pragma solidity =0.6.6;

import "./libraries/SafeMath.sol";
import "./interfaces/IImx.sol";
import "./interfaces/IClaimable.sol";
import "./interfaces/IVester.sol";

contract Vester is IVester, IClaimable {
	using SafeMath for uint;

	uint public constant override segments = 100;

	address public immutable imx;
	address public recipient;

	uint public immutable override vestingAmount;
	uint public immutable override vestingBegin;
	uint public immutable override vestingEnd;

	uint public previousPoint;
	uint public immutable finalPoint;

	constructor(
		address imx_,
		address recipient_,
		uint vestingAmount_,
		uint vestingBegin_,
		uint vestingEnd_
	) public {
		require(vestingEnd_ > vestingBegin_, "Vester: END_TOO_EARLY");

		imx = imx_;
		recipient = recipient_;

		vestingAmount = vestingAmount_;
		vestingBegin = vestingBegin_;
		vestingEnd = vestingEnd_;

		finalPoint = vestingCurve(1e18);
	}
	
	function vestingCurve(uint x) public virtual pure returns (uint y) {
		uint speed = 1e18;
		for (uint i = 0; i < 100e16; i += 1e16) {
			if (x < i + 1e16) return y + speed * (x - i) / 1e16;
			y += speed;
			speed = speed * 976 / 1000;
		}
	}
	
	function getUnlockedAmount() internal virtual returns (uint amount) {
		uint blockTimestamp = getBlockTimestamp();
		uint currentPoint = vestingCurve( (blockTimestamp - vestingBegin).mul(1e18).div(vestingEnd - vestingBegin) );
		amount = vestingAmount.mul(currentPoint.sub(previousPoint)).div(finalPoint);
		previousPoint = currentPoint;
	}
	
	function claim() public virtual override returns (uint amount) {
		require(msg.sender == recipient, "Vester: UNAUTHORIZED");
		uint blockTimestamp = getBlockTimestamp();
		if (blockTimestamp < vestingBegin) return 0;
		if (blockTimestamp > vestingEnd) {
			amount = IImx(imx).balanceOf(address(this));
		} else {
			amount = getUnlockedAmount();
		}
		if (amount > 0) IImx(imx).transfer(recipient, amount);
	}
	
	function setRecipient(address recipient_) public virtual {
		require(msg.sender == recipient, "Vester: UNAUTHORIZED");
		recipient = recipient_;
	}
	
	function getBlockTimestamp() public virtual view returns (uint) {
		return block.timestamp;
	}
}

pragma solidity =0.6.6;

interface IClaimable {
	function claim() external returns (uint amount);
	event Claim(address indexed account, uint amount);
}

pragma solidity =0.6.6;
//IERC20?
interface IImx {
    function balanceOf(address account) external view returns (uint);
    function transfer(address dst, uint rawAmount) external returns (bool);
}

pragma solidity >=0.5.0;

interface IVester {
	function segments() external pure returns (uint);
	function vestingAmount() external pure returns (uint);
	function vestingBegin() external pure returns (uint);
	function vestingEnd() external pure returns (uint);
}

pragma solidity =0.6.6;

// From https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/math/Math.sol
// Subject to the MIT license.

/**
 * @dev Wrappers over Solidity's arithmetic operations with added overflow
 * checks.
 *
 * Arithmetic operations in Solidity wrap on overflow. This can easily result
 * in bugs, because programmers usually assume that an overflow raises an
 * error, which is the standard behavior in high level programming languages.
 * `SafeMath` restores this intuition by reverting the transaction when an
 * operation overflows.
 *
 * Using this library instead of the unchecked operations eliminates an entire
 * class of bugs, so it's recommended to use it always.
 */
library SafeMath {
    /**
     * @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) {
        uint256 c = a + b;
        require(c >= a, "SafeMath: addition overflow");

        return c;
    }

    /**
     * @dev Returns the addition of two unsigned integers, reverting with custom message on overflow.
     *
     * Counterpart to Solidity's `+` operator.
     *
     * Requirements:
     * - Addition cannot overflow.
     */
    function add(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, errorMessage);

        return c;
    }

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

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on underflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     * - Subtraction cannot underflow.
     */
    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b <= a, errorMessage);
        uint256 c = a - b;

        return c;
    }

    /**
     * @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) {
        // 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 0;
        }

        uint256 c = a * b;
        require(c / a == b, "SafeMath: multiplication overflow");

        return c;
    }

    /**
     * @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, string memory errorMessage) internal pure returns (uint256) {
        // 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 0;
        }

        uint256 c = a * b;
        require(c / a == b, errorMessage);

        return c;
    }

    /**
     * @dev Returns the integer division of two unsigned integers.
     * Reverts 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) internal pure returns (uint256) {
        return div(a, b, "SafeMath: division by zero");
    }

    /**
     * @dev Returns the integer division of two unsigned integers.
     * Reverts 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) {
        // Solidity only automatically asserts when dividing by 0
        require(b > 0, errorMessage);
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold

        return c;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts 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 mod(a, b, "SafeMath: modulo by zero");
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts with custom message 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, string memory errorMessage) internal pure returns (uint256) {
        require(b != 0, errorMessage);
        return a % b;
    }
}