// File: contracts/intf/IERC20.sol

// This is a file copied from https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC20/IERC20.sol
// SPDX-License-Identifier: MIT

pragma solidity 0.6.9;
pragma experimental ABIEncoderV2;

/**
 * @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);

    function decimals() external view returns (uint8);

    function name() external view returns (string memory);

    function symbol() external view returns (string memory);

    /**
     * @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);
}

// File: contracts/lib/SafeMath.sol



/**
 * @title SafeMath
 * @author DODO Breeder
 *
 * @notice Math operations with safety checks that revert on error
 */
library SafeMath {
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        if (a == 0) {
            return 0;
        }

        uint256 c = a * b;
        require(c / a == b, "MUL_ERROR");

        return c;
    }

    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b > 0, "DIVIDING_ERROR");
        return a / b;
    }

    function divCeil(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 quotient = div(a, b);
        uint256 remainder = a - quotient * b;
        if (remainder > 0) {
            return quotient + 1;
        } else {
            return quotient;
        }
    }

    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b <= a, "SUB_ERROR");
        return a - b;
    }

    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, "ADD_ERROR");
        return c;
    }

    function sqrt(uint256 x) internal pure returns (uint256 y) {
        uint256 z = x / 2 + 1;
        y = x;
        while (z < y) {
            y = z;
            z = (x / z + z) / 2;
        }
    }
}

// File: contracts/lib/DecimalMath.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);
    }
}

// File: contracts/lib/InitializableOwnable.sol


/**
 * @title Ownable
 * @author DODO Breeder
 *
 * @notice Ownership related functions
 */
contract InitializableOwnable {
    address public _OWNER_;
    address public _NEW_OWNER_;
    bool internal _INITIALIZED_;

    // ============ Events ============

    event OwnershipTransferPrepared(address indexed previousOwner, address indexed newOwner);

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    // ============ Modifiers ============

    modifier notInitialized() {
        require(!_INITIALIZED_, "DODO_INITIALIZED");
        _;
    }

    modifier onlyOwner() {
        require(msg.sender == _OWNER_, "NOT_OWNER");
        _;
    }

    // ============ Functions ============

    function initOwner(address newOwner) public notInitialized {
        _INITIALIZED_ = true;
        _OWNER_ = newOwner;
    }

    function transferOwnership(address newOwner) public onlyOwner {
        emit OwnershipTransferPrepared(_OWNER_, newOwner);
        _NEW_OWNER_ = newOwner;
    }

    function claimOwnership() public {
        require(msg.sender == _NEW_OWNER_, "INVALID_CLAIM");
        emit OwnershipTransferred(_OWNER_, _NEW_OWNER_);
        _OWNER_ = _NEW_OWNER_;
        _NEW_OWNER_ = address(0);
    }
}

// File: contracts/DODOToken/DODOCirculationHelper.sol


contract DODOCirculationHelper is InitializableOwnable {
    using SafeMath for uint256;

    // ============ Storage ============

    address immutable _VDODO_TOKEN_;
    address immutable _DODO_TOKEN_;
    address[] _LOCKED_CONTRACT_ADDRESS_;

    uint256 public _MIN_PENALTY_RATIO_ = 5 * 10**16; // 5%
    uint256 public _MAX_PENALTY_RATIO_ = 15 * 10**16; // 15%

    constructor(address vDodoToken,address dodoToken) public {
        _VDODO_TOKEN_ = vDodoToken;
        _DODO_TOKEN_ = dodoToken;
    }

    function addLockedContractAddress(address lockedContract) external onlyOwner {
        require(lockedContract != address(0));
        _LOCKED_CONTRACT_ADDRESS_.push(lockedContract);
    }

    function removeLockedContractAddress(address lockedContract) external onlyOwner {
        require(lockedContract != address(0));
        address[] memory lockedContractAddress = _LOCKED_CONTRACT_ADDRESS_;
        for (uint256 i = 0; i < lockedContractAddress.length; i++) {
            if (lockedContractAddress[i] == lockedContract) {
                lockedContractAddress[i] = lockedContractAddress[lockedContractAddress.length - 1];
                break;
            }
        }
        _LOCKED_CONTRACT_ADDRESS_ = lockedContractAddress;
        _LOCKED_CONTRACT_ADDRESS_.pop();
    } 

    function getCirculation() public view returns (uint256 circulation) {
        circulation = 10**9 * 10**18;
        for (uint256 i = 0; i < _LOCKED_CONTRACT_ADDRESS_.length; i++) {
            circulation -= IERC20(_DODO_TOKEN_).balanceOf(_LOCKED_CONTRACT_ADDRESS_[i]);
        }
    }

    function getDodoWithdrawFeeRatio() external view returns (uint256 ratio) {
        uint256 dodoCirculationAmout = getCirculation();
        uint256 x =
            DecimalMath.divCeil(
                IERC20(_VDODO_TOKEN_).totalSupply() * 100,
                dodoCirculationAmout
            );
        
        ratio = geRatioValue(x);
    }

    function geRatioValue(uint256 input) public view returns (uint256) {
        
        // y = 15% (x < 0.1)
        // y = 5% (x > 0.5)
        // y = 0.175 - 0.25 * x
        
        if (input < 10**17) {
            return _MAX_PENALTY_RATIO_;
        } else if (input > 5 * 10**17) {
            return _MIN_PENALTY_RATIO_;
        } else {
            return 175 * 10**15 - DecimalMath.mulFloor(input, 25 * 10**16);
        }
    }
}