// File: /Users/jchudnov/defi/GammaProtocol/contracts/interfaces/OpynPricerInterface.sol



// SPDX-License-Identifier: UNLICENSED
pragma solidity 0.6.10;

interface OpynPricerInterface {
    function getPrice() external view returns (uint256);

    function getHistoricalPrice(uint80 _roundId) external view returns (uint256, uint256);
}

// File: /Users/jchudnov/defi/GammaProtocol/contracts/interfaces/OracleInterface.sol



// SPDX-License-Identifier: UNLICENSED
pragma solidity 0.6.10;

interface OracleInterface {
    function isLockingPeriodOver(address _asset, uint256 _expiryTimestamp) external view returns (bool);

    function isDisputePeriodOver(address _asset, uint256 _expiryTimestamp) external view returns (bool);

    function getExpiryPrice(address _asset, uint256 _expiryTimestamp) external view returns (uint256, bool);

    function getDisputer() external view returns (address);

    function getPricer(address _asset) external view returns (address);

    function getPrice(address _asset) external view returns (uint256);

    function getPricerLockingPeriod(address _pricer) external view returns (uint256);

    function getPricerDisputePeriod(address _pricer) external view returns (uint256);

    function getChainlinkRoundData(address _asset, uint80 _roundId) external view returns (uint256, uint256);

    // Non-view function

    function setAssetPricer(address _asset, address _pricer) external;

    function setLockingPeriod(address _pricer, uint256 _lockingPeriod) external;

    function setDisputePeriod(address _pricer, uint256 _disputePeriod) external;

    function setExpiryPrice(
        address _asset,
        uint256 _expiryTimestamp,
        uint256 _price
    ) external;

    function disputeExpiryPrice(
        address _asset,
        uint256 _expiryTimestamp,
        uint256 _price
    ) external;

    function setDisputer(address _disputer) external;
}

// File: /Users/jchudnov/defi/GammaProtocol/contracts/interfaces/RETHInterface.sol



// SPDX-License-Identifier: UNLICENSED
pragma solidity 0.6.10;

interface RETHInterface {
    function getExchangeRate() external view returns (uint256);

    function getETHValue(uint256 rethAmount) external view returns (uint256);

    function getRethValue(uint256 ethAmount) external view returns (uint256);
}

// File: /Users/jchudnov/defi/GammaProtocol/contracts/packages/oz/SafeMath.sol



// SPDX-License-Identifier: MIT
// openzeppelin-contracts v3.1.0

/* solhint-disable */
pragma solidity ^0.6.0;

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

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     * - Subtraction cannot overflow.
     */
    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 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;
    }
}

// File: /Users/jchudnov/defi/GammaProtocol/contracts/pricers/RethPricer.sol



// SPDX-License-Identifier: UNLICENSED
pragma solidity =0.6.10;

import {OracleInterface} from "../interfaces/OracleInterface.sol";
import {OpynPricerInterface} from "../interfaces/OpynPricerInterface.sol";
import {RETHInterface} from "../interfaces/RETHInterface.sol";
import {SafeMath} from "../packages/oz/SafeMath.sol";

/**
 * Error Codes
 * W1: cannot deploy pricer, rETH address cannot be 0
 * W2: cannot deploy pricer, underlying address cannot be 0
 * W3: cannot deploy pricer, oracle address cannot be 0
 * W4: cannot retrieve price, underlying price is 0
 * W5: cannot set expiry price in oracle, underlying price is 0 and has not been set
 * W6: cannot retrieve historical prices, getHistoricalPrice has been deprecated
 */

/**
 * @title RethPricer
 * @author Opyn Team
 * @notice A Pricer contract for a rETH token
 */
contract RethPricer is OpynPricerInterface {
    using SafeMath for uint256;

    /// @notice opyn oracle address
    OracleInterface public oracle;

    /// @notice rETH token
    RETHInterface public rETH;

    /// @notice underlying asset (WETH)
    address public underlying;

    /**
     * @param _rETH rETH
     * @param _underlying underlying asset for rETH
     * @param _oracle Opyn Oracle contract address
     */
    constructor(
        address _rETH,
        address _underlying,
        address _oracle
    ) public {
        require(_rETH != address(0), "W1");
        require(_underlying != address(0), "W2");
        require(_oracle != address(0), "W3");

        rETH = RETHInterface(_rETH);
        oracle = OracleInterface(_oracle);
        underlying = _underlying;
    }

    /**
     * @notice get the live price for the asset
     * @dev overrides the getPrice function in OpynPricerInterface
     * @return price of 1 rETH in USD, scaled by 1e8
     */
    function getPrice() external view override returns (uint256) {
        uint256 underlyingPrice = oracle.getPrice(underlying);
        require(underlyingPrice > 0, "W4");
        return _underlyingPriceToRethPrice(underlyingPrice);
    }

    /**
     * @notice set the expiry price in the oracle
     * @dev requires that the underlying price has been set before setting a rETH price
     * @param _expiryTimestamp expiry to set a price for
     */
    function setExpiryPriceInOracle(uint256 _expiryTimestamp) external {
        (uint256 underlyingPriceExpiry, ) = oracle.getExpiryPrice(underlying, _expiryTimestamp);
        require(underlyingPriceExpiry > 0, "W5");
        uint256 rEthPrice = _underlyingPriceToRethPrice(underlyingPriceExpiry);
        oracle.setExpiryPrice(address(rETH), _expiryTimestamp, rEthPrice);
    }

    /**
     * @dev convert underlying price to rETH price
     * @param _underlyingPrice price of 1 underlying token (ie 1e18 WETH) in USD, scaled by 1e8
     * @return price of 1 rETH in USD, scaled by 1e8
     */
    function _underlyingPriceToRethPrice(uint256 _underlyingPrice) private view returns (uint256) {
        uint256 ethPerReth = rETH.getExchangeRate();

        return ethPerReth.mul(_underlyingPrice).div(1e18);
    }

    function getHistoricalPrice(uint80) external view override returns (uint256, uint256) {
        revert("W6");
    }
}