pragma solidity ^0.5.16;

// Inheritance
import "./BaseSynthetix.sol";

// Internal references
import "./interfaces/IRewardEscrow.sol";
import "./interfaces/IRewardEscrowV2.sol";
import "./interfaces/ISupplySchedule.sol";


// https://docs.synthetix.io/contracts/source/contracts/synthetix
contract Synthetix is BaseSynthetix {
    // ========== ADDRESS RESOLVER CONFIGURATION ==========
    bytes32 private constant CONTRACT_REWARD_ESCROW = "RewardEscrow";
    bytes32 private constant CONTRACT_REWARDESCROW_V2 = "RewardEscrowV2";
    bytes32 private constant CONTRACT_SUPPLYSCHEDULE = "SupplySchedule";

    // ========== CONSTRUCTOR ==========

    constructor(
        address payable _proxy,
        TokenState _tokenState,
        address _owner,
        uint _totalSupply,
        address _resolver
    ) public BaseSynthetix(_proxy, _tokenState, _owner, _totalSupply, _resolver) {}

    function resolverAddressesRequired() public view returns (bytes32[] memory addresses) {
        bytes32[] memory existingAddresses = BaseSynthetix.resolverAddressesRequired();
        bytes32[] memory newAddresses = new bytes32[](3);
        newAddresses[0] = CONTRACT_REWARD_ESCROW;
        newAddresses[1] = CONTRACT_REWARDESCROW_V2;
        newAddresses[2] = CONTRACT_SUPPLYSCHEDULE;
        return combineArrays(existingAddresses, newAddresses);
    }

    // ========== VIEWS ==========

    function rewardEscrow() internal view returns (IRewardEscrow) {
        return IRewardEscrow(requireAndGetAddress(CONTRACT_REWARD_ESCROW));
    }

    function rewardEscrowV2() internal view returns (IRewardEscrowV2) {
        return IRewardEscrowV2(requireAndGetAddress(CONTRACT_REWARDESCROW_V2));
    }

    function supplySchedule() internal view returns (ISupplySchedule) {
        return ISupplySchedule(requireAndGetAddress(CONTRACT_SUPPLYSCHEDULE));
    }

    // ========== OVERRIDDEN FUNCTIONS ==========

    function exchange(
        bytes32 sourceCurrencyKey,
        uint sourceAmount,
        bytes32 destinationCurrencyKey
    ) external exchangeActive(sourceCurrencyKey, destinationCurrencyKey) optionalProxy returns (uint amountReceived) {
        return exchanger().exchange(messageSender, sourceCurrencyKey, sourceAmount, destinationCurrencyKey, messageSender);
    }

    function exchangeOnBehalf(
        address exchangeForAddress,
        bytes32 sourceCurrencyKey,
        uint sourceAmount,
        bytes32 destinationCurrencyKey
    ) external exchangeActive(sourceCurrencyKey, destinationCurrencyKey) optionalProxy returns (uint amountReceived) {
        return
            exchanger().exchangeOnBehalf(
                exchangeForAddress,
                messageSender,
                sourceCurrencyKey,
                sourceAmount,
                destinationCurrencyKey
            );
    }

    function exchangeWithTracking(
        bytes32 sourceCurrencyKey,
        uint sourceAmount,
        bytes32 destinationCurrencyKey,
        address originator,
        bytes32 trackingCode
    ) external exchangeActive(sourceCurrencyKey, destinationCurrencyKey) optionalProxy returns (uint amountReceived) {
        return
            exchanger().exchangeWithTracking(
                messageSender,
                sourceCurrencyKey,
                sourceAmount,
                destinationCurrencyKey,
                messageSender,
                originator,
                trackingCode
            );
    }

    function exchangeOnBehalfWithTracking(
        address exchangeForAddress,
        bytes32 sourceCurrencyKey,
        uint sourceAmount,
        bytes32 destinationCurrencyKey,
        address originator,
        bytes32 trackingCode
    ) external exchangeActive(sourceCurrencyKey, destinationCurrencyKey) optionalProxy returns (uint amountReceived) {
        return
            exchanger().exchangeOnBehalfWithTracking(
                exchangeForAddress,
                messageSender,
                sourceCurrencyKey,
                sourceAmount,
                destinationCurrencyKey,
                originator,
                trackingCode
            );
    }

    function exchangeWithVirtual(
        bytes32 sourceCurrencyKey,
        uint sourceAmount,
        bytes32 destinationCurrencyKey,
        bytes32 trackingCode
    )
        external
        exchangeActive(sourceCurrencyKey, destinationCurrencyKey)
        optionalProxy
        returns (uint amountReceived, IVirtualSynth vSynth)
    {
        return
            exchanger().exchangeWithVirtual(
                messageSender,
                sourceCurrencyKey,
                sourceAmount,
                destinationCurrencyKey,
                messageSender,
                trackingCode
            );
    }

    function settle(bytes32 currencyKey)
        external
        optionalProxy
        returns (
            uint reclaimed,
            uint refunded,
            uint numEntriesSettled
        )
    {
        return exchanger().settle(messageSender, currencyKey);
    }

    function mint() external issuanceActive returns (bool) {
        require(address(rewardsDistribution()) != address(0), "RewardsDistribution not set");

        ISupplySchedule _supplySchedule = supplySchedule();
        IRewardsDistribution _rewardsDistribution = rewardsDistribution();

        uint supplyToMint = _supplySchedule.mintableSupply();
        require(supplyToMint > 0, "No supply is mintable");

        // record minting event before mutation to token supply
        _supplySchedule.recordMintEvent(supplyToMint);

        // Set minted SNX balance to RewardEscrow's balance
        // Minus the minterReward and set balance of minter to add reward
        uint minterReward = _supplySchedule.minterReward();
        // Get the remainder
        uint amountToDistribute = supplyToMint.sub(minterReward);

        // Set the token balance to the RewardsDistribution contract
        tokenState.setBalanceOf(
            address(_rewardsDistribution),
            tokenState.balanceOf(address(_rewardsDistribution)).add(amountToDistribute)
        );
        emitTransfer(address(this), address(_rewardsDistribution), amountToDistribute);

        // Kick off the distribution of rewards
        _rewardsDistribution.distributeRewards(amountToDistribute);

        // Assign the minters reward.
        tokenState.setBalanceOf(msg.sender, tokenState.balanceOf(msg.sender).add(minterReward));
        emitTransfer(address(this), msg.sender, minterReward);

        totalSupply = totalSupply.add(supplyToMint);

        return true;
    }

    function liquidateDelinquentAccount(address account, uint susdAmount)
        external
        systemActive
        optionalProxy
        returns (bool)
    {
        (uint totalRedeemed, uint amountLiquidated) = issuer().liquidateDelinquentAccount(
            account,
            susdAmount,
            messageSender
        );

        emitAccountLiquidated(account, totalRedeemed, amountLiquidated, messageSender);

        // Transfer SNX redeemed to messageSender
        // Reverts if amount to redeem is more than balanceOf account, ie due to escrowed balance
        return _transferByProxy(account, messageSender, totalRedeemed);
    }

    /* Once off function for SIP-60 to migrate SNX balances in the RewardEscrow contract
     * To the new RewardEscrowV2 contract
     */
    function migrateEscrowBalanceToRewardEscrowV2() external onlyOwner {
        // Record balanceOf(RewardEscrow) contract
        uint rewardEscrowBalance = tokenState.balanceOf(address(rewardEscrow()));

        // transfer all of RewardEscrow's balance to RewardEscrowV2
        // _internalTransfer emits the transfer event
        _internalTransfer(address(rewardEscrow()), address(rewardEscrowV2()), rewardEscrowBalance);
    }

    // ========== EVENTS ==========
    event SynthExchange(
        address indexed account,
        bytes32 fromCurrencyKey,
        uint256 fromAmount,
        bytes32 toCurrencyKey,
        uint256 toAmount,
        address toAddress
    );
    bytes32 internal constant SYNTHEXCHANGE_SIG = keccak256(
        "SynthExchange(address,bytes32,uint256,bytes32,uint256,address)"
    );

    function emitSynthExchange(
        address account,
        bytes32 fromCurrencyKey,
        uint256 fromAmount,
        bytes32 toCurrencyKey,
        uint256 toAmount,
        address toAddress
    ) external onlyExchanger {
        proxy._emit(
            abi.encode(fromCurrencyKey, fromAmount, toCurrencyKey, toAmount, toAddress),
            2,
            SYNTHEXCHANGE_SIG,
            addressToBytes32(account),
            0,
            0
        );
    }

    event ExchangeTracking(bytes32 indexed trackingCode, bytes32 toCurrencyKey, uint256 toAmount);
    bytes32 internal constant EXCHANGE_TRACKING_SIG = keccak256("ExchangeTracking(bytes32,bytes32,uint256)");

    function emitExchangeTracking(
        bytes32 trackingCode,
        bytes32 toCurrencyKey,
        uint256 toAmount
    ) external onlyExchanger {
        proxy._emit(abi.encode(toCurrencyKey, toAmount), 2, EXCHANGE_TRACKING_SIG, trackingCode, 0, 0);
    }

    event ExchangeReclaim(address indexed account, bytes32 currencyKey, uint amount);
    bytes32 internal constant EXCHANGERECLAIM_SIG = keccak256("ExchangeReclaim(address,bytes32,uint256)");

    function emitExchangeReclaim(
        address account,
        bytes32 currencyKey,
        uint256 amount
    ) external onlyExchanger {
        proxy._emit(abi.encode(currencyKey, amount), 2, EXCHANGERECLAIM_SIG, addressToBytes32(account), 0, 0);
    }

    event ExchangeRebate(address indexed account, bytes32 currencyKey, uint amount);
    bytes32 internal constant EXCHANGEREBATE_SIG = keccak256("ExchangeRebate(address,bytes32,uint256)");

    function emitExchangeRebate(
        address account,
        bytes32 currencyKey,
        uint256 amount
    ) external onlyExchanger {
        proxy._emit(abi.encode(currencyKey, amount), 2, EXCHANGEREBATE_SIG, addressToBytes32(account), 0, 0);
    }

    event AccountLiquidated(address indexed account, uint snxRedeemed, uint amountLiquidated, address liquidator);
    bytes32 internal constant ACCOUNTLIQUIDATED_SIG = keccak256("AccountLiquidated(address,uint256,uint256,address)");

    function emitAccountLiquidated(
        address account,
        uint256 snxRedeemed,
        uint256 amountLiquidated,
        address liquidator
    ) internal {
        proxy._emit(
            abi.encode(snxRedeemed, amountLiquidated, liquidator),
            2,
            ACCOUNTLIQUIDATED_SIG,
            addressToBytes32(account),
            0,
            0
        );
    }

    // ========== MODIFIERS ==========

    modifier onlyExchanger() {
        _onlyExchanger();
        _;
    }

    function _onlyExchanger() private {
        require(msg.sender == address(exchanger()), "Only Exchanger can invoke this");
    }

    modifier exchangeActive(bytes32 src, bytes32 dest) {
        _exchangeActive(src, dest);
        _;
    }

    function _exchangeActive(bytes32 src, bytes32 dest) private {
        systemStatus().requireExchangeActive();
        systemStatus().requireSynthsActive(src, dest);
    }
}