// 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
pragma solidity ^0.8.0;

import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/token/ERC20/extensions/IERC20Metadata.sol";
import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/utils/math/SafeMath.sol";

contract FT500StakingWithRewards is Ownable {
    using SafeMath for uint256;

    IERC20 public stakingToken;
    uint256 public totalStaked;
    uint256 public totalRewards;

    struct Stake {
        uint256 amount;
        uint256 startTime;
        uint256 duration; // 1, 3, 6, or 12 months represented as seconds
        uint256 tier; // Tier 1, 2, 3, 4, or 5
        uint256 reward;
        uint256 rewardDebt;
    }

    // Mapping of user addresses to their staking positions
    mapping(address => Stake) public stakes;

    bool public ethHarvestActive = false;
    
    uint256[5][] public rewardPercentages = [
        [200, 400, 800, 1600], // Tier 1
        [300, 600, 1200, 1800], // Tier 2
        [400, 800, 1600, 2000], // Tier 3
        [500, 1000, 2000, 2500], // Tier 4
        [800, 1600, 2400, 3200] // Tier 5
    ];

    uint256 internal accRewardPerToken;

    // ==============
    //   CONSTANTS
    // ==============
    uint256 internal constant PRECISION = 1e18;


    // ==============
    //    EVENTS
    // ==============
    event Deposit(address indexed user, uint256 indexed stakedAmount);

    event Withdraw(address indexed user, uint256 indexed withdrawAmount);

    event HarvestEth(address indexed user, uint256 indexed harvestAmount);

    event RewardsAdded(uint256 amount);

    constructor(address _stakingToken) {
        stakingToken = IERC20(_stakingToken);
    }

    // Stake tokens with a specified lockup period and tier
    function stake(uint256 amount, uint256 duration) external {
        
        require(duration == 1 || duration == 3 || duration == 6 || duration == 12, "Invalid duration");

        // Transfer tokens to the contract
        require(stakingToken.transferFrom(msg.sender, address(this), amount), "Transfer failed");
        
        //check if user already has stake
        if(stakes[msg.sender].amount > 0){
            totalStaked = totalStaked.sub(stakes[msg.sender].amount);
            totalRewards = totalRewards.sub(stakes[msg.sender].reward);
            amount += stakes[msg.sender].amount;
        } 

        
        uint8 tier;
        if(amount < 100_000 * 1e18){
            tier = 1;    
        }else if(amount >= 100_000 * 1e18 && amount < 250_000 * 1e18){
            tier = 2;
        }else if(amount >= 250_000 * 1e18 && amount < 500_000 * 1e18){
            tier = 3;
        }else if(amount >= 500_000 * 1e18 && amount < 1_000_000 * 1e18){
            tier = 4;
        }else if(amount >= 1_000_000 * 1e18){
            tier = 5;
        }

        require(tier >= 1 && tier <= 5, "Invalid tier");

        uint8 rewardPecentageIndex;

        if(duration == 1){
            rewardPecentageIndex = 1;
        }else if(duration == 3){
            rewardPecentageIndex = 2;
        }else if(duration == 6){
            rewardPecentageIndex = 3;
        }else if(duration == 12){
            rewardPecentageIndex = 4;
        }


        uint256 rewardPercentage = rewardPercentages[tier - 1][rewardPecentageIndex - 1];

        // use updated amount to calculate reward
        uint256 reward = amount.mul(rewardPercentage).div(10_000);

        // Update user's staking position
        stakes[msg.sender] = Stake(amount, block.timestamp, duration * 30 days, tier, reward, 0);
        _updateUserDebt(msg.sender, amount);

        // Update total staked amount
        totalStaked = totalStaked.add(amount);
        // Update total reward
        totalRewards = totalRewards.add(reward);
    }

    // Withdraw staked tokens and rewards
    function withdraw() external {
        Stake storage userStake = stakes[msg.sender];
        require(userStake.amount > 0, "No staking position");

        _harvestEth();

        uint256 stakedAmount = userStake.amount;
        uint256 rewards = stakes[msg.sender].reward;

        // Calculate the time elapsed since the start of the stake
        uint256 elapsedTime = block.timestamp.sub(userStake.startTime);

        //else take earlyWithdrawal fees

        // Update total staked amount
        totalStaked = totalStaked.sub(stakedAmount);
        //  update total rewards
        totalRewards = totalRewards.sub(rewards);

        if(elapsedTime >= userStake.duration){
            delete stakes[msg.sender];
            //if stake time is elapsed, send rewards and send back staked funds
            require(stakingToken.transfer(msg.sender, rewards+stakedAmount), "Transfer failed");

        }else{
            delete stakes[msg.sender];

            // Calculate the early withdrawal fee (10% of the staked amount)
            uint256 earlyWithdrawalFee = (stakedAmount.mul(10)).div(100);
            // Adjust the staked amount after applying the fee
            stakedAmount = stakedAmount.sub(earlyWithdrawalFee);
            require(stakingToken.transfer(msg.sender, stakedAmount), "Transfer failed");
        }
    }
    //claim rewards
    function claimRewards() external{
        // ensure user has stake
        Stake storage userStake = stakes[msg.sender];
        require(userStake.amount > 0, "No staking position");

        uint256 rewards = userStake.reward;

        // Calculate the time elapsed since the start of the stake
        uint256 elapsedTime = block.timestamp.sub(userStake.startTime);
        require(elapsedTime >= userStake.duration, "Staking duration not completed");
        
        
        totalRewards = totalRewards.sub(rewards);
        stakes[msg.sender].reward = 0;
        require(stakingToken.transfer(msg.sender, rewards), "Transfer failed");
    }

    function recommit() external {
        // ensure user has stake
        Stake storage userStake = stakes[msg.sender];
        require(userStake.amount > 0, "No staking position");

        uint256 stakedAmount = userStake.amount;
        uint256 rewards = userStake.reward;

        // Calculate the time elapsed since the start of the stake
        uint256 elapsedTime = block.timestamp.sub(userStake.startTime);
        require(elapsedTime >= userStake.duration, "Staking duration not completed");
        
        totalStaked = totalStaked.sub(stakedAmount);
        totalRewards = totalRewards.sub(rewards);

        //update staked amount
        stakedAmount = stakedAmount.add(rewards);
        //update rewards based on increased amount
        uint8 rewardPecentageIndex;

        //recalculate reward and tier  
        uint256 duration = userStake.duration / 30 days;

        if(duration == 1){
            rewardPecentageIndex = 1;
        }else if(duration == 3){
            rewardPecentageIndex = 2;
        }else if(duration == 6){
            rewardPecentageIndex = 3;
        }else if(duration == 12){
            rewardPecentageIndex = 4;
        }

        uint8 tier;

        if(stakedAmount < 100_000 * 1e18){
            tier = 1;    
        }else if(stakedAmount >= 100_000 * 1e18 && stakedAmount < 250_000 * 1e18){
            tier = 2;
        }else if(stakedAmount >= 250_000 * 1e18 && stakedAmount < 500_000 * 1e18){
            tier = 3;
        }else if(stakedAmount >= 500_000 * 1e18 && stakedAmount < 1_000_000 * 1e18){
            tier = 4;
        }else if(stakedAmount >= 1_000_000 * 1e18){
            tier = 5;
        }

        require(tier >= 1 && tier <= 5, "Invalid tier");
        uint256 rewardPercentage = rewardPercentages[tier - 1][rewardPecentageIndex - 1];

        // use updated amount to calculate reward
        uint256 newReward = stakedAmount.mul(rewardPercentage).div(10_000);

        // Update total staked amount
        totalStaked = totalStaked.add(stakedAmount);
        // Update total reward
        totalRewards = totalRewards.add(newReward);

        stakes[msg.sender].amount = stakedAmount;
        stakes[msg.sender].amount = stakedAmount;
        stakes[msg.sender].startTime = block.timestamp;
        stakes[msg.sender].duration = duration * 30 days;      
        stakes[msg.sender].tier = tier;
        stakes[msg.sender].reward = newReward;

        _updateUserDebt(msg.sender, stakedAmount);

    }

    // Owner-only function to withdraw any remaining tokens from the contract
    function withdrawTokens(address tokenAddress, uint256 amount) external onlyOwner {
        IERC20 token = IERC20(tokenAddress);
        require(token.balanceOf(address(this)) > 0, "No tokens to withdraw");
        require(token.transfer(owner(), amount), "Transfer failed");
    }

    // Owner-only function to change the staking token
    function changeStakingToken(address newToken) external onlyOwner {
        stakingToken = IERC20(newToken);
    }

    // Check if a wallet has staked
    function hasStake(address user) external view returns (bool) {
        return stakes[user].amount > 0;
    }
    
    function withdrawStuckEth(address toAddr) external onlyOwner {
        (bool success, ) = toAddr.call{value: address(this).balance}("");
        require(success);
    }

    receive() external payable {}

    // =============
    //    ADMIN
    // =============

    // Distribute rewards
    function distributeRewards(uint amount) external payable onlyOwner {
        require(msg.value == amount, "Enter correct amount");
        
        if (totalStaked > 0) accRewardPerToken += (amount * PRECISION) / totalStaked;

        emit RewardsAdded(amount);
    }

    // Harvest rewards
    function _harvestEth() internal {

        uint256 minimumStakeDuration = 14 days;
        Stake memory _stake = stakes[msg.sender];
        uint256 elapsedTime = block.timestamp.sub(_stake.startTime);

        if(ethHarvestActive && elapsedTime >= minimumStakeDuration){
            require(ethHarvestActive, "Harvesting not started");
            uint pendingRewards = _pendingHarvestRewards(_stake);

            stakes[msg.sender].rewardDebt =
                (_stake.amount * accRewardPerToken) /
                PRECISION;

            (bool success, ) = msg.sender.call{value: pendingRewards}("");
            require(success);

            emit HarvestEth(msg.sender, pendingRewards);
        }
    }

    function harvestEth() public {

        require(ethHarvestActive, "Harvesting not started");
        uint256 minimumStakeDuration = 14 days;
        Stake memory _stake = stakes[msg.sender];
        uint256 elapsedTime = block.timestamp.sub(_stake.startTime);

        require(elapsedTime >= minimumStakeDuration, "Minimum staking duration not reached");

        _harvestEth();
    }

    function toggleEthHarvesting(bool _value) external payable onlyOwner {
        ethHarvestActive = _value;
    }
    // Rewards to be harvested
    function _pendingHarvestRewards(Stake memory _stake) internal view returns (uint) {
        return
            (_stake.amount * accRewardPerToken) / PRECISION - _stake.rewardDebt;
    }

    function _updateUserDebt(address user, uint256 newAmount) internal {
        stakes[user].rewardDebt = (newAmount * accRewardPerToken) / PRECISION;
    }

    function getPendingHarvestRewards() external view returns (uint){
        return _pendingHarvestRewards(stakes[msg.sender]);
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (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 v4.4.1 (token/ERC20/extensions/IERC20Metadata.sol)

pragma solidity ^0.8.0;

import "../IERC20.sol";

/**
 * @dev Interface for the optional metadata functions from the ERC20 standard.
 *
 * _Available since v4.1._
 */
interface IERC20Metadata is IERC20 {
    /**
     * @dev Returns the name of the token.
     */
    function name() external view returns (string memory);

    /**
     * @dev Returns the symbol of the token.
     */
    function symbol() external view returns (string memory);

    /**
     * @dev Returns the decimals places of the token.
     */
    function decimals() external view returns (uint8);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (access/Ownable.sol)

pragma solidity ^0.8.0;

import "../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.
 *
 * 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() {
        _transferOwnership(_msgSender());
    }

    /**
     * @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 {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
    }

    /**
     * @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 {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        _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);
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (utils/math/SafeMath.sol)

pragma solidity ^0.8.0;

// CAUTION
// This version of SafeMath should only be used with Solidity 0.8 or later,
// because it relies on the compiler's built in overflow checks.

/**
 * @dev Wrappers over Solidity's arithmetic operations.
 *
 * NOTE: `SafeMath` is generally not needed starting with Solidity 0.8, since the compiler
 * now has built in overflow checking.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function tryAdd(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            uint256 c = a + b;
            if (c < a) return (false, 0);
            return (true, c);
        }
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function trySub(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b > a) return (false, 0);
            return (true, a - b);
        }
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function tryMul(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
            // benefit is lost if 'b' is also tested.
            // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
            if (a == 0) return (true, 0);
            uint256 c = a * b;
            if (c / a != b) return (false, 0);
            return (true, c);
        }
    }

    /**
     * @dev Returns the division of two unsigned integers, with a division by zero flag.
     *
     * _Available since v3.4._
     */
    function tryDiv(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b == 0) return (false, 0);
            return (true, a / b);
        }
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers, with a division by zero flag.
     *
     * _Available since v3.4._
     */
    function tryMod(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b == 0) return (false, 0);
            return (true, a % b);
        }
    }

    /**
     * @dev Returns the addition of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `+` operator.
     *
     * Requirements:
     *
     * - Addition cannot overflow.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        return a + b;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        return a - b;
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `*` operator.
     *
     * Requirements:
     *
     * - Multiplication cannot overflow.
     */
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        return a * b;
    }

    /**
     * @dev Returns the integer division of two unsigned integers, reverting on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator.
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return a / b;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * reverting when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        return a % b;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {trySub}.
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        unchecked {
            require(b <= a, errorMessage);
            return a - b;
        }
    }

    /**
     * @dev Returns the integer division of two unsigned integers, reverting with custom message on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        unchecked {
            require(b > 0, errorMessage);
            return a / b;
        }
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * reverting with custom message when dividing by zero.
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {tryMod}.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        unchecked {
            require(b > 0, errorMessage);
            return a % b;
        }
    }
}

{
  "compilationTarget": {
    "contracts/FT500StakingWithRewards.sol": "FT500StakingWithRewards"
  },
  "evmVersion": "shanghai",
  "libraries": {},
  "metadata": {
    "bytecodeHash": "ipfs"
  },
  "optimizer": {
    "enabled": true,
    "runs": 200
  },
  "remappings": []
}