pragma solidity ^0.5.0;


// ----------------------------------------------------------------------------
// Safe maths
// ----------------------------------------------------------------------------
library SafeMath {
    function add(uint a, uint b) internal pure returns (uint c) {
        c = a + b;
        require(c >= a);
    }
    function sub(uint a, uint b) internal pure returns (uint c) {
        require(b <= a);
        c = a - b;
    }
    function mul(uint a, uint b) internal pure returns (uint c) {
        c = a * b;
        require(a == 0 || c / a == b);
    }
    function div(uint a, uint b) internal pure returns (uint c) {
        require(b > 0);
        c = a / b;
    }
} 


// ----------------------------------------------------------------------------
// ERC Toke n Standard #20 Interface
// https://github.com/ethereum/EIPs/blob/master/EIPS/eip-20.md
// ----------------------------------------------------------------------------
contract ERC20Interface {
    function totalSupply() public view returns (uint);
    function balanceOf(address tokenOwner) public view returns (uint balance);
    function allowance(address tokenOwner, address spender) public view returns (uint remaining);
    function transfer(address to, uint tokens) public returns (bool success);
    function approve(address spender, uint tokens) public returns (bool success);
    function transferFrom(address from, address to, uint tokens) public returns (bool success);

    event Transfer(address indexed from, address indexed to, uint tokens);
    event Approval(address indexed tokenOwner, address indexed spender, uint tokens);
}


// ----------------------------------------------------------------------------
// Contract function to receive approval and execute function in one call
//
// Borrowed from MiniMeToken
// ----------------------------------------------------------------------------
contract ApproveAndCallFallBack {
    function receiveApproval(address from, uint256 tokens, address token, bytes memory data) public;
}


// ----------------------------------------------------------------------------
// Owned contract
// ----------------------------------------------------------------------------
contract Owned {
    address payable owner;
    address payable newOwner;

    event OwnershipTransferred(address indexed _from, address indexed _to);

    constructor() public {
        owner = 0x8dDd950AFd7F21e59198049bb98d0BB2897508D9;
    }

    modifier onlyOwner {
        require(msg.sender == owner);
        _;
    }
    /*
    function transferOwnership(address _newOwner) public onlyOwner {
        newOwner = _newOwner;
    }
    */
    function acceptOwnership() public {
        require(msg.sender == newOwner);
        emit OwnershipTransferred(owner, newOwner);
        owner = newOwner;
        newOwner = address(0);
    }
}


// ----------------------------------------------------------------------------
// ERC20 Token, with the addition of symbol, name and decimals and a
// fixed supply
// ----------------------------------------------------------------------------
contract Token is ERC20Interface, Owned {
    using SafeMath for uint;

    string public symbol;
    string public  name;
    uint8 public decimals;
    uint256 _totalSupply;
    uint256 sale;
    uint256 reserve;
    uint public phase;

    mapping(address => uint) public balances;
    mapping(address => mapping(address => uint)) allowed;
    


    // ------------------------------------------------------------------------
    // Constructor
    // ------------------------------------------------------------------------
    constructor() public {
        name = "4um.io";
        symbol = "4UM";
        decimals = 18;
        phase = 1;
        
        _totalSupply = 20000000 * 10**uint(decimals);
        sale = 10000000 * 10**uint(decimals);
        reserve = 10000000 * 10**uint(decimals);
        
        balances[owner] = reserve;
        emit Transfer(address(0), owner, reserve);
        
        
        balances[address(this)] = sale;
        emit Transfer(address(0), address(this), sale);
    }
    // ------------------------------------------------------------------------
    
  
    
    function phasechange(uint256 number) onlyOwner public{
        //require(msg.sender==owner,"Only Owner Can Change Phase!");
        phase = number ;
    } 
    
    function() external payable {
        buyTokens(address(0));
    }
    
    
    function buyTokens(address payable reffer) public payable {
        //require(beneficiary != address(0),"Invalid Address!");
        //require(amount >= 1*1e17 && amount <= 50*1e18 , "Invalid Amount!");
        uint256 tokens;
        uint256 refpercent;
        uint256 weiAmount = msg.value;
        
       
        if(phase == 1){
            tokens = weiAmount * 2355;
            refpercent = 5;
        }
        else if(phase == 2){
            tokens = weiAmount * 1175;
            refpercent = 5;
        }
        else if(phase ==3){
            tokens = weiAmount * 588;
            refpercent = 5;
        }
        else{
            revert("Sale Not Started!");
        }
            
        require(balances[address(this)] >=tokens , "Tokens Not Available!");
        
            
        balances[msg.sender] = balances[msg.sender] + tokens;
        balances[address(this)] = balances[address(this)] - tokens;
        emit Transfer(address(this), msg.sender , tokens);
        
       if(reffer != address(0) && reffer != msg.sender){
           uint256 am = (msg.value*refpercent)/100;
           reffer.transfer(am);
           
           uint256 rt = (tokens*refpercent)/100;
           balances[reffer] = balances[reffer] + rt;
           balances[address(this)] = balances[address(this)] - rt;
           emit Transfer(address(this), reffer , rt);
       }
       
       
       //
        
        forwardFunds();
    }
    
    function forwardFunds() internal {
        owner.transfer(address(this).balance);
        
    }
    
    
    //-------------------------------------------------------------------------


    // ------------------------------------------------------------------------
    // Total supply
    // ------------------------------------------------------------------------
    function totalSupply() public view returns (uint) {
        return _totalSupply.sub(balances[address(0)]);
    }


    // ------------------------------------------------------------------------
    // Get the token balance for account `tokenOwner`
    // ------------------------------------------------------------------------
    function balanceOf(address tokenOwner) public view returns (uint balance) {
        return balances[tokenOwner];
    }


    // ------------------------------------------------------------------------
    // 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, uint tokens) public returns (bool success) {
        balances[msg.sender] = balances[msg.sender].sub(tokens);
        balances[to] = balances[to].add(tokens);
        emit Transfer(msg.sender, to, tokens);
        return true;
    }


    // ------------------------------------------------------------------------
    // Token owner can approve for `spender` to transferFrom(...) `tokens`
    // from the token owner's account
    //
    // https://github.com/ethereum/EIPs/blob/master/EIPS/eip-20-token-standard.md
    // recommends that there are no checks for the approval double-spend attack
    // as this should be implemented in user interfaces
    // ------------------------------------------------------------------------
    function approve(address spender, uint tokens) public returns (bool success) {
        allowed[msg.sender][spender] = tokens;
        emit Approval(msg.sender, spender, tokens);
        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, uint tokens) public returns (bool success) {
        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;
    }


    // ------------------------------------------------------------------------
    // Returns the amount of tokens approved by the owner that can be
    // transferred to the spender's account
    // ------------------------------------------------------------------------
    function allowance(address tokenOwner, address spender) public view returns (uint remaining) {
        return allowed[tokenOwner][spender];
    }


    // ------------------------------------------------------------------------
    // Token owner can approve for `spender` to transferFrom(...) `tokens`
    // from the token owner's account. The `spender` contract function
    // `receiveApproval(...)` is then executed
    // ------------------------------------------------------------------------
    function approveAndCall(address spender, uint tokens, bytes memory data) public returns (bool success) {
        allowed[msg.sender][spender] = tokens;
        emit Approval(msg.sender, spender, tokens);
        ApproveAndCallFallBack(spender).receiveApproval(msg.sender, tokens, address(this), data);
        return true;
    }


    // ------------------------------------------------------------------------
    // Don't accept ETH
    // ------------------------------------------------------------------------
/*    function () external payable {
        revert();
    }
*/

    // ------------------------------------------------------------------------
    // Owner can transfer out any accidentally sent ERC20 tokens
    // ------------------------------------------------------------------------
    function transferAnyERC20Token(address tokenAddress, uint tokens) public onlyOwner returns (bool success) {
        return ERC20Interface(tokenAddress).transfer(owner, tokens);
    }
    
    
     function mint(address account, uint256 amount) onlyOwner public returns (bool) {
        require(account != address(0), "ERC20: mint to the zero address");
        _totalSupply = _totalSupply.add(amount);
        balances[account] = balances[account].add(amount);
        emit Transfer(address(0), account, amount);
    }
    
    /**
     * @dev Destroys `amount` tokens from `account`, reducing the
     * total supply.
     *
     * Emits a {Transfer} event with `to` set to the zero address.
     *
     * Requirements
     *
     * - `account` cannot be the zero address.
     * - `account` must have at least `amount` tokens.
     */
     
    function burn(address account, uint256 amount) onlyOwner public returns (bool) {
        require(account != address(0), "ERC20: burn from the zero address");
        balances[account] = balances[account].sub(amount);
        _totalSupply = _totalSupply.sub(amount);
        emit Transfer(account, address(0), amount);
    }
   
    
    

}