Received

redeem

rewardPerTokenPerDay

rewardToken

rewardWallet

stake

withdraw

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "@openzeppelin/contracts/utils/Context.sol";
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/token/ERC721/IERC721.sol";
import "@openzeppelin/contracts/token/ERC721/IERC721Receiver.sol";

/**
 * @title NFT Staking with Infinite Rewards
 * @author Breakthrough Labs Inc.
 * @notice Staking, NFT, ERC721
 * @custom:version 1.0.0
 * @custom:address 51
 * @custom:default-precision 0
 * @custom:simple-description NFT staking contract that rewards stakers with an exact number of ERC20 tokens per day.
 * @dev NFT staking contract that rewards stakers with an exact number of ERC20 tokens per day. On deployment, the owner specifies a daily reward rate,
 * and an address that tokens will be pulled from. Neither of these can be changed. Each staked NFT receives the same number of tokens every day. The per NFT
 * rate stays the same even when the number of staked NFTs increases/decreases.
 *
 * A common usecase is for blockchain-based games, where each NFT rewards a certain number of lives per day.
 *
 */
contract NFTStakingPerToken is Context, IERC721Receiver {
    IERC721 public nft;
    IERC20 public rewardToken;
    address public rewardWallet;
    /// @custom:precision 18
    uint256 public rewardPerTokenPerDay;

    mapping(uint256 => address) private stakedTokens;
    mapping(address => uint256) public balanceOf;
    mapping(address => uint256) public lastUpdateTime;
    mapping(address => uint256) private reward;

    /**
     * @param nftAddress  Staked NFT Address
     * @param rewardTokenAddress Reward Token Address
     * @param rewardWalletAddress Wallet that holds rewards to be paid out
     * @param rewardRate # of tokens per staked NFT per day | precision:18
     */
    constructor(
        address nftAddress,
        address rewardTokenAddress,
        address rewardWalletAddress,
        uint256 rewardRate
    ) {
        nft = IERC721(nftAddress);
        rewardToken = IERC20(rewardTokenAddress);
        rewardWallet = rewardWalletAddress;
        rewardPerTokenPerDay = rewardRate;
    }

    modifier update(address account) {
        reward[account] = available(account);
        lastUpdateTime[account] = block.timestamp;
        _;
    }

    /**
     * @dev returns the number of reward tokens available for an address
     * @param account account
     */
    function available(address account) public view returns (uint256) {
        uint256 timeElapsed = block.timestamp - lastUpdateTime[account];
        uint256 earned = (balanceOf[account] *
            timeElapsed *
            rewardPerTokenPerDay) / 86400;
        return reward[account] + earned;
    }

    /**
     * @dev stakes a specific tokenID
     * @param tokenId tokenId
     */
    function stake(uint256 tokenId) external {
        nft.safeTransferFrom(_msgSender(), address(this), tokenId);
    }

    /**
     * @dev withdraws a token from the staking contract
     * @param tokenId tokenId
     */
    function withdraw(uint256 tokenId) external update(_msgSender()) {
        require(stakedTokens[tokenId] == _msgSender(), "Token is not staked.");
        delete stakedTokens[tokenId];
        balanceOf[_msgSender()]--;
        nft.transferFrom(address(this), _msgSender(), tokenId);
    }

    /**
     * @dev redeems all of a user's reward tokens.
     */
    function redeem() external update(_msgSender()) {
        uint256 amount = reward[_msgSender()];
        require(amount > 0, "Nothing to redeem");
        reward[_msgSender()] = 0;
        rewardToken.transferFrom(rewardWallet, _msgSender(), amount);
    }

    function onERC721Received(
        address,
        address from,
        uint256 tokenId,
        bytes calldata
    ) external update(from) returns (bytes4) {
        stakedTokens[tokenId] = from;
        balanceOf[from]++;
        return IERC721Receiver.onERC721Received.selector;
    }
}



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)

pragma solidity ^0.8.0;

/**
 * @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;
    }
}


// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC20/IERC20.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);

    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `to`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address to, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `from` to `to` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(
        address from,
        address to,
        uint256 amount
    ) external returns (bool);
}


// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (token/ERC721/IERC721.sol)

pragma solidity ^0.8.0;

import "../../utils/introspection/IERC165.sol";

/**
 * @dev Required interface of an ERC721 compliant contract.
 */
interface IERC721 is IERC165 {
    /**
     * @dev Emitted when `tokenId` token is transferred from `from` to `to`.
     */
    event Transfer(address indexed from, address indexed to, uint256 indexed tokenId);

    /**
     * @dev Emitted when `owner` enables `approved` to manage the `tokenId` token.
     */
    event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId);

    /**
     * @dev Emitted when `owner` enables or disables (`approved`) `operator` to manage all of its assets.
     */
    event ApprovalForAll(address indexed owner, address indexed operator, bool approved);

    /**
     * @dev Returns the number of tokens in ``owner``'s account.
     */
    function balanceOf(address owner) external view returns (uint256 balance);

    /**
     * @dev Returns the owner of the `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function ownerOf(uint256 tokenId) external view returns (address owner);

    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId,
        bytes calldata data
    ) external;

    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients
     * are aware of the ERC721 protocol to prevent tokens from being forever locked.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If the caller is not `from`, it must have been allowed to move this token by either {approve} or {setApprovalForAll}.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId
    ) external;

    /**
     * @dev Transfers `tokenId` token from `from` to `to`.
     *
     * WARNING: Usage of this method is discouraged, use {safeTransferFrom} whenever possible.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must be owned by `from`.
     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(
        address from,
        address to,
        uint256 tokenId
    ) external;

    /**
     * @dev Gives permission to `to` to transfer `tokenId` token to another account.
     * The approval is cleared when the token is transferred.
     *
     * Only a single account can be approved at a time, so approving the zero address clears previous approvals.
     *
     * Requirements:
     *
     * - The caller must own the token or be an approved operator.
     * - `tokenId` must exist.
     *
     * Emits an {Approval} event.
     */
    function approve(address to, uint256 tokenId) external;

    /**
     * @dev Approve or remove `operator` as an operator for the caller.
     * Operators can call {transferFrom} or {safeTransferFrom} for any token owned by the caller.
     *
     * Requirements:
     *
     * - The `operator` cannot be the caller.
     *
     * Emits an {ApprovalForAll} event.
     */
    function setApprovalForAll(address operator, bool _approved) external;

    /**
     * @dev Returns the account approved for `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function getApproved(uint256 tokenId) external view returns (address operator);

    /**
     * @dev Returns if the `operator` is allowed to manage all of the assets of `owner`.
     *
     * See {setApprovalForAll}
     */
    function isApprovedForAll(address owner, address operator) external view returns (bool);
}


// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC721/IERC721Receiver.sol)

pragma solidity ^0.8.0;

/**
 * @title ERC721 token receiver interface
 * @dev Interface for any contract that wants to support safeTransfers
 * from ERC721 asset contracts.
 */
interface IERC721Receiver {
    /**
     * @dev Whenever an {IERC721} `tokenId` token is transferred to this contract via {IERC721-safeTransferFrom}
     * by `operator` from `from`, this function is called.
     *
     * It must return its Solidity selector to confirm the token transfer.
     * If any other value is returned or the interface is not implemented by the recipient, the transfer will be reverted.
     *
     * The selector can be obtained in Solidity with `IERC721Receiver.onERC721Received.selector`.
     */
    function onERC721Received(
        address operator,
        address from,
        uint256 tokenId,
        bytes calldata data
    ) external returns (bytes4);
}


// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/introspection/IERC165.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC165 standard, as defined in the
 * https://eips.ethereum.org/EIPS/eip-165[EIP].
 *
 * Implementers can declare support of contract interfaces, which can then be
 * queried by others ({ERC165Checker}).
 *
 * For an implementation, see {ERC165}.
 */
interface IERC165 {
    /**
     * @dev Returns true if this contract implements the interface defined by
     * `interfaceId`. See the corresponding
     * https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[EIP section]
     * to learn more about how these ids are created.
     *
     * This function call must use less than 30 000 gas.
     */
    function supportsInterface(bytes4 interfaceId) external view returns (bool);
}


NFT staking contract that rewards stakers with an exact number of ERC20 tokens per day. On deployment, the owner specifies a daily reward rate, and an address that tokens will be pulled from. Neither of these can be changed. Each staked NFT receives the same number of tokens every day. The per NFT rate stays the same even when the number of staked NFTs increases/decreases. A common usecase is for blockchain-based games, where each NFT rewards a certain number of lives per day.

ERC721 NFT Staking with Infinite Rewards

returns the number of reward tokens available for an address

withdraws a token from the staking contract

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (token/ERC721/IERC721.sol)

pragma solidity ^0.8.0;

import "IERC165.sol";

/**
 * @dev Required interface of an ERC721 compliant contract.
 */
interface IERC721 is IERC165 {
    /**
     * @dev Emitted when `tokenId` token is transferred from `from` to `to`.
     */
    event Transfer(address indexed from, address indexed to, uint256 indexed tokenId);

    /**
     * @dev Emitted when `owner` enables `approved` to manage the `tokenId` token.
     */
    event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId);

    /**
     * @dev Emitted when `owner` enables or disables (`approved`) `operator` to manage all of its assets.
     */
    event ApprovalForAll(address indexed owner, address indexed operator, bool approved);

    /**
     * @dev Returns the number of tokens in ``owner``'s account.
     */
    function balanceOf(address owner) external view returns (uint256 balance);

    /**
     * @dev Returns the owner of the `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function ownerOf(uint256 tokenId) external view returns (address owner);

    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId,
        bytes calldata data
    ) external;

    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients
     * are aware of the ERC721 protocol to prevent tokens from being forever locked.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If the caller is not `from`, it must have been allowed to move this token by either {approve} or {setApprovalForAll}.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId
    ) external;

    /**
     * @dev Transfers `tokenId` token from `from` to `to`.
     *
     * WARNING: Usage of this method is discouraged, use {safeTransferFrom} whenever possible.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must be owned by `from`.
     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(
        address from,
        address to,
        uint256 tokenId
    ) external;

    /**
     * @dev Gives permission to `to` to transfer `tokenId` token to another account.
     * The approval is cleared when the token is transferred.
     *
     * Only a single account can be approved at a time, so approving the zero address clears previous approvals.
     *
     * Requirements:
     *
     * - The caller must own the token or be an approved operator.
     * - `tokenId` must exist.
     *
     * Emits an {Approval} event.
     */
    function approve(address to, uint256 tokenId) external;

    /**
     * @dev Approve or remove `operator` as an operator for the caller.
     * Operators can call {transferFrom} or {safeTransferFrom} for any token owned by the caller.
     *
     * Requirements:
     *
     * - The `operator` cannot be the caller.
     *
     * Emits an {ApprovalForAll} event.
     */
    function setApprovalForAll(address operator, bool _approved) external;

    /**
     * @dev Returns the account approved for `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function getApproved(uint256 tokenId) external view returns (address operator);

    /**
     * @dev Returns if the `operator` is allowed to manage all of the assets of `owner`.
     *
     * See {setApprovalForAll}
     */
    function isApprovedForAll(address owner, address operator) external view returns (bool);
}


// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "Context.sol";
import "IERC20.sol";
import "IERC721.sol";
import "IERC721Receiver.sol";

/**
 * @title NFT Staking with Infinite Rewards
 * @author Breakthrough Labs Inc.
 * @notice Staking, NFT, ERC721
 * @custom:version 1.0.0
 * @custom:address 51
 * @custom:default-precision 0
 * @custom:simple-description NFT staking contract that rewards stakers with an exact number of ERC20 tokens per day.
 * @dev NFT staking contract that rewards stakers with an exact number of ERC20 tokens per day. On deployment, the owner specifies a daily reward rate,
 * and an address that tokens will be pulled from. Neither of these can be changed. Each staked NFT receives the same number of tokens every day. The per NFT
 * rate stays the same even when the number of staked NFTs increases/decreases.
 *
 * A common usecase is for blockchain-based games, where each NFT rewards a certain number of lives per day.
 *
 */
contract NFTStakingPerToken is Context, IERC721Receiver {
    IERC721 public nft;
    IERC20 public rewardToken;
    address public rewardWallet;
    /// @custom:precision 18
    uint256 public rewardPerTokenPerDay;

    mapping(uint256 => address) private stakedTokens;
    mapping(address => uint256) public balanceOf;
    mapping(address => uint256) public lastUpdateTime;
    mapping(address => uint256) private reward;

    /**
     * @param nftAddress  Staked NFT Address
     * @param rewardTokenAddress Reward Token Address
     * @param rewardWalletAddress Wallet that holds rewards to be paid out
     * @param rewardRate # of tokens per staked NFT per day | precision:18
     */
    constructor(
        address nftAddress,
        address rewardTokenAddress,
        address rewardWalletAddress,
        uint256 rewardRate
    ) {
        nft = IERC721(nftAddress);
        rewardToken = IERC20(rewardTokenAddress);
        rewardWallet = rewardWalletAddress;
        rewardPerTokenPerDay = rewardRate;
    }

    modifier update(address account) {
        reward[account] = available(account);
        lastUpdateTime[account] = block.timestamp;
        _;
    }

    /**
     * @dev returns the number of reward tokens available for an address
     * @param account account
     */
    function available(address account) public view returns (uint256) {
        uint256 timeElapsed = block.timestamp - lastUpdateTime[account];
        uint256 earned = (balanceOf[account] *
            timeElapsed *
            rewardPerTokenPerDay) / 86400;
        return reward[account] + earned;
    }

    /**
     * @dev stakes a specific tokenID
     * @param tokenId tokenId
     */
    function stake(uint256 tokenId) external {
        nft.safeTransferFrom(_msgSender(), address(this), tokenId);
    }

    /**
     * @dev withdraws a token from the staking contract
     * @param tokenId tokenId
     */
    function withdraw(uint256 tokenId) external update(_msgSender()) {
        require(stakedTokens[tokenId] == _msgSender(), "Token is not staked.");
        delete stakedTokens[tokenId];
        balanceOf[_msgSender()]--;
        nft.transferFrom(address(this), _msgSender(), tokenId);
    }

    /**
     * @dev redeems all of a user's reward tokens.
     */
    function redeem() external update(_msgSender()) {
        uint256 amount = reward[_msgSender()];
        require(amount > 0, "Nothing to redeem");
        reward[_msgSender()] = 0;
        rewardToken.transferFrom(rewardWallet, _msgSender(), amount);
    }

    function onERC721Received(
        address,
        address from,
        uint256 tokenId,
        bytes calldata
    ) external update(from) returns (bytes4) {
        stakedTokens[tokenId] = from;
        balanceOf[from]++;
        return IERC721Receiver.onERC721Received.selector;
    }
}
