// File: @openzeppelin/contracts/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;
    }
}

// File: @openzeppelin/contracts/access/Ownable.sol



pragma solidity ^0.8.0;


/**
 * @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.
 *
 * By default, the owner account will be the one that deploys the contract. 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;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor() {
        _setOwner(_msgSender());
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
        _;
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        _setOwner(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 {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        _setOwner(newOwner);
    }

    function _setOwner(address newOwner) private {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}

// File: contracts/staking.sol


pragma solidity ^0.8.0;


interface IERC20 {
    function transfer(address recipient, uint256 amount) external returns (bool);
    function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);
    function balanceOf(address account) external view returns (uint256);
    function allowance(address owner, address spender) external view returns (uint256);
}

contract StakingContract is Ownable {
    IERC20 token;
    uint256 cycleRewardPercentage;
    uint256 totalStaked;
    uint256 minStaking;
    uint256 constant stakingCycle = 1 hours;

    event UserStaked(address user, uint256 amount);
    event UserRestaked(address user, uint256 amount, uint256 restakedReward);
    event UserWithdrew(address user, uint256 withdrawAmount);

    struct Stake {
        uint256 amount;
        uint256 depositTime;
    }

    mapping(address => Stake) public stakes;

    constructor(
        address _tokenAddress,
        uint256 _cycleRewardPercentage, //5 = 0,5%
        uint256 _minStaking
    ) {
            require(_cycleRewardPercentage > 0, "Cycle reward must be greater than 0");
            token = IERC20(_tokenAddress);
            cycleRewardPercentage = _cycleRewardPercentage;
            minStaking = _minStaking;
    }

    function getUserRewardAmount(address _addr) public view returns (uint256) {
        Stake storage stake = stakes[_addr];

        if(stake.amount > 0) {
            uint256 stakingDuration = block.timestamp - stake.depositTime;
            return (stakingDuration / stakingCycle) * stake.amount * cycleRewardPercentage / 1000;
        } else {
            return 0;
        }
    }

    function getUserStakedAndRewards(address _addr) public view returns (uint256, uint256) {
        uint256 rewards = getUserRewardAmount(_addr);
        Stake storage stake = stakes[_addr];
        return (stake.amount, rewards);
    }

    function getUserTotalWithdrawAmount(address _addr) public view returns (uint256) {
        Stake storage stake = stakes[_addr];
        uint256 reward = getUserRewardAmount(_addr);
        return reward + stake.amount;
    }


    function stakeTokens(uint256 _amount) external {
        require(_amount >= minStaking, "Amount must be greater or equal to minStaking");
        require(token.allowance(msg.sender, address(this)) >= _amount, "Not enough allowance");
        require(token.transferFrom(msg.sender, address(this), _amount), "Invalid transfer");

        Stake storage userStake = stakes[msg.sender];
        if(userStake.amount > 0) {
            //Calculate userStake, and increase with rewards
            uint256 currentReward = getUserRewardAmount(msg.sender);
            if(currentReward > 0) {
                userStake.amount += currentReward;
                totalStaked += currentReward;
                emit UserRestaked(msg.sender, _amount, currentReward);
            }
        }
        userStake.amount += _amount;
        userStake.depositTime = block.timestamp;
        
        totalStaked += _amount;
        emit UserStaked(msg.sender, _amount);
    }

    function withdraw() external {
        Stake storage stake = stakes[msg.sender];
        uint256 reward = getUserRewardAmount(msg.sender);
        uint256 totalWithdrawAmount = reward + stake.amount;

        require(totalWithdrawAmount > 0, "Nothing to withdraw");
        require(stake.depositTime > 1 days, "Staking unlocks after 24 hours of your last deposit");
    
        require(token.transfer(msg.sender, totalWithdrawAmount), "Transfer failed");

        totalStaked -= stake.amount;
        stake.amount = 0;
        emit UserWithdrew(msg.sender, totalWithdrawAmount);
    }
}