// SPDX-License-Identifier: agpl-3.0
pragma solidity 0.6.12;

import {Errors} from '../helpers/Errors.sol';
import {DataTypes} from '../types/DataTypes.sol';

/**
 * @title ReserveConfiguration library
 * @author Aave
 * @notice Implements the bitmap logic to handle the reserve configuration
 */
library ReserveConfiguration {
  uint256 constant LTV_MASK =                   0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF0000; // prettier-ignore
  uint256 constant LIQUIDATION_THRESHOLD_MASK = 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF0000FFFF; // prettier-ignore
  uint256 constant LIQUIDATION_BONUS_MASK =     0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF0000FFFFFFFF; // prettier-ignore
  uint256 constant DECIMALS_MASK =              0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF00FFFFFFFFFFFF; // prettier-ignore
  uint256 constant ACTIVE_MASK =                0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFFFFFFFFFFF; // prettier-ignore
  uint256 constant FROZEN_MASK =                0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFDFFFFFFFFFFFFFF; // prettier-ignore
  uint256 constant BORROWING_MASK =             0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFBFFFFFFFFFFFFFF; // prettier-ignore
  uint256 constant STABLE_BORROWING_MASK =      0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF7FFFFFFFFFFFFFF; // prettier-ignore
  uint256 constant RESERVE_FACTOR_MASK =        0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF0000FFFFFFFFFFFFFFFF; // prettier-ignore

  /// @dev For the LTV, the start bit is 0 (up to 15), hence no bitshifting is needed
  uint256 constant LIQUIDATION_THRESHOLD_START_BIT_POSITION = 16;
  uint256 constant LIQUIDATION_BONUS_START_BIT_POSITION = 32;
  uint256 constant RESERVE_DECIMALS_START_BIT_POSITION = 48;
  uint256 constant IS_ACTIVE_START_BIT_POSITION = 56;
  uint256 constant IS_FROZEN_START_BIT_POSITION = 57;
  uint256 constant BORROWING_ENABLED_START_BIT_POSITION = 58;
  uint256 constant STABLE_BORROWING_ENABLED_START_BIT_POSITION = 59;
  uint256 constant RESERVE_FACTOR_START_BIT_POSITION = 64;

  uint256 constant MAX_VALID_LTV = 65535;
  uint256 constant MAX_VALID_LIQUIDATION_THRESHOLD = 65535;
  uint256 constant MAX_VALID_LIQUIDATION_BONUS = 65535;
  uint256 constant MAX_VALID_DECIMALS = 255;
  uint256 constant MAX_VALID_RESERVE_FACTOR = 65535;

  /**
   * @dev Sets the Loan to Value of the reserve
   * @param self The reserve configuration
   * @param ltv the new ltv
   **/
  function setLtv(DataTypes.ReserveConfigurationMap memory self, uint256 ltv) internal pure {
    require(ltv <= MAX_VALID_LTV, Errors.RC_INVALID_LTV);

    self.data = (self.data & LTV_MASK) | ltv;
  }

  /**
   * @dev Gets the Loan to Value of the reserve
   * @param self The reserve configuration
   * @return The loan to value
   **/
  function getLtv(DataTypes.ReserveConfigurationMap storage self) internal view returns (uint256) {
    return self.data & ~LTV_MASK;
  }

  /**
   * @dev Sets the liquidation threshold of the reserve
   * @param self The reserve configuration
   * @param threshold The new liquidation threshold
   **/
  function setLiquidationThreshold(DataTypes.ReserveConfigurationMap memory self, uint256 threshold)
    internal
    pure
  {
    require(threshold <= MAX_VALID_LIQUIDATION_THRESHOLD, Errors.RC_INVALID_LIQ_THRESHOLD);

    self.data =
      (self.data & LIQUIDATION_THRESHOLD_MASK) |
      (threshold << LIQUIDATION_THRESHOLD_START_BIT_POSITION);
  }

  /**
   * @dev Gets the liquidation threshold of the reserve
   * @param self The reserve configuration
   * @return The liquidation threshold
   **/
  function getLiquidationThreshold(DataTypes.ReserveConfigurationMap storage self)
    internal
    view
    returns (uint256)
  {
    return (self.data & ~LIQUIDATION_THRESHOLD_MASK) >> LIQUIDATION_THRESHOLD_START_BIT_POSITION;
  }

  /**
   * @dev Sets the liquidation bonus of the reserve
   * @param self The reserve configuration
   * @param bonus The new liquidation bonus
   **/
  function setLiquidationBonus(DataTypes.ReserveConfigurationMap memory self, uint256 bonus)
    internal
    pure
  {
    require(bonus <= MAX_VALID_LIQUIDATION_BONUS, Errors.RC_INVALID_LIQ_BONUS);

    self.data =
      (self.data & LIQUIDATION_BONUS_MASK) |
      (bonus << LIQUIDATION_BONUS_START_BIT_POSITION);
  }

  /**
   * @dev Gets the liquidation bonus of the reserve
   * @param self The reserve configuration
   * @return The liquidation bonus
   **/
  function getLiquidationBonus(DataTypes.ReserveConfigurationMap storage self)
    internal
    view
    returns (uint256)
  {
    return (self.data & ~LIQUIDATION_BONUS_MASK) >> LIQUIDATION_BONUS_START_BIT_POSITION;
  }

  /**
   * @dev Sets the decimals of the underlying asset of the reserve
   * @param self The reserve configuration
   * @param decimals The decimals
   **/
  function setDecimals(DataTypes.ReserveConfigurationMap memory self, uint256 decimals)
    internal
    pure
  {
    require(decimals <= MAX_VALID_DECIMALS, Errors.RC_INVALID_DECIMALS);

    self.data = (self.data & DECIMALS_MASK) | (decimals << RESERVE_DECIMALS_START_BIT_POSITION);
  }

  /**
   * @dev Gets the decimals of the underlying asset of the reserve
   * @param self The reserve configuration
   * @return The decimals of the asset
   **/
  function getDecimals(DataTypes.ReserveConfigurationMap storage self)
    internal
    view
    returns (uint256)
  {
    return (self.data & ~DECIMALS_MASK) >> RESERVE_DECIMALS_START_BIT_POSITION;
  }

  /**
   * @dev Sets the active state of the reserve
   * @param self The reserve configuration
   * @param active The active state
   **/
  function setActive(DataTypes.ReserveConfigurationMap memory self, bool active) internal pure {
    self.data =
      (self.data & ACTIVE_MASK) |
      (uint256(active ? 1 : 0) << IS_ACTIVE_START_BIT_POSITION);
  }

  /**
   * @dev Gets the active state of the reserve
   * @param self The reserve configuration
   * @return The active state
   **/
  function getActive(DataTypes.ReserveConfigurationMap storage self) internal view returns (bool) {
    return (self.data & ~ACTIVE_MASK) != 0;
  }

  /**
   * @dev Sets the frozen state of the reserve
   * @param self The reserve configuration
   * @param frozen The frozen state
   **/
  function setFrozen(DataTypes.ReserveConfigurationMap memory self, bool frozen) internal pure {
    self.data =
      (self.data & FROZEN_MASK) |
      (uint256(frozen ? 1 : 0) << IS_FROZEN_START_BIT_POSITION);
  }

  /**
   * @dev Gets the frozen state of the reserve
   * @param self The reserve configuration
   * @return The frozen state
   **/
  function getFrozen(DataTypes.ReserveConfigurationMap storage self) internal view returns (bool) {
    return (self.data & ~FROZEN_MASK) != 0;
  }

  /**
   * @dev Enables or disables borrowing on the reserve
   * @param self The reserve configuration
   * @param enabled True if the borrowing needs to be enabled, false otherwise
   **/
  function setBorrowingEnabled(DataTypes.ReserveConfigurationMap memory self, bool enabled)
    internal
    pure
  {
    self.data =
      (self.data & BORROWING_MASK) |
      (uint256(enabled ? 1 : 0) << BORROWING_ENABLED_START_BIT_POSITION);
  }

  /**
   * @dev Gets the borrowing state of the reserve
   * @param self The reserve configuration
   * @return The borrowing state
   **/
  function getBorrowingEnabled(DataTypes.ReserveConfigurationMap storage self)
    internal
    view
    returns (bool)
  {
    return (self.data & ~BORROWING_MASK) != 0;
  }

  /**
   * @dev Enables or disables stable rate borrowing on the reserve
   * @param self The reserve configuration
   * @param enabled True if the stable rate borrowing needs to be enabled, false otherwise
   **/
  function setStableRateBorrowingEnabled(
    DataTypes.ReserveConfigurationMap memory self,
    bool enabled
  ) internal pure {
    self.data =
      (self.data & STABLE_BORROWING_MASK) |
      (uint256(enabled ? 1 : 0) << STABLE_BORROWING_ENABLED_START_BIT_POSITION);
  }

  /**
   * @dev Gets the stable rate borrowing state of the reserve
   * @param self The reserve configuration
   * @return The stable rate borrowing state
   **/
  function getStableRateBorrowingEnabled(DataTypes.ReserveConfigurationMap storage self)
    internal
    view
    returns (bool)
  {
    return (self.data & ~STABLE_BORROWING_MASK) != 0;
  }

  /**
   * @dev Sets the reserve factor of the reserve
   * @param self The reserve configuration
   * @param reserveFactor The reserve factor
   **/
  function setReserveFactor(DataTypes.ReserveConfigurationMap memory self, uint256 reserveFactor)
    internal
    pure
  {
    require(reserveFactor <= MAX_VALID_RESERVE_FACTOR, Errors.RC_INVALID_RESERVE_FACTOR);

    self.data =
      (self.data & RESERVE_FACTOR_MASK) |
      (reserveFactor << RESERVE_FACTOR_START_BIT_POSITION);
  }

  /**
   * @dev Gets the reserve factor of the reserve
   * @param self The reserve configuration
   * @return The reserve factor
   **/
  function getReserveFactor(DataTypes.ReserveConfigurationMap storage self)
    internal
    view
    returns (uint256)
  {
    return (self.data & ~RESERVE_FACTOR_MASK) >> RESERVE_FACTOR_START_BIT_POSITION;
  }

  /**
   * @dev Gets the configuration flags of the reserve
   * @param self The reserve configuration
   * @return The state flags representing active, frozen, borrowing enabled, stableRateBorrowing enabled
   **/
  function getFlags(DataTypes.ReserveConfigurationMap storage self)
    internal
    view
    returns (
      bool,
      bool,
      bool,
      bool
    )
  {
    uint256 dataLocal = self.data;

    return (
      (dataLocal & ~ACTIVE_MASK) != 0,
      (dataLocal & ~FROZEN_MASK) != 0,
      (dataLocal & ~BORROWING_MASK) != 0,
      (dataLocal & ~STABLE_BORROWING_MASK) != 0
    );
  }

  /**
   * @dev Gets the configuration paramters of the reserve
   * @param self The reserve configuration
   * @return The state params representing ltv, liquidation threshold, liquidation bonus, the reserve decimals
   **/
  function getParams(DataTypes.ReserveConfigurationMap storage self)
    internal
    view
    returns (
      uint256,
      uint256,
      uint256,
      uint256,
      uint256
    )
  {
    uint256 dataLocal = self.data;

    return (
      dataLocal & ~LTV_MASK,
      (dataLocal & ~LIQUIDATION_THRESHOLD_MASK) >> LIQUIDATION_THRESHOLD_START_BIT_POSITION,
      (dataLocal & ~LIQUIDATION_BONUS_MASK) >> LIQUIDATION_BONUS_START_BIT_POSITION,
      (dataLocal & ~DECIMALS_MASK) >> RESERVE_DECIMALS_START_BIT_POSITION,
      (dataLocal & ~RESERVE_FACTOR_MASK) >> RESERVE_FACTOR_START_BIT_POSITION
    );
  }

  /**
   * @dev Gets the configuration paramters of the reserve from a memory object
   * @param self The reserve configuration
   * @return The state params representing ltv, liquidation threshold, liquidation bonus, the reserve decimals
   **/
  function getParamsMemory(DataTypes.ReserveConfigurationMap memory self)
    internal
    pure
    returns (
      uint256,
      uint256,
      uint256,
      uint256,
      uint256
    )
  {
    return (
      self.data & ~LTV_MASK,
      (self.data & ~LIQUIDATION_THRESHOLD_MASK) >> LIQUIDATION_THRESHOLD_START_BIT_POSITION,
      (self.data & ~LIQUIDATION_BONUS_MASK) >> LIQUIDATION_BONUS_START_BIT_POSITION,
      (self.data & ~DECIMALS_MASK) >> RESERVE_DECIMALS_START_BIT_POSITION,
      (self.data & ~RESERVE_FACTOR_MASK) >> RESERVE_FACTOR_START_BIT_POSITION
    );
  }

  /**
   * @dev Gets the configuration flags of the reserve from a memory object
   * @param self The reserve configuration
   * @return The state flags representing active, frozen, borrowing enabled, stableRateBorrowing enabled
   **/
  function getFlagsMemory(DataTypes.ReserveConfigurationMap memory self)
    internal
    pure
    returns (
      bool,
      bool,
      bool,
      bool
    )
  {
    return (
      (self.data & ~ACTIVE_MASK) != 0,
      (self.data & ~FROZEN_MASK) != 0,
      (self.data & ~BORROWING_MASK) != 0,
      (self.data & ~STABLE_BORROWING_MASK) != 0
    );
  }
}