contract MixinSystemSettings is MixinResolver {
    // must match the one defined SystemSettingsLib, defined in both places due to sol v0.5 limitations
    bytes32 internal constant SETTING_CONTRACT_NAME = "SystemSettings";

    bytes32 internal constant SETTING_WAITING_PERIOD_SECS = "waitingPeriodSecs";
    bytes32 internal constant SETTING_PRICE_DEVIATION_THRESHOLD_FACTOR = "priceDeviationThresholdFactor";
    bytes32 internal constant SETTING_ISSUANCE_RATIO = "issuanceRatio";
    bytes32 internal constant SETTING_FEE_PERIOD_DURATION = "feePeriodDuration";
    bytes32 internal constant SETTING_TARGET_THRESHOLD = "targetThreshold";
    bytes32 internal constant SETTING_LIQUIDATION_DELAY = "liquidationDelay";
    bytes32 internal constant SETTING_LIQUIDATION_RATIO = "liquidationRatio";
    bytes32 internal constant SETTING_LIQUIDATION_PENALTY = "liquidationPenalty";
    bytes32 internal constant SETTING_RATE_STALE_PERIOD = "rateStalePeriod";
    /* ========== Exchange Fees Related ========== */
    bytes32 internal constant SETTING_EXCHANGE_FEE_RATE = "exchangeFeeRate";
    bytes32 internal constant SETTING_EXCHANGE_DYNAMIC_FEE_THRESHOLD = "exchangeDynamicFeeThreshold";
    bytes32 internal constant SETTING_EXCHANGE_DYNAMIC_FEE_WEIGHT_DECAY = "exchangeDynamicFeeWeightDecay";
    bytes32 internal constant SETTING_EXCHANGE_DYNAMIC_FEE_ROUNDS = "exchangeDynamicFeeRounds";
    bytes32 internal constant SETTING_EXCHANGE_MAX_DYNAMIC_FEE = "exchangeMaxDynamicFee";
    /* ========== End Exchange Fees Related ========== */
    bytes32 internal constant SETTING_MINIMUM_STAKE_TIME = "minimumStakeTime";
    bytes32 internal constant SETTING_AGGREGATOR_WARNING_FLAGS = "aggregatorWarningFlags";
    bytes32 internal constant SETTING_TRADING_REWARDS_ENABLED = "tradingRewardsEnabled";
    bytes32 internal constant SETTING_DEBT_SNAPSHOT_STALE_TIME = "debtSnapshotStaleTime";
    bytes32 internal constant SETTING_CROSS_DOMAIN_DEPOSIT_GAS_LIMIT = "crossDomainDepositGasLimit";
    bytes32 internal constant SETTING_CROSS_DOMAIN_ESCROW_GAS_LIMIT = "crossDomainEscrowGasLimit";
    bytes32 internal constant SETTING_CROSS_DOMAIN_REWARD_GAS_LIMIT = "crossDomainRewardGasLimit";
    bytes32 internal constant SETTING_CROSS_DOMAIN_WITHDRAWAL_GAS_LIMIT = "crossDomainWithdrawalGasLimit";
    bytes32 internal constant SETTING_CROSS_DOMAIN_FEE_PERIOD_CLOSE_GAS_LIMIT = "crossDomainCloseGasLimit";
    bytes32 internal constant SETTING_CROSS_DOMAIN_RELAY_GAS_LIMIT = "crossDomainRelayGasLimit";
    bytes32 internal constant SETTING_ETHER_WRAPPER_MAX_ETH = "etherWrapperMaxETH";
    bytes32 internal constant SETTING_ETHER_WRAPPER_MINT_FEE_RATE = "etherWrapperMintFeeRate";
    bytes32 internal constant SETTING_ETHER_WRAPPER_BURN_FEE_RATE = "etherWrapperBurnFeeRate";
    bytes32 internal constant SETTING_WRAPPER_MAX_TOKEN_AMOUNT = "wrapperMaxTokens";
    bytes32 internal constant SETTING_WRAPPER_MINT_FEE_RATE = "wrapperMintFeeRate";
    bytes32 internal constant SETTING_WRAPPER_BURN_FEE_RATE = "wrapperBurnFeeRate";
    bytes32 internal constant SETTING_INTERACTION_DELAY = "interactionDelay";
    bytes32 internal constant SETTING_COLLAPSE_FEE_RATE = "collapseFeeRate";
    bytes32 internal constant SETTING_ATOMIC_MAX_VOLUME_PER_BLOCK = "atomicMaxVolumePerBlock";
    bytes32 internal constant SETTING_ATOMIC_TWAP_WINDOW = "atomicTwapWindow";
    bytes32 internal constant SETTING_ATOMIC_EQUIVALENT_FOR_DEX_PRICING = "atomicEquivalentForDexPricing";
    bytes32 internal constant SETTING_ATOMIC_EXCHANGE_FEE_RATE = "atomicExchangeFeeRate";
    bytes32 internal constant SETTING_ATOMIC_PRICE_BUFFER = "atomicPriceBuffer";
    bytes32 internal constant SETTING_ATOMIC_VOLATILITY_CONSIDERATION_WINDOW = "atomicVolConsiderationWindow";
    bytes32 internal constant SETTING_ATOMIC_VOLATILITY_UPDATE_THRESHOLD = "atomicVolUpdateThreshold";

    bytes32 internal constant CONTRACT_FLEXIBLESTORAGE = "FlexibleStorage";

    enum CrossDomainMessageGasLimits {Deposit, Escrow, Reward, Withdrawal, CloseFeePeriod, Relay}

    struct DynamicFeeConfig {
        uint threshold;
        uint weightDecay;
        uint rounds;
        uint maxFee;
    }

    constructor(address _resolver) internal MixinResolver(_resolver) {}

    function resolverAddressesRequired() public view returns (bytes32[] memory addresses) {
        addresses = new bytes32[](1);
        addresses[0] = CONTRACT_FLEXIBLESTORAGE;
    }

    function flexibleStorage() internal view returns (IFlexibleStorage) {
        return IFlexibleStorage(requireAndGetAddress(CONTRACT_FLEXIBLESTORAGE));
    }

    function _getGasLimitSetting(CrossDomainMessageGasLimits gasLimitType) internal pure returns (bytes32) {
        if (gasLimitType == CrossDomainMessageGasLimits.Deposit) {
            return SETTING_CROSS_DOMAIN_DEPOSIT_GAS_LIMIT;
        } else if (gasLimitType == CrossDomainMessageGasLimits.Escrow) {
            return SETTING_CROSS_DOMAIN_ESCROW_GAS_LIMIT;
        } else if (gasLimitType == CrossDomainMessageGasLimits.Reward) {
            return SETTING_CROSS_DOMAIN_REWARD_GAS_LIMIT;
        } else if (gasLimitType == CrossDomainMessageGasLimits.Withdrawal) {
            return SETTING_CROSS_DOMAIN_WITHDRAWAL_GAS_LIMIT;
        } else if (gasLimitType == CrossDomainMessageGasLimits.Relay) {
            return SETTING_CROSS_DOMAIN_RELAY_GAS_LIMIT;
        } else if (gasLimitType == CrossDomainMessageGasLimits.CloseFeePeriod) {
            return SETTING_CROSS_DOMAIN_FEE_PERIOD_CLOSE_GAS_LIMIT;
        } else {
            revert("Unknown gas limit type");
        }
    }

    function getCrossDomainMessageGasLimit(CrossDomainMessageGasLimits gasLimitType) internal view returns (uint) {
        return flexibleStorage().getUIntValue(SETTING_CONTRACT_NAME, _getGasLimitSetting(gasLimitType));
    }

    function getTradingRewardsEnabled() internal view returns (bool) {
        return flexibleStorage().getBoolValue(SETTING_CONTRACT_NAME, SETTING_TRADING_REWARDS_ENABLED);
    }

    function getWaitingPeriodSecs() internal view returns (uint) {
        return flexibleStorage().getUIntValue(SETTING_CONTRACT_NAME, SETTING_WAITING_PERIOD_SECS);
    }

    function getPriceDeviationThresholdFactor() internal view returns (uint) {
        return flexibleStorage().getUIntValue(SETTING_CONTRACT_NAME, SETTING_PRICE_DEVIATION_THRESHOLD_FACTOR);
    }

    function getIssuanceRatio() internal view returns (uint) {
        // lookup on flexible storage directly for gas savings (rather than via SystemSettings)
        return flexibleStorage().getUIntValue(SETTING_CONTRACT_NAME, SETTING_ISSUANCE_RATIO);
    }

    function getFeePeriodDuration() internal view returns (uint) {
        // lookup on flexible storage directly for gas savings (rather than via SystemSettings)
        return flexibleStorage().getUIntValue(SETTING_CONTRACT_NAME, SETTING_FEE_PERIOD_DURATION);
    }

    function getTargetThreshold() internal view returns (uint) {
        // lookup on flexible storage directly for gas savings (rather than via SystemSettings)
        return flexibleStorage().getUIntValue(SETTING_CONTRACT_NAME, SETTING_TARGET_THRESHOLD);
    }

    function getLiquidationDelay() internal view returns (uint) {
        return flexibleStorage().getUIntValue(SETTING_CONTRACT_NAME, SETTING_LIQUIDATION_DELAY);
    }

    function getLiquidationRatio() internal view returns (uint) {
        return flexibleStorage().getUIntValue(SETTING_CONTRACT_NAME, SETTING_LIQUIDATION_RATIO);
    }

    function getLiquidationPenalty() internal view returns (uint) {
        return flexibleStorage().getUIntValue(SETTING_CONTRACT_NAME, SETTING_LIQUIDATION_PENALTY);
    }

    function getRateStalePeriod() internal view returns (uint) {
        return flexibleStorage().getUIntValue(SETTING_CONTRACT_NAME, SETTING_RATE_STALE_PERIOD);
    }

    /* ========== Exchange Related Fees ========== */
    function getExchangeFeeRate(bytes32 currencyKey) internal view returns (uint) {
        return
            flexibleStorage().getUIntValue(
                SETTING_CONTRACT_NAME,
                keccak256(abi.encodePacked(SETTING_EXCHANGE_FEE_RATE, currencyKey))
            );
    }

    /// @notice Get exchange dynamic fee related keys
    /// @return threshold, weight decay, rounds, and max fee
    function getExchangeDynamicFeeConfig() internal view returns (DynamicFeeConfig memory) {
        bytes32[] memory keys = new bytes32[](4);
        keys[0] = SETTING_EXCHANGE_DYNAMIC_FEE_THRESHOLD;
        keys[1] = SETTING_EXCHANGE_DYNAMIC_FEE_WEIGHT_DECAY;
        keys[2] = SETTING_EXCHANGE_DYNAMIC_FEE_ROUNDS;
        keys[3] = SETTING_EXCHANGE_MAX_DYNAMIC_FEE;
        uint[] memory values = flexibleStorage().getUIntValues(SETTING_CONTRACT_NAME, keys);
        return DynamicFeeConfig({threshold: values[0], weightDecay: values[1], rounds: values[2], maxFee: values[3]});
    }

    /* ========== End Exchange Related Fees ========== */

    function getMinimumStakeTime() internal view returns (uint) {
        return flexibleStorage().getUIntValue(SETTING_CONTRACT_NAME, SETTING_MINIMUM_STAKE_TIME);
    }

    function getAggregatorWarningFlags() internal view returns (address) {
        return flexibleStorage().getAddressValue(SETTING_CONTRACT_NAME, SETTING_AGGREGATOR_WARNING_FLAGS);
    }

    function getDebtSnapshotStaleTime() internal view returns (uint) {
        return flexibleStorage().getUIntValue(SETTING_CONTRACT_NAME, SETTING_DEBT_SNAPSHOT_STALE_TIME);
    }

    function getEtherWrapperMaxETH() internal view returns (uint) {
        return flexibleStorage().getUIntValue(SETTING_CONTRACT_NAME, SETTING_ETHER_WRAPPER_MAX_ETH);
    }

    function getEtherWrapperMintFeeRate() internal view returns (uint) {
        return flexibleStorage().getUIntValue(SETTING_CONTRACT_NAME, SETTING_ETHER_WRAPPER_MINT_FEE_RATE);
    }

    function getEtherWrapperBurnFeeRate() internal view returns (uint) {
        return flexibleStorage().getUIntValue(SETTING_CONTRACT_NAME, SETTING_ETHER_WRAPPER_BURN_FEE_RATE);
    }

    function getWrapperMaxTokenAmount(address wrapper) internal view returns (uint) {
        return
            flexibleStorage().getUIntValue(
                SETTING_CONTRACT_NAME,
                keccak256(abi.encodePacked(SETTING_WRAPPER_MAX_TOKEN_AMOUNT, wrapper))
            );
    }

    function getWrapperMintFeeRate(address wrapper) internal view returns (int) {
        return
            flexibleStorage().getIntValue(
                SETTING_CONTRACT_NAME,
                keccak256(abi.encodePacked(SETTING_WRAPPER_MINT_FEE_RATE, wrapper))
            );
    }

    function getWrapperBurnFeeRate(address wrapper) internal view returns (int) {
        return
            flexibleStorage().getIntValue(
                SETTING_CONTRACT_NAME,
                keccak256(abi.encodePacked(SETTING_WRAPPER_BURN_FEE_RATE, wrapper))
            );
    }

    function getInteractionDelay(address collateral) internal view returns (uint) {
        return
            flexibleStorage().getUIntValue(
                SETTING_CONTRACT_NAME,
                keccak256(abi.encodePacked(SETTING_INTERACTION_DELAY, collateral))
            );
    }

    function getCollapseFeeRate(address collateral) internal view returns (uint) {
        return
            flexibleStorage().getUIntValue(
                SETTING_CONTRACT_NAME,
                keccak256(abi.encodePacked(SETTING_COLLAPSE_FEE_RATE, collateral))
            );
    }

    function getAtomicMaxVolumePerBlock() internal view returns (uint) {
        return flexibleStorage().getUIntValue(SETTING_CONTRACT_NAME, SETTING_ATOMIC_MAX_VOLUME_PER_BLOCK);
    }

    function getAtomicTwapWindow() internal view returns (uint) {
        return flexibleStorage().getUIntValue(SETTING_CONTRACT_NAME, SETTING_ATOMIC_TWAP_WINDOW);
    }

    function getAtomicEquivalentForDexPricing(bytes32 currencyKey) internal view returns (address) {
        return
            flexibleStorage().getAddressValue(
                SETTING_CONTRACT_NAME,
                keccak256(abi.encodePacked(SETTING_ATOMIC_EQUIVALENT_FOR_DEX_PRICING, currencyKey))
            );
    }

    function getAtomicExchangeFeeRate(bytes32 currencyKey) internal view returns (uint) {
        return
            flexibleStorage().getUIntValue(
                SETTING_CONTRACT_NAME,
                keccak256(abi.encodePacked(SETTING_ATOMIC_EXCHANGE_FEE_RATE, currencyKey))
            );
    }

    function getAtomicPriceBuffer(bytes32 currencyKey) internal view returns (uint) {
        return
            flexibleStorage().getUIntValue(
                SETTING_CONTRACT_NAME,
                keccak256(abi.encodePacked(SETTING_ATOMIC_PRICE_BUFFER, currencyKey))
            );
    }

    function getAtomicVolatilityConsiderationWindow(bytes32 currencyKey) internal view returns (uint) {
        return
            flexibleStorage().getUIntValue(
                SETTING_CONTRACT_NAME,
                keccak256(abi.encodePacked(SETTING_ATOMIC_VOLATILITY_CONSIDERATION_WINDOW, currencyKey))
            );
    }

    function getAtomicVolatilityUpdateThreshold(bytes32 currencyKey) internal view returns (uint) {
        return
            flexibleStorage().getUIntValue(
                SETTING_CONTRACT_NAME,
                keccak256(abi.encodePacked(SETTING_ATOMIC_VOLATILITY_UPDATE_THRESHOLD, currencyKey))
            );
    }
}
// Internal references
// https://docs.synthetix.io/contracts/source/contracts/mixinsystemsettings
function getExchangeDynamicFeeConfig() internal view returns (DynamicFeeConfig memory) {
    bytes32[] memory keys = new bytes32[](4);
    keys[0] = SETTING_EXCHANGE_DYNAMIC_FEE_THRESHOLD;
    keys[1] = SETTING_EXCHANGE_DYNAMIC_FEE_WEIGHT_DECAY;
    keys[2] = SETTING_EXCHANGE_DYNAMIC_FEE_ROUNDS;
    keys[3] = SETTING_EXCHANGE_MAX_DYNAMIC_FEE;
    uint[] memory values = flexibleStorage().getUIntValues(SETTING_CONTRACT_NAME, keys);
    return DynamicFeeConfig({threshold: values[0], weightDecay: values[1], rounds: values[2], maxFee: values[3]});
}

/// @notice Get exchange dynamic fee related keys
/// @return threshold, weight decay, rounds, and max fee