// File: contracts/PlanetRewards.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.13;

import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v4.9.3/contracts/token/ERC20/IERC20.sol";
import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v4.9.3/contracts/access/Ownable.sol";
import "./IPlanetRewards.sol";

contract PlanetRewards is IPlanetRewards, Ownable {
    address public immutable PLANET;

    bool public stakingEnabled;
    uint256 public rewardRate = 100;
    uint256 public minStake = 100_000 ether;
    uint256 public cooldown = 1 days;
    uint256 public maxStakeDurationWithoutNewEntry = 52 weeks;
    uint256 public minStakeDuration;
    uint256 public globalTotalStaked;
    uint256 public totalUniqueStakers;

    mapping(address => Account) public account;

    address[] public lastWinners;

    constructor(address planet) {
        PLANET = planet;
    }

    function stake(uint256 amount) public {
        if (!stakingEnabled) revert StakingNotEnabled();
        if (amount < minStake) revert InvalidStakingAmount();

        IERC20(PLANET).transferFrom(msg.sender, address(this), amount);

        uint256 stakedBefore = account[msg.sender].totalStaked;
        bool isNewStaker = stakedBefore == 0;

        if (isNewStaker) totalUniqueStakers++;
        globalTotalStaked += amount;

        uint256 points = isNewStaker ? 0 : totalPoints(msg.sender);

        account[msg.sender] = Account(
            {
                lastStakedAt: block.timestamp,
                totalStaked: stakedBefore + amount,
                creditedPoints: points
            }
        );
        
        emit Stake(msg.sender, amount, points, block.timestamp);
    }

    function unstake() public {
        uint256 stakedTokens = account[msg.sender].totalStaked;

        if (stakedTokens == 0) revert NoStakedTokens();
        if (block.timestamp - account[msg.sender].lastStakedAt < minStakeDuration) {
            revert UnstakingNotPermitted();
        }

        IERC20(PLANET).transfer(msg.sender, stakedTokens);

        totalUniqueStakers--;
        globalTotalStaked -= stakedTokens;
        
        delete account[msg.sender];

        emit Unstake(msg.sender, stakedTokens, block.timestamp);
    }

    function totalPoints(address wallet) public view returns (uint256) {
        uint256 timePassed = block.timestamp - account[wallet].lastStakedAt;

        if (
            timePassed == block.timestamp ||
            timePassed >= maxStakeDurationWithoutNewEntry)
        {
            return 0;
        }

        uint256 accumulated =
            ((timePassed / cooldown) * account[wallet].totalStaked) / rewardRate;

        return account[wallet].creditedPoints + accumulated;
    }


    /* -------------------------------------------------------------------------- */
    /*                         OWNER RESTRICTED FUNCTIONS                         */
    /* -------------------------------------------------------------------------- */

    function resetWinners(address[] calldata winners) external onlyOwner {
        uint256 length = winners.length;
        for (uint256 i = 0; i < length; i++) {
            account[winners[i]].lastStakedAt = block.timestamp;
            delete account[winners[i]].creditedPoints;
            emit ResetWinner(winners[i]);
        }
        lastWinners = winners;
    }

    function setMinStake(uint256 newValue) external onlyOwner {
        if (newValue == 0) revert ZeroValue();
        minStake = newValue;
    }

    function setMinStakeDuration(uint256 newValue) external onlyOwner {
        minStakeDuration = newValue;
    }

    function setRewardRate(uint256 newValue) external onlyOwner {
        if (newValue == 0) revert ZeroValue();
        rewardRate = newValue;
    }

    function setStakingEnabled(bool newValue) external onlyOwner {
        stakingEnabled = newValue;
        emit StakingEnabled(newValue);
    }

    function setMaxStakePeriodWithoutNewEntry(uint256 newValue) external onlyOwner {
        maxStakeDurationWithoutNewEntry = newValue;
    }

    function setCooldown(uint256 newValue) external onlyOwner {
        if (newValue == 0) revert ZeroValue();
        cooldown = newValue;
    }
}

// File: contracts/IPlanetRewards.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.13;

contract IPlanetRewards {
    struct Account {
        uint256 lastStakedAt;
        uint256 totalStaked;
        uint256 creditedPoints;
    }

    event Stake(address indexed staker, uint256 amount, uint256 totalCreditedPoints, uint256 timestamp);
    event Unstake(address indexed staker, uint256 amount, uint256 timestamp);
    event StakingEnabled(bool enabled);
    event ResetWinner(address winner);

    error InvalidStakingAmount();
    error NoStakedTokens();
    error StakingNotEnabled();
    error UnstakingNotPermitted();
    error ZeroValue();
}

// File: https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v4.9.3/contracts/access/Ownable.sol



// 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);
    }
}

// File: https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v4.9.3/contracts/token/ERC20/IERC20.sol



// 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);
}

// File: https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v4.9.3/contracts/utils/Context.sol



// 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;
    }
}