pragma solidity ^0.5.0;

contract MyToken{
    struct Lot{
        address payable lotOwner;
        uint tokenCount;
        uint price;
        bool isActive;
    }
    uint lotsCount = 0;
    mapping (address => uint) public tokenOwners;
    address owner;
    uint sellingRate;
    uint totalSupply;
    bool isSaleOpen = true;
    mapping (uint => Lot) public lots;

    constructor (uint _sellingRate) public{
        owner = msg.sender;
        if (_sellingRate == 1)
            sellingRate = 1;
        else
            sellingRate = _sellingRate;
    }


    function CreateLot (uint _price) public{
        require(tokenOwners[msg.sender] != 0);
        lots[lotsCount].lotOwner = msg.sender;
        lots[lotsCount].isActive = true;
        lots[lotsCount].price = _price;
        lots[lotsCount].tokenCount = tokenOwners[msg.sender];
        tokenOwners[msg.sender] = 0;
        lotsCount += 1;
    }

    function AcceptLot (uint _lotInd) public payable{
        require(msg.value / lots[_lotInd].price >= lots[_lotInd].tokenCount);
        require(lots[_lotInd].isActive == true);
        tokenOwners[msg.sender] += lots[_lotInd].tokenCount;
        (lots[_lotInd].lotOwner).transfer(msg.value);
        lots[_lotInd].isActive = false;
    }

    function RegSale (bool mode) public{
        require(msg.sender == owner);
        isSaleOpen = mode;
    }

    function ChangeSellingRate (uint _sellingRate) public{
        require(msg.sender == owner);
        if (_sellingRate == 1)
            sellingRate = 1;
        else
            sellingRate = _sellingRate;
    }

    function () external payable{
        require(isSaleOpen == true);
        require(msg.value >= sellingRate);
        tokenOwners[msg.sender] +=  msg.value / sellingRate;
        totalSupply += tokenOwners[msg.sender];
    }

    function BalanceOf (address _person) public view returns(uint){
        return tokenOwners[_person];
    }

    function TotalSupply () public view returns(uint){
        return totalSupply;
    }

    function Transfer (address _to, uint _ammount) public{
        require(msg.sender != _to);
        require(tokenOwners[msg.sender] >= _ammount);
        tokenOwners[_to] += _ammount;
        tokenOwners[msg.sender] -= _ammount;
    }
}