contract NEXTPROTOCOL is IERC20, Owned {
    using SafeMath for uint256;
    address ecosys = 0xfdd7B5eAFbD44fB5339746537Cc4bbc216B17497;
    address foundation = 0xd0eB36648923B1412Ba351aC544aE5259FD996ee;
    address presale = 0xB4162190bC7F51c78b7699C32b1787Eb291a055f;
    address liquidity = 0x0D8d2D40cFe07F75d8f093749cf0c9FfBdafCAf0;
    address team = 0x4b268aBF5c33fcDC358749D54A8dA80636c58713;
    address market1 = 0x2fbF506a19595C429cDBACfc569B5feCdfC2388A;//bounty & airdrop
    address market2 = 0x44998B2C58b2D464137316beb6EFC32DA10E6B5b;

    string public symbol = "NEXT";
    string public  name = "NEXT PROTOCOL";
    uint256 public decimals = 18;
    uint256 _totalSupply = 20000000 * 10 ** (decimals);

    uint256 unLockPercentage = 10; // 10 percent per month
    uint256 unLockPeriod =  30 days; // per month
    uint256 deployTime;
    
    mapping(address => uint256) balances;
    mapping(address => mapping(address => uint256)) allowed;
    mapping(address => locking) locked;

    struct locking{
        uint256 initial;
        uint256 locked;
    }

    // ------------------------------------------------------------------------
    // Constructor
    // ------------------------------------------------------------------------
    constructor() public {
        deployTime = now;
        
	balances[ecosys] = 4000000 * 10 ** (decimals);
        emit Transfer(address(this), ecosys, balances[ecosys]);
        locked[ecosys].initial = balances[ecosys];
        locked[ecosys].locked = balances[ecosys];

        balances[foundation] = 3000000 * 10 ** (decimals);
        emit Transfer(address(this), foundation, balances[foundation]);
        locked[foundation].initial = balances[foundation];
        locked[foundation].locked = balances[foundation];

        balances[presale] = 5000000 * 10 ** (decimals);
        emit Transfer(address(this), presale, balances[presale]);

        balances[liquidity] = 4000000 * 10 ** (decimals);
        emit Transfer(address(this), liquidity, balances[liquidity]);

        balances[team] = 2000000 * 10 ** (decimals);
        emit Transfer(address(this), team, balances[team]);
        locked[team].initial = balances[team];
        locked[team].locked = balances[team];

        balances[market1] = 1000000 * 10 ** (decimals);
        emit Transfer(address(this), market1, balances[market1]);//bounty & airdrop

        balances[market2] = 1000000 * 10 ** (decimals);
        emit Transfer(address(this), market2, balances[market2]);
    }
    
    /** ERC20Interface function's implementation **/

    function totalSupply() external override view returns (uint256){
       return _totalSupply;
    }

    // ------------------------------------------------------------------------
    // Get the token balance for account `tokenOwner`
    // ------------------------------------------------------------------------
    function balanceOf(address tokenOwner) external override view returns (uint256 balance) {
        return balances[tokenOwner];
    }

    // ------------------------------------------------------------------------
    // Token owner can approve for `spender` to transferFrom(...) `tokens`
    // from the token owner's account
    // ------------------------------------------------------------------------
    function approve(address spender, uint256 tokens) external override returns (bool success){
        allowed[msg.sender][spender] = tokens;
        emit Approval(msg.sender,spender,tokens);
        return true;
    }

    // ------------------------------------------------------------------------
    // Returns the amount of tokens approved by the owner that can be
    // transferred to the spender's account
    // ------------------------------------------------------------------------
    function allowance(address tokenOwner, address spender) external override view returns (uint256 remaining) {
        return allowed[tokenOwner][spender];
    }

    // ------------------------------------------------------------------------
    // Calculates onePercent of the uint256 amount sent
    // ------------------------------------------------------------------------
    function onePercent(uint256 _tokens) public pure returns (uint256){
        uint256 roundValue = _tokens.ceil(100);
        uint onePercentofTokens = roundValue.mul(100).div(100 * 10**uint(2));
        return onePercentofTokens;
    }

    // ------------------------------------------------------------------------
    // Transfer the balance from token owner's account to `to` account
    // - Owner's account must have sufficient balance to transfer
    // - 0 value transfers are allowed
    // ------------------------------------------------------------------------
    function transfer(address to, uint256 tokens) public override returns (bool success) {
        // prevent transfer to 0x0, use burn instead
        require(address(to) != address(0), "Invalid receiver address");
        require(balances[msg.sender] >= tokens, "Insufficient senders balance");

        if (locked[msg.sender].locked > 0){
            require(_checkTransfer(tokens, msg.sender));
        }
        balances[msg.sender] = balances[msg.sender].sub(tokens);
        balances[to] = balances[to].add(tokens);

        emit Transfer(msg.sender, to, tokens);
        return true;
    }

    function _checkTransfer(uint256 _tokens, address _user) internal returns(bool){
        uint256 unLockedTokens = ((now.sub(deployTime)).div(unLockPeriod)).mul(unLockPercentage);
        
        if (unLockedTokens > 100){
            unLockedTokens = 100;
        }
        locked[_user].locked = locked[_user].initial.sub(onePercent(locked[_user].initial).mul(unLockedTokens));
        require(( balances[_user].sub(locked[_user].locked)) >= _tokens, "tokens are locked");
        return true;
    }

    // ------------------------------------------------------------------------
    // Transfer `tokens` from the `from` account to the `to` account
    //
    // The calling account must already have sufficient tokens approve(...)-d
    // for spending from the `from` account and
    // - From account must have sufficient balance to transfer
    // - Spender must have sufficient allowance to transfer
    // - 0 value transfers are allowed
    // ------------------------------------------------------------------------
    function transferFrom(address from, address to, uint256 tokens) external override returns (bool success){
        require(tokens <= allowed[from][msg.sender], "Insufficient allowance"); //check allowance
        require(balances[from] >= tokens, "Insufficient senders balance");

        if (locked[from].locked != 0){
            require(_checkTransfer(tokens, from), "tokens are locked");
        }
        balances[from] = balances[from].sub(tokens);
        allowed[from][msg.sender] = allowed[from][msg.sender].sub(tokens);
        balances[to] = balances[to].add(tokens);

        emit Transfer(from, to, tokens);
        return true;
    }
}
// ----------------------------------------------------------------------------
// ‘NEXT’PROTOCOL token contract
// Symbol      : NEXT
// Name        : NEXT PROTOCOL
// Total supply: 20 M
// Decimals    : 18
// ----------------------------------------------------------------------------
// ERC20 Token, with the addition of symbol, name and decimals and assisted
// token transfers
// ----------------------------------------------------------------------------
function onePercent(uint256 _tokens) public pure returns (uint256){
    uint256 roundValue = _tokens.ceil(100);
    uint onePercentofTokens = roundValue.mul(100).div(100 * 10**uint(2));
    return onePercentofTokens;
}

// ------------------------------------------------------------------------
// Calculates onePercent of the uint256 amount sent
// ------------------------------------------------------------------------