/**
 * Source Code first verified at https://etherscan.io on Thursday, August 16, 2018
 (UTC) */

pragma solidity ^0.4.24;


/**
*
*/

/**
 * Math operations with safety checks
 */
library SafeMath {
function mul(uint256 a, uint256 b) internal constant returns (uint256) {
    uint256 c = a * b;
    assert(a == 0 || c / a == b);
    return c;
  }

  function div(uint256 a, uint256 b) internal constant 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 constant returns (uint256) {
    assert(b <= a);
    return a - b;
  }

  function add(uint256 a, uint256 b) internal constant returns (uint256) {
    uint256 c = a + b;
    assert(c >= a);
    return c;
  }

  function assert(bool assertion) internal {
    if (!assertion) {
      throw;
    }
  }
}


/**
 * @title ERC20Basic
 * @dev Simpler version of ERC20 interface
 * @dev see https://github.com/ethereum/EIPs/issues/20
 */
contract ERC20Basic {
  uint256 public totalSupply;
  function balanceOf(address who) constant returns (uint256);
  function transfer(address to, uint256 value);
  event Transfer(address indexed from, address indexed to, uint256 value);
}


/**
 * @title Basic token
 * @dev Basic version of StandardToken, with no allowances.
 */
contract BasicToken is ERC20Basic {
  using SafeMath for uint256;

  mapping(address => uint256) balances;

  /**
   * @dev Fix for the ERC20 short address attack.
   */
  modifier onlyPayloadSize(uint size) {
     if(msg.data.length < size + 4) {
       throw;
     }
     _;
  }

  /**
  * @dev transfer token for a specified address
  * @param _to The address to transfer to.
  * @param _value The amount to be transferred.
  */
  function transfer(address _to, uint256 _value) onlyPayloadSize(2 * 32) {
    balances[msg.sender] = balances[msg.sender].sub(_value);
    balances[_to] = balances[_to].add(_value);
    Transfer(msg.sender, _to, _value);
  }

  /**
  * @dev Gets the balance of the specified address.
  * @param _owner The address to query the the balance of.
  * @return An uint representing the amount owned by the passed address.
  */
  function balanceOf(address _owner) constant returns (uint256 balance) {
    return balances[_owner];
  }

}


/**
 * @title ERC20 interface
 * @dev see https://github.com/ethereum/EIPs/issues/20
 */
contract ERC20 is ERC20Basic {
  function allowance(address owner, address spender) constant returns (uint256);
  function transferFrom(address from, address to, uint256 value);
  function approve(address spender, uint256 value);
  event Approval(address indexed owner, address indexed spender, uint256 value);
}


/**
 * @title Standard ERC20 token
 *
 * @dev Implemantation of the basic standart token.
 * @dev https://github.com/ethereum/EIPs/issues/20
 * @dev Based on code by FirstBlood: https://github.com/Firstbloodio/token/blob/master/smart_contract/FirstBloodToken.sol
 */
contract StandardToken is BasicToken, ERC20 {

  mapping (address => mapping (address => uint256)) allowed;


  /**
   * @dev Transfer tokens from one address to another
   * @param _from address The address which you want to send tokens from
   * @param _to address The address which you want to transfer to
   * @param _value uint the amout of tokens to be transfered
   */
  function transferFrom(address _from, address _to, uint256 _value) onlyPayloadSize(3 * 32) {
    var _allowance = allowed[_from][msg.sender];

    // Check is not needed because sub(_allowance, _value) will already throw if this condition is not met
    // if (_value > _allowance) throw;

    balances[_to] = balances[_to].add(_value);
    balances[_from] = balances[_from].sub(_value);
    allowed[_from][msg.sender] = _allowance.sub(_value);
    Transfer(_from, _to, _value);
  }

  /**
   * @dev Aprove the passed address to spend the specified amount of tokens on beahlf of msg.sender.
   * @param _spender The address which will spend the funds.
   * @param _value The amount of tokens to be spent.
   */
  function approve(address _spender, uint256 _value) {

    // To change the approve amount you first have to reduce the addresses`
    //  allowance to zero by calling `approve(_spender, 0)` if it is not
    //  already 0 to mitigate the race condition described here:
    //  https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
    if ((_value != 0) && (allowed[msg.sender][_spender] != 0)) throw;

    allowed[msg.sender][_spender] = _value;
    Approval(msg.sender, _spender, _value);
  }

  /**
   * @dev Function to check the amount of tokens than an owner allowed to a spender.
   * @param _owner address The address which owns the funds.
   * @param _spender address The address which will spend the funds.
   * @return A uint specifing the amount of tokens still avaible for the spender.
   */
  function allowance(address _owner, address _spender) constant returns (uint256 remaining) {
    return allowed[_owner][_spender];
  }

}


/**
 * @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;


  /**
   * @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() {
    if (msg.sender != owner) {
      throw;
    }
    _;
  }


  /**
   * @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 {
    if (newOwner != address(0)) {
      owner = newOwner;
    }
  }

}


/**
 * @title Mintable token
 * @dev Simple ERC20 Token example, with mintable token creation
 * @dev Issue: * https://github.com/OpenZeppelin/zeppelin-solidity/issues/120
 * Based on code by TokenMarketNet: https://github.com/TokenMarketNet/ico/blob/master/contracts/MintableToken.sol
 */

contract MintableToken is StandardToken, Ownable {
  event Mint(address indexed to, uint256 value);
  event MintFinished();

  bool public mintingFinished = false;
  uint256 public totalSupply = 0;


  modifier canMint() {
    if(mintingFinished) throw;
    _;
  }

  /**
   * @dev Function to mint tokens
   * @param _to The address that will recieve the minted tokens.
   * @param _amount The amount of tokens to mint.
   * @return A boolean that indicates if the operation was successful.
   */
  function mint(address _to, uint256 _amount) onlyOwner canMint returns (bool) {
    totalSupply = totalSupply.add(_amount);
    balances[_to] = balances[_to].add(_amount);
    Mint(_to, _amount);
    return true;
  }

  /**
   * @dev Function to stop minting new tokens.
   * @return True if the operation was successful.
   */
  function finishMinting() onlyOwner returns (bool) {
    mintingFinished = true;
    MintFinished();
    return true;
  }
}

contract TimeLockToken is Ownable, MintableToken{
  using SafeMath for uint256;
  struct LockedBalance {  
    uint256 releaseTime; 
    uint256 amount;
  }

  event MintLock(address indexed to, uint256 releaseTime, uint256 value);
  mapping(address => LockedBalance) lockedBalances;
  /**
   * @dev mint timelocked tokens
   */
  function mintTimelocked(address _to, uint256 _releaseTime, uint256 _amount)
    onlyOwner canMint returns (bool){
    require(_releaseTime > now);
    require(_amount > 0);
    LockedBalance exist = lockedBalances[_to];
    require(exist.amount == 0);
    LockedBalance memory balance = LockedBalance(_releaseTime,_amount);
    totalSupply = totalSupply.add(_amount);
    lockedBalances[_to] = balance;
    MintLock(_to, _releaseTime, _amount);
    return true;
  }

  /**
   * @dev beneficiary claims tokens held by time lock
   */
  function claim() {
    LockedBalance balance = lockedBalances[msg.sender];
    require(balance.amount > 0);
    require(now >= balance.releaseTime);
    uint256 amount = balance.amount;
    delete lockedBalances[msg.sender];
    balances[msg.sender] = balances[msg.sender].add(amount);
    Transfer(0, msg.sender, amount);
  }

  /**
  * @dev Gets the locked balance of the specified address.
  * @param _owner The address to query the the locked balance of.
  * @return An uint representing the amount owned by the passed address.
  */
  function lockedBalanceOf(address _owner) constant returns (uint256 lockedAmount) {
    return lockedBalances[_owner].amount;
  }

  /**
  * @dev Gets the releaseTime of the specified address.
  * @param _owner The address to query the the releaseTime of.
  * @return An uint representing the amount owned by the passed address.
  */
  function releaseTimeOf(address _owner) constant returns (uint256 releaseTime) {
    return lockedBalances[_owner].releaseTime;
  }
  
}


/**
 * @title PRECT Token
 */
contract PRECToken is TimeLockToken {
  using SafeMath for uint256;
  event Freeze(address indexed to, uint256 value);
  event Unfreeze(address indexed to, uint256 value);
  event Burn(address indexed to, uint256 value);
  mapping (address => uint256) public freezeOf;
  string public name = "PreCT token";
  string public symbol = "PRECT";
  uint public decimals = 8;


  function burn(address _to,uint256 _value) onlyOwner returns (bool success) {
    require(_value >= 0);
    require(balances[_to] >= _value);
    
    balances[_to] = balances[_to].sub(_value);                      // Subtract from the sender
    totalSupply = totalSupply.sub(_value);                                // Updates totalSupply
    Burn(_to, _value);
    return true;
  }
  
  function freeze(address _to,uint256 _value) onlyOwner returns (bool success) {
    require(_value >= 0);
    require(balances[_to] >= _value);
    balances[_to] = balances[_to].sub(_value);                      // Subtract from the sender
    freezeOf[_to] = freezeOf[_to].add(_value);                                // Updates totalSupply
    Freeze(_to, _value);
    return true;
  }
  
  function unfreeze(address _to,uint256 _value) onlyOwner returns (bool success) {
    require(_value >= 0);
    require(freezeOf[_to] >= _value);
    freezeOf[_to] = freezeOf[_to].sub(_value);                      // Subtract from the sender
    balances[_to] = balances[_to].add(_value);
    Unfreeze(_to, _value);
    return true;
  }

}