/**
 * Source Code first verified at https://etherscan.io on Sunday, March 24, 2019
 (UTC) */

pragma solidity 0.4.24;

library SafeMath {

  function mul(uint256 a, uint256 b) internal pure returns (uint256 c) {
    if (a == 0) {
      return 0;
    }

    c = a * b;
    assert(c / a == b);
    return c;
  }

  function div(uint256 a, uint256 b) internal pure returns (uint256) {
    return a / b;
  }

  function sub(uint256 a, uint256 b) internal pure returns (uint256) {
    assert(b <= a);
    return a - b;
  }

  function add(uint256 a, uint256 b) internal pure returns (uint256 c) {
    c = a + b;
    assert(c >= a);
    return c;
  }
}

contract customIcoToken{
    using SafeMath for uint256;

    /* Events */
    event Transfer(address indexed from, address indexed to, uint256 value);
    event Approval(address indexed owner, address indexed spender, uint256 value);
    event LogRefund(address indexed _to, uint256 _value);
    event CreateToken(address indexed _to, uint256 _value);

    // metadata
    string public name;
    string public symbol;
    uint256 public decimals;

    // contracts
    address public ethFundDeposit;      // deposit address for ETH
    address public tokenFundDeposit;

    // crowdsale parameters
    bool public isFinalized;              // switched to true in operational state
    uint256 public fundingStartBlock;
    uint256 public fundingEndBlock;
    uint256 public tokenFund;
    uint256 public tokenExchangeRate;
    uint256 public tokenCreationCap;
    uint256 public tokenCreationMin;

    /* Storage */
    mapping(address => uint256) balances;
    mapping (address => mapping (address => uint256)) internal allowed;

    uint256 public totalSupply;

    /* Getters */
    function totalSupply() public view returns (uint256) {
        return totalSupply;
    }

    function balanceOf(address _owner) public view returns (uint256 balance) {
        return balances[_owner];
    }

    function allowance(address _owner, address _spender) public view returns (uint256) {
        return allowed[_owner][_spender];
    }

    /* Methods */
    function transferFrom(address _from, address _to, uint256 _value) public returns (bool) {
    require(_to != address(0));
    require(_value <= balances[_from]);
    require(_value <= allowed[_from][msg.sender]);

    balances[_from] = balances[_from].sub(_value);
    balances[_to] = balances[_to].add(_value);
    allowed[_from][msg.sender] = allowed[_from][msg.sender].sub(_value);
    emit Transfer(_from, _to, _value);
    return true;
    }

    function approve(address _spender, uint256 _value) public returns (bool) {
        allowed[msg.sender][_spender] = _value;
        emit Approval(msg.sender, _spender, _value);
        return true;
    }

    function increaseApproval(address _spender, uint _addedValue) public returns (bool) {
        allowed[msg.sender][_spender] = allowed[msg.sender][_spender].add(_addedValue);
        emit Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
        return true;
    }

    function decreaseApproval(address _spender, uint _subtractedValue) public returns (bool) {
        uint oldValue = allowed[msg.sender][_spender];
        if (_subtractedValue > oldValue) {
            allowed[msg.sender][_spender] = 0;
        } else {
            allowed[msg.sender][_spender] = oldValue.sub(_subtractedValue);
        }
        emit Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
        return true;
  }

    function transfer(address _to, uint256 _value) public returns (bool) {
    require(_to != address(0));
    require(_value <= balances[msg.sender]);

    // SafeMath.sub will throw if there is not enough balance.
    balances[msg.sender] = balances[msg.sender].sub(_value);
    balances[_to] = balances[_to].add(_value);
    emit Transfer(msg.sender, _to, _value);
    return true;
    }

    /* Crowdsale methods */

    /// @dev Accepts ether and creates new tokens.
    function createTokens() payable external {
      require (isFinalized == false);
      require(block.number > fundingStartBlock);
      require(block.number < fundingEndBlock);
      require(msg.value > 0);

      uint256 tokens = msg.value.mul(tokenExchangeRate);
      uint256 checkedSupply = totalSupply.add(tokens);

      // return money if something goes wrong
      require(tokenCreationCap >= checkedSupply); // odd fractions won't be found

      totalSupply = checkedSupply;
      balances[msg.sender] += tokens;  // safeAdd not needed; bad semantics to use here
      emit CreateToken(msg.sender, tokens);  // logs token creation
    }

    /// @dev Ends the funding period and sends the ETH home
    function finalize() external {
      require(isFinalized == false);
      require(msg.sender == ethFundDeposit);
      require(totalSupply > tokenCreationMin); // have to sell minimum to move to operational
      require(block.number > fundingEndBlock || totalSupply == tokenCreationCap);
      // move to operational
      isFinalized = true;
      assert(ethFundDeposit.send(address(this).balance)); // send the eth
    }

    /// @dev Allows contributors to recover their ether in the case of a failed funding campaign.
    function refund() external {
      require(isFinalized == false);                       // prevents refund if operational
      require(block.number > fundingEndBlock); // prevents refund until sale period is over
      require(totalSupply < tokenCreationMin); // no refunds if we sold enough
      require(msg.sender != tokenFundDeposit);    // team not entitled to a refund
      uint256 tokenVal = balances[msg.sender];
      require(tokenVal > 0);
      balances[msg.sender] = 0;
      totalSupply = totalSupply.sub(tokenVal); // extra safe
      uint256 ethVal = tokenVal / tokenExchangeRate; // should be safe; previous throws covers edges
      emit LogRefund(msg.sender, ethVal); // log it
      assert(msg.sender.send(ethVal)); // if you're using a contract; make sure it works with .send gas limits
    }

    constructor(
        string _name,
        string _symbol,
        uint8 _decimals,
        address _ethFundDeposit,
        address _tokenFundDeposit,
        uint256 _tokenFund,
        uint256 _tokenExchangeRate,
        uint256 _tokenCreationCap,
        uint256 _tokenCreationMin,
        uint256 _fundingStartBlock,
        uint256 _fundingEndBlock) public
    {
      name = _name;
      symbol = _symbol;
      decimals = _decimals;
      isFinalized = false;                   //controls pre through crowdsale state
      ethFundDeposit = _ethFundDeposit;
      tokenFundDeposit = _tokenFundDeposit;
      tokenFund = _tokenFund*10**decimals;
      tokenExchangeRate = _tokenExchangeRate;
      tokenCreationCap = _tokenCreationCap*10**decimals;
      tokenCreationMin = _tokenCreationMin*10**decimals;
      fundingStartBlock = _fundingStartBlock;
      fundingEndBlock = _fundingEndBlock;
      totalSupply = tokenFund;
      balances[tokenFundDeposit] = tokenFund;
      emit CreateToken(tokenFundDeposit, tokenFund);
    }
}