// 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 ^0.8.4;

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


contract Vesting is Ownable {
    IERC20 public immutable CPOOL;

    struct VestingParams {
        uint amount;
        uint vestingBegin;
        uint vestingCliff;
        uint vestingEnd;
        uint lastUpdate;
        uint claimed;
    }

    mapping (address => VestingParams) public recipients;
    uint public totalVest;

    constructor(address tokenAddress) {
        CPOOL = IERC20(tokenAddress);
    }


    function holdTokens(
        address recipient_,
        uint amount_,
        uint vestingBegin_,
        uint vestingCliff_,
        uint vestingEnd_
    )
        onlyOwner
        external
    {
        require(vestingBegin_ >= block.timestamp, 'Vesting::holdTokens: vesting begin too early');
        require(vestingEnd_ > vestingCliff_, 'Vesting::holdTokens: end is too early');
        require(vestingCliff_ >= vestingBegin_, 'Vesting::holdTokens: cliff is too early');
        require(totalVest + amount_ <= CPOOL.balanceOf(address(this)), 'Vesting::holdTokens: notEnoughFunds');
        require(recipients[recipient_].amount == 0, 'Vesting::holdTokens: recipient already have lockup');

        totalVest += amount_;
        recipients[recipient_] = VestingParams({
            amount: amount_,
            vestingBegin: vestingBegin_,
            vestingCliff: vestingCliff_,
            vestingEnd: vestingEnd_,
            lastUpdate: vestingBegin_,
            claimed: 0
        });
    }

    function claim(address recipient_) external {
        require(block.timestamp >= recipients[recipient_].vestingCliff, 'Vesting::claim: not time yet');
        require(recipients[recipient_].amount > 0, 'Vesting::claim: recipient not valid');

        uint amount = getAvailableBalance(recipient_);
        recipients[recipient_].lastUpdate = block.timestamp;
        recipients[recipient_].claimed += amount;
        totalVest -= amount;
        require(IERC20(CPOOL).transfer(recipient_, amount), 'Vesting::claim: transfer error');
    }

    function getAvailableBalance(address recipient_) public view returns(uint) {
        VestingParams memory vestParams = recipients[recipient_];
        uint amount;
        if (block.timestamp < vestParams.vestingCliff) {
            return 0;
        }
        if (block.timestamp >= vestParams.vestingEnd) {
            amount = vestParams.amount - vestParams.claimed;
        } else {
            amount = vestParams.amount * (block.timestamp - vestParams.lastUpdate) / (vestParams.vestingEnd - vestParams.vestingBegin);
        }
        return amount;
    }
}

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