pragma solidity ^0.4.11;


/**
 * @title Ownable
 * @dev The Ownable contract has an owner address, and provides basic authorization control
 * functions, this simplifies the implementation of "user permissions".
 */
contract Ownable {
  address public owner;


  event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);


  /**
   * @dev The Ownable constructor sets the original `owner` of the contract to the sender
   * account.
   */
  function Ownable() {
    owner = msg.sender;
  }


  /**
   * @dev Throws if called by any account other than the owner.
   */
  modifier onlyOwner() {
    require(msg.sender == owner);
    _;
  }


  /**
   * @dev Allows the current owner to transfer control of the contract to a newOwner.
   * @param newOwner The address to transfer ownership to.
   */
  function transferOwnership(address newOwner) onlyOwner public {
    require(newOwner != address(0));
    OwnershipTransferred(owner, newOwner);
    owner = newOwner;
  }

}




/**
 * @title SafeMath
 * @dev Math operations with safety checks that throw on error
 */
library SafeMath {
  function mul(uint256 a, uint256 b) internal returns (uint256) {
    if (a == 0) {
      return 0;
    }
    uint256 c = a * b;
    assert(c / a == b);
    return c;
  }

  function div(uint256 a, uint256 b) internal returns (uint256) {
    // assert(b > 0); // Solidity automatically throws when dividing by 0
    uint256 c = a / b;
    // assert(a == b * c + a % b); // There is no case in which this doesn't hold
    return c;
  }

  function sub(uint256 a, uint256 b) internal returns (uint256) {
    assert(b <= a);
    return a - b;
  }

  function add(uint256 a, uint256 b) internal returns (uint256) {
    uint256 c = a + b;
    assert(c >= a);
    return c;
  }
}







/**
 * @title Pausable
 * @dev Base contract which allows children to implement an emergency stop mechanism.
 */
contract Pausable is Ownable {
  event Pause();
  event Unpause();

  bool public paused = false;


  /**
   * @dev Modifier to make a function callable only when the contract is not paused.
   */
  modifier whenNotPaused() {
    require(!paused);
    _;
  }

  /**
   * @dev Modifier to make a function callable only when the contract is paused.
   */
  modifier whenPaused() {
    require(paused);
    _;
  }

  modifier stopInEmergency {
    if (paused) {
      throw;
    }
    _;
  }

  /**
   * @dev called by the owner to pause, triggers stopped state
   */
  function pause() onlyOwner whenNotPaused public {
    paused = true;
    Pause();
  }

  /**
   * @dev called by the owner to unpause, returns to normal state
   */
  function unpause() onlyOwner whenPaused public {
    paused = false;
    Unpause();
  }
}


contract Token {
    uint256 public totalSupply;
    function balanceOf(address _owner) constant returns (uint256 balance);
    function transfer(address _to, uint256 _value) returns (bool success);
    function transferFrom(address _from, address _to, uint256 _value) returns (bool success);
    function approve(address _spender, uint256 _value) returns (bool success);
    function allowance(address _owner, address _spender) constant returns (uint256 remaining);
    event Transfer(address indexed _from, address indexed _to, uint256 _value);
    event Approval(address indexed _owner, address indexed _spender, uint256 _value);
}


/*  ERC 20 token */
contract CevacToken is Token,Ownable {
    string public constant name = "Cevac Token";
    string public constant symbol = "CEVAC";
    uint256 public constant decimals = 8;
    string public version = "1.0";
    uint public valueToBeSent = 1;

    bool public finalizedICO = false;

    uint256 public ethraised;
    uint256 public btcraised;
    uint256 public usdraised;


    uint256 public numberOfBackers;

    bool public istransferAllowed;

    uint256 public constant CevacFund = 36 * (10**8) * 10**decimals; 
    uint256 public fundingStartBlock; //start = 1533081600 //1 august 2018
    uint256 public fundingEndBlock; ///end = 1585612800 ///31 march 2020
    uint256 public tokenCreationMax= 1836 * (10**6) * 10**decimals;//TODO
    mapping (address => bool) public ownership;
    uint256 public minCapUSD = 210000000;
    uint256 public maxCapUSD = 540000000;

    address public ownerWallet = 0x46F525e84B5C59CA63a5E1503fa82dF98fBb026b;


    mapping (address => uint256) public balances;
    mapping (address => mapping (address => uint256)) public allowed;

    modifier onlyPayloadSize(uint size) {
        require(msg.data.length >= size + 4);
        _;
    }

    function transfer(address _to, uint256 _value) onlyPayloadSize(2 * 32) returns (bool success) {
      if(!istransferAllowed) throw;
      if (balances[msg.sender] >= _value && _value > 0) {
        balances[msg.sender] -= _value;
        balances[_to] += _value;
        Transfer(msg.sender, _to, _value);
        return true;
      } else {
        return false;
      }
    }

    function burnTokens(uint256 _value) public{
        require(balances[msg.sender]>=_value);
        balances[msg.sender] = SafeMath.sub(balances[msg.sender],_value);
        totalSupply =SafeMath.sub(totalSupply,_value);
    }


    //this is the default constructor
    function CevacToken(uint256 _fundingStartBlock, uint256 _fundingEndBlock){
        balances[ownerWallet] = CevacFund;
        totalSupply = CevacFund;
        fundingStartBlock = _fundingStartBlock;
        fundingEndBlock = _fundingEndBlock;
       

    }

    ///change the funding end block
    function changeEndBlock(uint256 _newFundingEndBlock) public onlyOwner{
        fundingEndBlock = _newFundingEndBlock;
    }

    ///change the funding start block
    function changeStartBlock(uint256 _newFundingStartBlock) public onlyOwner{
        fundingStartBlock = _newFundingStartBlock;
    }

    ///the Min Cap USD 
    ///function too chage the miin cap usd
    function changeMinCapUSD(uint256 _newMinCap) public onlyOwner{
        minCapUSD = _newMinCap;
    }


    ///fucntion to change the max cap usd
    function changeMaxCapUSD(uint256 _newMaxCap) public onlyOwner{
        maxCapUSD = _newMaxCap;
    }


    function transferFrom(address _from, address _to, uint256 _value) onlyPayloadSize(3 * 32) returns (bool success) {
      if(!istransferAllowed) throw;
      if (balances[_from] >= _value && allowed[_from][msg.sender] >= _value && _value > 0) {
        balances[_to] += _value;
        balances[_from] -= _value;
        allowed[_from][msg.sender] -= _value;
        Transfer(_from, _to, _value);
        return true;
      } else {
        return false;
      }
    }


    function addToBalances(address _person,uint256 value) {
        if(!ownership[msg.sender]) throw;
        balances[ownerWallet] = SafeMath.sub(balances[ownerWallet],value);
        balances[_person] = SafeMath.add(balances[_person],value);
        Transfer(address(this), _person, value);
    }

    /**
    This is to add the token sale platform ownership to send tokens
    **/
    function addToOwnership(address owners) onlyOwner{
        ownership[owners] = true;
    }

    /**
    To be done after killing the old conttract else conflicts can take place
    This is to remove the token sale platform ownership to send tokens
    **/
    function removeFromOwnership(address owners) onlyOwner{
        ownership[owners] = false;
    }

    function balanceOf(address _owner) view returns (uint256 balance) {
        return balances[_owner];
    }

    function approve(address _spender, uint256 _value) onlyPayloadSize(2 * 32) returns (bool success) {
        require((_value == 0) || (allowed[msg.sender][_spender] == 0));
        allowed[msg.sender][_spender] = _value;
        Approval(msg.sender, _spender, _value);
        return true;
    }

    function allowance(address _owner, address _spender) view returns (uint256 remaining) {
      return allowed[_owner][_spender];
    }

    function increaseEthRaised(uint256 value){
        require(ownership[msg.sender]);
        ethraised+=value;
    }

    function increaseBTCRaised(uint256 value){
        require(ownership[msg.sender]);
        btcraised+=value;
    }

    function increaseUSDRaised(uint256 value){
        require(ownership[msg.sender]);
        usdraised+=value;
    }

    function finalizeICO() public{
    require(ownership[msg.sender]);
    require(usdraised>=minCapUSD);
    finalizedICO = true;
    istransferAllowed = true;
    }

    function enableTransfers() public onlyOwner{
        istransferAllowed = true;
    }

    function disableTransfers() public onlyOwner{
        istransferAllowed = false;
    }

    //functiion to force finalize the ICO by the owner no checks called here
    function finalizeICOOwner() onlyOwner{
        finalizedICO = true;
        istransferAllowed = true;
    }

    function isValid() returns(bool){
        if(now>=fundingStartBlock && now<fundingEndBlock ){
            return true;
        }else{
            return false;
        }
        if(usdraised>maxCapUSD) throw;
    }

    ///do not allow payments on this address

    function() payable{
        throw;
    }
}