// File: contracts/vault-managers/CDPManager_Fallback.sol



// SPDX-License-Identifier: bsl-1.1

/*
  Copyright 2020 Unit Protocol: Artem Zakharov (az@unit.xyz).
*/
pragma solidity 0.7.6;
pragma abicoder v2;

import './BaseCDPManager.sol';

import '../interfaces/IOracleRegistry.sol';
import '../oracles/KeydonixOracleAbstract.sol';
import '../interfaces/IToken.sol';
import '../interfaces/IVault.sol';
import '../interfaces/ICDPRegistry.sol';
import '../interfaces/vault-managers/parameters/IVaultManagerParameters.sol';
import '../interfaces/IVaultParameters.sol';

import '../helpers/ReentrancyGuard.sol';
import '../helpers/SafeMath.sol';


/**
 * @title CDPManager01_Fallback
 **/
contract CDPManager01_Fallback is BaseCDPManager {
  using SafeMath for uint;

  /**
   * @param _vaultManagerParameters The address of the contract with Vault manager parameters
   * @param _oracleRegistry The address of the oracle registry
   * @param _cdpRegistry The address of the CDP registry
   * @param _vaultManagerBorrowFeeParameters The address of the vault manager borrow fee parameters
   **/
  constructor(address _vaultManagerParameters, address _oracleRegistry, address _cdpRegistry, address _vaultManagerBorrowFeeParameters)
    BaseCDPManager(_vaultManagerParameters, _oracleRegistry, _cdpRegistry, _vaultManagerBorrowFeeParameters) {}

  /**
    * @notice Depositing tokens must be pre-approved to Vault address
    * @notice Borrow fee in USDP tokens must be pre-approved to CDP manager address
    * @notice position actually considered as spawned only when debt > 0
    * @dev Deposits collateral and/or borrows USDP
    * @param asset The address of the collateral
    * @param assetAmount The amount of the collateral to deposit
    * @param usdpAmount The amount of USDP token to borrow
    **/
  function join(address asset, uint assetAmount, uint usdpAmount, KeydonixOracleAbstract.ProofDataStruct calldata proofData) public nonReentrant checkpoint(asset, msg.sender) {
    require(usdpAmount != 0 || assetAmount != 0, "Unit Protocol: USELESS_TX");

    require(IToken(asset).decimals() <= 18, "Unit Protocol: NOT_SUPPORTED_DECIMALS");

    if (usdpAmount == 0) {

      vault.depositMain(asset, msg.sender, assetAmount);

    } else {

      uint oracleType = _selectOracleType(asset);

      bool spawned = vault.debts(asset, msg.sender) != 0;

      if (!spawned) {
        // spawn a position
        vault.spawn(asset, msg.sender, oracleType);
      }

      if (assetAmount != 0) {
        vault.depositMain(asset, msg.sender, assetAmount);
      }

      // mint USDP to owner
      vault.borrow(asset, msg.sender, usdpAmount);
      _chargeBorrowFee(asset, msg.sender, usdpAmount);

      // check collateralization
      _ensurePositionCollateralization(asset, msg.sender, proofData);

    }

    // fire an event
    emit Join(asset, msg.sender, assetAmount, usdpAmount);
  }

  /**
    * @notice Tx sender must have a sufficient USDP balance to pay the debt
    * @dev Withdraws collateral and repays specified amount of debt
    * @param asset The address of the collateral
    * @param assetAmount The amount of the collateral to withdraw
    * @param usdpAmount The amount of USDP to repay
    **/
  function exit(address asset, uint assetAmount, uint usdpAmount, KeydonixOracleAbstract.ProofDataStruct calldata proofData) public nonReentrant checkpoint(asset, msg.sender) returns (uint) {

    // check usefulness of tx
    require(assetAmount != 0 || usdpAmount != 0, "Unit Protocol: USELESS_TX");

    uint debt = vault.debts(asset, msg.sender);

    // catch full repayment
    if (usdpAmount > debt) { usdpAmount = debt; }

    if (assetAmount == 0) {
      _repay(asset, msg.sender, usdpAmount);
    } else {
      if (debt == usdpAmount) {
        vault.withdrawMain(asset, msg.sender, assetAmount);
        if (usdpAmount != 0) {
          _repay(asset, msg.sender, usdpAmount);
        }
      } else {
        // withdraw collateral to the owner address
        vault.withdrawMain(asset, msg.sender, assetAmount);

        if (usdpAmount != 0) {
          _repay(asset, msg.sender, usdpAmount);
        }

        vault.update(asset, msg.sender);

        _ensurePositionCollateralization(asset, msg.sender, proofData);
      }
    }

    // fire an event
    emit Exit(asset, msg.sender, assetAmount, usdpAmount);

    return usdpAmount;
  }

  /**
    * @notice Repayment is the sum of the principal and interest
    * @dev Withdraws collateral and repays specified amount of debt
    * @param asset The address of the collateral
    * @param assetAmount The amount of the collateral to withdraw
    * @param repayment The target repayment amount
    **/
  function exit_targetRepayment(address asset, uint assetAmount, uint repayment, KeydonixOracleAbstract.ProofDataStruct calldata proofData) external returns (uint) {

    uint usdpAmount = _calcPrincipal(asset, msg.sender, repayment);

    return exit(asset, assetAmount, usdpAmount, proofData);
  }

  function _ensurePositionCollateralization(address asset, address owner, KeydonixOracleAbstract.ProofDataStruct calldata proofData) internal view {
    // collateral value of the position in USD
    uint usdValue_q112 = getCollateralUsdValue_q112(asset, owner, proofData);

    // USD limit of the position
    uint usdLimit = usdValue_q112 * vaultManagerParameters.initialCollateralRatio(asset) / Q112 / 100;

    // revert if collateralization is not enough
    require(vault.getTotalDebt(asset, owner) <= usdLimit, "Unit Protocol: UNDERCOLLATERALIZED");
  }

  // Liquidation Trigger

  /**
   * @dev Triggers liquidation of a position
   * @param asset The address of the collateral token of a position
   * @param owner The owner of the position
   **/
  function triggerLiquidation(address asset, address owner, KeydonixOracleAbstract.ProofDataStruct calldata proofData) external nonReentrant {

    // USD value of the collateral
    uint usdValue_q112 = getCollateralUsdValue_q112(asset, owner, proofData);

    // reverts if a position is not liquidatable
    require(_isLiquidatablePosition(asset, owner, usdValue_q112), "Unit Protocol: SAFE_POSITION");

    uint liquidationDiscount_q112 = usdValue_q112.mul(
      vaultManagerParameters.liquidationDiscount(asset)
    ).div(DENOMINATOR_1E5);

    uint initialLiquidationPrice = usdValue_q112.sub(liquidationDiscount_q112).div(Q112);

    // sends liquidation command to the Vault
    vault.triggerLiquidation(asset, owner, initialLiquidationPrice);

    // fire an liquidation event
    emit LiquidationTriggered(asset, owner);
  }

  function getCollateralUsdValue_q112(address asset, address owner, KeydonixOracleAbstract.ProofDataStruct calldata proofData) public view returns (uint) {
    uint oracleType = _selectOracleType(asset);
    return KeydonixOracleAbstract(oracleRegistry.oracleByType(oracleType)).assetToUsd(asset, vault.collaterals(asset, owner), proofData);
  }


  function _selectOracleType(address asset) internal view returns (uint oracleType) {
    oracleType = _getOracleType(asset);
    require(oracleType != 0, "Unit Protocol: INVALID_ORACLE_TYPE");
    address oracle = oracleRegistry.oracleByType(oracleType);
    require(oracle != address(0), "Unit Protocol: DISABLED_ORACLE");
  }

  /**
   * @dev Determines whether a position is liquidatable
   * @param asset The address of the collateral
   * @param owner The owner of the position
   * @return boolean value, whether a position is liquidatable
   **/
  function isLiquidatablePosition(
    address asset,
    address owner,
    KeydonixOracleAbstract.ProofDataStruct calldata proofData
  ) external view returns (bool) {

    uint usdValue_q112 = getCollateralUsdValue_q112(asset, owner, proofData);

    return _isLiquidatablePosition(asset, owner, usdValue_q112);
  }

  /**
   * @dev Calculates current utilization ratio
   * @param asset The address of the collateral
   * @param owner The owner of the position
   * @return utilization ratio
   **/
  function utilizationRatio(
    address asset,
    address owner,
    KeydonixOracleAbstract.ProofDataStruct calldata proofData
  ) public view returns (uint) {
    uint debt = vault.getTotalDebt(asset, owner);
    if (debt == 0) return uint(0);

    uint usdValue_q112 = getCollateralUsdValue_q112(asset, owner, proofData);

    return debt.mul(100).mul(Q112).div(usdValue_q112);
  }

  function _getOracleType(address asset) internal view returns (uint) {
    uint[] memory keydonixOracleTypes = oracleRegistry.getKeydonixOracleTypes();
    for (uint i = 0; i < keydonixOracleTypes.length; i++) {
      if (IVaultParameters(vaultManagerParameters.vaultParameters()).isOracleTypeEnabled(keydonixOracleTypes[i], asset)) {
        return keydonixOracleTypes[i];
      }
    }
    revert("Unit Protocol: NO_ORACLE_FOUND");
  }
}

// File: contracts/vault-managers/BaseCDPManager.sol



// SPDX-License-Identifier: bsl-1.1

/*
  Copyright 2021 Unit Protocol: Artem Zakharov (az@unit.xyz).
*/
pragma solidity 0.7.6;

import "../interfaces/IVault.sol";
import '../interfaces/IVaultParameters.sol';
import "../interfaces/IOracleRegistry.sol";
import "../interfaces/ICDPRegistry.sol";
import '../interfaces/IToken.sol';
import "../interfaces/vault-managers/parameters/IVaultManagerParameters.sol";
import "../interfaces/vault-managers/parameters/IVaultManagerBorrowFeeParameters.sol";

import "../helpers/ReentrancyGuard.sol";
import '../helpers/TransferHelper.sol';
import "../helpers/SafeMath.sol";

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


/**
 * @title BaseCDPManager
 * @dev all common logic should be moved here in future
 **/
abstract contract BaseCDPManager is ReentrancyGuard {
    using SafeMath for uint;

    IVault public immutable vault;
    IVaultManagerParameters public immutable vaultManagerParameters;
    IOracleRegistry public immutable oracleRegistry;
    ICDPRegistry public immutable cdpRegistry;
    IVaultManagerBorrowFeeParameters public immutable vaultManagerBorrowFeeParameters;
    IERC20 public immutable usdp;

    uint public constant Q112 = 2 ** 112;
    uint public constant DENOMINATOR_1E5 = 1e5;

    /**
     * @dev Trigger when joins are happened
    **/
    event Join(address indexed asset, address indexed owner, uint main, uint usdp);

    /**
     * @dev Trigger when exits are happened
    **/
    event Exit(address indexed asset, address indexed owner, uint main, uint usdp);

    /**
     * @dev Trigger when liquidations are initiated
    **/
    event LiquidationTriggered(address indexed asset, address indexed owner);

    modifier checkpoint(address asset, address owner) {
        _;
        cdpRegistry.checkpoint(asset, owner);
    }

    /**
     * @param _vaultManagerParameters The address of the contract with Vault manager parameters
     * @param _oracleRegistry The address of the oracle registry
     * @param _cdpRegistry The address of the CDP registry
     * @param _vaultManagerBorrowFeeParameters The address of the vault manager borrow fee parameters
     **/
    constructor(address _vaultManagerParameters, address _oracleRegistry, address _cdpRegistry, address _vaultManagerBorrowFeeParameters) {
        require(
            _vaultManagerParameters != address(0) &&
            _oracleRegistry != address(0) &&
            _cdpRegistry != address(0) &&
            _vaultManagerBorrowFeeParameters != address(0),
            "Unit Protocol: INVALID_ARGS"
        );
        vaultManagerParameters = IVaultManagerParameters(_vaultManagerParameters);
        IVault vaultLocal = IVault(IVaultParameters(IVaultManagerParameters(_vaultManagerParameters).vaultParameters()).vault());
        vault = vaultLocal;
        oracleRegistry = IOracleRegistry(_oracleRegistry);
        cdpRegistry = ICDPRegistry(_cdpRegistry);
        vaultManagerBorrowFeeParameters = IVaultManagerBorrowFeeParameters(_vaultManagerBorrowFeeParameters);
        usdp = IERC20(vaultLocal.usdp());
    }

    /**
     * @notice Charge borrow fee if needed
     */
    function _chargeBorrowFee(address asset, address user, uint usdpAmount) internal {
        uint borrowFee = vaultManagerBorrowFeeParameters.calcBorrowFeeAmount(asset, usdpAmount);
        if (borrowFee == 0) { // very small amount case
            return;
        }

        // to fail with concrete reason, not with TRANSFER_FROM_FAILED from safeTransferFrom
        require(usdp.allowance(user, address(this)) >= borrowFee, "Unit Protocol: BORROW_FEE_NOT_APPROVED");

        TransferHelper.safeTransferFrom(
            address(usdp),
            user,
            vaultManagerBorrowFeeParameters.feeReceiver(),
            borrowFee
        );
    }

    // decreases debt
    function _repay(address asset, address owner, uint usdpAmount) internal {
        uint fee = vault.calculateFee(asset, owner, usdpAmount);
        vault.chargeFee(vault.usdp(), owner, fee);

        // burn USDP from the owner's balance
        uint debtAfter = vault.repay(asset, owner, usdpAmount);
        if (debtAfter == 0) {
            // clear unused storage
            vault.destroy(asset, owner);
        }
    }

    /**
     * @dev Calculates liquidation price
     * @param asset The address of the collateral
     * @param owner The owner of the position
     * @return Q112-encoded liquidation price
     **/
    function liquidationPrice_q112(
        address asset,
        address owner
    ) external view returns (uint) {
        uint debt = vault.getTotalDebt(asset, owner);
        if (debt == 0) return uint(-1);

        uint collateralLiqPrice = debt.mul(100).mul(Q112).div(vaultManagerParameters.liquidationRatio(asset));

        require(IToken(asset).decimals() <= 18, "Unit Protocol: NOT_SUPPORTED_DECIMALS");

        return collateralLiqPrice / vault.collaterals(asset, owner) / 10 ** (18 - IToken(asset).decimals());
    }

    function _calcPrincipal(address asset, address owner, uint repayment) internal view returns (uint) {
        uint fee = vault.stabilityFee(asset, owner) * (block.timestamp - vault.lastUpdate(asset, owner)) / 365 days;
        return repayment * DENOMINATOR_1E5 / (DENOMINATOR_1E5 + fee);
    }

    /**
     * @dev Determines whether a position is liquidatable
     * @param asset The address of the collateral
     * @param owner The owner of the position
     * @param usdValue_q112 Q112-encoded USD value of the collateral
     * @return boolean value, whether a position is liquidatable
     **/
    function _isLiquidatablePosition(
        address asset,
        address owner,
        uint usdValue_q112
    ) internal view returns (bool) {
        uint debt = vault.getTotalDebt(asset, owner);

        // position is collateralized if there is no debt
        if (debt == 0) return false;

        return debt.mul(100).mul(Q112).div(usdValue_q112) >= vaultManagerParameters.liquidationRatio(asset);
    }
}

// File: contracts/interfaces/IOracleRegistry.sol



// SPDX-License-Identifier: bsl-1.1

/*
  Copyright 2020 Unit Protocol: Artem Zakharov (az@unit.xyz).
*/
pragma solidity ^0.7.6;
pragma abicoder v2;

interface IOracleRegistry {

    struct Oracle {
        uint oracleType;
        address oracleAddress;
    }

    function WETH (  ) external view returns ( address );
    function getKeydonixOracleTypes (  ) external view returns ( uint256[] memory );
    function getOracles (  ) external view returns ( Oracle[] memory foundOracles );
    function keydonixOracleTypes ( uint256 ) external view returns ( uint256 );
    function maxOracleType (  ) external view returns ( uint256 );
    function oracleByAsset ( address asset ) external view returns ( address );
    function oracleByType ( uint256 ) external view returns ( address );
    function oracleTypeByAsset ( address ) external view returns ( uint256 );
    function oracleTypeByOracle ( address ) external view returns ( uint256 );
    function setKeydonixOracleTypes ( uint256[] memory _keydonixOracleTypes ) external;
    function setOracle ( uint256 oracleType, address oracle ) external;
    function setOracleTypeForAsset ( address asset, uint256 oracleType ) external;
    function setOracleTypeForAssets ( address[] memory assets, uint256 oracleType ) external;
    function unsetOracle ( uint256 oracleType ) external;
    function unsetOracleForAsset ( address asset ) external;
    function unsetOracleForAssets ( address[] memory assets ) external;
    function vaultParameters (  ) external view returns ( address );
}

// File: contracts/oracles/KeydonixOracleAbstract.sol



// SPDX-License-Identifier: bsl-1.1

/*
  Copyright 2020 Unit Protocol: Artem Zakharov (az@unit.xyz).
*/
pragma solidity 0.7.6;
pragma experimental ABIEncoderV2;


/**
 * @title KeydonixOracleAbstract
 **/
abstract contract KeydonixOracleAbstract {

    uint public constant Q112 = 2 ** 112;

    struct ProofDataStruct {
        bytes block;
        bytes accountProofNodesRlp;
        bytes reserveAndTimestampProofNodesRlp;
        bytes priceAccumulatorProofNodesRlp;
    }

    function assetToUsd(
        address asset,
        uint amount,
        ProofDataStruct memory proofData
    ) public virtual view returns (uint);
}

// File: contracts/interfaces/IToken.sol



// SPDX-License-Identifier: bsl-1.1

/*
  Copyright 2020 Unit Protocol: Artem Zakharov (az@unit.xyz).
*/
pragma solidity ^0.7.6;

interface IToken {
    function decimals() external view returns (uint8);
}
// File: contracts/interfaces/IVault.sol



// SPDX-License-Identifier: bsl-1.1

/*
  Copyright 2020 Unit Protocol: Artem Zakharov (az@unit.xyz).
*/
pragma solidity ^0.7.6;

interface IVault {
    function DENOMINATOR_1E2 (  ) external view returns ( uint256 );
    function DENOMINATOR_1E5 (  ) external view returns ( uint256 );
    function borrow ( address asset, address user, uint256 amount ) external returns ( uint256 );
    function calculateFee ( address asset, address user, uint256 amount ) external view returns ( uint256 );
    function changeOracleType ( address asset, address user, uint256 newOracleType ) external;
    function chargeFee ( address asset, address user, uint256 amount ) external;
    function col (  ) external view returns ( address );
    function colToken ( address, address ) external view returns ( uint256 );
    function collaterals ( address, address ) external view returns ( uint256 );
    function debts ( address, address ) external view returns ( uint256 );
    function depositCol ( address asset, address user, uint256 amount ) external;
    function depositEth ( address user ) external payable;
    function depositMain ( address asset, address user, uint256 amount ) external;
    function destroy ( address asset, address user ) external;
    function getTotalDebt ( address asset, address user ) external view returns ( uint256 );
    function lastUpdate ( address, address ) external view returns ( uint256 );
    function liquidate ( address asset, address positionOwner, uint256 mainAssetToLiquidator, uint256 colToLiquidator, uint256 mainAssetToPositionOwner, uint256 colToPositionOwner, uint256 repayment, uint256 penalty, address liquidator ) external;
    function liquidationBlock ( address, address ) external view returns ( uint256 );
    function liquidationFee ( address, address ) external view returns ( uint256 );
    function liquidationPrice ( address, address ) external view returns ( uint256 );
    function oracleType ( address, address ) external view returns ( uint256 );
    function repay ( address asset, address user, uint256 amount ) external returns ( uint256 );
    function spawn ( address asset, address user, uint256 _oracleType ) external;
    function stabilityFee ( address, address ) external view returns ( uint256 );
    function tokenDebts ( address ) external view returns ( uint256 );
    function triggerLiquidation ( address asset, address positionOwner, uint256 initialPrice ) external;
    function update ( address asset, address user ) external;
    function usdp (  ) external view returns ( address );
    function vaultParameters (  ) external view returns ( address );
    function weth (  ) external view returns ( address payable );
    function withdrawCol ( address asset, address user, uint256 amount ) external;
    function withdrawEth ( address user, uint256 amount ) external;
    function withdrawMain ( address asset, address user, uint256 amount ) external;
}

// File: contracts/interfaces/ICDPRegistry.sol



// SPDX-License-Identifier: bsl-1.1

/*
  Copyright 2020 Unit Protocol: Artem Zakharov (az@unit.xyz).
*/
pragma solidity ^0.7.6;
pragma experimental ABIEncoderV2;

interface ICDPRegistry {

    struct CDP {
        address asset;
        address owner;
    }

    function batchCheckpoint ( address[] calldata assets, address[] calldata owners ) external;
    function batchCheckpointForAsset ( address asset, address[] calldata owners ) external;
    function checkpoint ( address asset, address owner ) external;
    function cr (  ) external view returns ( address );
    function getAllCdps (  ) external view returns ( CDP[] memory r );
    function getCdpsByCollateral ( address asset ) external view returns ( CDP[] memory cdps );
    function getCdpsByOwner ( address owner ) external view returns ( CDP[] memory r );
    function getCdpsCount (  ) external view returns ( uint256 totalCdpCount );
    function getCdpsCountForCollateral ( address asset ) external view returns ( uint256 );
    function isAlive ( address asset, address owner ) external view returns ( bool );
    function isListed ( address asset, address owner ) external view returns ( bool );
    function vault (  ) external view returns ( address );
}

// File: contracts/interfaces/vault-managers/parameters/IVaultManagerParameters.sol



// SPDX-License-Identifier: bsl-1.1

/*
  Copyright 2020 Unit Protocol: Artem Zakharov (az@unit.xyz).
*/
pragma solidity ^0.7.6;

interface IVaultManagerParameters {
    function devaluationPeriod ( address ) external view returns ( uint256 );
    function initialCollateralRatio ( address ) external view returns ( uint256 );
    function liquidationDiscount ( address ) external view returns ( uint256 );
    function liquidationRatio ( address ) external view returns ( uint256 );
    function maxColPercent ( address ) external view returns ( uint256 );
    function minColPercent ( address ) external view returns ( uint256 );
    function setColPartRange ( address asset, uint256 min, uint256 max ) external;
    function setCollateral (
        address asset,
        uint256 stabilityFeeValue,
        uint256 liquidationFeeValue,
        uint256 initialCollateralRatioValue,
        uint256 liquidationRatioValue,
        uint256 liquidationDiscountValue,
        uint256 devaluationPeriodValue,
        uint256 usdpLimit,
        uint256[] calldata oracles,
        uint256 minColP,
        uint256 maxColP
    ) external;
    function setDevaluationPeriod ( address asset, uint256 newValue ) external;
    function setInitialCollateralRatio ( address asset, uint256 newValue ) external;
    function setLiquidationDiscount ( address asset, uint256 newValue ) external;
    function setLiquidationRatio ( address asset, uint256 newValue ) external;
    function vaultParameters (  ) external view returns ( address );
}

// File: contracts/interfaces/IVaultParameters.sol



// SPDX-License-Identifier: bsl-1.1

/*
  Copyright 2020 Unit Protocol: Artem Zakharov (az@unit.xyz).
*/
pragma solidity ^0.7.6;

interface IVaultParameters {
    function canModifyVault ( address ) external view returns ( bool );
    function foundation (  ) external view returns ( address );
    function isManager ( address ) external view returns ( bool );
    function isOracleTypeEnabled ( uint256, address ) external view returns ( bool );
    function liquidationFee ( address ) external view returns ( uint256 );
    function setCollateral ( address asset, uint256 stabilityFeeValue, uint256 liquidationFeeValue, uint256 usdpLimit, uint256[] calldata oracles ) external;
    function setFoundation ( address newFoundation ) external;
    function setLiquidationFee ( address asset, uint256 newValue ) external;
    function setManager ( address who, bool permit ) external;
    function setOracleType ( uint256 _type, address asset, bool enabled ) external;
    function setStabilityFee ( address asset, uint256 newValue ) external;
    function setTokenDebtLimit ( address asset, uint256 limit ) external;
    function setVaultAccess ( address who, bool permit ) external;
    function stabilityFee ( address ) external view returns ( uint256 );
    function tokenDebtLimit ( address ) external view returns ( uint256 );
    function vault (  ) external view returns ( address );
    function vaultParameters (  ) external view returns ( address );
}

// File: contracts/helpers/ReentrancyGuard.sol



// SPDX-License-Identifier: MIT

pragma solidity 0.7.6;

/**
 * @dev Contract module that helps prevent reentrant calls to a function.
 *
 * Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier
 * available, which can be applied to functions to make sure there are no nested
 * (reentrant) calls to them.
 *
 * Note that because there is a single `nonReentrant` guard, functions marked as
 * `nonReentrant` may not call one another. This can be worked around by making
 * those functions `private`, and then adding `external` `nonReentrant` entry
 * points to them.
 *
 * TIP: If you would like to learn more about reentrancy and alternative ways
 * to protect against it, check out our blog post
 * https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].
 */
contract ReentrancyGuard {
    // Booleans are more expensive than uint256 or any type that takes up a full
    // word because each write operation emits an extra SLOAD to first read the
    // slot's contents, replace the bits taken up by the boolean, and then write
    // back. This is the compiler's defense against contract upgrades and
    // pointer aliasing, and it cannot be disabled.

    // The values being non-zero value makes deployment a bit more expensive,
    // but in exchange the refund on every call to nonReentrant will be lower in
    // amount. Since refunds are capped to a percentage of the total
    // transaction's gas, it is best to keep them low in cases like this one, to
    // increase the likelihood of the full refund coming into effect.
    uint256 private constant _NOT_ENTERED = 1;
    uint256 private constant _ENTERED = 2;

    uint256 private _status;

    constructor () {
        _status = _NOT_ENTERED;
    }

    /**
     * @dev Prevents a contract from calling itself, directly or indirectly.
     * Calling a `nonReentrant` function from another `nonReentrant`
     * function is not supported. It is possible to prevent this from happening
     * by making the `nonReentrant` function external, and make it call a
     * `private` function that does the actual work.
     */
    modifier nonReentrant() {
        // On the first call to nonReentrant, _notEntered will be true
        require(_status != _ENTERED, "ReentrancyGuard: reentrant call");

        // Any calls to nonReentrant after this point will fail
        _status = _ENTERED;

        _;

        // By storing the original value once again, a refund is triggered (see
        // https://eips.ethereum.org/EIPS/eip-2200)
        _status = _NOT_ENTERED;
    }
}

// File: contracts/helpers/SafeMath.sol



// SPDX-License-Identifier: bsl-1.1

/*
  Copyright 2020 Unit Protocol: Artem Zakharov (az@unit.xyz).
*/
pragma solidity 0.7.6;


/**
 * @title SafeMath
 * @dev Math operations with safety checks that throw on error
 */
library SafeMath {

    /**
    * @dev Multiplies two numbers, throws on overflow.
    */
    function mul(uint256 a, uint256 b) internal pure returns (uint256 c) {
        if (a == 0) {
            return 0;
        }
        c = a * b;
        assert(c / a == b);
        return c;
    }

    /**
    * @dev Integer division of two numbers, truncating the quotient.
    */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b != 0, "SafeMath: division by zero");
        return a / b;
    }

    /**
    * @dev Subtracts two numbers, throws on overflow (i.e. if subtrahend is greater than minuend).
    */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        assert(b <= a);
        return a - b;
    }

    /**
    * @dev Adds two numbers, throws on overflow.
    */
    function add(uint256 a, uint256 b) internal pure returns (uint256 c) {
        c = a + b;
        assert(c >= a);
        return c;
    }
}

// File: contracts/interfaces/vault-managers/parameters/IVaultManagerBorrowFeeParameters.sol



// SPDX-License-Identifier: bsl-1.1

/*
  Copyright 2021 Unit Protocol: Artem Zakharov (az@unit.xyz).
*/
pragma solidity ^0.7.6;

interface IVaultManagerBorrowFeeParameters {

    /**
     * @notice 1 = 100% = 10000 basis points
     **/
    function BASIS_POINTS_IN_1() external view returns (uint);

    /**
     * @notice Borrow fee receiver
     **/
    function feeReceiver() external view returns (address);

    /**
     * @notice Sets the borrow fee receiver. Only manager is able to call this function
     * @param newFeeReceiver The address of fee receiver
     **/
    function setFeeReceiver(address newFeeReceiver) external;

    /**
     * @notice Sets the base borrow fee in basis points (1bp = 0.01% = 0.0001). Only manager is able to call this function
     * @param newBaseBorrowFeeBasisPoints The borrow fee in basis points
     **/
    function setBaseBorrowFee(uint16 newBaseBorrowFeeBasisPoints) external;

    /**
     * @notice Sets the borrow fee for a particular collateral in basis points (1bp = 0.01% = 0.0001). Only manager is able to call this function
     * @param asset The address of the main collateral token
     * @param newEnabled Is custom fee enabled for asset
     * @param newFeeBasisPoints The borrow fee in basis points
     **/
    function setAssetBorrowFee(address asset, bool newEnabled, uint16 newFeeBasisPoints) external;

    /**
     * @notice Returns borrow fee for particular collateral in basis points (1bp = 0.01% = 0.0001)
     * @param asset The address of the main collateral token
     * @return feeBasisPoints The borrow fee in basis points
     **/
    function getBorrowFee(address asset) external view returns (uint16 feeBasisPoints);

    /**
     * @notice Returns borrow fee for usdp amount for particular collateral
     * @param asset The address of the main collateral token
     * @return The borrow fee
     **/
    function calcBorrowFeeAmount(address asset, uint usdpAmount) external view returns (uint);
}

// File: contracts/helpers/TransferHelper.sol



// SPDX-License-Identifier: GPL-3.0-or-later

/*
  Copyright 2020 Unit Protocol: Artem Zakharov (az@unit.xyz).
*/
pragma solidity 0.7.6;

// helper methods for interacting with ERC20 tokens and sending ETH that do not consistently return true/false
library TransferHelper {
    function safeApprove(address token, address to, uint value) internal {
        // bytes4(keccak256(bytes('approve(address,uint256)')));
        (bool success, bytes memory data) = token.call(abi.encodeWithSelector(0x095ea7b3, to, value));
        require(success && (data.length == 0 || abi.decode(data, (bool))), 'TransferHelper: APPROVE_FAILED');
    }

    function safeTransfer(address token, address to, uint value) internal {
        // bytes4(keccak256(bytes('transfer(address,uint256)')));
        (bool success, bytes memory data) = token.call(abi.encodeWithSelector(0xa9059cbb, to, value));
        require(success && (data.length == 0 || abi.decode(data, (bool))), 'TransferHelper: TRANSFER_FAILED');
    }

    function safeTransferFrom(address token, address from, address to, uint value) internal {
        // bytes4(keccak256(bytes('transferFrom(address,address,uint256)')));
        (bool success, bytes memory data) = token.call(abi.encodeWithSelector(0x23b872dd, from, to, value));
        require(success && (data.length == 0 || abi.decode(data, (bool))), 'TransferHelper: TRANSFER_FROM_FAILED');
    }

    function safeTransferETH(address to, uint value) internal {
        (bool success,) = to.call{value:value}(new bytes(0));
        require(success, 'TransferHelper: ETH_TRANSFER_FAILED');
    }
}

// File: @openzeppelin/contracts/token/ERC20/IERC20.sol



// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <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);
}