Transaction Decoder

pragma solidity ^0.5.4;

library RLPReader {
    uint8 constant STRING_SHORT_START = 0x80;
    uint8 constant STRING_LONG_START  = 0xb8;
    uint8 constant LIST_SHORT_START   = 0xc0;
    uint8 constant LIST_LONG_START    = 0xf8;
    uint8 constant WORD_SIZE = 32;

    struct RLPItem {
        uint len;
        uint memPtr;
    }

    struct Iterator {
        RLPItem item;   // Item that's being iterated over.
        uint nextPtr;   // Position of the next item in the list.
    }

    /*
    * @dev Returns the next element in the iteration. Reverts if it has not next element.
    * @param self The iterator.
    * @return The next element in the iteration.
    */
    function next(Iterator memory self) internal pure returns (RLPItem memory) {
        require(hasNext(self));

        uint ptr = self.nextPtr;
        uint itemLength = _itemLength(ptr);
        self.nextPtr = ptr + itemLength;

        return RLPItem(itemLength, ptr);
    }

    /*
    * @dev Returns true if the iteration has more elements.
    * @param self The iterator.
    * @return true if the iteration has more elements.
    */
    function hasNext(Iterator memory self) internal pure returns (bool) {
        RLPItem memory item = self.item;
        return self.nextPtr < item.memPtr + item.len;
    }

    /*
    * @param item RLP encoded bytes
    */
    function toRlpItem(bytes memory item) internal pure returns (RLPItem memory) {
        uint memPtr;
        assembly {
            memPtr := add(item, 0x20)
        }

        return RLPItem(item.length, memPtr);
    }

    /*
    * @dev Create an iterator. Reverts if item is not a list.
    * @param self The RLP item.
    * @return An 'Iterator' over the item.
    */
    function iterator(RLPItem memory self) internal pure returns (Iterator memory) {
        require(isList(self));

        uint ptr = self.memPtr + _payloadOffset(self.memPtr);
        return Iterator(self, ptr);
    }

    /*
    * @param item RLP encoded bytes
    */
    function rlpLen(RLPItem memory item) internal pure returns (uint) {
        return item.len;
    }

    /*
    * @param item RLP encoded bytes
    */
    function payloadLen(RLPItem memory item) internal pure returns (uint) {
        return item.len - _payloadOffset(item.memPtr);
    }

    /*
    * @param item RLP encoded list in bytes
    */
    function toList(RLPItem memory item) internal pure returns (RLPItem[] memory) {
        require(isList(item));

        uint items = numItems(item);
        RLPItem[] memory result = new RLPItem[](items);

        uint memPtr = item.memPtr + _payloadOffset(item.memPtr);
        uint dataLen;
        for (uint i = 0; i < items; i++) {
            dataLen = _itemLength(memPtr);
            result[i] = RLPItem(dataLen, memPtr); 
            memPtr = memPtr + dataLen;
        }

        return result;
    }

    // @return indicator whether encoded payload is a list. negate this function call for isData.
    function isList(RLPItem memory item) internal pure returns (bool) {
        if (item.len == 0) return false;

        uint8 byte0;
        uint memPtr = item.memPtr;
        assembly {
            byte0 := byte(0, mload(memPtr))
        }

        if (byte0 < LIST_SHORT_START)
            return false;
        return true;
    }

    /** RLPItem conversions into data types **/

    // @returns raw rlp encoding in bytes
    function toRlpBytes(RLPItem memory item) internal pure returns (bytes memory) {
        bytes memory result = new bytes(item.len);
        if (result.length == 0) return result;
        
        uint ptr;
        assembly {
            ptr := add(0x20, result)
        }

        copy(item.memPtr, ptr, item.len);
        return result;
    }

    // any non-zero byte is considered true
    function toBoolean(RLPItem memory item) internal pure returns (bool) {
        require(item.len == 1);
        uint result;
        uint memPtr = item.memPtr;
        assembly {
            result := byte(0, mload(memPtr))
        }

        return result == 0 ? false : true;
    }

    function toAddress(RLPItem memory item) internal pure returns (address) {
        // 1 byte for the length prefix
        require(item.len == 21);

        return address(toUint(item));
    }

    function toUint(RLPItem memory item) internal pure returns (uint) {
        require(item.len > 0 && item.len <= 33);

        uint offset = _payloadOffset(item.memPtr);
        uint len = item.len - offset;

        uint result;
        uint memPtr = item.memPtr + offset;
        assembly {
            result := mload(memPtr)

            // shfit to the correct location if neccesary
            if lt(len, 32) {
                result := div(result, exp(256, sub(32, len)))
            }
        }

        return result;
    }

    // enforces 32 byte length
    function toUintStrict(RLPItem memory item) internal pure returns (uint) {
        // one byte prefix
        require(item.len == 33);

        uint result;
        uint memPtr = item.memPtr + 1;
        assembly {
            result := mload(memPtr)
        }

        return result;
    }

    function toBytes(RLPItem memory item) internal pure returns (bytes memory) {
        require(item.len > 0);

        uint offset = _payloadOffset(item.memPtr);
        uint len = item.len - offset; // data length
        bytes memory result = new bytes(len);

        uint destPtr;
        assembly {
            destPtr := add(0x20, result)
        }

        copy(item.memPtr + offset, destPtr, len);
        return result;
    }

    /*
    * Private Helpers
    */

    // @return number of payload items inside an encoded list.
    function numItems(RLPItem memory item) private pure returns (uint) {
        if (item.len == 0) return 0;

        uint count = 0;
        uint currPtr = item.memPtr + _payloadOffset(item.memPtr);
        uint endPtr = item.memPtr + item.len;
        while (currPtr < endPtr) {
           currPtr = currPtr + _itemLength(currPtr); // skip over an item
           count++;
        }

        return count;
    }

    // @return entire rlp item byte length
    function _itemLength(uint memPtr) private pure returns (uint) {
        uint itemLen;
        uint byte0;
        assembly {
            byte0 := byte(0, mload(memPtr))
        }

        if (byte0 < STRING_SHORT_START)
            itemLen = 1;
        
        else if (byte0 < STRING_LONG_START)
            itemLen = byte0 - STRING_SHORT_START + 1;

        else if (byte0 < LIST_SHORT_START) {
            assembly {
                let byteLen := sub(byte0, 0xb7) // # of bytes the actual length is
                memPtr := add(memPtr, 1) // skip over the first byte
                
                /* 32 byte word size */
                let dataLen := div(mload(memPtr), exp(256, sub(32, byteLen))) // right shifting to get the len
                itemLen := add(dataLen, add(byteLen, 1))
            }
        }

        else if (byte0 < LIST_LONG_START) {
            itemLen = byte0 - LIST_SHORT_START + 1;
        } 

        else {
            assembly {
                let byteLen := sub(byte0, 0xf7)
                memPtr := add(memPtr, 1)

                let dataLen := div(mload(memPtr), exp(256, sub(32, byteLen))) // right shifting to the correct length
                itemLen := add(dataLen, add(byteLen, 1))
            }
        }

        return itemLen;
    }

    // @return number of bytes until the data
    function _payloadOffset(uint memPtr) private pure returns (uint) {
        uint byte0;
        assembly {
            byte0 := byte(0, mload(memPtr))
        }

        if (byte0 < STRING_SHORT_START) 
            return 0;
        else if (byte0 < STRING_LONG_START || (byte0 >= LIST_SHORT_START && byte0 < LIST_LONG_START))
            return 1;
        else if (byte0 < LIST_SHORT_START)  // being explicit
            return byte0 - (STRING_LONG_START - 1) + 1;
        else
            return byte0 - (LIST_LONG_START - 1) + 1;
    }

    /*
    * @param src Pointer to source
    * @param dest Pointer to destination
    * @param len Amount of memory to copy from the source
    */
    function copy(uint src, uint dest, uint len) private pure {
        if (len == 0) return;

        // copy as many word sizes as possible
        for (; len >= WORD_SIZE; len -= WORD_SIZE) {
            assembly {
                mstore(dest, mload(src))
            }

            src += WORD_SIZE;
            dest += WORD_SIZE;
        }

        // left over bytes. Mask is used to remove unwanted bytes from the word
        uint mask = 256 ** (WORD_SIZE - len) - 1;
        assembly {
            let srcpart := and(mload(src), not(mask)) // zero out src
            let destpart := and(mload(dest), mask) // retrieve the bytes
            mstore(dest, or(destpart, srcpart))
        }
    }
}

contract Account {

    // The implementation of the proxy
    address public implementation;

    // Logic manager
    address public manager;
    
    // The enabled static calls
    mapping (bytes4 => address) public enabled;

    event EnabledStaticCall(address indexed module, bytes4 indexed method);
    event Invoked(address indexed module, address indexed target, uint indexed value, bytes data);
    event Received(uint indexed value, address indexed sender, bytes data);

    event AccountInit(address indexed account);
    event ManagerChanged(address indexed mgr);

    modifier allowAuthorizedLogicContractsCallsOnly {
        require(LogicManager(manager).isAuthorized(msg.sender), "not an authorized logic");
        _;
    }

    function init(address _manager, address _accountStorage, address[] calldata _logics, address[] calldata _keys, address[] calldata _backups)
        external
    {
        require(manager == address(0), "Account: account already initialized");
        require(_manager != address(0) && _accountStorage != address(0), "Account: address is null");
        manager = _manager;

        for (uint i = 0; i < _logics.length; i++) {
            address logic = _logics[i];
            require(LogicManager(manager).isAuthorized(logic), "must be authorized logic");

            BaseLogic(logic).initAccount(this);
        }

        AccountStorage(_accountStorage).initAccount(this, _keys, _backups);

        emit AccountInit(address(this));
    }

    function invoke(address _target, uint _value, bytes calldata _data)
        external
        allowAuthorizedLogicContractsCallsOnly
        returns (bytes memory _res)
    {
        bool success;
        // solium-disable-next-line security/no-call-value
        (success, _res) = _target.call.value(_value)(_data);
        require(success, "call to target failed");
        emit Invoked(msg.sender, _target, _value, _data);
    }

    /**
    * @dev Enables a static method by specifying the target module to which the call must be delegated.
    * @param _module The target module.
    * @param _method The static method signature.
    */
    function enableStaticCall(address _module, bytes4 _method) external allowAuthorizedLogicContractsCallsOnly {
        enabled[_method] = _module;
        emit EnabledStaticCall(_module, _method);
    }

    function changeManager(address _newMgr) external allowAuthorizedLogicContractsCallsOnly {
        require(_newMgr != address(0), "address cannot be null");
        require(_newMgr != manager, "already changed");
        manager = _newMgr;
        emit ManagerChanged(_newMgr);
    }

     /**
     * @dev This method makes it possible for the wallet to comply to interfaces expecting the wallet to
     * implement specific static methods. It delegates the static call to a target contract if the data corresponds
     * to an enabled method, or logs the call otherwise.
     */
    function() external payable {
        if(msg.data.length > 0) {
            address logic = enabled[msg.sig];
            if(logic == address(0)) {
                emit Received(msg.value, msg.sender, msg.data);
            }
            else {
                require(LogicManager(manager).isAuthorized(logic), "must be an authorized logic for static call");
                // solium-disable-next-line security/no-inline-assembly
                assembly {
                    calldatacopy(0, 0, calldatasize())
                    let result := staticcall(gas, logic, 0, calldatasize(), 0, 0)
                    returndatacopy(0, 0, returndatasize())
                    switch result
                    case 0 {revert(0, returndatasize())}
                    default {return (0, returndatasize())}
                }
            }
        }
    }
}

contract Owned {

    // The owner
    address public owner;

    event OwnerChanged(address indexed _newOwner);

    /**
     * @dev Throws if the sender is not the owner.
     */
    modifier onlyOwner {
        require(msg.sender == owner, "Must be owner");
        _;
    }

    constructor() public {
        owner = msg.sender;
    }

    /**
     * @dev Lets the owner transfer ownership of the contract to a new owner.
     * @param _newOwner The new owner.
     */
    function changeOwner(address _newOwner) external onlyOwner {
        require(_newOwner != address(0), "Address must not be null");
        owner = _newOwner;
        emit OwnerChanged(_newOwner);
    }
}

contract LogicManager is Owned {

    event UpdateLogicSubmitted(address indexed logic, bool value);
    event UpdateLogicCancelled(address indexed logic);
    event UpdateLogicDone(address indexed logic, bool value);

    struct pending {
        bool value;
        uint dueTime;
    }

    // The authorized logic modules
    mapping (address => bool) public authorized;

    /*
    array
    index 0: AccountLogic address
          1: TransferLogic address
          2: DualsigsLogic address
          3: DappLogic address
          4: ...
     */
    address[] public authorizedLogics;

    // updated logics and their due time of becoming effective
    mapping (address => pending) public pendingLogics;

    // pending time before updated logics take effect
    struct pendingTime {
        uint curPendingTime;
        uint nextPendingTime;
        uint dueTime;
    }

    pendingTime public pt;

    // how many authorized logics
    uint public logicCount;

    constructor(address[] memory _initialLogics, uint256 _pendingTime) public
    {
        for (uint i = 0; i < _initialLogics.length; i++) {
            address logic = _initialLogics[i];
            authorized[logic] = true;
            logicCount += 1;
        }
        authorizedLogics = _initialLogics;

        pt.curPendingTime = _pendingTime;
        pt.nextPendingTime = _pendingTime;
        pt.dueTime = now;
    }

    function submitUpdatePendingTime(uint _pendingTime) external onlyOwner {
        pt.nextPendingTime = _pendingTime;
        pt.dueTime = pt.curPendingTime + now;
    }

    function triggerUpdatePendingTime() external {
        require(pt.dueTime <= now, "too early to trigger updatePendingTime");
        pt.curPendingTime = pt.nextPendingTime;
    }

    function isAuthorized(address _logic) external view returns (bool) {
        return authorized[_logic];
    }

    function getAuthorizedLogics() external view returns (address[] memory) {
        return authorizedLogics;
    }

    function submitUpdate(address _logic, bool _value) external onlyOwner {
        pending storage p = pendingLogics[_logic];
        p.value = _value;
        p.dueTime = now + pt.curPendingTime;
        emit UpdateLogicSubmitted(_logic, _value);
    }

    function cancelUpdate(address _logic) external onlyOwner {
        delete pendingLogics[_logic];
        emit UpdateLogicCancelled(_logic);
    }

    function triggerUpdateLogic(address _logic) external {
        pending memory p = pendingLogics[_logic];
        require(p.dueTime > 0, "pending logic not found");
        require(p.dueTime <= now, "too early to trigger updateLogic");
        updateLogic(_logic, p.value);
        delete pendingLogics[_logic];
    }

    function updateLogic(address _logic, bool _value) internal {
        if (authorized[_logic] != _value) {
            if(_value) {
                logicCount += 1;
                authorized[_logic] = true;
                authorizedLogics.push(_logic);
            }
            else {
                logicCount -= 1;
                require(logicCount > 0, "must have at least one logic module");
                delete authorized[_logic];
                removeLogic(_logic);
            }
            emit UpdateLogicDone(_logic, _value);
        }
    }

    function removeLogic(address _logic) internal {
        uint len = authorizedLogics.length;
        address lastLogic = authorizedLogics[len - 1];
        if (_logic != lastLogic) {
            for (uint i = 0; i < len; i++) {
                 if (_logic == authorizedLogics[i]) {
                     authorizedLogics[i] = lastLogic;
                     break;
                 }
            }
        }
        authorizedLogics.length--;
    }
}

contract AccountStorage {

    modifier allowAccountCallsOnly(Account _account) {
        require(msg.sender == address(_account), "caller must be account");
        _;
    }

    modifier allowAuthorizedLogicContractsCallsOnly(address payable _account) {
        require(LogicManager(Account(_account).manager()).isAuthorized(msg.sender), "not an authorized logic");
        _;
    }

    struct KeyItem {
        address pubKey;
        uint256 status;
    }

    struct BackupAccount {
        address backup;
        uint256 effectiveDate;//means not effective until this timestamp
        uint256 expiryDate;//means effective until this timestamp
    }

    struct DelayItem {
        bytes32 hash;
        uint256 dueTime;
    }

    struct Proposal {
        bytes32 hash;
        address[] approval;
    }

    // account => quantity of operation keys (index >= 1)
    mapping (address => uint256) operationKeyCount;

    // account => index => KeyItem
    mapping (address => mapping(uint256 => KeyItem)) keyData;

    // account => index => backup account
    mapping (address => mapping(uint256 => BackupAccount)) backupData;

    /* account => actionId => DelayItem

       delayData applies to these 4 actions:
       changeAdminKey, changeAllOperationKeys, unfreeze, changeAdminKeyByBackup
    */
    mapping (address => mapping(bytes4 => DelayItem)) delayData;

    // client account => proposer account => proposed actionId => Proposal
    mapping (address => mapping(address => mapping(bytes4 => Proposal))) proposalData;

    // *************** keyCount ********************** //

    function getOperationKeyCount(address _account) external view returns(uint256) {
        return operationKeyCount[_account];
    }

    function increaseKeyCount(address payable _account) external allowAuthorizedLogicContractsCallsOnly(_account) {
        operationKeyCount[_account] = operationKeyCount[_account] + 1;
    }

    // *************** keyData ********************** //

    function getKeyData(address _account, uint256 _index) public view returns(address) {
        KeyItem memory item = keyData[_account][_index];
        return item.pubKey;
    }

    function setKeyData(address payable _account, uint256 _index, address _key) external allowAuthorizedLogicContractsCallsOnly(_account) {
        require(_key != address(0), "invalid _key value");
        KeyItem storage item = keyData[_account][_index];
        item.pubKey = _key;
    }

    // *************** keyStatus ********************** //

    function getKeyStatus(address _account, uint256 _index) external view returns(uint256) {
        KeyItem memory item = keyData[_account][_index];
        return item.status;
    }

    function setKeyStatus(address payable _account, uint256 _index, uint256 _status) external allowAuthorizedLogicContractsCallsOnly(_account) {
        KeyItem storage item = keyData[_account][_index];
        item.status = _status;
    }

    // *************** backupData ********************** //

    function getBackupAddress(address _account, uint256 _index) external view returns(address) {
        BackupAccount memory b = backupData[_account][_index];
        return b.backup;
    }

    function getBackupEffectiveDate(address _account, uint256 _index) external view returns(uint256) {
        BackupAccount memory b = backupData[_account][_index];
        return b.effectiveDate;
    }

    function getBackupExpiryDate(address _account, uint256 _index) external view returns(uint256) {
        BackupAccount memory b = backupData[_account][_index];
        return b.expiryDate;
    }

    function setBackup(address payable _account, uint256 _index, address _backup, uint256 _effective, uint256 _expiry)
        external
        allowAuthorizedLogicContractsCallsOnly(_account)
    {
        BackupAccount storage b = backupData[_account][_index];
        b.backup = _backup;
        b.effectiveDate = _effective;
        b.expiryDate = _expiry;
    }

    function setBackupExpiryDate(address payable _account, uint256 _index, uint256 _expiry)
        external
        allowAuthorizedLogicContractsCallsOnly(_account)
    {
        BackupAccount storage b = backupData[_account][_index];
        b.expiryDate = _expiry;
    }

    function clearBackupData(address payable _account, uint256 _index) external allowAuthorizedLogicContractsCallsOnly(_account) {
        delete backupData[_account][_index];
    }

    // *************** delayData ********************** //

    function getDelayDataHash(address payable _account, bytes4 _actionId) external view returns(bytes32) {
        DelayItem memory item = delayData[_account][_actionId];
        return item.hash;
    }

    function getDelayDataDueTime(address payable _account, bytes4 _actionId) external view returns(uint256) {
        DelayItem memory item = delayData[_account][_actionId];
        return item.dueTime;
    }

    function setDelayData(address payable _account, bytes4 _actionId, bytes32 _hash, uint256 _dueTime) external allowAuthorizedLogicContractsCallsOnly(_account) {
        DelayItem storage item = delayData[_account][_actionId];
        item.hash = _hash;
        item.dueTime = _dueTime;
    }

    function clearDelayData(address payable _account, bytes4 _actionId) external allowAuthorizedLogicContractsCallsOnly(_account) {
        delete delayData[_account][_actionId];
    }

    // *************** proposalData ********************** //

    function getProposalDataHash(address _client, address _proposer, bytes4 _actionId) external view returns(bytes32) {
        Proposal memory p = proposalData[_client][_proposer][_actionId];
        return p.hash;
    }

    function getProposalDataApproval(address _client, address _proposer, bytes4 _actionId) external view returns(address[] memory) {
        Proposal memory p = proposalData[_client][_proposer][_actionId];
        return p.approval;
    }

    function setProposalData(address payable _client, address _proposer, bytes4 _actionId, bytes32 _hash, address _approvedBackup)
        external
        allowAuthorizedLogicContractsCallsOnly(_client)
    {
        Proposal storage p = proposalData[_client][_proposer][_actionId];
        if (p.hash > 0) {
            if (p.hash == _hash) {
                for (uint256 i = 0; i < p.approval.length; i++) {
                    require(p.approval[i] != _approvedBackup, "backup already exists");
                }
                p.approval.push(_approvedBackup);
            } else {
                p.hash = _hash;
                p.approval.length = 0;
            }
        } else {
            p.hash = _hash;
            p.approval.push(_approvedBackup);
        }
    }

    function clearProposalData(address payable _client, address _proposer, bytes4 _actionId) external allowAuthorizedLogicContractsCallsOnly(_client) {
        delete proposalData[_client][_proposer][_actionId];
    }


    // *************** init ********************** //
    function initAccount(Account _account, address[] calldata _keys, address[] calldata _backups)
        external
        allowAccountCallsOnly(_account)
    {
        require(getKeyData(address(_account), 0) == address(0), "AccountStorage: account already initialized!");
        require(_keys.length > 0, "empty keys array");

        operationKeyCount[address(_account)] = _keys.length - 1;

        for (uint256 index = 0; index < _keys.length; index++) {
            address _key = _keys[index];
            require(_key != address(0), "_key cannot be 0x0");
            KeyItem storage item = keyData[address(_account)][index];
            item.pubKey = _key;
            item.status = 0;
        }

        // avoid backup duplication if _backups.length > 1
        // normally won't check duplication, in most cases only one initial backup when initialization
        if (_backups.length > 1) {
            address[] memory bkps = _backups;
            for (uint256 i = 0; i < _backups.length; i++) {
                for (uint256 j = 0; j < i; j++) {
                    require(bkps[j] != _backups[i], "duplicate backup");
                }
            }
        }

        for (uint256 index = 0; index < _backups.length; index++) {
            address _backup = _backups[index];
            require(_backup != address(0), "backup cannot be 0x0");
            require(_backup != address(_account), "cannot be backup of oneself");

            backupData[address(_account)][index] = BackupAccount(_backup, now, uint256(-1));
        }
    }
}

/* The MIT License (MIT)

Copyright (c) 2016 Smart Contract Solutions, Inc.

Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:

The above copyright notice and this permission notice shall be included
in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */

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

    /**
    * @dev Multiplies two numbers, reverts on 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-solidity/pull/522
        if (a == 0) {
            return 0;
        }

        uint256 c = a * b;
        require(c / a == b);

        return c;
    }

    /**
    * @dev Integer division of two numbers truncating the quotient, reverts on division by zero.
    */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b > 0); // Solidity only automatically asserts when dividing by 0
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold

        return c;
    }

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

        return c;
    }

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

        return c;
    }

    /**
    * @dev Divides two numbers and returns the remainder (unsigned integer modulo),
    * reverts when dividing by zero.
    */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b != 0);
        return a % b;
    }

    /**
    * @dev Returns ceil(a / b).
    */
    function ceil(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a / b;
        if(a % b == 0) {
            return c;
        }
        else {
            return c + 1;
        }
    }
}

contract BaseLogic {

    bytes constant internal SIGN_HASH_PREFIX = "\x19Ethereum Signed Message:\n32";

    mapping (address => uint256) keyNonce;
    AccountStorage public accountStorage;

    modifier allowSelfCallsOnly() {
        require (msg.sender == address(this), "only internal call is allowed");
        _;
    }

    modifier allowAccountCallsOnly(Account _account) {
        require(msg.sender == address(_account), "caller must be account");
        _;
    }

    event LogicInitialised(address wallet);

    // *************** Constructor ********************** //

    constructor(AccountStorage _accountStorage) public {
        accountStorage = _accountStorage;
    }

    // *************** Initialization ********************* //

    function initAccount(Account _account) external allowAccountCallsOnly(_account){
        emit LogicInitialised(address(_account));
    }

    // *************** Getter ********************** //

    function getKeyNonce(address _key) external view returns(uint256) {
        return keyNonce[_key];
    }

    // *************** Signature ********************** //

    function getSignHash(bytes memory _data, uint256 _nonce) internal view returns(bytes32) {
        // use EIP 191
        // 0x1900 + this logic address + data + nonce of signing key
        bytes32 msgHash = keccak256(abi.encodePacked(byte(0x19), byte(0), address(this), _data, _nonce));
        bytes32 prefixedHash = keccak256(abi.encodePacked(SIGN_HASH_PREFIX, msgHash));
        return prefixedHash;
    }

    function verifySig(address _signingKey, bytes memory _signature, bytes32 _signHash) internal pure {
        require(_signingKey != address(0), "invalid signing key");
        address recoveredAddr = recover(_signHash, _signature);
        require(recoveredAddr == _signingKey, "signature verification failed");
    }

    /**
     * @dev Returns the address that signed a hashed message (`hash`) with
     * `signature`. This address can then be used for verification purposes.
     *
     * The `ecrecover` EVM opcode allows for malleable (non-unique) signatures:
     * this function rejects them by requiring the `s` value to be in the lower
     * half order, and the `v` value to be either 27 or 28.
     *
     * NOTE: This call _does not revert_ if the signature is invalid, or
     * if the signer is otherwise unable to be retrieved. In those scenarios,
     * the zero address is returned.
     *
     * IMPORTANT: `hash` _must_ be the result of a hash operation for the
     * verification to be secure: it is possible to craft signatures that
     * recover to arbitrary addresses for non-hashed data. A safe way to ensure
     * this is by receiving a hash of the original message (which may otherwise)
     * be too long), and then calling {toEthSignedMessageHash} on it.
     */
    function recover(bytes32 hash, bytes memory signature) internal pure returns (address) {
        // Check the signature length
        if (signature.length != 65) {
            return (address(0));
        }

        // Divide the signature in r, s and v variables
        bytes32 r;
        bytes32 s;
        uint8 v;

        // ecrecover takes the signature parameters, and the only way to get them
        // currently is to use assembly.
        // solhint-disable-next-line no-inline-assembly
        assembly {
            r := mload(add(signature, 0x20))
            s := mload(add(signature, 0x40))
            v := byte(0, mload(add(signature, 0x60)))
        }

        // EIP-2 still allows signature malleability for ecrecover(). Remove this possibility and make the signature
        // unique. Appendix F in the Ethereum Yellow paper (https://ethereum.github.io/yellowpaper/paper.pdf), defines
        // the valid range for s in (281): 0 < s < secp256k1n ÷ 2 + 1, and for v in (282): v ∈ {27, 28}. Most
        // signatures from current libraries generate a unique signature with an s-value in the lower half order.
        //
        // If your library generates malleable signatures, such as s-values in the upper range, calculate a new s-value
        // with 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141 - s1 and flip v from 27 to 28 or
        // vice versa. If your library also generates signatures with 0/1 for v instead 27/28, add 27 to v to accept
        // these malleable signatures as well.
        if (uint256(s) > 0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF5D576E7357A4501DDFE92F46681B20A0) {
            return address(0);
        }

        if (v != 27 && v != 28) {
            return address(0);
        }

        // If the signature is valid (and not malleable), return the signer address
        return ecrecover(hash, v, r, s);
    }

    /* get signer address from data
    * @dev Gets an address encoded as the first argument in transaction data
    * @param b The byte array that should have an address as first argument
    * @returns a The address retrieved from the array
    */
    function getSignerAddress(bytes memory _b) internal pure returns (address _a) {
        require(_b.length >= 36, "invalid bytes");
        // solium-disable-next-line security/no-inline-assembly
        assembly {
            let mask := 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
            _a := and(mask, mload(add(_b, 36)))
            // b = {length:32}{method sig:4}{address:32}{...}
            // 36 is the offset of the first parameter of the data, if encoded properly.
            // 32 bytes for the length of the bytes array, and the first 4 bytes for the function signature.
            // 32 bytes is the length of the bytes array!!!!
        }
    }

    // get method id, first 4 bytes of data
    function getMethodId(bytes memory _b) internal pure returns (bytes4 _a) {
        require(_b.length >= 4, "invalid data");
        // solium-disable-next-line security/no-inline-assembly
        assembly {
            // 32 bytes is the length of the bytes array
            _a := mload(add(_b, 32))
        }
    }

    function checkKeyStatus(address _account, uint256 _index) internal {
        // check operation key status
        if (_index > 0) {
            require(accountStorage.getKeyStatus(_account, _index) != 1, "frozen key");
        }
    }

    // _nonce is timestamp in microsecond(1/1000000 second)
    function checkAndUpdateNonce(address _key, uint256 _nonce) internal {
        require(_nonce > keyNonce[_key], "nonce too small");
        require(SafeMath.div(_nonce, 1000000) <= now + 86400, "nonce too big"); // 86400=24*3600 seconds

        keyNonce[_key] = _nonce;
    }
}

contract DappLogic is BaseLogic {
    
    using RLPReader for RLPReader.RLPItem;
    using RLPReader for bytes;

    /*
    index 0: admin key
          1: asset(transfer)
          2: adding
          3: reserved(dapp)
          4: assist
     */
    uint constant internal DAPP_KEY_INDEX = 3;

    // *************** Events *************************** //

    event DappLogicInitialised(address indexed account);
    event DappLogicEntered(bytes data, uint256 indexed nonce);

    // *************** Constructor ********************** //
    constructor(AccountStorage _accountStorage)
        BaseLogic(_accountStorage)
        public
    {
    }

    // *************** Initialization ********************* //

    function initAccount(Account _account) external allowAccountCallsOnly(_account){
        emit DappLogicInitialised(address(_account));
    }

    // *************** action entry ********************* //

    function enter(bytes calldata _data, bytes calldata _signature, uint256 _nonce) external {
        address account = getSignerAddress(_data);
        checkKeyStatus(account, DAPP_KEY_INDEX);

        address dappKey = accountStorage.getKeyData(account, DAPP_KEY_INDEX);
        checkAndUpdateNonce(dappKey, _nonce);
        bytes32 signHash = getSignHash(_data, _nonce);
        verifySig(dappKey, _signature, signHash);

        // solium-disable-next-line security/no-low-level-calls
        (bool success,) = address(this).call(_data);
        require(success, "calling self failed");
        emit DappLogicEntered(_data, _nonce);
    }

    // *************** call Dapp ********************* //

    // called from 'enter'
    // call other contract from base account
    function callContract(address payable _account, address payable _target, uint256 _value, bytes calldata _methodData) external allowSelfCallsOnly {
        // Account(_account).invoke(_target, _value, _methodData);
        bool success;
        // solium-disable-next-line security/no-low-level-calls
        (success,) = _account.call(abi.encodeWithSignature("invoke(address,uint256,bytes)", _target, _value, _methodData));
        require(success, "calling invoke failed");
    }
    
    // called from 'enter'
    // call serveral other contracts at a time
    // rlp encode _methodData array into rlpBytes
    function callMultiContract(address payable _account, address[] calldata _targets, uint256[] calldata _values, bytes calldata _rlpBytes) external allowSelfCallsOnly {
        RLPReader.RLPItem[] memory ls = _rlpBytes.toRlpItem().toList();

        uint256 len = _targets.length;
        require(len == _values.length && len == ls.length, "length mismatch");
        for (uint256 i = 0; i < len; i++) {
            bool success;
            RLPReader.RLPItem memory item = ls[i];
            // solium-disable-next-line security/no-low-level-calls
            (success,) = _account.call(abi.encodeWithSignature("invoke(address,uint256,bytes)", _targets[i], _values[i], bytes(item.toBytes())));
            require(success, "calling invoke failed");
        }
    }

}

// Copyright (C) 2015, 2016, 2017 Dapphub

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

pragma solidity ^0.4.18;

contract WETH9 {
    string public name     = "Wrapped Ether";
    string public symbol   = "WETH";
    uint8  public decimals = 18;

    event  Approval(address indexed src, address indexed guy, uint wad);
    event  Transfer(address indexed src, address indexed dst, uint wad);
    event  Deposit(address indexed dst, uint wad);
    event  Withdrawal(address indexed src, uint wad);

    mapping (address => uint)                       public  balanceOf;
    mapping (address => mapping (address => uint))  public  allowance;

    function() public payable {
        deposit();
    }
    function deposit() public payable {
        balanceOf[msg.sender] += msg.value;
        Deposit(msg.sender, msg.value);
    }
    function withdraw(uint wad) public {
        require(balanceOf[msg.sender] >= wad);
        balanceOf[msg.sender] -= wad;
        msg.sender.transfer(wad);
        Withdrawal(msg.sender, wad);
    }

    function totalSupply() public view returns (uint) {
        return this.balance;
    }

    function approve(address guy, uint wad) public returns (bool) {
        allowance[msg.sender][guy] = wad;
        Approval(msg.sender, guy, wad);
        return true;
    }

    function transfer(address dst, uint wad) public returns (bool) {
        return transferFrom(msg.sender, dst, wad);
    }

    function transferFrom(address src, address dst, uint wad)
        public
        returns (bool)
    {
        require(balanceOf[src] >= wad);

        if (src != msg.sender && allowance[src][msg.sender] != uint(-1)) {
            require(allowance[src][msg.sender] >= wad);
            allowance[src][msg.sender] -= wad;
        }

        balanceOf[src] -= wad;
        balanceOf[dst] += wad;

        Transfer(src, dst, wad);

        return true;
    }
}


/*
                    GNU GENERAL PUBLIC LICENSE
                       Version 3, 29 June 2007

 Copyright (C) 2007 Free Software Foundation, Inc. <http://fsf.org/>
 Everyone is permitted to copy and distribute verbatim copies
 of this license document, but changing it is not allowed.

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            How to Apply These Terms to Your New Programs

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possible use to the public, the best way to achieve this is to make it
free software which everyone can redistribute and change under these terms.

  To do so, attach the following notices to the program.  It is safest
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Also add information on how to contact you by electronic and paper mail.

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    <program>  Copyright (C) <year>  <name of author>
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    under certain conditions; type `show c' for details.

The hypothetical commands `show w' and `show c' should show the appropriate
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  You should also get your employer (if you work as a programmer) or school,
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For more information on this, and how to apply and follow the GNU GPL, see
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  The GNU General Public License does not permit incorporating your program
into proprietary programs.  If your program is a subroutine library, you
may consider it more useful to permit linking proprietary applications with
the library.  If this is what you want to do, use the GNU Lesser General
Public License instead of this License.  But first, please read
<http://www.gnu.org/philosophy/why-not-lgpl.html>.

*/

pragma solidity =0.6.6;

interface IUniswapV2Factory {
    event PairCreated(address indexed token0, address indexed token1, address pair, uint);

    function feeTo() external view returns (address);
    function feeToSetter() external view returns (address);

    function getPair(address tokenA, address tokenB) external view returns (address pair);
    function allPairs(uint) external view returns (address pair);
    function allPairsLength() external view returns (uint);

    function createPair(address tokenA, address tokenB) external returns (address pair);

    function setFeeTo(address) external;
    function setFeeToSetter(address) external;
}

interface IUniswapV2Pair {
    event Approval(address indexed owner, address indexed spender, uint value);
    event Transfer(address indexed from, address indexed to, uint value);

    function name() external pure returns (string memory);
    function symbol() external pure returns (string memory);
    function decimals() external pure returns (uint8);
    function totalSupply() external view returns (uint);
    function balanceOf(address owner) external view returns (uint);
    function allowance(address owner, address spender) external view returns (uint);

    function approve(address spender, uint value) external returns (bool);
    function transfer(address to, uint value) external returns (bool);
    function transferFrom(address from, address to, uint value) external returns (bool);

    function DOMAIN_SEPARATOR() external view returns (bytes32);
    function PERMIT_TYPEHASH() external pure returns (bytes32);
    function nonces(address owner) external view returns (uint);

    function permit(address owner, address spender, uint value, uint deadline, uint8 v, bytes32 r, bytes32 s) external;

    event Mint(address indexed sender, uint amount0, uint amount1);
    event Burn(address indexed sender, uint amount0, uint amount1, address indexed to);
    event Swap(
        address indexed sender,
        uint amount0In,
        uint amount1In,
        uint amount0Out,
        uint amount1Out,
        address indexed to
    );
    event Sync(uint112 reserve0, uint112 reserve1);

    function MINIMUM_LIQUIDITY() external pure returns (uint);
    function factory() external view returns (address);
    function token0() external view returns (address);
    function token1() external view returns (address);
    function getReserves() external view returns (uint112 reserve0, uint112 reserve1, uint32 blockTimestampLast);
    function price0CumulativeLast() external view returns (uint);
    function price1CumulativeLast() external view returns (uint);
    function kLast() external view returns (uint);

    function mint(address to) external returns (uint liquidity);
    function burn(address to) external returns (uint amount0, uint amount1);
    function swap(uint amount0Out, uint amount1Out, address to, bytes calldata data) external;
    function skim(address to) external;
    function sync() external;

    function initialize(address, address) external;
}

interface IUniswapV2Router01 {
    function factory() external pure returns (address);
    function WETH() external pure returns (address);

    function addLiquidity(
        address tokenA,
        address tokenB,
        uint amountADesired,
        uint amountBDesired,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline
    ) external returns (uint amountA, uint amountB, uint liquidity);
    function addLiquidityETH(
        address token,
        uint amountTokenDesired,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external payable returns (uint amountToken, uint amountETH, uint liquidity);
    function removeLiquidity(
        address tokenA,
        address tokenB,
        uint liquidity,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline
    ) external returns (uint amountA, uint amountB);
    function removeLiquidityETH(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external returns (uint amountToken, uint amountETH);
    function removeLiquidityWithPermit(
        address tokenA,
        address tokenB,
        uint liquidity,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline,
        bool approveMax, uint8 v, bytes32 r, bytes32 s
    ) external returns (uint amountA, uint amountB);
    function removeLiquidityETHWithPermit(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline,
        bool approveMax, uint8 v, bytes32 r, bytes32 s
    ) external returns (uint amountToken, uint amountETH);
    function swapExactTokensForTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external returns (uint[] memory amounts);
    function swapTokensForExactTokens(
        uint amountOut,
        uint amountInMax,
        address[] calldata path,
        address to,
        uint deadline
    ) external returns (uint[] memory amounts);
    function swapExactETHForTokens(uint amountOutMin, address[] calldata path, address to, uint deadline)
        external
        payable
        returns (uint[] memory amounts);
    function swapTokensForExactETH(uint amountOut, uint amountInMax, address[] calldata path, address to, uint deadline)
        external
        returns (uint[] memory amounts);
    function swapExactTokensForETH(uint amountIn, uint amountOutMin, address[] calldata path, address to, uint deadline)
        external
        returns (uint[] memory amounts);
    function swapETHForExactTokens(uint amountOut, address[] calldata path, address to, uint deadline)
        external
        payable
        returns (uint[] memory amounts);

    function quote(uint amountA, uint reserveA, uint reserveB) external pure returns (uint amountB);
    function getAmountOut(uint amountIn, uint reserveIn, uint reserveOut) external pure returns (uint amountOut);
    function getAmountIn(uint amountOut, uint reserveIn, uint reserveOut) external pure returns (uint amountIn);
    function getAmountsOut(uint amountIn, address[] calldata path) external view returns (uint[] memory amounts);
    function getAmountsIn(uint amountOut, address[] calldata path) external view returns (uint[] memory amounts);
}

interface IUniswapV2Router02 is IUniswapV2Router01 {
    function removeLiquidityETHSupportingFeeOnTransferTokens(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external returns (uint amountETH);
    function removeLiquidityETHWithPermitSupportingFeeOnTransferTokens(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline,
        bool approveMax, uint8 v, bytes32 r, bytes32 s
    ) external returns (uint amountETH);

    function swapExactTokensForTokensSupportingFeeOnTransferTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external;
    function swapExactETHForTokensSupportingFeeOnTransferTokens(
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external payable;
    function swapExactTokensForETHSupportingFeeOnTransferTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external;
}

interface IERC20 {
    event Approval(address indexed owner, address indexed spender, uint value);
    event Transfer(address indexed from, address indexed to, uint value);

    function name() external view returns (string memory);
    function symbol() external view returns (string memory);
    function decimals() external view returns (uint8);
    function totalSupply() external view returns (uint);
    function balanceOf(address owner) external view returns (uint);
    function allowance(address owner, address spender) external view returns (uint);

    function approve(address spender, uint value) external returns (bool);
    function transfer(address to, uint value) external returns (bool);
    function transferFrom(address from, address to, uint value) external returns (bool);
}

interface IWETH {
    function deposit() external payable;
    function transfer(address to, uint value) external returns (bool);
    function withdraw(uint) external;
}

contract UniswapV2Router02 is IUniswapV2Router02 {
    using SafeMath for uint;

    address public immutable override factory;
    address public immutable override WETH;

    modifier ensure(uint deadline) {
        require(deadline >= block.timestamp, 'UniswapV2Router: EXPIRED');
        _;
    }

    constructor(address _factory, address _WETH) public {
        factory = _factory;
        WETH = _WETH;
    }

    receive() external payable {
        assert(msg.sender == WETH); // only accept ETH via fallback from the WETH contract
    }

    // **** ADD LIQUIDITY ****
    function _addLiquidity(
        address tokenA,
        address tokenB,
        uint amountADesired,
        uint amountBDesired,
        uint amountAMin,
        uint amountBMin
    ) internal virtual returns (uint amountA, uint amountB) {
        // create the pair if it doesn't exist yet
        if (IUniswapV2Factory(factory).getPair(tokenA, tokenB) == address(0)) {
            IUniswapV2Factory(factory).createPair(tokenA, tokenB);
        }
        (uint reserveA, uint reserveB) = UniswapV2Library.getReserves(factory, tokenA, tokenB);
        if (reserveA == 0 && reserveB == 0) {
            (amountA, amountB) = (amountADesired, amountBDesired);
        } else {
            uint amountBOptimal = UniswapV2Library.quote(amountADesired, reserveA, reserveB);
            if (amountBOptimal <= amountBDesired) {
                require(amountBOptimal >= amountBMin, 'UniswapV2Router: INSUFFICIENT_B_AMOUNT');
                (amountA, amountB) = (amountADesired, amountBOptimal);
            } else {
                uint amountAOptimal = UniswapV2Library.quote(amountBDesired, reserveB, reserveA);
                assert(amountAOptimal <= amountADesired);
                require(amountAOptimal >= amountAMin, 'UniswapV2Router: INSUFFICIENT_A_AMOUNT');
                (amountA, amountB) = (amountAOptimal, amountBDesired);
            }
        }
    }
    function addLiquidity(
        address tokenA,
        address tokenB,
        uint amountADesired,
        uint amountBDesired,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline
    ) external virtual override ensure(deadline) returns (uint amountA, uint amountB, uint liquidity) {
        (amountA, amountB) = _addLiquidity(tokenA, tokenB, amountADesired, amountBDesired, amountAMin, amountBMin);
        address pair = UniswapV2Library.pairFor(factory, tokenA, tokenB);
        TransferHelper.safeTransferFrom(tokenA, msg.sender, pair, amountA);
        TransferHelper.safeTransferFrom(tokenB, msg.sender, pair, amountB);
        liquidity = IUniswapV2Pair(pair).mint(to);
    }
    function addLiquidityETH(
        address token,
        uint amountTokenDesired,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external virtual override payable ensure(deadline) returns (uint amountToken, uint amountETH, uint liquidity) {
        (amountToken, amountETH) = _addLiquidity(
            token,
            WETH,
            amountTokenDesired,
            msg.value,
            amountTokenMin,
            amountETHMin
        );
        address pair = UniswapV2Library.pairFor(factory, token, WETH);
        TransferHelper.safeTransferFrom(token, msg.sender, pair, amountToken);
        IWETH(WETH).deposit{value: amountETH}();
        assert(IWETH(WETH).transfer(pair, amountETH));
        liquidity = IUniswapV2Pair(pair).mint(to);
        // refund dust eth, if any
        if (msg.value > amountETH) TransferHelper.safeTransferETH(msg.sender, msg.value - amountETH);
    }

    // **** REMOVE LIQUIDITY ****
    function removeLiquidity(
        address tokenA,
        address tokenB,
        uint liquidity,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline
    ) public virtual override ensure(deadline) returns (uint amountA, uint amountB) {
        address pair = UniswapV2Library.pairFor(factory, tokenA, tokenB);
        IUniswapV2Pair(pair).transferFrom(msg.sender, pair, liquidity); // send liquidity to pair
        (uint amount0, uint amount1) = IUniswapV2Pair(pair).burn(to);
        (address token0,) = UniswapV2Library.sortTokens(tokenA, tokenB);
        (amountA, amountB) = tokenA == token0 ? (amount0, amount1) : (amount1, amount0);
        require(amountA >= amountAMin, 'UniswapV2Router: INSUFFICIENT_A_AMOUNT');
        require(amountB >= amountBMin, 'UniswapV2Router: INSUFFICIENT_B_AMOUNT');
    }
    function removeLiquidityETH(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) public virtual override ensure(deadline) returns (uint amountToken, uint amountETH) {
        (amountToken, amountETH) = removeLiquidity(
            token,
            WETH,
            liquidity,
            amountTokenMin,
            amountETHMin,
            address(this),
            deadline
        );
        TransferHelper.safeTransfer(token, to, amountToken);
        IWETH(WETH).withdraw(amountETH);
        TransferHelper.safeTransferETH(to, amountETH);
    }
    function removeLiquidityWithPermit(
        address tokenA,
        address tokenB,
        uint liquidity,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline,
        bool approveMax, uint8 v, bytes32 r, bytes32 s
    ) external virtual override returns (uint amountA, uint amountB) {
        address pair = UniswapV2Library.pairFor(factory, tokenA, tokenB);
        uint value = approveMax ? uint(-1) : liquidity;
        IUniswapV2Pair(pair).permit(msg.sender, address(this), value, deadline, v, r, s);
        (amountA, amountB) = removeLiquidity(tokenA, tokenB, liquidity, amountAMin, amountBMin, to, deadline);
    }
    function removeLiquidityETHWithPermit(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline,
        bool approveMax, uint8 v, bytes32 r, bytes32 s
    ) external virtual override returns (uint amountToken, uint amountETH) {
        address pair = UniswapV2Library.pairFor(factory, token, WETH);
        uint value = approveMax ? uint(-1) : liquidity;
        IUniswapV2Pair(pair).permit(msg.sender, address(this), value, deadline, v, r, s);
        (amountToken, amountETH) = removeLiquidityETH(token, liquidity, amountTokenMin, amountETHMin, to, deadline);
    }

    // **** REMOVE LIQUIDITY (supporting fee-on-transfer tokens) ****
    function removeLiquidityETHSupportingFeeOnTransferTokens(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) public virtual override ensure(deadline) returns (uint amountETH) {
        (, amountETH) = removeLiquidity(
            token,
            WETH,
            liquidity,
            amountTokenMin,
            amountETHMin,
            address(this),
            deadline
        );
        TransferHelper.safeTransfer(token, to, IERC20(token).balanceOf(address(this)));
        IWETH(WETH).withdraw(amountETH);
        TransferHelper.safeTransferETH(to, amountETH);
    }
    function removeLiquidityETHWithPermitSupportingFeeOnTransferTokens(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline,
        bool approveMax, uint8 v, bytes32 r, bytes32 s
    ) external virtual override returns (uint amountETH) {
        address pair = UniswapV2Library.pairFor(factory, token, WETH);
        uint value = approveMax ? uint(-1) : liquidity;
        IUniswapV2Pair(pair).permit(msg.sender, address(this), value, deadline, v, r, s);
        amountETH = removeLiquidityETHSupportingFeeOnTransferTokens(
            token, liquidity, amountTokenMin, amountETHMin, to, deadline
        );
    }

    // **** SWAP ****
    // requires the initial amount to have already been sent to the first pair
    function _swap(uint[] memory amounts, address[] memory path, address _to) internal virtual {
        for (uint i; i < path.length - 1; i++) {
            (address input, address output) = (path[i], path[i + 1]);
            (address token0,) = UniswapV2Library.sortTokens(input, output);
            uint amountOut = amounts[i + 1];
            (uint amount0Out, uint amount1Out) = input == token0 ? (uint(0), amountOut) : (amountOut, uint(0));
            address to = i < path.length - 2 ? UniswapV2Library.pairFor(factory, output, path[i + 2]) : _to;
            IUniswapV2Pair(UniswapV2Library.pairFor(factory, input, output)).swap(
                amount0Out, amount1Out, to, new bytes(0)
            );
        }
    }
    function swapExactTokensForTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external virtual override ensure(deadline) returns (uint[] memory amounts) {
        amounts = UniswapV2Library.getAmountsOut(factory, amountIn, path);
        require(amounts[amounts.length - 1] >= amountOutMin, 'UniswapV2Router: INSUFFICIENT_OUTPUT_AMOUNT');
        TransferHelper.safeTransferFrom(
            path[0], msg.sender, UniswapV2Library.pairFor(factory, path[0], path[1]), amounts[0]
        );
        _swap(amounts, path, to);
    }
    function swapTokensForExactTokens(
        uint amountOut,
        uint amountInMax,
        address[] calldata path,
        address to,
        uint deadline
    ) external virtual override ensure(deadline) returns (uint[] memory amounts) {
        amounts = UniswapV2Library.getAmountsIn(factory, amountOut, path);
        require(amounts[0] <= amountInMax, 'UniswapV2Router: EXCESSIVE_INPUT_AMOUNT');
        TransferHelper.safeTransferFrom(
            path[0], msg.sender, UniswapV2Library.pairFor(factory, path[0], path[1]), amounts[0]
        );
        _swap(amounts, path, to);
    }
    function swapExactETHForTokens(uint amountOutMin, address[] calldata path, address to, uint deadline)
        external
        virtual
        override
        payable
        ensure(deadline)
        returns (uint[] memory amounts)
    {
        require(path[0] == WETH, 'UniswapV2Router: INVALID_PATH');
        amounts = UniswapV2Library.getAmountsOut(factory, msg.value, path);
        require(amounts[amounts.length - 1] >= amountOutMin, 'UniswapV2Router: INSUFFICIENT_OUTPUT_AMOUNT');
        IWETH(WETH).deposit{value: amounts[0]}();
        assert(IWETH(WETH).transfer(UniswapV2Library.pairFor(factory, path[0], path[1]), amounts[0]));
        _swap(amounts, path, to);
    }
    function swapTokensForExactETH(uint amountOut, uint amountInMax, address[] calldata path, address to, uint deadline)
        external
        virtual
        override
        ensure(deadline)
        returns (uint[] memory amounts)
    {
        require(path[path.length - 1] == WETH, 'UniswapV2Router: INVALID_PATH');
        amounts = UniswapV2Library.getAmountsIn(factory, amountOut, path);
        require(amounts[0] <= amountInMax, 'UniswapV2Router: EXCESSIVE_INPUT_AMOUNT');
        TransferHelper.safeTransferFrom(
            path[0], msg.sender, UniswapV2Library.pairFor(factory, path[0], path[1]), amounts[0]
        );
        _swap(amounts, path, address(this));
        IWETH(WETH).withdraw(amounts[amounts.length - 1]);
        TransferHelper.safeTransferETH(to, amounts[amounts.length - 1]);
    }
    function swapExactTokensForETH(uint amountIn, uint amountOutMin, address[] calldata path, address to, uint deadline)
        external
        virtual
        override
        ensure(deadline)
        returns (uint[] memory amounts)
    {
        require(path[path.length - 1] == WETH, 'UniswapV2Router: INVALID_PATH');
        amounts = UniswapV2Library.getAmountsOut(factory, amountIn, path);
        require(amounts[amounts.length - 1] >= amountOutMin, 'UniswapV2Router: INSUFFICIENT_OUTPUT_AMOUNT');
        TransferHelper.safeTransferFrom(
            path[0], msg.sender, UniswapV2Library.pairFor(factory, path[0], path[1]), amounts[0]
        );
        _swap(amounts, path, address(this));
        IWETH(WETH).withdraw(amounts[amounts.length - 1]);
        TransferHelper.safeTransferETH(to, amounts[amounts.length - 1]);
    }
    function swapETHForExactTokens(uint amountOut, address[] calldata path, address to, uint deadline)
        external
        virtual
        override
        payable
        ensure(deadline)
        returns (uint[] memory amounts)
    {
        require(path[0] == WETH, 'UniswapV2Router: INVALID_PATH');
        amounts = UniswapV2Library.getAmountsIn(factory, amountOut, path);
        require(amounts[0] <= msg.value, 'UniswapV2Router: EXCESSIVE_INPUT_AMOUNT');
        IWETH(WETH).deposit{value: amounts[0]}();
        assert(IWETH(WETH).transfer(UniswapV2Library.pairFor(factory, path[0], path[1]), amounts[0]));
        _swap(amounts, path, to);
        // refund dust eth, if any
        if (msg.value > amounts[0]) TransferHelper.safeTransferETH(msg.sender, msg.value - amounts[0]);
    }

    // **** SWAP (supporting fee-on-transfer tokens) ****
    // requires the initial amount to have already been sent to the first pair
    function _swapSupportingFeeOnTransferTokens(address[] memory path, address _to) internal virtual {
        for (uint i; i < path.length - 1; i++) {
            (address input, address output) = (path[i], path[i + 1]);
            (address token0,) = UniswapV2Library.sortTokens(input, output);
            IUniswapV2Pair pair = IUniswapV2Pair(UniswapV2Library.pairFor(factory, input, output));
            uint amountInput;
            uint amountOutput;
            { // scope to avoid stack too deep errors
            (uint reserve0, uint reserve1,) = pair.getReserves();
            (uint reserveInput, uint reserveOutput) = input == token0 ? (reserve0, reserve1) : (reserve1, reserve0);
            amountInput = IERC20(input).balanceOf(address(pair)).sub(reserveInput);
            amountOutput = UniswapV2Library.getAmountOut(amountInput, reserveInput, reserveOutput);
            }
            (uint amount0Out, uint amount1Out) = input == token0 ? (uint(0), amountOutput) : (amountOutput, uint(0));
            address to = i < path.length - 2 ? UniswapV2Library.pairFor(factory, output, path[i + 2]) : _to;
            pair.swap(amount0Out, amount1Out, to, new bytes(0));
        }
    }
    function swapExactTokensForTokensSupportingFeeOnTransferTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external virtual override ensure(deadline) {
        TransferHelper.safeTransferFrom(
            path[0], msg.sender, UniswapV2Library.pairFor(factory, path[0], path[1]), amountIn
        );
        uint balanceBefore = IERC20(path[path.length - 1]).balanceOf(to);
        _swapSupportingFeeOnTransferTokens(path, to);
        require(
            IERC20(path[path.length - 1]).balanceOf(to).sub(balanceBefore) >= amountOutMin,
            'UniswapV2Router: INSUFFICIENT_OUTPUT_AMOUNT'
        );
    }
    function swapExactETHForTokensSupportingFeeOnTransferTokens(
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    )
        external
        virtual
        override
        payable
        ensure(deadline)
    {
        require(path[0] == WETH, 'UniswapV2Router: INVALID_PATH');
        uint amountIn = msg.value;
        IWETH(WETH).deposit{value: amountIn}();
        assert(IWETH(WETH).transfer(UniswapV2Library.pairFor(factory, path[0], path[1]), amountIn));
        uint balanceBefore = IERC20(path[path.length - 1]).balanceOf(to);
        _swapSupportingFeeOnTransferTokens(path, to);
        require(
            IERC20(path[path.length - 1]).balanceOf(to).sub(balanceBefore) >= amountOutMin,
            'UniswapV2Router: INSUFFICIENT_OUTPUT_AMOUNT'
        );
    }
    function swapExactTokensForETHSupportingFeeOnTransferTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    )
        external
        virtual
        override
        ensure(deadline)
    {
        require(path[path.length - 1] == WETH, 'UniswapV2Router: INVALID_PATH');
        TransferHelper.safeTransferFrom(
            path[0], msg.sender, UniswapV2Library.pairFor(factory, path[0], path[1]), amountIn
        );
        _swapSupportingFeeOnTransferTokens(path, address(this));
        uint amountOut = IERC20(WETH).balanceOf(address(this));
        require(amountOut >= amountOutMin, 'UniswapV2Router: INSUFFICIENT_OUTPUT_AMOUNT');
        IWETH(WETH).withdraw(amountOut);
        TransferHelper.safeTransferETH(to, amountOut);
    }

    // **** LIBRARY FUNCTIONS ****
    function quote(uint amountA, uint reserveA, uint reserveB) public pure virtual override returns (uint amountB) {
        return UniswapV2Library.quote(amountA, reserveA, reserveB);
    }

    function getAmountOut(uint amountIn, uint reserveIn, uint reserveOut)
        public
        pure
        virtual
        override
        returns (uint amountOut)
    {
        return UniswapV2Library.getAmountOut(amountIn, reserveIn, reserveOut);
    }

    function getAmountIn(uint amountOut, uint reserveIn, uint reserveOut)
        public
        pure
        virtual
        override
        returns (uint amountIn)
    {
        return UniswapV2Library.getAmountIn(amountOut, reserveIn, reserveOut);
    }

    function getAmountsOut(uint amountIn, address[] memory path)
        public
        view
        virtual
        override
        returns (uint[] memory amounts)
    {
        return UniswapV2Library.getAmountsOut(factory, amountIn, path);
    }

    function getAmountsIn(uint amountOut, address[] memory path)
        public
        view
        virtual
        override
        returns (uint[] memory amounts)
    {
        return UniswapV2Library.getAmountsIn(factory, amountOut, path);
    }
}

// a library for performing overflow-safe math, courtesy of DappHub (https://github.com/dapphub/ds-math)

library SafeMath {
    function add(uint x, uint y) internal pure returns (uint z) {
        require((z = x + y) >= x, 'ds-math-add-overflow');
    }

    function sub(uint x, uint y) internal pure returns (uint z) {
        require((z = x - y) <= x, 'ds-math-sub-underflow');
    }

    function mul(uint x, uint y) internal pure returns (uint z) {
        require(y == 0 || (z = x * y) / y == x, 'ds-math-mul-overflow');
    }
}

library UniswapV2Library {
    using SafeMath for uint;

    // returns sorted token addresses, used to handle return values from pairs sorted in this order
    function sortTokens(address tokenA, address tokenB) internal pure returns (address token0, address token1) {
        require(tokenA != tokenB, 'UniswapV2Library: IDENTICAL_ADDRESSES');
        (token0, token1) = tokenA < tokenB ? (tokenA, tokenB) : (tokenB, tokenA);
        require(token0 != address(0), 'UniswapV2Library: ZERO_ADDRESS');
    }

    // calculates the CREATE2 address for a pair without making any external calls
    function pairFor(address factory, address tokenA, address tokenB) internal pure returns (address pair) {
        (address token0, address token1) = sortTokens(tokenA, tokenB);
        pair = address(uint(keccak256(abi.encodePacked(
                hex'ff',
                factory,
                keccak256(abi.encodePacked(token0, token1)),
                hex'96e8ac4277198ff8b6f785478aa9a39f403cb768dd02cbee326c3e7da348845f' // init code hash
            ))));
    }

    // fetches and sorts the reserves for a pair
    function getReserves(address factory, address tokenA, address tokenB) internal view returns (uint reserveA, uint reserveB) {
        (address token0,) = sortTokens(tokenA, tokenB);
        (uint reserve0, uint reserve1,) = IUniswapV2Pair(pairFor(factory, tokenA, tokenB)).getReserves();
        (reserveA, reserveB) = tokenA == token0 ? (reserve0, reserve1) : (reserve1, reserve0);
    }

    // given some amount of an asset and pair reserves, returns an equivalent amount of the other asset
    function quote(uint amountA, uint reserveA, uint reserveB) internal pure returns (uint amountB) {
        require(amountA > 0, 'UniswapV2Library: INSUFFICIENT_AMOUNT');
        require(reserveA > 0 && reserveB > 0, 'UniswapV2Library: INSUFFICIENT_LIQUIDITY');
        amountB = amountA.mul(reserveB) / reserveA;
    }

    // given an input amount of an asset and pair reserves, returns the maximum output amount of the other asset
    function getAmountOut(uint amountIn, uint reserveIn, uint reserveOut) internal pure returns (uint amountOut) {
        require(amountIn > 0, 'UniswapV2Library: INSUFFICIENT_INPUT_AMOUNT');
        require(reserveIn > 0 && reserveOut > 0, 'UniswapV2Library: INSUFFICIENT_LIQUIDITY');
        uint amountInWithFee = amountIn.mul(997);
        uint numerator = amountInWithFee.mul(reserveOut);
        uint denominator = reserveIn.mul(1000).add(amountInWithFee);
        amountOut = numerator / denominator;
    }

    // given an output amount of an asset and pair reserves, returns a required input amount of the other asset
    function getAmountIn(uint amountOut, uint reserveIn, uint reserveOut) internal pure returns (uint amountIn) {
        require(amountOut > 0, 'UniswapV2Library: INSUFFICIENT_OUTPUT_AMOUNT');
        require(reserveIn > 0 && reserveOut > 0, 'UniswapV2Library: INSUFFICIENT_LIQUIDITY');
        uint numerator = reserveIn.mul(amountOut).mul(1000);
        uint denominator = reserveOut.sub(amountOut).mul(997);
        amountIn = (numerator / denominator).add(1);
    }

    // performs chained getAmountOut calculations on any number of pairs
    function getAmountsOut(address factory, uint amountIn, address[] memory path) internal view returns (uint[] memory amounts) {
        require(path.length >= 2, 'UniswapV2Library: INVALID_PATH');
        amounts = new uint[](path.length);
        amounts[0] = amountIn;
        for (uint i; i < path.length - 1; i++) {
            (uint reserveIn, uint reserveOut) = getReserves(factory, path[i], path[i + 1]);
            amounts[i + 1] = getAmountOut(amounts[i], reserveIn, reserveOut);
        }
    }

    // performs chained getAmountIn calculations on any number of pairs
    function getAmountsIn(address factory, uint amountOut, address[] memory path) internal view returns (uint[] memory amounts) {
        require(path.length >= 2, 'UniswapV2Library: INVALID_PATH');
        amounts = new uint[](path.length);
        amounts[amounts.length - 1] = amountOut;
        for (uint i = path.length - 1; i > 0; i--) {
            (uint reserveIn, uint reserveOut) = getReserves(factory, path[i - 1], path[i]);
            amounts[i - 1] = getAmountIn(amounts[i], reserveIn, reserveOut);
        }
    }
}

// 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: contracts/interfaces/IUniswapV2Pair.sol

pragma solidity >=0.5.0;

interface IUniswapV2Pair {
    event Approval(address indexed owner, address indexed spender, uint value);
    event Transfer(address indexed from, address indexed to, uint value);

    function name() external pure returns (string memory);
    function symbol() external pure returns (string memory);
    function decimals() external pure returns (uint8);
    function totalSupply() external view returns (uint);
    function balanceOf(address owner) external view returns (uint);
    function allowance(address owner, address spender) external view returns (uint);

    function approve(address spender, uint value) external returns (bool);
    function transfer(address to, uint value) external returns (bool);
    function transferFrom(address from, address to, uint value) external returns (bool);

    function DOMAIN_SEPARATOR() external view returns (bytes32);
    function PERMIT_TYPEHASH() external pure returns (bytes32);
    function nonces(address owner) external view returns (uint);

    function permit(address owner, address spender, uint value, uint deadline, uint8 v, bytes32 r, bytes32 s) external;

    event Mint(address indexed sender, uint amount0, uint amount1);
    event Burn(address indexed sender, uint amount0, uint amount1, address indexed to);
    event Swap(
        address indexed sender,
        uint amount0In,
        uint amount1In,
        uint amount0Out,
        uint amount1Out,
        address indexed to
    );
    event Sync(uint112 reserve0, uint112 reserve1);

    function MINIMUM_LIQUIDITY() external pure returns (uint);
    function factory() external view returns (address);
    function token0() external view returns (address);
    function token1() external view returns (address);
    function getReserves() external view returns (uint112 reserve0, uint112 reserve1, uint32 blockTimestampLast);
    function price0CumulativeLast() external view returns (uint);
    function price1CumulativeLast() external view returns (uint);
    function kLast() external view returns (uint);

    function mint(address to) external returns (uint liquidity);
    function burn(address to) external returns (uint amount0, uint amount1);
    function swap(uint amount0Out, uint amount1Out, address to, bytes calldata data) external;
    function skim(address to) external;
    function sync() external;

    function initialize(address, address) external;
}

// File: contracts/interfaces/IUniswapV2ERC20.sol

pragma solidity >=0.5.0;

interface IUniswapV2ERC20 {
    event Approval(address indexed owner, address indexed spender, uint value);
    event Transfer(address indexed from, address indexed to, uint value);

    function name() external pure returns (string memory);
    function symbol() external pure returns (string memory);
    function decimals() external pure returns (uint8);
    function totalSupply() external view returns (uint);
    function balanceOf(address owner) external view returns (uint);
    function allowance(address owner, address spender) external view returns (uint);

    function approve(address spender, uint value) external returns (bool);
    function transfer(address to, uint value) external returns (bool);
    function transferFrom(address from, address to, uint value) external returns (bool);

    function DOMAIN_SEPARATOR() external view returns (bytes32);
    function PERMIT_TYPEHASH() external pure returns (bytes32);
    function nonces(address owner) external view returns (uint);

    function permit(address owner, address spender, uint value, uint deadline, uint8 v, bytes32 r, bytes32 s) external;
}

// File: contracts/libraries/SafeMath.sol

pragma solidity =0.5.16;

// a library for performing overflow-safe math, courtesy of DappHub (https://github.com/dapphub/ds-math)

library SafeMath {
    function add(uint x, uint y) internal pure returns (uint z) {
        require((z = x + y) >= x, 'ds-math-add-overflow');
    }

    function sub(uint x, uint y) internal pure returns (uint z) {
        require((z = x - y) <= x, 'ds-math-sub-underflow');
    }

    function mul(uint x, uint y) internal pure returns (uint z) {
        require(y == 0 || (z = x * y) / y == x, 'ds-math-mul-overflow');
    }
}

// File: contracts/UniswapV2ERC20.sol

pragma solidity =0.5.16;



contract UniswapV2ERC20 is IUniswapV2ERC20 {
    using SafeMath for uint;

    string public constant name = 'Uniswap V2';
    string public constant symbol = 'UNI-V2';
    uint8 public constant decimals = 18;
    uint  public totalSupply;
    mapping(address => uint) public balanceOf;
    mapping(address => mapping(address => uint)) public allowance;

    bytes32 public DOMAIN_SEPARATOR;
    // keccak256("Permit(address owner,address spender,uint256 value,uint256 nonce,uint256 deadline)");
    bytes32 public constant PERMIT_TYPEHASH = 0x6e71edae12b1b97f4d1f60370fef10105fa2faae0126114a169c64845d6126c9;
    mapping(address => uint) public nonces;

    event Approval(address indexed owner, address indexed spender, uint value);
    event Transfer(address indexed from, address indexed to, uint value);

    constructor() public {
        uint chainId;
        assembly {
            chainId := chainid
        }
        DOMAIN_SEPARATOR = keccak256(
            abi.encode(
                keccak256('EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)'),
                keccak256(bytes(name)),
                keccak256(bytes('1')),
                chainId,
                address(this)
            )
        );
    }

    function _mint(address to, uint value) internal {
        totalSupply = totalSupply.add(value);
        balanceOf[to] = balanceOf[to].add(value);
        emit Transfer(address(0), to, value);
    }

    function _burn(address from, uint value) internal {
        balanceOf[from] = balanceOf[from].sub(value);
        totalSupply = totalSupply.sub(value);
        emit Transfer(from, address(0), value);
    }

    function _approve(address owner, address spender, uint value) private {
        allowance[owner][spender] = value;
        emit Approval(owner, spender, value);
    }

    function _transfer(address from, address to, uint value) private {
        balanceOf[from] = balanceOf[from].sub(value);
        balanceOf[to] = balanceOf[to].add(value);
        emit Transfer(from, to, value);
    }

    function approve(address spender, uint value) external returns (bool) {
        _approve(msg.sender, spender, value);
        return true;
    }

    function transfer(address to, uint value) external returns (bool) {
        _transfer(msg.sender, to, value);
        return true;
    }

    function transferFrom(address from, address to, uint value) external returns (bool) {
        if (allowance[from][msg.sender] != uint(-1)) {
            allowance[from][msg.sender] = allowance[from][msg.sender].sub(value);
        }
        _transfer(from, to, value);
        return true;
    }

    function permit(address owner, address spender, uint value, uint deadline, uint8 v, bytes32 r, bytes32 s) external {
        require(deadline >= block.timestamp, 'UniswapV2: EXPIRED');
        bytes32 digest = keccak256(
            abi.encodePacked(
                '\x19\x01',
                DOMAIN_SEPARATOR,
                keccak256(abi.encode(PERMIT_TYPEHASH, owner, spender, value, nonces[owner]++, deadline))
            )
        );
        address recoveredAddress = ecrecover(digest, v, r, s);
        require(recoveredAddress != address(0) && recoveredAddress == owner, 'UniswapV2: INVALID_SIGNATURE');
        _approve(owner, spender, value);
    }
}

// File: contracts/libraries/Math.sol

pragma solidity =0.5.16;

// a library for performing various math operations

library Math {
    function min(uint x, uint y) internal pure returns (uint z) {
        z = x < y ? x : y;
    }

    // babylonian method (https://en.wikipedia.org/wiki/Methods_of_computing_square_roots#Babylonian_method)
    function sqrt(uint y) internal pure returns (uint z) {
        if (y > 3) {
            z = y;
            uint x = y / 2 + 1;
            while (x < z) {
                z = x;
                x = (y / x + x) / 2;
            }
        } else if (y != 0) {
            z = 1;
        }
    }
}

// File: contracts/libraries/UQ112x112.sol

pragma solidity =0.5.16;

// a library for handling binary fixed point numbers (https://en.wikipedia.org/wiki/Q_(number_format))

// range: [0, 2**112 - 1]
// resolution: 1 / 2**112

library UQ112x112 {
    uint224 constant Q112 = 2**112;

    // encode a uint112 as a UQ112x112
    function encode(uint112 y) internal pure returns (uint224 z) {
        z = uint224(y) * Q112; // never overflows
    }

    // divide a UQ112x112 by a uint112, returning a UQ112x112
    function uqdiv(uint224 x, uint112 y) internal pure returns (uint224 z) {
        z = x / uint224(y);
    }
}

// File: contracts/interfaces/IERC20.sol

pragma solidity >=0.5.0;

interface IERC20 {
    event Approval(address indexed owner, address indexed spender, uint value);
    event Transfer(address indexed from, address indexed to, uint value);

    function name() external view returns (string memory);
    function symbol() external view returns (string memory);
    function decimals() external view returns (uint8);
    function totalSupply() external view returns (uint);
    function balanceOf(address owner) external view returns (uint);
    function allowance(address owner, address spender) external view returns (uint);

    function approve(address spender, uint value) external returns (bool);
    function transfer(address to, uint value) external returns (bool);
    function transferFrom(address from, address to, uint value) external returns (bool);
}

// File: contracts/interfaces/IUniswapV2Factory.sol

pragma solidity >=0.5.0;

interface IUniswapV2Factory {
    event PairCreated(address indexed token0, address indexed token1, address pair, uint);

    function feeTo() external view returns (address);
    function feeToSetter() external view returns (address);

    function getPair(address tokenA, address tokenB) external view returns (address pair);
    function allPairs(uint) external view returns (address pair);
    function allPairsLength() external view returns (uint);

    function createPair(address tokenA, address tokenB) external returns (address pair);

    function setFeeTo(address) external;
    function setFeeToSetter(address) external;
}

// File: contracts/interfaces/IUniswapV2Callee.sol

pragma solidity >=0.5.0;

interface IUniswapV2Callee {
    function uniswapV2Call(address sender, uint amount0, uint amount1, bytes calldata data) external;
}

// File: contracts/UniswapV2Pair.sol

pragma solidity =0.5.16;








contract UniswapV2Pair is IUniswapV2Pair, UniswapV2ERC20 {
    using SafeMath  for uint;
    using UQ112x112 for uint224;

    uint public constant MINIMUM_LIQUIDITY = 10**3;
    bytes4 private constant SELECTOR = bytes4(keccak256(bytes('transfer(address,uint256)')));

    address public factory;
    address public token0;
    address public token1;

    uint112 private reserve0;           // uses single storage slot, accessible via getReserves
    uint112 private reserve1;           // uses single storage slot, accessible via getReserves
    uint32  private blockTimestampLast; // uses single storage slot, accessible via getReserves

    uint public price0CumulativeLast;
    uint public price1CumulativeLast;
    uint public kLast; // reserve0 * reserve1, as of immediately after the most recent liquidity event

    uint private unlocked = 1;
    modifier lock() {
        require(unlocked == 1, 'UniswapV2: LOCKED');
        unlocked = 0;
        _;
        unlocked = 1;
    }

    function getReserves() public view returns (uint112 _reserve0, uint112 _reserve1, uint32 _blockTimestampLast) {
        _reserve0 = reserve0;
        _reserve1 = reserve1;
        _blockTimestampLast = blockTimestampLast;
    }

    function _safeTransfer(address token, address to, uint value) private {
        (bool success, bytes memory data) = token.call(abi.encodeWithSelector(SELECTOR, to, value));
        require(success && (data.length == 0 || abi.decode(data, (bool))), 'UniswapV2: TRANSFER_FAILED');
    }

    event Mint(address indexed sender, uint amount0, uint amount1);
    event Burn(address indexed sender, uint amount0, uint amount1, address indexed to);
    event Swap(
        address indexed sender,
        uint amount0In,
        uint amount1In,
        uint amount0Out,
        uint amount1Out,
        address indexed to
    );
    event Sync(uint112 reserve0, uint112 reserve1);

    constructor() public {
        factory = msg.sender;
    }

    // called once by the factory at time of deployment
    function initialize(address _token0, address _token1) external {
        require(msg.sender == factory, 'UniswapV2: FORBIDDEN'); // sufficient check
        token0 = _token0;
        token1 = _token1;
    }

    // update reserves and, on the first call per block, price accumulators
    function _update(uint balance0, uint balance1, uint112 _reserve0, uint112 _reserve1) private {
        require(balance0 <= uint112(-1) && balance1 <= uint112(-1), 'UniswapV2: OVERFLOW');
        uint32 blockTimestamp = uint32(block.timestamp % 2**32);
        uint32 timeElapsed = blockTimestamp - blockTimestampLast; // overflow is desired
        if (timeElapsed > 0 && _reserve0 != 0 && _reserve1 != 0) {
            // * never overflows, and + overflow is desired
            price0CumulativeLast += uint(UQ112x112.encode(_reserve1).uqdiv(_reserve0)) * timeElapsed;
            price1CumulativeLast += uint(UQ112x112.encode(_reserve0).uqdiv(_reserve1)) * timeElapsed;
        }
        reserve0 = uint112(balance0);
        reserve1 = uint112(balance1);
        blockTimestampLast = blockTimestamp;
        emit Sync(reserve0, reserve1);
    }

    // if fee is on, mint liquidity equivalent to 1/6th of the growth in sqrt(k)
    function _mintFee(uint112 _reserve0, uint112 _reserve1) private returns (bool feeOn) {
        address feeTo = IUniswapV2Factory(factory).feeTo();
        feeOn = feeTo != address(0);
        uint _kLast = kLast; // gas savings
        if (feeOn) {
            if (_kLast != 0) {
                uint rootK = Math.sqrt(uint(_reserve0).mul(_reserve1));
                uint rootKLast = Math.sqrt(_kLast);
                if (rootK > rootKLast) {
                    uint numerator = totalSupply.mul(rootK.sub(rootKLast));
                    uint denominator = rootK.mul(5).add(rootKLast);
                    uint liquidity = numerator / denominator;
                    if (liquidity > 0) _mint(feeTo, liquidity);
                }
            }
        } else if (_kLast != 0) {
            kLast = 0;
        }
    }

    // this low-level function should be called from a contract which performs important safety checks
    function mint(address to) external lock returns (uint liquidity) {
        (uint112 _reserve0, uint112 _reserve1,) = getReserves(); // gas savings
        uint balance0 = IERC20(token0).balanceOf(address(this));
        uint balance1 = IERC20(token1).balanceOf(address(this));
        uint amount0 = balance0.sub(_reserve0);
        uint amount1 = balance1.sub(_reserve1);

        bool feeOn = _mintFee(_reserve0, _reserve1);
        uint _totalSupply = totalSupply; // gas savings, must be defined here since totalSupply can update in _mintFee
        if (_totalSupply == 0) {
            liquidity = Math.sqrt(amount0.mul(amount1)).sub(MINIMUM_LIQUIDITY);
           _mint(address(0), MINIMUM_LIQUIDITY); // permanently lock the first MINIMUM_LIQUIDITY tokens
        } else {
            liquidity = Math.min(amount0.mul(_totalSupply) / _reserve0, amount1.mul(_totalSupply) / _reserve1);
        }
        require(liquidity > 0, 'UniswapV2: INSUFFICIENT_LIQUIDITY_MINTED');
        _mint(to, liquidity);

        _update(balance0, balance1, _reserve0, _reserve1);
        if (feeOn) kLast = uint(reserve0).mul(reserve1); // reserve0 and reserve1 are up-to-date
        emit Mint(msg.sender, amount0, amount1);
    }

    // this low-level function should be called from a contract which performs important safety checks
    function burn(address to) external lock returns (uint amount0, uint amount1) {
        (uint112 _reserve0, uint112 _reserve1,) = getReserves(); // gas savings
        address _token0 = token0;                                // gas savings
        address _token1 = token1;                                // gas savings
        uint balance0 = IERC20(_token0).balanceOf(address(this));
        uint balance1 = IERC20(_token1).balanceOf(address(this));
        uint liquidity = balanceOf[address(this)];

        bool feeOn = _mintFee(_reserve0, _reserve1);
        uint _totalSupply = totalSupply; // gas savings, must be defined here since totalSupply can update in _mintFee
        amount0 = liquidity.mul(balance0) / _totalSupply; // using balances ensures pro-rata distribution
        amount1 = liquidity.mul(balance1) / _totalSupply; // using balances ensures pro-rata distribution
        require(amount0 > 0 && amount1 > 0, 'UniswapV2: INSUFFICIENT_LIQUIDITY_BURNED');
        _burn(address(this), liquidity);
        _safeTransfer(_token0, to, amount0);
        _safeTransfer(_token1, to, amount1);
        balance0 = IERC20(_token0).balanceOf(address(this));
        balance1 = IERC20(_token1).balanceOf(address(this));

        _update(balance0, balance1, _reserve0, _reserve1);
        if (feeOn) kLast = uint(reserve0).mul(reserve1); // reserve0 and reserve1 are up-to-date
        emit Burn(msg.sender, amount0, amount1, to);
    }

    // this low-level function should be called from a contract which performs important safety checks
    function swap(uint amount0Out, uint amount1Out, address to, bytes calldata data) external lock {
        require(amount0Out > 0 || amount1Out > 0, 'UniswapV2: INSUFFICIENT_OUTPUT_AMOUNT');
        (uint112 _reserve0, uint112 _reserve1,) = getReserves(); // gas savings
        require(amount0Out < _reserve0 && amount1Out < _reserve1, 'UniswapV2: INSUFFICIENT_LIQUIDITY');

        uint balance0;
        uint balance1;
        { // scope for _token{0,1}, avoids stack too deep errors
        address _token0 = token0;
        address _token1 = token1;
        require(to != _token0 && to != _token1, 'UniswapV2: INVALID_TO');
        if (amount0Out > 0) _safeTransfer(_token0, to, amount0Out); // optimistically transfer tokens
        if (amount1Out > 0) _safeTransfer(_token1, to, amount1Out); // optimistically transfer tokens
        if (data.length > 0) IUniswapV2Callee(to).uniswapV2Call(msg.sender, amount0Out, amount1Out, data);
        balance0 = IERC20(_token0).balanceOf(address(this));
        balance1 = IERC20(_token1).balanceOf(address(this));
        }
        uint amount0In = balance0 > _reserve0 - amount0Out ? balance0 - (_reserve0 - amount0Out) : 0;
        uint amount1In = balance1 > _reserve1 - amount1Out ? balance1 - (_reserve1 - amount1Out) : 0;
        require(amount0In > 0 || amount1In > 0, 'UniswapV2: INSUFFICIENT_INPUT_AMOUNT');
        { // scope for reserve{0,1}Adjusted, avoids stack too deep errors
        uint balance0Adjusted = balance0.mul(1000).sub(amount0In.mul(3));
        uint balance1Adjusted = balance1.mul(1000).sub(amount1In.mul(3));
        require(balance0Adjusted.mul(balance1Adjusted) >= uint(_reserve0).mul(_reserve1).mul(1000**2), 'UniswapV2: K');
        }

        _update(balance0, balance1, _reserve0, _reserve1);
        emit Swap(msg.sender, amount0In, amount1In, amount0Out, amount1Out, to);
    }

    // force balances to match reserves
    function skim(address to) external lock {
        address _token0 = token0; // gas savings
        address _token1 = token1; // gas savings
        _safeTransfer(_token0, to, IERC20(_token0).balanceOf(address(this)).sub(reserve0));
        _safeTransfer(_token1, to, IERC20(_token1).balanceOf(address(this)).sub(reserve1));
    }

    // force reserves to match balances
    function sync() external lock {
        _update(IERC20(token0).balanceOf(address(this)), IERC20(token1).balanceOf(address(this)), reserve0, reserve1);
    }
}

pragma solidity ^0.5.4;

contract AccountProxy {

    address implementation;

    event Received(uint indexed value, address indexed sender, bytes data);

    constructor(address _implementation) public {
        implementation = _implementation;
    }

    function() external payable {

        if(msg.data.length == 0 && msg.value > 0) {
            emit Received(msg.value, msg.sender, msg.data);
        }
        else {
            // solium-disable-next-line security/no-inline-assembly
            assembly {
                let target := sload(0)
                calldatacopy(0, 0, calldatasize())
                let result := delegatecall(gas, target, 0, calldatasize(), 0, 0)
                returndatacopy(0, 0, returndatasize())
                switch result
                case 0 {revert(0, returndatasize())}
                default {return (0, returndatasize())}
            }
        }
    }
}

pragma solidity ^0.4.24;

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

  /**
  * @dev Multiplies two numbers, reverts on 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-solidity/pull/522
    if (a == 0) {
      return 0;
    }

    uint256 c = a * b;
    require(c / a == b);

    return c;
  }

  /**
  * @dev Integer division of two numbers truncating the quotient, reverts on division by zero.
  */
  function div(uint256 a, uint256 b) internal pure returns (uint256) {
    require(b > 0); // Solidity only automatically asserts when dividing by 0
    uint256 c = a / b;
    // assert(a == b * c + a % b); // There is no case in which this doesn't hold

    return c;
  }

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

    return c;
  }

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

    return c;
  }

  /**
  * @dev Divides two numbers and returns the remainder (unsigned integer modulo),
  * reverts when dividing by zero.
  */
  function mod(uint256 a, uint256 b) internal pure returns (uint256) {
    require(b != 0);
    return a % b;
  }
}

/**
 * @title ERC20 interface
 * @dev see https://github.com/ethereum/EIPs/issues/20
 */
 interface IERC20 {
   function totalSupply() external view returns (uint256);

   function balanceOf(address who) external view returns (uint256);

   function allowance(address owner, address spender)
     external view returns (uint256);

   function transfer(address to, uint256 value) external returns (bool);

   function approve(address spender, uint256 value)
     external returns (bool);

   function transferFrom(address from, address to, uint256 value)
     external returns (bool);

   event Transfer(
     address indexed from,
     address indexed to,
     uint256 value
   );

   event Approval(
     address indexed owner,
     address indexed spender,
     uint256 value
   );
 }

contract ERC20 is IERC20 {
  using SafeMath for uint256;

  mapping (address => uint256) private _balances;

  mapping (address => mapping (address => uint256)) private _allowed;

  uint256 private _totalSupply;
  string private _name;
  string private _symbol;
  uint8 private _decimals;

  constructor(string name, string symbol, uint8 decimals, uint256 totalSupply) public {
    _name = name;
    _symbol = symbol;
    _decimals = decimals;
    _totalSupply = totalSupply;
    _balances[msg.sender] = _balances[msg.sender].add(_totalSupply);
    emit Transfer(address(0), msg.sender, totalSupply);
  }

  /**
   * @return the name of the token.
   */
  function name() public view returns(string) {
    return _name;
  }

  /**
   * @return the symbol of the token.
   */
  function symbol() public view returns(string) {
    return _symbol;
  }

  /**
   * @return the number of decimals of the token.
   */
  function decimals() public view returns(uint8) {
    return _decimals;
  }

  /**
  * @dev Total number of tokens in existence
  */
  function totalSupply() public view returns (uint256) {
    return _totalSupply;
  }

  /**
  * @dev Gets the balance of the specified address.
  * @param owner The address to query the balance of.
  * @return An uint256 representing the amount owned by the passed address.
  */
  function balanceOf(address owner) public view returns (uint256) {
    return _balances[owner];
  }

  /**
   * @dev Function to check the amount of tokens that an owner allowed to a spender.
   * @param owner address The address which owns the funds.
   * @param spender address The address which will spend the funds.
   * @return A uint256 specifying the amount of tokens still available for the spender.
   */
  function allowance(
    address owner,
    address spender
   )
    public
    view
    returns (uint256)
  {
    return _allowed[owner][spender];
  }

  /**
  * @dev Transfer token for a specified address
  * @param to The address to transfer to.
  * @param value The amount to be transferred.
  */
  function transfer(address to, uint256 value) public returns (bool) {
    _transfer(msg.sender, to, value);
    return true;
  }

  /**
   * @dev Approve the passed address to spend the specified amount of tokens on behalf of msg.sender.
   * 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
   * @param spender The address which will spend the funds.
   * @param value The amount of tokens to be spent.
   */
  function approve(address spender, uint256 value) public returns (bool) {
    require(spender != address(0));

    _allowed[msg.sender][spender] = value;
    emit Approval(msg.sender, spender, value);
    return true;
  }

  /**
   * @dev Transfer tokens from one address to another
   * @param from address The address which you want to send tokens from
   * @param to address The address which you want to transfer to
   * @param value uint256 the amount of tokens to be transferred
   */
  function transferFrom(
    address from,
    address to,
    uint256 value
  )
    public
    returns (bool)
  {
    require(value <= _allowed[from][msg.sender]);

    _allowed[from][msg.sender] = _allowed[from][msg.sender].sub(value);
    _transfer(from, to, value);
    return true;
  }

  /**
   * @dev Increase the amount of tokens that an owner allowed to a spender.
   * approve should be called when allowed_[_spender] == 0. To increment
   * allowed value is better to use this function to avoid 2 calls (and wait until
   * the first transaction is mined)
   * From MonolithDAO Token.sol
   * @param spender The address which will spend the funds.
   * @param addedValue The amount of tokens to increase the allowance by.
   */
  function increaseAllowance(
    address spender,
    uint256 addedValue
  )
    public
    returns (bool)
  {
    require(spender != address(0));

    _allowed[msg.sender][spender] = (
      _allowed[msg.sender][spender].add(addedValue));
    emit Approval(msg.sender, spender, _allowed[msg.sender][spender]);
    return true;
  }

  /**
   * @dev Decrease the amount of tokens that an owner allowed to a spender.
   * approve should be called when allowed_[_spender] == 0. To decrement
   * allowed value is better to use this function to avoid 2 calls (and wait until
   * the first transaction is mined)
   * From MonolithDAO Token.sol
   * @param spender The address which will spend the funds.
   * @param subtractedValue The amount of tokens to decrease the allowance by.
   */
  function decreaseAllowance(
    address spender,
    uint256 subtractedValue
  )
    public
    returns (bool)
  {
    require(spender != address(0));

    _allowed[msg.sender][spender] = (
      _allowed[msg.sender][spender].sub(subtractedValue));
    emit Approval(msg.sender, spender, _allowed[msg.sender][spender]);
    return true;
  }

  /**
  * @dev Transfer token for a specified addresses
  * @param from The address to transfer from.
  * @param to The address to transfer to.
  * @param value The amount to be transferred.
  */
  function _transfer(address from, address to, uint256 value) internal {
    require(value <= _balances[from]);
    require(to != address(0));

    _balances[from] = _balances[from].sub(value);
    _balances[to] = _balances[to].add(value);
    emit Transfer(from, to, value);
  }
}

pragma solidity ^0.5.4;

library SafeMath {

    /**
    * @dev Multiplies two numbers, reverts on 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-solidity/pull/522
        if (a == 0) {
            return 0;
        }

        uint256 c = a * b;
        require(c / a == b);

        return c;
    }

    /**
    * @dev Integer division of two numbers truncating the quotient, reverts on division by zero.
    */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b > 0); // Solidity only automatically asserts when dividing by 0
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold

        return c;
    }

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

        return c;
    }

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

        return c;
    }

    /**
    * @dev Divides two numbers and returns the remainder (unsigned integer modulo),
    * reverts when dividing by zero.
    */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b != 0);
        return a % b;
    }

    /**
    * @dev Returns ceil(a / b).
    */
    function ceil(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a / b;
        if(a % b == 0) {
            return c;
        }
        else {
            return c + 1;
        }
    }
}

contract Owned {

    // The owner
    address public owner;

    event OwnerChanged(address indexed _newOwner);

    /**
     * @dev Throws if the sender is not the owner.
     */
    modifier onlyOwner {
        require(msg.sender == owner, "Must be owner");
        _;
    }

    constructor() public {
        owner = msg.sender;
    }

    /**
     * @dev Lets the owner transfer ownership of the contract to a new owner.
     * @param _newOwner The new owner.
     */
    function changeOwner(address _newOwner) external onlyOwner {
        require(_newOwner != address(0), "Address must not be null");
        owner = _newOwner;
        emit OwnerChanged(_newOwner);
    }
}

contract LogicManager is Owned {

    event UpdateLogicSubmitted(address indexed logic, bool value);
    event UpdateLogicCancelled(address indexed logic);
    event UpdateLogicDone(address indexed logic, bool value);

    struct pending {
        bool value;
        uint dueTime;
    }

    // The authorized logic modules
    mapping (address => bool) public authorized;

    /*
    array
    index 0: AccountLogic address
          1: TransferLogic address
          2: DualsigsLogic address
          3: DappLogic address
          4: ...
     */
    address[] public authorizedLogics;

    // updated logics and their due time of becoming effective
    mapping (address => pending) public pendingLogics;

    // pending time before updated logics take effect
    uint public pendingTime;

    // how many authorized logics
    uint public logicCount;

    constructor(address[] memory _initialLogics, uint256 _pendingTime) public
    {
        for (uint i = 0; i < _initialLogics.length; i++) {
            address logic = _initialLogics[i];
            authorized[logic] = true;
            logicCount += 1;
        }
        authorizedLogics = _initialLogics;

        // pendingTime: 4 days for mainnet, 4 minutes for ropsten testnet
        pendingTime = _pendingTime;
    }

    function isAuthorized(address _logic) external view returns (bool) {
        return authorized[_logic];
    }

    function getAuthorizedLogics() external view returns (address[] memory) {
        return authorizedLogics;
    }

    function submitUpdate(address _logic, bool _value) external onlyOwner {
        pending storage p = pendingLogics[_logic];
        p.value = _value;
        p.dueTime = now + pendingTime;
        emit UpdateLogicSubmitted(_logic, _value);
    }

    function cancelUpdate(address _logic) external onlyOwner {
        delete pendingLogics[_logic];
        emit UpdateLogicCancelled(_logic);
    }

    function triggerUpdateLogic(address _logic) external {
        pending memory p = pendingLogics[_logic];
        require(p.dueTime > 0, "pending logic not found");
        require(p.dueTime <= now, "too early to trigger updateLogic");
        updateLogic(_logic, p.value);
        delete pendingLogics[_logic];
    }

    function updateLogic(address _logic, bool _value) internal {
        if (authorized[_logic] != _value) {
            if(_value) {
                logicCount += 1;
                authorized[_logic] = true;
                authorizedLogics.push(_logic);
            }
            else {
                logicCount -= 1;
                require(logicCount > 0, "must have at least one logic module");
                delete authorized[_logic];
                removeLogic(_logic);
            }
            emit UpdateLogicDone(_logic, _value);
        }
    }

    function removeLogic(address _logic) internal {
        uint len = authorizedLogics.length;
        address lastLogic = authorizedLogics[len - 1];
        if (_logic != lastLogic) {
            for (uint i = 0; i < len; i++) {
                 if (_logic == authorizedLogics[i]) {
                     authorizedLogics[i] = lastLogic;
                     break;
                 }
            }
        }
        authorizedLogics.length--;
    }
}

contract BaseLogic {

    bytes constant internal SIGN_HASH_PREFIX = "\x19Ethereum Signed Message:\n32";

    mapping (address => uint256) keyNonce;
    AccountStorage public accountStorage;

    modifier allowSelfCallsOnly() {
        require (msg.sender == address(this), "only internal call is allowed");
        _;
    }

    modifier allowAccountCallsOnly(Account _account) {
        require(msg.sender == address(_account), "caller must be account");
        _;
    }

    event LogicInitialised(address wallet);

    // *************** Constructor ********************** //

    constructor(AccountStorage _accountStorage) public {
        accountStorage = _accountStorage;
    }

    // *************** Initialization ********************* //

    function initAccount(Account _account) external allowAccountCallsOnly(_account){
        emit LogicInitialised(address(_account));
    }

    // *************** Getter ********************** //

    function getKeyNonce(address _key) external view returns(uint256) {
        return keyNonce[_key];
    }

    // *************** Signature ********************** //

    function getSignHash(bytes memory _data, uint256 _nonce) internal view returns(bytes32) {
        // use EIP 191
        // 0x1900 + this logic address + data + nonce of signing key
        bytes32 msgHash = keccak256(abi.encodePacked(byte(0x19), byte(0), address(this), _data, _nonce));
        bytes32 prefixedHash = keccak256(abi.encodePacked(SIGN_HASH_PREFIX, msgHash));
        return prefixedHash;
    }

    function verifySig(address _signingKey, bytes memory _signature, bytes32 _signHash) internal pure {
        require(_signingKey != address(0), "invalid signing key");
        address recoveredAddr = recover(_signHash, _signature);
        require(recoveredAddr == _signingKey, "signature verification failed");
    }

    /**
     * @dev Returns the address that signed a hashed message (`hash`) with
     * `signature`. This address can then be used for verification purposes.
     *
     * The `ecrecover` EVM opcode allows for malleable (non-unique) signatures:
     * this function rejects them by requiring the `s` value to be in the lower
     * half order, and the `v` value to be either 27 or 28.
     *
     * NOTE: This call _does not revert_ if the signature is invalid, or
     * if the signer is otherwise unable to be retrieved. In those scenarios,
     * the zero address is returned.
     *
     * IMPORTANT: `hash` _must_ be the result of a hash operation for the
     * verification to be secure: it is possible to craft signatures that
     * recover to arbitrary addresses for non-hashed data. A safe way to ensure
     * this is by receiving a hash of the original message (which may otherwise)
     * be too long), and then calling {toEthSignedMessageHash} on it.
     */
    function recover(bytes32 hash, bytes memory signature) internal pure returns (address) {
        // Check the signature length
        if (signature.length != 65) {
            return (address(0));
        }

        // Divide the signature in r, s and v variables
        bytes32 r;
        bytes32 s;
        uint8 v;

        // ecrecover takes the signature parameters, and the only way to get them
        // currently is to use assembly.
        // solhint-disable-next-line no-inline-assembly
        assembly {
            r := mload(add(signature, 0x20))
            s := mload(add(signature, 0x40))
            v := byte(0, mload(add(signature, 0x60)))
        }

        // EIP-2 still allows signature malleability for ecrecover(). Remove this possibility and make the signature
        // unique. Appendix F in the Ethereum Yellow paper (https://ethereum.github.io/yellowpaper/paper.pdf), defines
        // the valid range for s in (281): 0 < s < secp256k1n ÷ 2 + 1, and for v in (282): v ∈ {27, 28}. Most
        // signatures from current libraries generate a unique signature with an s-value in the lower half order.
        //
        // If your library generates malleable signatures, such as s-values in the upper range, calculate a new s-value
        // with 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141 - s1 and flip v from 27 to 28 or
        // vice versa. If your library also generates signatures with 0/1 for v instead 27/28, add 27 to v to accept
        // these malleable signatures as well.
        if (uint256(s) > 0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF5D576E7357A4501DDFE92F46681B20A0) {
            return address(0);
        }

        if (v != 27 && v != 28) {
            return address(0);
        }

        // If the signature is valid (and not malleable), return the signer address
        return ecrecover(hash, v, r, s);
    }

    /* get signer address from data
    * @dev Gets an address encoded as the first argument in transaction data
    * @param b The byte array that should have an address as first argument
    * @returns a The address retrieved from the array
    */
    function getSignerAddress(bytes memory _b) internal pure returns (address _a) {
        require(_b.length >= 36, "invalid bytes");
        // solium-disable-next-line security/no-inline-assembly
        assembly {
            let mask := 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
            _a := and(mask, mload(add(_b, 36)))
            // b = {length:32}{method sig:4}{address:32}{...}
            // 36 is the offset of the first parameter of the data, if encoded properly.
            // 32 bytes for the length of the bytes array, and the first 4 bytes for the function signature.
            // 32 bytes is the length of the bytes array!!!!
        }
    }

    // get method id, first 4 bytes of data
    function getMethodId(bytes memory _b) internal pure returns (bytes4 _a) {
        require(_b.length >= 4, "invalid data");
        // solium-disable-next-line security/no-inline-assembly
        assembly {
            // 32 bytes is the length of the bytes array
            _a := mload(add(_b, 32))
        }
    }

    function checkKeyStatus(address _account, uint256 _index) internal {
        // check operation key status
        if (_index > 0) {
            require(accountStorage.getKeyStatus(_account, _index) != 1, "frozen key");
        }
    }

    // _nonce is timestamp in microsecond(1/1000000 second)
    function checkAndUpdateNonce(address _key, uint256 _nonce) internal {
        require(_nonce > keyNonce[_key], "nonce too small");
        require(SafeMath.div(_nonce, 1000000) <= now + 86400, "nonce too big"); // 86400=24*3600 seconds

        keyNonce[_key] = _nonce;
    }
}

contract Account {

    // The implementation of the proxy
    address public implementation;

    // Logic manager
    address public manager;
    
    // The enabled static calls
    mapping (bytes4 => address) public enabled;

    event EnabledStaticCall(address indexed module, bytes4 indexed method);
    event Invoked(address indexed module, address indexed target, uint indexed value, bytes data);
    event Received(uint indexed value, address indexed sender, bytes data);

    event AccountInit(address indexed account);
    event ManagerChanged(address indexed mgr);

    modifier allowAuthorizedLogicContractsCallsOnly {
        require(LogicManager(manager).isAuthorized(msg.sender), "not an authorized logic");
        _;
    }

    function init(address _manager, address _accountStorage, address[] calldata _logics, address[] calldata _keys, address[] calldata _backups)
        external
    {
        require(manager == address(0), "Account: account already initialized");
        require(_manager != address(0) && _accountStorage != address(0), "Account: address is null");
        manager = _manager;

        for (uint i = 0; i < _logics.length; i++) {
            address logic = _logics[i];
            require(LogicManager(manager).isAuthorized(logic), "must be authorized logic");

            BaseLogic(logic).initAccount(this);
        }

        AccountStorage(_accountStorage).initAccount(this, _keys, _backups);

        emit AccountInit(address(this));
    }

    function invoke(address _target, uint _value, bytes calldata _data)
        external
        allowAuthorizedLogicContractsCallsOnly
        returns (bytes memory _res)
    {
        bool success;
        // solium-disable-next-line security/no-call-value
        (success, _res) = _target.call.value(_value)(_data);
        require(success, "call to target failed");
        emit Invoked(msg.sender, _target, _value, _data);
    }

    /**
    * @dev Enables a static method by specifying the target module to which the call must be delegated.
    * @param _module The target module.
    * @param _method The static method signature.
    */
    function enableStaticCall(address _module, bytes4 _method) external allowAuthorizedLogicContractsCallsOnly {
        enabled[_method] = _module;
        emit EnabledStaticCall(_module, _method);
    }

    function changeManager(address _newMgr) external allowAuthorizedLogicContractsCallsOnly {
        require(_newMgr != address(0), "address cannot be null");
        require(_newMgr != manager, "already changed");
        manager = _newMgr;
        emit ManagerChanged(_newMgr);
    }

     /**
     * @dev This method makes it possible for the wallet to comply to interfaces expecting the wallet to
     * implement specific static methods. It delegates the static call to a target contract if the data corresponds
     * to an enabled method, or logs the call otherwise.
     */
    function() external payable {
        if(msg.data.length > 0) {
            address logic = enabled[msg.sig];
            if(logic == address(0)) {
                emit Received(msg.value, msg.sender, msg.data);
            }
            else {
                require(LogicManager(manager).isAuthorized(logic), "must be an authorized logic for static call");
                // solium-disable-next-line security/no-inline-assembly
                assembly {
                    calldatacopy(0, 0, calldatasize())
                    let result := staticcall(gas, logic, 0, calldatasize(), 0, 0)
                    returndatacopy(0, 0, returndatasize())
                    switch result
                    case 0 {revert(0, returndatasize())}
                    default {return (0, returndatasize())}
                }
            }
        }
    }
}


contract AccountStorage {

    modifier allowAccountCallsOnly(Account _account) {
        require(msg.sender == address(_account), "caller must be account");
        _;
    }

    modifier allowAuthorizedLogicContractsCallsOnly(address payable _account) {
        require(LogicManager(Account(_account).manager()).isAuthorized(msg.sender), "not an authorized logic");
        _;
    }

    struct KeyItem {
        address pubKey;
        uint256 status;
    }

    struct BackupAccount {
        address backup;
        uint256 effectiveDate;//means not effective until this timestamp
        uint256 expiryDate;//means effective until this timestamp
    }

    struct DelayItem {
        bytes32 hash;
        uint256 dueTime;
    }

    struct Proposal {
        bytes32 hash;
        address[] approval;
    }

    // account => quantity of operation keys (index >= 1)
    mapping (address => uint256) operationKeyCount;

    // account => index => KeyItem
    mapping (address => mapping(uint256 => KeyItem)) keyData;

    // account => index => backup account
    mapping (address => mapping(uint256 => BackupAccount)) backupData;

    /* account => actionId => DelayItem

       delayData applies to these 4 actions:
       changeAdminKey, changeAllOperationKeys, unfreeze, changeAdminKeyByBackup
    */
    mapping (address => mapping(bytes4 => DelayItem)) delayData;

    // client account => proposer account => proposed actionId => Proposal
    mapping (address => mapping(address => mapping(bytes4 => Proposal))) proposalData;

    // *************** keyCount ********************** //

    function getOperationKeyCount(address _account) external view returns(uint256) {
        return operationKeyCount[_account];
    }

    function increaseKeyCount(address payable _account) external allowAuthorizedLogicContractsCallsOnly(_account) {
        operationKeyCount[_account] = operationKeyCount[_account] + 1;
    }

    // *************** keyData ********************** //

    function getKeyData(address _account, uint256 _index) public view returns(address) {
        KeyItem memory item = keyData[_account][_index];
        return item.pubKey;
    }

    function setKeyData(address payable _account, uint256 _index, address _key) external allowAuthorizedLogicContractsCallsOnly(_account) {
        require(_key != address(0), "invalid _key value");
        KeyItem storage item = keyData[_account][_index];
        item.pubKey = _key;
    }

    // *************** keyStatus ********************** //

    function getKeyStatus(address _account, uint256 _index) external view returns(uint256) {
        KeyItem memory item = keyData[_account][_index];
        return item.status;
    }

    function setKeyStatus(address payable _account, uint256 _index, uint256 _status) external allowAuthorizedLogicContractsCallsOnly(_account) {
        KeyItem storage item = keyData[_account][_index];
        item.status = _status;
    }

    // *************** backupData ********************** //

    function getBackupAddress(address _account, uint256 _index) external view returns(address) {
        BackupAccount memory b = backupData[_account][_index];
        return b.backup;
    }

    function getBackupEffectiveDate(address _account, uint256 _index) external view returns(uint256) {
        BackupAccount memory b = backupData[_account][_index];
        return b.effectiveDate;
    }

    function getBackupExpiryDate(address _account, uint256 _index) external view returns(uint256) {
        BackupAccount memory b = backupData[_account][_index];
        return b.expiryDate;
    }

    function setBackup(address payable _account, uint256 _index, address _backup, uint256 _effective, uint256 _expiry)
        external
        allowAuthorizedLogicContractsCallsOnly(_account)
    {
        BackupAccount storage b = backupData[_account][_index];
        b.backup = _backup;
        b.effectiveDate = _effective;
        b.expiryDate = _expiry;
    }

    function setBackupExpiryDate(address payable _account, uint256 _index, uint256 _expiry)
        external
        allowAuthorizedLogicContractsCallsOnly(_account)
    {
        BackupAccount storage b = backupData[_account][_index];
        b.expiryDate = _expiry;
    }

    function clearBackupData(address payable _account, uint256 _index) external allowAuthorizedLogicContractsCallsOnly(_account) {
        delete backupData[_account][_index];
    }

    // *************** delayData ********************** //

    function getDelayDataHash(address payable _account, bytes4 _actionId) external view returns(bytes32) {
        DelayItem memory item = delayData[_account][_actionId];
        return item.hash;
    }

    function getDelayDataDueTime(address payable _account, bytes4 _actionId) external view returns(uint256) {
        DelayItem memory item = delayData[_account][_actionId];
        return item.dueTime;
    }

    function setDelayData(address payable _account, bytes4 _actionId, bytes32 _hash, uint256 _dueTime) external allowAuthorizedLogicContractsCallsOnly(_account) {
        DelayItem storage item = delayData[_account][_actionId];
        item.hash = _hash;
        item.dueTime = _dueTime;
    }

    function clearDelayData(address payable _account, bytes4 _actionId) external allowAuthorizedLogicContractsCallsOnly(_account) {
        delete delayData[_account][_actionId];
    }

    // *************** proposalData ********************** //

    function getProposalDataHash(address _client, address _proposer, bytes4 _actionId) external view returns(bytes32) {
        Proposal memory p = proposalData[_client][_proposer][_actionId];
        return p.hash;
    }

    function getProposalDataApproval(address _client, address _proposer, bytes4 _actionId) external view returns(address[] memory) {
        Proposal memory p = proposalData[_client][_proposer][_actionId];
        return p.approval;
    }

    function setProposalData(address payable _client, address _proposer, bytes4 _actionId, bytes32 _hash, address _approvedBackup)
        external
        allowAuthorizedLogicContractsCallsOnly(_client)
    {
        Proposal storage p = proposalData[_client][_proposer][_actionId];
        if (p.hash > 0) {
            if (p.hash == _hash) {
                for (uint256 i = 0; i < p.approval.length; i++) {
                    require(p.approval[i] != _approvedBackup, "backup already exists");
                }
                p.approval.push(_approvedBackup);
            } else {
                p.hash = _hash;
                p.approval.length = 0;
            }
        } else {
            p.hash = _hash;
            p.approval.push(_approvedBackup);
        }
    }

    function clearProposalData(address payable _client, address _proposer, bytes4 _actionId) external allowAuthorizedLogicContractsCallsOnly(_client) {
        delete proposalData[_client][_proposer][_actionId];
    }


    // *************** init ********************** //
    function initAccount(Account _account, address[] calldata _keys, address[] calldata _backups)
        external
        allowAccountCallsOnly(_account)
    {
        require(getKeyData(address(_account), 0) == address(0), "AccountStorage: account already initialized!");
        require(_keys.length > 0, "empty keys array");

        operationKeyCount[address(_account)] = _keys.length - 1;

        for (uint256 index = 0; index < _keys.length; index++) {
            address _key = _keys[index];
            require(_key != address(0), "_key cannot be 0x0");
            KeyItem storage item = keyData[address(_account)][index];
            item.pubKey = _key;
            item.status = 0;
        }

        // avoid backup duplication if _backups.length > 1
        // normally won't check duplication, in most cases only one initial backup when initialization
        if (_backups.length > 1) {
            address[] memory bkps = _backups;
            for (uint256 i = 0; i < _backups.length; i++) {
                for (uint256 j = 0; j < i; j++) {
                    require(bkps[j] != _backups[i], "duplicate backup");
                }
            }
        }

        for (uint256 index = 0; index < _backups.length; index++) {
            address _backup = _backups[index];
            require(_backup != address(0), "backup cannot be 0x0");
            require(_backup != address(_account), "cannot be backup of oneself");

            backupData[address(_account)][index] = BackupAccount(_backup, now, uint256(-1));
        }
    }
}

pragma solidity ^0.5.4;

/* The MIT License (MIT)

Copyright (c) 2016 Smart Contract Solutions, Inc.

Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:

The above copyright notice and this permission notice shall be included
in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */

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

    /**
    * @dev Multiplies two numbers, reverts on 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-solidity/pull/522
        if (a == 0) {
            return 0;
        }

        uint256 c = a * b;
        require(c / a == b);

        return c;
    }

    /**
    * @dev Integer division of two numbers truncating the quotient, reverts on division by zero.
    */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b > 0); // Solidity only automatically asserts when dividing by 0
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold

        return c;
    }

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

        return c;
    }

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

        return c;
    }

    /**
    * @dev Divides two numbers and returns the remainder (unsigned integer modulo),
    * reverts when dividing by zero.
    */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b != 0);
        return a % b;
    }

    /**
    * @dev Returns ceil(a / b).
    */
    function ceil(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a / b;
        if(a % b == 0) {
            return c;
        }
        else {
            return c + 1;
        }
    }
}

contract BaseLogic {

    bytes constant internal SIGN_HASH_PREFIX = "\x19Ethereum Signed Message:\n32";

    mapping (address => uint256) keyNonce;
    AccountStorage public accountStorage;

    modifier allowSelfCallsOnly() {
        require (msg.sender == address(this), "only internal call is allowed");
        _;
    }

    modifier allowAccountCallsOnly(Account _account) {
        require(msg.sender == address(_account), "caller must be account");
        _;
    }

    event LogicInitialised(address wallet);

    // *************** Constructor ********************** //

    constructor(AccountStorage _accountStorage) public {
        accountStorage = _accountStorage;
    }

    // *************** Initialization ********************* //

    function initAccount(Account _account) external allowAccountCallsOnly(_account){
        emit LogicInitialised(address(_account));
    }

    // *************** Getter ********************** //

    function getKeyNonce(address _key) external view returns(uint256) {
        return keyNonce[_key];
    }

    // *************** Signature ********************** //

    function getSignHash(bytes memory _data, uint256 _nonce) internal view returns(bytes32) {
        // use EIP 191
        // 0x1900 + this logic address + data + nonce of signing key
        bytes32 msgHash = keccak256(abi.encodePacked(byte(0x19), byte(0), address(this), _data, _nonce));
        bytes32 prefixedHash = keccak256(abi.encodePacked(SIGN_HASH_PREFIX, msgHash));
        return prefixedHash;
    }

    function verifySig(address _signingKey, bytes memory _signature, bytes32 _signHash) internal pure {
        require(_signingKey != address(0), "invalid signing key");
        address recoveredAddr = recover(_signHash, _signature);
        require(recoveredAddr == _signingKey, "signature verification failed");
    }

    /**
     * @dev Returns the address that signed a hashed message (`hash`) with
     * `signature`. This address can then be used for verification purposes.
     *
     * The `ecrecover` EVM opcode allows for malleable (non-unique) signatures:
     * this function rejects them by requiring the `s` value to be in the lower
     * half order, and the `v` value to be either 27 or 28.
     *
     * NOTE: This call _does not revert_ if the signature is invalid, or
     * if the signer is otherwise unable to be retrieved. In those scenarios,
     * the zero address is returned.
     *
     * IMPORTANT: `hash` _must_ be the result of a hash operation for the
     * verification to be secure: it is possible to craft signatures that
     * recover to arbitrary addresses for non-hashed data. A safe way to ensure
     * this is by receiving a hash of the original message (which may otherwise)
     * be too long), and then calling {toEthSignedMessageHash} on it.
     */
    function recover(bytes32 hash, bytes memory signature) internal pure returns (address) {
        // Check the signature length
        if (signature.length != 65) {
            return (address(0));
        }

        // Divide the signature in r, s and v variables
        bytes32 r;
        bytes32 s;
        uint8 v;

        // ecrecover takes the signature parameters, and the only way to get them
        // currently is to use assembly.
        // solhint-disable-next-line no-inline-assembly
        assembly {
            r := mload(add(signature, 0x20))
            s := mload(add(signature, 0x40))
            v := byte(0, mload(add(signature, 0x60)))
        }

        // EIP-2 still allows signature malleability for ecrecover(). Remove this possibility and make the signature
        // unique. Appendix F in the Ethereum Yellow paper (https://ethereum.github.io/yellowpaper/paper.pdf), defines
        // the valid range for s in (281): 0 < s < secp256k1n ÷ 2 + 1, and for v in (282): v ∈ {27, 28}. Most
        // signatures from current libraries generate a unique signature with an s-value in the lower half order.
        //
        // If your library generates malleable signatures, such as s-values in the upper range, calculate a new s-value
        // with 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141 - s1 and flip v from 27 to 28 or
        // vice versa. If your library also generates signatures with 0/1 for v instead 27/28, add 27 to v to accept
        // these malleable signatures as well.
        if (uint256(s) > 0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF5D576E7357A4501DDFE92F46681B20A0) {
            return address(0);
        }

        if (v != 27 && v != 28) {
            return address(0);
        }

        // If the signature is valid (and not malleable), return the signer address
        return ecrecover(hash, v, r, s);
    }

    /* get signer address from data
    * @dev Gets an address encoded as the first argument in transaction data
    * @param b The byte array that should have an address as first argument
    * @returns a The address retrieved from the array
    */
    function getSignerAddress(bytes memory _b) internal pure returns (address _a) {
        require(_b.length >= 36, "invalid bytes");
        // solium-disable-next-line security/no-inline-assembly
        assembly {
            let mask := 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
            _a := and(mask, mload(add(_b, 36)))
            // b = {length:32}{method sig:4}{address:32}{...}
            // 36 is the offset of the first parameter of the data, if encoded properly.
            // 32 bytes for the length of the bytes array, and the first 4 bytes for the function signature.
            // 32 bytes is the length of the bytes array!!!!
        }
    }

    // get method id, first 4 bytes of data
    function getMethodId(bytes memory _b) internal pure returns (bytes4 _a) {
        require(_b.length >= 4, "invalid data");
        // solium-disable-next-line security/no-inline-assembly
        assembly {
            // 32 bytes is the length of the bytes array
            _a := mload(add(_b, 32))
        }
    }

    function checkKeyStatus(address _account, uint256 _index) internal {
        // check operation key status
        if (_index > 0) {
            require(accountStorage.getKeyStatus(_account, _index) != 1, "frozen key");
        }
    }

    // _nonce is timestamp in microsecond(1/1000000 second)
    function checkAndUpdateNonce(address _key, uint256 _nonce) internal {
        require(_nonce > keyNonce[_key], "nonce too small");
        require(SafeMath.div(_nonce, 1000000) <= now + 86400, "nonce too big"); // 86400=24*3600 seconds

        keyNonce[_key] = _nonce;
    }
}

contract Owned {

    // The owner
    address public owner;

    event OwnerChanged(address indexed _newOwner);

    /**
     * @dev Throws if the sender is not the owner.
     */
    modifier onlyOwner {
        require(msg.sender == owner, "Must be owner");
        _;
    }

    constructor() public {
        owner = msg.sender;
    }

    /**
     * @dev Lets the owner transfer ownership of the contract to a new owner.
     * @param _newOwner The new owner.
     */
    function changeOwner(address _newOwner) external onlyOwner {
        require(_newOwner != address(0), "Address must not be null");
        owner = _newOwner;
        emit OwnerChanged(_newOwner);
    }
}

contract LogicManager is Owned {

    event UpdateLogicSubmitted(address indexed logic, bool value);
    event UpdateLogicCancelled(address indexed logic);
    event UpdateLogicDone(address indexed logic, bool value);

    struct pending {
        bool value;
        uint dueTime;
    }

    // The authorized logic modules
    mapping (address => bool) public authorized;

    /*
    array
    index 0: AccountLogic address
          1: TransferLogic address
          2: DualsigsLogic address
          3: DappLogic address
          4: ...
     */
    address[] public authorizedLogics;

    // updated logics and their due time of becoming effective
    mapping (address => pending) public pendingLogics;

    // pending time before updated logics take effect
    struct pendingTime {
        uint curPendingTime;
        uint nextPendingTime;
        uint dueTime;
    }

    pendingTime public pt;

    // how many authorized logics
    uint public logicCount;

    constructor(address[] memory _initialLogics, uint256 _pendingTime) public
    {
        for (uint i = 0; i < _initialLogics.length; i++) {
            address logic = _initialLogics[i];
            authorized[logic] = true;
            logicCount += 1;
        }
        authorizedLogics = _initialLogics;

        pt.curPendingTime = _pendingTime;
        pt.nextPendingTime = _pendingTime;
        pt.dueTime = now;
    }

    function submitUpdatePendingTime(uint _pendingTime) external onlyOwner {
        pt.nextPendingTime = _pendingTime;
        pt.dueTime = pt.curPendingTime + now;
    }

    function triggerUpdatePendingTime() external {
        require(pt.dueTime <= now, "too early to trigger updatePendingTime");
        pt.curPendingTime = pt.nextPendingTime;
    }

    function isAuthorized(address _logic) external view returns (bool) {
        return authorized[_logic];
    }

    function getAuthorizedLogics() external view returns (address[] memory) {
        return authorizedLogics;
    }

    function submitUpdate(address _logic, bool _value) external onlyOwner {
        pending storage p = pendingLogics[_logic];
        p.value = _value;
        p.dueTime = now + pt.curPendingTime;
        emit UpdateLogicSubmitted(_logic, _value);
    }

    function cancelUpdate(address _logic) external onlyOwner {
        delete pendingLogics[_logic];
        emit UpdateLogicCancelled(_logic);
    }

    function triggerUpdateLogic(address _logic) external {
        pending memory p = pendingLogics[_logic];
        require(p.dueTime > 0, "pending logic not found");
        require(p.dueTime <= now, "too early to trigger updateLogic");
        updateLogic(_logic, p.value);
        delete pendingLogics[_logic];
    }

    function updateLogic(address _logic, bool _value) internal {
        if (authorized[_logic] != _value) {
            if(_value) {
                logicCount += 1;
                authorized[_logic] = true;
                authorizedLogics.push(_logic);
            }
            else {
                logicCount -= 1;
                require(logicCount > 0, "must have at least one logic module");
                delete authorized[_logic];
                removeLogic(_logic);
            }
            emit UpdateLogicDone(_logic, _value);
        }
    }

    function removeLogic(address _logic) internal {
        uint len = authorizedLogics.length;
        address lastLogic = authorizedLogics[len - 1];
        if (_logic != lastLogic) {
            for (uint i = 0; i < len; i++) {
                 if (_logic == authorizedLogics[i]) {
                     authorizedLogics[i] = lastLogic;
                     break;
                 }
            }
        }
        authorizedLogics.length--;
    }
}


contract AccountStorage {

    modifier allowAccountCallsOnly(Account _account) {
        require(msg.sender == address(_account), "caller must be account");
        _;
    }

    modifier allowAuthorizedLogicContractsCallsOnly(address payable _account) {
        require(LogicManager(Account(_account).manager()).isAuthorized(msg.sender), "not an authorized logic");
        _;
    }

    struct KeyItem {
        address pubKey;
        uint256 status;
    }

    struct BackupAccount {
        address backup;
        uint256 effectiveDate;//means not effective until this timestamp
        uint256 expiryDate;//means effective until this timestamp
    }

    struct DelayItem {
        bytes32 hash;
        uint256 dueTime;
    }

    struct Proposal {
        bytes32 hash;
        address[] approval;
    }

    // account => quantity of operation keys (index >= 1)
    mapping (address => uint256) operationKeyCount;

    // account => index => KeyItem
    mapping (address => mapping(uint256 => KeyItem)) keyData;

    // account => index => backup account
    mapping (address => mapping(uint256 => BackupAccount)) backupData;

    /* account => actionId => DelayItem

       delayData applies to these 4 actions:
       changeAdminKey, changeAllOperationKeys, unfreeze, changeAdminKeyByBackup
    */
    mapping (address => mapping(bytes4 => DelayItem)) delayData;

    // client account => proposer account => proposed actionId => Proposal
    mapping (address => mapping(address => mapping(bytes4 => Proposal))) proposalData;

    // *************** keyCount ********************** //

    function getOperationKeyCount(address _account) external view returns(uint256) {
        return operationKeyCount[_account];
    }

    function increaseKeyCount(address payable _account) external allowAuthorizedLogicContractsCallsOnly(_account) {
        operationKeyCount[_account] = operationKeyCount[_account] + 1;
    }

    // *************** keyData ********************** //

    function getKeyData(address _account, uint256 _index) public view returns(address) {
        KeyItem memory item = keyData[_account][_index];
        return item.pubKey;
    }

    function setKeyData(address payable _account, uint256 _index, address _key) external allowAuthorizedLogicContractsCallsOnly(_account) {
        require(_key != address(0), "invalid _key value");
        KeyItem storage item = keyData[_account][_index];
        item.pubKey = _key;
    }

    // *************** keyStatus ********************** //

    function getKeyStatus(address _account, uint256 _index) external view returns(uint256) {
        KeyItem memory item = keyData[_account][_index];
        return item.status;
    }

    function setKeyStatus(address payable _account, uint256 _index, uint256 _status) external allowAuthorizedLogicContractsCallsOnly(_account) {
        KeyItem storage item = keyData[_account][_index];
        item.status = _status;
    }

    // *************** backupData ********************** //

    function getBackupAddress(address _account, uint256 _index) external view returns(address) {
        BackupAccount memory b = backupData[_account][_index];
        return b.backup;
    }

    function getBackupEffectiveDate(address _account, uint256 _index) external view returns(uint256) {
        BackupAccount memory b = backupData[_account][_index];
        return b.effectiveDate;
    }

    function getBackupExpiryDate(address _account, uint256 _index) external view returns(uint256) {
        BackupAccount memory b = backupData[_account][_index];
        return b.expiryDate;
    }

    function setBackup(address payable _account, uint256 _index, address _backup, uint256 _effective, uint256 _expiry)
        external
        allowAuthorizedLogicContractsCallsOnly(_account)
    {
        BackupAccount storage b = backupData[_account][_index];
        b.backup = _backup;
        b.effectiveDate = _effective;
        b.expiryDate = _expiry;
    }

    function setBackupExpiryDate(address payable _account, uint256 _index, uint256 _expiry)
        external
        allowAuthorizedLogicContractsCallsOnly(_account)
    {
        BackupAccount storage b = backupData[_account][_index];
        b.expiryDate = _expiry;
    }

    function clearBackupData(address payable _account, uint256 _index) external allowAuthorizedLogicContractsCallsOnly(_account) {
        delete backupData[_account][_index];
    }

    // *************** delayData ********************** //

    function getDelayDataHash(address payable _account, bytes4 _actionId) external view returns(bytes32) {
        DelayItem memory item = delayData[_account][_actionId];
        return item.hash;
    }

    function getDelayDataDueTime(address payable _account, bytes4 _actionId) external view returns(uint256) {
        DelayItem memory item = delayData[_account][_actionId];
        return item.dueTime;
    }

    function setDelayData(address payable _account, bytes4 _actionId, bytes32 _hash, uint256 _dueTime) external allowAuthorizedLogicContractsCallsOnly(_account) {
        DelayItem storage item = delayData[_account][_actionId];
        item.hash = _hash;
        item.dueTime = _dueTime;
    }

    function clearDelayData(address payable _account, bytes4 _actionId) external allowAuthorizedLogicContractsCallsOnly(_account) {
        delete delayData[_account][_actionId];
    }

    // *************** proposalData ********************** //

    function getProposalDataHash(address _client, address _proposer, bytes4 _actionId) external view returns(bytes32) {
        Proposal memory p = proposalData[_client][_proposer][_actionId];
        return p.hash;
    }

    function getProposalDataApproval(address _client, address _proposer, bytes4 _actionId) external view returns(address[] memory) {
        Proposal memory p = proposalData[_client][_proposer][_actionId];
        return p.approval;
    }

    function setProposalData(address payable _client, address _proposer, bytes4 _actionId, bytes32 _hash, address _approvedBackup)
        external
        allowAuthorizedLogicContractsCallsOnly(_client)
    {
        Proposal storage p = proposalData[_client][_proposer][_actionId];
        if (p.hash > 0) {
            if (p.hash == _hash) {
                for (uint256 i = 0; i < p.approval.length; i++) {
                    require(p.approval[i] != _approvedBackup, "backup already exists");
                }
                p.approval.push(_approvedBackup);
            } else {
                p.hash = _hash;
                p.approval.length = 0;
            }
        } else {
            p.hash = _hash;
            p.approval.push(_approvedBackup);
        }
    }

    function clearProposalData(address payable _client, address _proposer, bytes4 _actionId) external allowAuthorizedLogicContractsCallsOnly(_client) {
        delete proposalData[_client][_proposer][_actionId];
    }


    // *************** init ********************** //
    function initAccount(Account _account, address[] calldata _keys, address[] calldata _backups)
        external
        allowAccountCallsOnly(_account)
    {
        require(getKeyData(address(_account), 0) == address(0), "AccountStorage: account already initialized!");
        require(_keys.length > 0, "empty keys array");

        operationKeyCount[address(_account)] = _keys.length - 1;

        for (uint256 index = 0; index < _keys.length; index++) {
            address _key = _keys[index];
            require(_key != address(0), "_key cannot be 0x0");
            KeyItem storage item = keyData[address(_account)][index];
            item.pubKey = _key;
            item.status = 0;
        }

        // avoid backup duplication if _backups.length > 1
        // normally won't check duplication, in most cases only one initial backup when initialization
        if (_backups.length > 1) {
            address[] memory bkps = _backups;
            for (uint256 i = 0; i < _backups.length; i++) {
                for (uint256 j = 0; j < i; j++) {
                    require(bkps[j] != _backups[i], "duplicate backup");
                }
            }
        }

        for (uint256 index = 0; index < _backups.length; index++) {
            address _backup = _backups[index];
            require(_backup != address(0), "backup cannot be 0x0");
            require(_backup != address(_account), "cannot be backup of oneself");

            backupData[address(_account)][index] = BackupAccount(_backup, now, uint256(-1));
        }
    }
}

contract Account {

    // The implementation of the proxy
    address public implementation;

    // Logic manager
    address public manager;
    
    // The enabled static calls
    mapping (bytes4 => address) public enabled;

    event EnabledStaticCall(address indexed module, bytes4 indexed method);
    event Invoked(address indexed module, address indexed target, uint indexed value, bytes data);
    event Received(uint indexed value, address indexed sender, bytes data);

    event AccountInit(address indexed account);
    event ManagerChanged(address indexed mgr);

    modifier allowAuthorizedLogicContractsCallsOnly {
        require(LogicManager(manager).isAuthorized(msg.sender), "not an authorized logic");
        _;
    }

    function init(address _manager, address _accountStorage, address[] calldata _logics, address[] calldata _keys, address[] calldata _backups)
        external
    {
        require(manager == address(0), "Account: account already initialized");
        require(_manager != address(0) && _accountStorage != address(0), "Account: address is null");
        manager = _manager;

        for (uint i = 0; i < _logics.length; i++) {
            address logic = _logics[i];
            require(LogicManager(manager).isAuthorized(logic), "must be authorized logic");

            BaseLogic(logic).initAccount(this);
        }

        AccountStorage(_accountStorage).initAccount(this, _keys, _backups);

        emit AccountInit(address(this));
    }

    function invoke(address _target, uint _value, bytes calldata _data)
        external
        allowAuthorizedLogicContractsCallsOnly
        returns (bytes memory _res)
    {
        bool success;
        // solium-disable-next-line security/no-call-value
        (success, _res) = _target.call.value(_value)(_data);
        require(success, "call to target failed");
        emit Invoked(msg.sender, _target, _value, _data);
    }

    /**
    * @dev Enables a static method by specifying the target module to which the call must be delegated.
    * @param _module The target module.
    * @param _method The static method signature.
    */
    function enableStaticCall(address _module, bytes4 _method) external allowAuthorizedLogicContractsCallsOnly {
        enabled[_method] = _module;
        emit EnabledStaticCall(_module, _method);
    }

    function changeManager(address _newMgr) external allowAuthorizedLogicContractsCallsOnly {
        require(_newMgr != address(0), "address cannot be null");
        require(_newMgr != manager, "already changed");
        manager = _newMgr;
        emit ManagerChanged(_newMgr);
    }

     /**
     * @dev This method makes it possible for the wallet to comply to interfaces expecting the wallet to
     * implement specific static methods. It delegates the static call to a target contract if the data corresponds
     * to an enabled method, or logs the call otherwise.
     */
    function() external payable {
        if(msg.data.length > 0) {
            address logic = enabled[msg.sig];
            if(logic == address(0)) {
                emit Received(msg.value, msg.sender, msg.data);
            }
            else {
                require(LogicManager(manager).isAuthorized(logic), "must be an authorized logic for static call");
                // solium-disable-next-line security/no-inline-assembly
                assembly {
                    calldatacopy(0, 0, calldatasize())
                    let result := staticcall(gas, logic, 0, calldatasize(), 0, 0)
                    returndatacopy(0, 0, returndatasize())
                    switch result
                    case 0 {revert(0, returndatasize())}
                    default {return (0, returndatasize())}
                }
            }
        }
    }
}

pragma solidity ^0.5.4;

contract Owned {

    // The owner
    address public owner;

    event OwnerChanged(address indexed _newOwner);

    /**
     * @dev Throws if the sender is not the owner.
     */
    modifier onlyOwner {
        require(msg.sender == owner, "Must be owner");
        _;
    }

    constructor() public {
        owner = msg.sender;
    }

    /**
     * @dev Lets the owner transfer ownership of the contract to a new owner.
     * @param _newOwner The new owner.
     */
    function changeOwner(address _newOwner) external onlyOwner {
        require(_newOwner != address(0), "Address must not be null");
        owner = _newOwner;
        emit OwnerChanged(_newOwner);
    }
}

contract LogicManager is Owned {

    event UpdateLogicSubmitted(address indexed logic, bool value);
    event UpdateLogicCancelled(address indexed logic);
    event UpdateLogicDone(address indexed logic, bool value);

    struct pending {
        bool value;
        uint dueTime;
    }

    // The authorized logic modules
    mapping (address => bool) public authorized;

    /*
    array
    index 0: AccountLogic address
          1: TransferLogic address
          2: DualsigsLogic address
          3: DappLogic address
          4: ...
     */
    address[] public authorizedLogics;

    // updated logics and their due time of becoming effective
    mapping (address => pending) public pendingLogics;

    // pending time before updated logics take effect
    struct pendingTime {
        uint curPendingTime;
        uint nextPendingTime;
        uint dueTime;
    }

    pendingTime public pt;

    // how many authorized logics
    uint public logicCount;

    constructor(address[] memory _initialLogics, uint256 _pendingTime) public
    {
        for (uint i = 0; i < _initialLogics.length; i++) {
            address logic = _initialLogics[i];
            authorized[logic] = true;
            logicCount += 1;
        }
        authorizedLogics = _initialLogics;

        pt.curPendingTime = _pendingTime;
        pt.nextPendingTime = _pendingTime;
        pt.dueTime = now;
    }

    function submitUpdatePendingTime(uint _pendingTime) external onlyOwner {
        pt.nextPendingTime = _pendingTime;
        pt.dueTime = pt.curPendingTime + now;
    }

    function triggerUpdatePendingTime() external {
        require(pt.dueTime <= now, "too early to trigger updatePendingTime");
        pt.curPendingTime = pt.nextPendingTime;
    }

    function isAuthorized(address _logic) external view returns (bool) {
        return authorized[_logic];
    }

    function getAuthorizedLogics() external view returns (address[] memory) {
        return authorizedLogics;
    }

    function submitUpdate(address _logic, bool _value) external onlyOwner {
        pending storage p = pendingLogics[_logic];
        p.value = _value;
        p.dueTime = now + pt.curPendingTime;
        emit UpdateLogicSubmitted(_logic, _value);
    }

    function cancelUpdate(address _logic) external onlyOwner {
        delete pendingLogics[_logic];
        emit UpdateLogicCancelled(_logic);
    }

    function triggerUpdateLogic(address _logic) external {
        pending memory p = pendingLogics[_logic];
        require(p.dueTime > 0, "pending logic not found");
        require(p.dueTime <= now, "too early to trigger updateLogic");
        updateLogic(_logic, p.value);
        delete pendingLogics[_logic];
    }

    function updateLogic(address _logic, bool _value) internal {
        if (authorized[_logic] != _value) {
            if(_value) {
                logicCount += 1;
                authorized[_logic] = true;
                authorizedLogics.push(_logic);
            }
            else {
                logicCount -= 1;
                require(logicCount > 0, "must have at least one logic module");
                delete authorized[_logic];
                removeLogic(_logic);
            }
            emit UpdateLogicDone(_logic, _value);
        }
    }

    function removeLogic(address _logic) internal {
        uint len = authorizedLogics.length;
        address lastLogic = authorizedLogics[len - 1];
        if (_logic != lastLogic) {
            for (uint i = 0; i < len; i++) {
                 if (_logic == authorizedLogics[i]) {
                     authorizedLogics[i] = lastLogic;
                     break;
                 }
            }
        }
        authorizedLogics.length--;
    }
}