contract TexToken is ERC20("Total.Exchange", "TEX"), Ownable {
    uint256 private _cap = 80000000e18;
    uint256 private _initial_supply = 35000000e18;
    uint256 private _totalLock;

    uint256 public lockFromBlock;
    uint256 public lockToBlock;
    uint256 public transferBurnRate;
    bool public farmingEnabled;


    mapping(address => uint256) private _locks;
    mapping(address => bool) private _transferBurnExceptAddresses;
    mapping(address => uint256) private _lastUnlockBlock;

    event Lock(address indexed to, uint256 value);

    /**
     * @dev Returns the cap on the token's total supply.
     */
    function cap() public view returns (uint256) {
        return _cap;
    }

    function circulatingSupply() public view returns (uint256) {
        return totalSupply().sub(_totalLock);
    }

    function totalLock() public view returns (uint256) {
        return _totalLock;
    }

    /**
     * @dev See {ERC20-_beforeTokenTransfer}.
     *
     * Requirements:
     *
     * - minted tokens must not cause the total supply to go over the cap.
     */
    function _beforeTokenTransfer(address from, address to, uint256 amount) internal virtual override {
        super._beforeTokenTransfer(from, to, amount);

        if (from == address(0)) { // When minting tokens
            require(totalSupply().add(amount) <= _cap, "ERC20Capped: cap exceeded");
        }
    }

    /**
     * @dev Moves tokens `amount` from `sender` to `recipient`.
     *
     * This is internal function is equivalent to {transfer}, and can be used to
     * e.g. implement automatic token fees, slashing mechanisms, etc.
     *
     * Emits a {Transfer} event.
     *
     * Requirements:
     *
     * - `sender` cannot be the zero address.
     * - `recipient` cannot be the zero address.
     * - `sender` must have a balance of at least `amount`.
     */
    function _transfer(address sender, address recipient, uint256 amount) internal virtual override {
        if (transferBurnRate > 0 && _transferBurnExceptAddresses[sender] != true && _transferBurnExceptAddresses[recipient] != true && recipient != address(0)) {
            uint256 _burntAmount = amount * transferBurnRate / 100;
            // Burn transferBurnRate% from amount
            super._burn(sender, _burntAmount);
            // Recalibrate the transfer amount
            amount = amount - _burntAmount;
        }

        super._transfer(sender, recipient, amount);
        _moveDelegates(_delegates[sender], _delegates[recipient], amount);
    }

    /// @notice Creates `_amount` token to `_to`. Must only be called by the owner (MasterChef).
    function mint(address _to, uint256 _amount) public onlyOwner {
        _mint(_to, _amount);
        _moveDelegates(address(0), _delegates[_to], _amount);
    }

    function totalBalanceOf(address _holder) public view returns (uint256) {
        return _locks[_holder].add(balanceOf(_holder));
    }

    function lockOf(address _holder) public view returns (uint256) {
        return _locks[_holder];
    }

    function lastUnlockBlock(address _holder) public view returns (uint256) {
        return _lastUnlockBlock[_holder];
    }

    function lock(address _holder, uint256 _amount) public onlyOwner {
        require(_holder != address(0), "ERC20: lock to the zero address");
        require(_amount <= balanceOf(_holder), "ERC20: lock amount over blance");

        _transfer(_holder, address(this), _amount);

        _locks[_holder] = _locks[_holder].add(_amount);
        _totalLock = _totalLock.add(_amount);
        if (_lastUnlockBlock[_holder] < lockFromBlock) {
            _lastUnlockBlock[_holder] = lockFromBlock;
        }
        emit Lock(_holder, _amount);
    }

    function canUnlockAmount(address _holder) public view returns (uint256) {
        if (block.number < lockFromBlock) {
            return 0;
        }
        else if (block.number >= lockToBlock) {
            return _locks[_holder];
        }
        else {
            uint256 releaseBlock = block.number.sub(_lastUnlockBlock[_holder]);
            uint256 numberLockBlock = lockToBlock.sub(_lastUnlockBlock[_holder]);
            return _locks[_holder].mul(releaseBlock).div(numberLockBlock);
        }
    }

    function unlock() public {
        require(_locks[msg.sender] > 0, "ERC20: cannot unlock");

        uint256 amount = canUnlockAmount(msg.sender);
        // just for sure
        if (amount > balanceOf(address(this))) {
            amount = balanceOf(address(this));
        }
        _transfer(address(this), msg.sender, amount);
        _locks[msg.sender] = _locks[msg.sender].sub(amount);
        _lastUnlockBlock[msg.sender] = block.number;
        _totalLock = _totalLock.sub(amount);
    }

    // This function is for dev address migrate all balance to a multi sig address
    function transferAll(address _to) public {
        _locks[_to] = _locks[_to].add(_locks[msg.sender]);

        if (_lastUnlockBlock[_to] < lockFromBlock) {
            _lastUnlockBlock[_to] = lockFromBlock;
        }

        if (_lastUnlockBlock[_to] < _lastUnlockBlock[msg.sender]) {
            _lastUnlockBlock[_to] = _lastUnlockBlock[msg.sender];
        }

        _locks[msg.sender] = 0;
        _lastUnlockBlock[msg.sender] = 0;

        _transfer(msg.sender, _to, balanceOf(msg.sender));
    }

    // Copied and modified from YAM code:
    // https://github.com/yam-finance/yam-protocol/blob/master/contracts/token/YAMGovernanceStorage.sol
    // https://github.com/yam-finance/yam-protocol/blob/master/contracts/token/YAMGovernance.sol
    // Which is copied and modified from COMPOUND:
    // https://github.com/compound-finance/compound-protocol/blob/master/contracts/Governance/Comp.sol

    /// @dev A record of each accounts delegate
    mapping (address => address) internal _delegates;

    /// @notice A checkpoint for marking number of votes from a given block
    struct Checkpoint {
        uint32 fromBlock;
        uint256 votes;
    }

    /// @notice A record of votes checkpoints for each account, by index
    mapping (address => mapping (uint32 => Checkpoint)) public checkpoints;

    /// @notice The number of checkpoints for each account
    mapping (address => uint32) public numCheckpoints;

    /// @notice The EIP-712 typehash for the contract's domain
    bytes32 public constant DOMAIN_TYPEHASH = keccak256("EIP712Domain(string name,uint256 chainId,address verifyingContract)");

    /// @notice The EIP-712 typehash for the delegation struct used by the contract
    bytes32 public constant DELEGATION_TYPEHASH = keccak256("Delegation(address delegatee,uint256 nonce,uint256 expiry)");

    /// @notice A record of states for signing / validating signatures
    mapping (address => uint) public nonces;

      /// @notice An event thats emitted when an account changes its delegate
    event DelegateChanged(address indexed delegator, address indexed fromDelegate, address indexed toDelegate);

    /// @notice An event thats emitted when a delegate account's vote balance changes
    event DelegateVotesChanged(address indexed delegate, uint previousBalance, uint newBalance);

    /**
     * @notice Delegate votes from `msg.sender` to `delegatee`
     * @param delegator The address to get delegatee for
     */
    function delegates(address delegator)
        external
        view
        returns (address)
    {
        return _delegates[delegator];
    }

   /**
    * @notice Delegate votes from `msg.sender` to `delegatee`
    * @param delegatee The address to delegate votes to
    */
    function delegate(address delegatee) external {
        return _delegate(msg.sender, delegatee);
    }

    /**
     * @notice Delegates votes from signatory to `delegatee`
     * @param delegatee The address to delegate votes to
     * @param nonce The contract state required to match the signature
     * @param expiry The time at which to expire the signature
     * @param v The recovery byte of the signature
     * @param r Half of the ECDSA signature pair
     * @param s Half of the ECDSA signature pair
     */
    function delegateBySig(
        address delegatee,
        uint nonce,
        uint expiry,
        uint8 v,
        bytes32 r,
        bytes32 s
    )
        external
    {
        bytes32 domainSeparator = keccak256(
            abi.encode(
                DOMAIN_TYPEHASH,
                keccak256(bytes(name())),
                getChainId(),
                address(this)
            )
        );

        bytes32 structHash = keccak256(
            abi.encode(
                DELEGATION_TYPEHASH,
                delegatee,
                nonce,
                expiry
            )
        );

        bytes32 digest = keccak256(
            abi.encodePacked(
                "\x19\x01",
                domainSeparator,
                structHash
            )
        );

        address signatory = ecrecover(digest, v, r, s);
        require(signatory != address(0), "TEX::delegateBySig: invalid signature");
        require(nonce == nonces[signatory]++, "TEX::delegateBySig: invalid nonce");
        require(now <= expiry, "TEX::delegateBySig: signature expired");
        return _delegate(signatory, delegatee);
    }

    /**
     * @notice Gets the current votes balance for `account`
     * @param account The address to get votes balance
     * @return The number of current votes for `account`
     */
    function getCurrentVotes(address account)
        external
        view
        returns (uint256)
    {
        uint32 nCheckpoints = numCheckpoints[account];
        return nCheckpoints > 0 ? checkpoints[account][nCheckpoints - 1].votes : 0;
    }

    /**
     * @notice Determine the prior number of votes for an account as of a block number
     * @dev Block number must be a finalized block or else this function will revert to prevent misinformation.
     * @param account The address of the account to check
     * @param blockNumber The block number to get the vote balance at
     * @return The number of votes the account had as of the given block
     */
    function getPriorVotes(address account, uint blockNumber)
        external
        view
        returns (uint256)
    {
        require(blockNumber < block.number, "TEX::getPriorVotes: not yet determined");

        uint32 nCheckpoints = numCheckpoints[account];
        if (nCheckpoints == 0) {
            return 0;
        }

        // First check most recent balance
        if (checkpoints[account][nCheckpoints - 1].fromBlock <= blockNumber) {
            return checkpoints[account][nCheckpoints - 1].votes;
        }

        // Next check implicit zero balance
        if (checkpoints[account][0].fromBlock > blockNumber) {
            return 0;
        }

        uint32 lower = 0;
        uint32 upper = nCheckpoints - 1;
        while (upper > lower) {
            uint32 center = upper - (upper - lower) / 2; // ceil, avoiding overflow
            Checkpoint memory cp = checkpoints[account][center];
            if (cp.fromBlock == blockNumber) {
                return cp.votes;
            } else if (cp.fromBlock < blockNumber) {
                lower = center;
            } else {
                upper = center - 1;
            }
        }
        return checkpoints[account][lower].votes;
    }

    function _delegate(address delegator, address delegatee)
        internal
    {
        address currentDelegate = _delegates[delegator];
        uint256 delegatorBalance = balanceOf(delegator);
        _delegates[delegator] = delegatee;

        emit DelegateChanged(delegator, currentDelegate, delegatee);

        _moveDelegates(currentDelegate, delegatee, delegatorBalance);
    }

    function _moveDelegates(address srcRep, address dstRep, uint256 amount) internal {
        if (srcRep != dstRep && amount > 0) {
            if (srcRep != address(0)) {
                // decrease old representative
                uint32 srcRepNum = numCheckpoints[srcRep];
                uint256 srcRepOld = srcRepNum > 0 ? checkpoints[srcRep][srcRepNum - 1].votes : 0;
                uint256 srcRepNew = srcRepOld.sub(amount);
                _writeCheckpoint(srcRep, srcRepNum, srcRepOld, srcRepNew);
            }

            if (dstRep != address(0)) {
                // increase new representative
                uint32 dstRepNum = numCheckpoints[dstRep];
                uint256 dstRepOld = dstRepNum > 0 ? checkpoints[dstRep][dstRepNum - 1].votes : 0;
                uint256 dstRepNew = dstRepOld.add(amount);
                _writeCheckpoint(dstRep, dstRepNum, dstRepOld, dstRepNew);
            }
        }
    }

    function _writeCheckpoint(
        address delegatee,
        uint32 nCheckpoints,
        uint256 oldVotes,
        uint256 newVotes
    )
        internal
    {
        uint32 blockNumber = safe32(block.number, "TEX::_writeCheckpoint: block number exceeds 32 bits");

        if (nCheckpoints > 0 && checkpoints[delegatee][nCheckpoints - 1].fromBlock == blockNumber) {
            checkpoints[delegatee][nCheckpoints - 1].votes = newVotes;
        } else {
            checkpoints[delegatee][nCheckpoints] = Checkpoint(blockNumber, newVotes);
            numCheckpoints[delegatee] = nCheckpoints + 1;
        }

        emit DelegateVotesChanged(delegatee, oldVotes, newVotes);
    }

    function safe32(uint n, string memory errorMessage) internal pure returns (uint32) {
        require(n < 2**32, errorMessage);
        return uint32(n);
    }

    function getChainId() internal pure returns (uint) {
        uint256 chainId;
        assembly { chainId := chainid() }
        return chainId;
    }

    /**
     * @dev Destroys `amount` tokens from the caller.
     *
     * See {ERC20-_burn}.
     */
    function burn(uint256 amount) public virtual returns (bool) {
        _burn(_msgSender(), amount);
        return true;
    }

    /**
     * @dev Destroys `amount` tokens from `account`, deducting from the caller's
     * allowance.
     *
     * See {ERC20-_burn} and {ERC20-allowance}.
     *
     * Requirements:
     *
     * - the caller must have allowance for ``accounts``'s tokens of at least
     * `amount`.
     */
    function burnFrom(address account, uint256 amount) public virtual returns (bool) {
        uint256 decreasedAllowance = allowance(account, _msgSender()).sub(amount, "ERC20: burn amount exceeds allowance");

        _approve(account, _msgSender(), decreasedAllowance);
        _burn(account, amount);
        return true;
    }


    function setTransferBurnRate(uint256 _tranferBurnRate) public onlyOwner {
        require(_tranferBurnRate <= 100, "Burning Rate on Transfer cannot be more than 100%");
        transferBurnRate = _tranferBurnRate;
    }

    // In some circumstance, we should not burn TEX on transfer, eg: Transfer from owner to distribute bounty, from depositing to swap for liquidity
    function addTransferBurnExceptAddress(address _transferBurnExceptAddress) public onlyOwner {
        _transferBurnExceptAddresses[_transferBurnExceptAddress] = true;
    }

    function removeTransferBurnExceptAddress(address _transferBurnExceptAddress) public onlyOwner {
        delete _transferBurnExceptAddresses[_transferBurnExceptAddress];
    }

    function startFarming() public onlyOwner {
        require(farmingEnabled == false, "Farming has been started already!");
        lockFromBlock = block.number;
        lockToBlock = lockFromBlock + 2000;
        farmingEnabled = true;
    }

    constructor() public {
        lockFromBlock = 999999999;
        lockToBlock = 999999999;
        farmingEnabled = false;
        _mint(msg.sender, _initial_supply); // Mint 5000 TEX for bounty program
        _moveDelegates(address(0), msg.sender, _initial_supply);
    }
}
// TexToken with Governance.
function delegate(address delegatee) external {
    return _delegate(msg.sender, delegatee);
}

/**
 * @notice Delegate votes from `msg.sender` to `delegatee`
 * @param delegatee The address to delegate votes to
 */