/*

    Copyright 2020 DODO ZOO.
    SPDX-License-Identifier: Apache-2.0

*/

pragma solidity 0.6.9;
pragma experimental ABIEncoderV2;

import {SafeMath} from "./SafeMath.sol";

/**
 * @title DecimalMath
 * @author DODO Breeder
 *
 * @notice Functions for fixed point number with 18 decimals
 */
library DecimalMath {
    using SafeMath for uint256;

    uint256 internal constant ONE = 10**18;
    uint256 internal constant ONE2 = 10**36;

    function mulFloor(uint256 target, uint256 d) internal pure returns (uint256) {
        return target.mul(d) / (10**18);
    }

    function mulCeil(uint256 target, uint256 d) internal pure returns (uint256) {
        return target.mul(d).divCeil(10**18);
    }

    function divFloor(uint256 target, uint256 d) internal pure returns (uint256) {
        return target.mul(10**18).div(d);
    }

    function divCeil(uint256 target, uint256 d) internal pure returns (uint256) {
        return target.mul(10**18).divCeil(d);
    }

    function reciprocalFloor(uint256 target) internal pure returns (uint256) {
        return uint256(10**36).div(target);
    }

    function reciprocalCeil(uint256 target) internal pure returns (uint256) {
        return uint256(10**36).divCeil(target);
    }

    function powFloor(uint256 target, uint256 e) internal pure returns (uint256) {
        if (e == 0) {
            return 10 ** 18;
        } else if (e == 1) {
            return target;
        } else {
            uint p = powFloor(target, e.div(2));
            p = p.mul(p) / (10**18);
            if (e % 2 == 1) {
                p = p.mul(target) / (10**18);
            }
            return p;
        }
    }
}