// SPDX-License-Identifier: MIT

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;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @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 `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, 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 `sender` to `recipient` 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 sender,
        address recipient,
        uint256 amount
    ) external returns (bool);

    /**
     * @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);
}

// SPDX-License-Identifier: MIT

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() {
        _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);
    }
}

// SPDX-License-Identifier: MIT

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 no longer needed starting with Solidity 0.8. 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 substraction 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;
        }
    }
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

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

/**
 * @title VestingPeriod
 * @dev The vesting vault contract after the token sale
 * Taken from https://github.com/dandelionlabs-io/polkafantasy-linear-vesting//blob/master/contracts/Vesting.sol
 */
contract VestingPeriod is Ownable {
    using SafeMath for uint256;

    /// @notice Grant definition
    struct Grant {
        uint256 amount;             // Total amount to claim
        uint256 totalClaimed;       // Already claimed
        uint256 perSecond;          // Reward per second
    }

    struct Pool {
        uint256 startTime;          // Starting time of the vesting period in unix timestamp format
        uint256 endTime;            // Ending time of the vesting period in unix timestamp format
        uint256 vestingDuration;    // In seconds
        uint256 amount;             // Total size of pool
        uint256 totalClaimed;       // Total amount claimed till moment
        uint256 grants;             // Amount of investors
    }

    /// @dev Used to translate vesting periods specified in days to seconds
    uint256 constant internal SECONDS_PER_DAY = 86400;

    /// @notice PolkaFantasy token
    IERC20 public token;

    /// @notice Mapping of recipient address > token grant
    mapping (address => Grant) public tokenGrants;

    /// @notice Current vesting period is the same for all grants.
    /// @dev Each pool has its own contract.
    Pool public pool;

    /// @notice List of investors who got blacklist tokens.
    /// @dev Structure of the map: investor => new address
    mapping(address => address) public blacklist;

    /// @notice Event emitted when a new grant is created
    event GrantAdded(address indexed recipient, uint256 indexed amount);

    /// @notice Event emitted when tokens are claimed by a recipient from a grant
    event GrantTokensClaimed(address indexed recipient, uint256 indexed amountClaimed);

    /// @notice Event emitted when the grant investor is changed
    event ChangeInvestor(address indexed oldOwner, address indexed newOwner);

    /**
     * @notice Construct a new Vesting contract
     * @param _token Address of PolkaFantasy token
     * @param _startTime starting time of the vesting period in timestamp format
     * @param _vestingDuration duration time of the vesting period in timestamp format
     */
    constructor(address _token, uint256 _startTime, uint256 _vestingDuration) {
        require(_token != address(0), "VestingPeriod::constructor: _token must be valid token address");
        require(_startTime > 0 && _vestingDuration > 0, "VestingPeriod::constructor: One of the time parameters is 0");
        require(_startTime > block.timestamp, "VestingPeriod::constructor: Starting time shalll be in a future time");
        require(_vestingDuration > 0, "VestingPeriod::constructor: Duration of the period must be > 0");
        if (_vestingDuration < SECONDS_PER_DAY) {
            require(_vestingDuration <= SECONDS_PER_DAY.mul(10).mul(365), "VestingPeriod::constructor: Duration should be less than 10 years");
        }
        
        token = IERC20(_token);
        
        pool.startTime = _startTime;
        pool.vestingDuration = _vestingDuration;
        pool.endTime = _startTime.add(_vestingDuration);
    }

    /**
     * @notice In case if the user doesn't want to change the grant.
     * @param _oldAddress existing address from the investor which we want to change
     * @param _newAddress new address from the investor which we want to give
     */
    function changeInvestor(address _oldAddress, address _newAddress) external onlyOwner {
        require(blacklist[_oldAddress] == address(0), "VestingPeriod::changeInvestor: oldaddress already in the blacklist");
        require(blacklist[_newAddress] == address(0), "VestingPeriod::changeInvestor: new address is a blacklisted address");
        require(tokenGrants[_newAddress].amount == 0, "VestingPeriod::changeInvestor: requires a different address than existing granted");
        require(tokenGrants[_oldAddress].amount > 0, "VestingPeriod::changeInvestor: oldAddress has no remaining balance");

        tokenGrants[_newAddress] = Grant(tokenGrants[_oldAddress].amount, tokenGrants[_oldAddress].totalClaimed, tokenGrants[_oldAddress].perSecond);
        delete tokenGrants[_oldAddress];

        blacklist[_oldAddress] = _newAddress;

        emit ChangeInvestor(_oldAddress, _newAddress);
    }

    /**
     * @notice Add list of grants in batch.
     * @param _recipients list of addresses of the stakeholders
     * @param _amounts list of amounts to be assigned to the stakeholders
     */
    function addTokenGrants(address[] memory _recipients, uint256[] memory _amounts) external onlyOwner {
        require(_recipients.length > 0, "VestingPeriod::addTokenGrants: no recipients");
        require(_recipients.length <= 100, "VestingPeriod::addTokenGrants: too many grants, it will probably fail");
        require(_recipients.length == _amounts.length, "VestingPeriod::addTokenGrants: invalid parameters length (they should be same)");

        uint256 amountSum = 0;
        for (uint16 i = 0; i < _recipients.length; i++) {
            require(_recipients[i] != address(0), "VestingPeriod:addTokenGrants: there is an address with value 0");
            require(tokenGrants[_recipients[i]].amount == 0, "VestingPeriod::addTokenGrants: a grant already exists for one of the accounts");
            require(blacklist[_recipients[i]] == address(0), "VestingPeriod:addTOkenGrants: Blacklisted address");

            require(_amounts[i] > 0, "VestingPeriod::addTokenGrant: amount == 0");
            amountSum = amountSum.add(_amounts[i]);
        }

        // Transfer the grant tokens under the control of the vesting contract
        require(token.transferFrom(msg.sender, address(this), amountSum), "VestingPeriod::addTokenGrants: transfer failed");

        for (uint16 i = 0; i < _recipients.length; i++) {
 
            Grant memory grant = Grant({
                amount: _amounts[i],
                totalClaimed: 0,
                perSecond: _amounts[i].div(pool.vestingDuration)
            });
            tokenGrants[_recipients[i]] = grant;
            emit GrantAdded(_recipients[i], _amounts[i]);
        }

        pool.amount = pool.amount.add(amountSum);
    }

    /**
     * @notice Get token grant for recipient
     * @param _recipient The address that has a grant
     * @return the grant
     */
    function getTokenGrant(address _recipient) external view returns (Grant memory) {
        return tokenGrants[_recipient];
    }

    /**
     * @notice Calculate the vested and unclaimed tokens available for `recipient` to claim
     * @dev Due to rounding errors once grant duration is reached, returns the entire left grant amount
     * @param _recipient The address that has a grant
     * @return The amount recipient can claim
     */
    function calculateGrantClaim(address _recipient) public view returns (uint256) {

        // For grants created with a future start date, that hasn't been reached, return 0, 0
        if (block.timestamp < pool.startTime) {
            return 0;
        }

        uint256 cap = block.timestamp;
        if (cap > pool.endTime) {
            cap = pool.endTime;
        }
        uint256 elapsedTime = cap.sub(pool.startTime);
        
        // If over vesting duration, all tokens vested
        if (elapsedTime >= pool.vestingDuration) {
            uint256 remainingGrant = tokenGrants[_recipient].amount.sub(tokenGrants[_recipient].totalClaimed);
            return remainingGrant;
        } else {
            uint256 amountVested = tokenGrants[_recipient].perSecond.mul(elapsedTime);
            uint256 claimableAmount = amountVested.sub(tokenGrants[_recipient].totalClaimed);
            return claimableAmount;
        }
    }

    /**
     * @notice Calculate the vested (claimed + unclaimed) tokens for `recipient`
     * @param _recipient The address that has a grant
     * @return Total vested balance (claimed + unclaimed)
     */
    function vestedBalance(address _recipient) external view returns (uint256) {

        // For grants created with a future start date, that hasn't been reached, return 0, 0
        if (block.timestamp < pool.startTime) {
            return 0;
        }

        uint256 cap = block.timestamp;
        if (cap > pool.endTime) {
            cap = pool.endTime;
        }
        
        // If over vesting duration, all tokens vested
        if (cap == pool.endTime) {
            return tokenGrants[_recipient].amount;
        } else {
            uint256 elapsedTime = cap.sub(pool.startTime);
            uint256 amountVested = tokenGrants[_recipient].perSecond.mul(elapsedTime);
            return amountVested;
        }
    }

    /**
     * @notice The balance claimed by `recipient`
     * @param _recipient The address that has a grant
     * @return the number of claimed tokens by `recipient`
     */
    function claimedBalance(address _recipient) external view returns (uint256) {

        return tokenGrants[_recipient].totalClaimed;
    }

    /**
     * @notice Allows a grant recipient to claim their vested tokens
     * @dev Errors if no tokens have vested
     * @dev It is advised recipients check they are entitled to claim via `calculateGrantClaim` before calling this
     * @param _recipient The address that has a grant
     */
    function claimVestedTokens(address _recipient) external {
        uint256 amountVested = calculateGrantClaim(_recipient);
        require(amountVested > 0, "VestingPeriod::claimVestedTokens: amountVested is 0");
        require(token.transfer(_recipient, amountVested), "VestingPeriod::claimVestedTokens: transfer failed");
        
        Grant storage tokenGrant = tokenGrants[_recipient];

        tokenGrant.totalClaimed = uint256(tokenGrant.totalClaimed.add(amountVested));
        pool.totalClaimed = pool.totalClaimed.add(amountVested);

        emit GrantTokensClaimed(_recipient, amountVested);
    }

    /**
     * @notice Calculate the number of tokens that will vest per day for the given recipient
     * @param _recipient The address that has a grant
     * @return Number of tokens that will vest per day
     */
    function tokensVestedPerDay(address _recipient) external view returns(uint256) {
        
        return tokenGrants[_recipient].amount.div(pool.vestingDuration.div(SECONDS_PER_DAY));
    }
    
    /**
     * @notice Calculate the number of tokens that will vest per day in the given period for an amount
     * @param _amount the amount to be checked
     * @return Number of tokens that will vest per day
     */
    function tokensVestedPerDay(uint256 _amount) external view returns(uint256) {
        
        return _amount.div(pool.vestingDuration.div(SECONDS_PER_DAY));
    }
}

{
  "compilationTarget": {
    "Vesting.sol": "VestingPeriod"
  },
  "evmVersion": "london",
  "libraries": {},
  "metadata": {
    "bytecodeHash": "ipfs"
  },
  "optimizer": {
    "enabled": false,
    "runs": 200
  },
  "remappings": []
}