// ooooo  oooo oooooooooo  ooooooooo             oooooooo8 ooooooooooo   o      oooo   oooo ooooo oooo   oooo  ooooooo8  
//  888    88   888    888  888    88o          888        88  888  88  888      888  o88    888   8888o  88 o888    88  
//   888  88    888oooo88   888    888 ooooooooo 888oooooo     888     8  88     888888      888   88 888o88 888    oooo 
//    88888     888  88o    888    888                  888    888    8oooo88    888  88o    888   88   8888 888o    88  
//     888     o888o  88o8 o888ooo88            o88oooo888    o888o o88o  o888o o888o o888o o888o o88o    88  888ooo888                                                                                                    

// File: @openzeppelin/contracts/token/ERC20/IERC20.sol
// OpenZeppelin Contracts (last updated v5.0.0) (token/ERC20/IERC20.sol)

pragma solidity ^0.8.20;

/**
 * @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 value of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the value of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves a `value` amount of 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 value) 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 a `value` amount of tokens 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 value) external returns (bool);

    /**
     * @dev Moves a `value` amount of tokens from `from` to `to` using the
     * allowance mechanism. `value` 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 value) external returns (bool);
}

// File: contracts/VRDStaking.sol
pragma solidity ^0.8.20;


contract VRDStaking {
    IERC20 public vrdToken;

    struct Stake {
        uint256 amountStaked;
        address stakerAddress;
        uint256 unstakeRequestTimestamp; // Timestamp when the unstake request was made
        bool isStaked;
    }

    mapping(address => Stake) public stakes;
    constructor(address _vrdTokenAddress) {
        vrdToken = IERC20(_vrdTokenAddress);
    }

    function stake(uint256 _amount) external {
        require(_amount > 0, "Amount must be greater than 0");
        require(vrdToken.transferFrom(msg.sender, address(this), _amount), "VRD Transfer failed");
   
        Stake storage stake = stakes[msg.sender];

        stake.amountStaked += _amount;
        stake.stakerAddress = msg.sender;
        stake.isStaked = true;
        stake.unstakeRequestTimestamp = 0; // Resetting the unstake request timestamp
    }

    function requestUnstake() external {
        Stake storage stake = stakes[msg.sender];
        require(stake.amountStaked > 0, "No tokens to unstake");
        require(stake.amountStaked > 0, "Nothing staked");
        require(stake.unstakeRequestTimestamp == 0, "Unstake request already made");

        stake.isStaked = false;
        stake.unstakeRequestTimestamp = block.timestamp;
    }

    function unstake() external {
        Stake storage stake = stakes[msg.sender];
        require(stake.amountStaked > 0, "Nothing staked");
        require(block.timestamp >= stake.unstakeRequestTimestamp + 14 days, "Unstake request is still in the notice period");
        
        require(vrdToken.transfer(msg.sender, stake.amountStaked), "Transfer failed");
        
        stake.amountStaked = 0;
        stake.unstakeRequestTimestamp = 0; // Resetting the unstake request timestamp
    }
}