ERC720Staking.sol

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.18;
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
import "@openzeppelin/contracts/token/ERC721/IERC721.sol";
import "@openzeppelin/contracts/security/ReentrancyGuard.sol";
contract ERC720Staking is ReentrancyGuard {
    using SafeERC20 for IERC20;
    IERC20 public immutable rewardsToken;
    IERC721 public immutable nftCollection;
    constructor(IERC721 _nftCollection, IERC20 _rewardsToken) {
        nftCollection = _nftCollection;
        rewardsToken = _rewardsToken;
    }
    struct StakedToken {
        address staker;
        uint256 tokenId;
    }
    struct Staker {
        uint256 amountStaked;
        StakedToken[] StakedTokens;
        uint256 timeOfLastUpdate;
        uint256 unclaimedRewards;
    }
    uint256 private rewardsPerHour = 100000;
    mapping(address => Staker) public stakers;
    mapping(uint256 => address) public stakerAddress;
    function stake(uint256 _tokenId) external nonReentrant {
    if (stakers[msg.sender].amountStaked > 0) {
        uint256 rewards = calculateRewards(msg.sender);
        stakers[msg.sender].unclaimedRewards += rewards;
    }
    require(nftCollection.ownerOf(_tokenId) == msg.sender, "You don't own this Token!");
    nftCollection.transferFrom(msg.sender, address(this), _tokenId);
    StakedToken memory stakedToken = StakedToken(msg.sender, _tokenId);
    stakers[msg.sender].StakedTokens.push(stakedToken);
    stakers[msg.sender].amountStaked++;
    stakerAddress[_tokenId] = msg.sender; // Add this line to update the stakerAddress mapping
}
    function withdraw(uint256 _tokenId) external nonReentrant {
        require(stakers[msg.sender].amountStaked > 0, "You have no tokens staked");
        require(stakerAddress[_tokenId] == msg.sender, "You don't own this token");
        uint256 rewards = calculateRewards(msg.sender);
        stakers[msg.sender].unclaimedRewards += rewards;
        uint256 index = 0;
        for (uint256 i = 0; i < stakers[msg.sender].StakedTokens.length; i++) {
            if (stakers[msg.sender].StakedTokens[i].tokenId == _tokenId) {
                index = i;
                break;
            }
        }
        stakers[msg.sender].StakedTokens[index].staker = address(0);
        stakers[msg.sender].amountStaked--;
        stakerAddress[_tokenId] = address(0);
        nftCollection.transferFrom(address(this), msg.sender, _tokenId);
        stakers[msg.sender].timeOfLastUpdate = block.timestamp;
    }
    function clainReward() external {
        uint256 rewards = calculateRewards(msg.sender) +
            stakers[msg.sender].unclaimedRewards;
        require(rewards > 0, "You don't have rewards to claim!");
        stakers[msg.sender].timeOfLastUpdate = block.timestamp;
        stakers[msg.sender].unclaimedRewards = 0;
        rewardsToken.safeTransfer(msg.sender, rewards);

    }
    function calculateRewards(address _staker)
        internal
        view
        returns(uint256 _rewards)
    { 
        return (((
            ((block.timestamp - stakers[_staker].timeOfLastUpdate) *
                stakers[_staker].amountStaked)
        ) * rewardsPerHour) / 3600);
    }
    function availableReward(address _staker) public view returns (uint256) {
        uint256 reward =  calculateRewards(_staker) +
            stakers[_staker].unclaimedRewards;
        return reward;
    } 
    function getStakedTokens(address _user) public view returns (StakedToken[] memory) {
        if (stakers[_user].amountStaked > 0) {
            StakedToken[] memory _stakedTokens = new StakedToken[](stakers[_user].amountStaked);
            uint256 _index = 0;
            for (uint256 j = 0; j < stakers[_user].StakedTokens.length; j++) {
                if (stakers[_user].StakedTokens[j].staker != (address(0))) {
                    _stakedTokens[_index] = stakers[_user].StakedTokens[j];
                    _index++;
                }
            }
            return _stakedTokens;
        }
        else {
            return new StakedToken[](0);
        }
    }
}