pragma solidity ^0.4.13;

/**
 * @title Math
 * @dev Assorted math operations
 */

contract Math {
  function max64(uint64 a, uint64 b) internal constant returns (uint64) {
    return a >= b ? a : b;
  }

  function min64(uint64 a, uint64 b) internal constant returns (uint64) {
    return a < b ? a : b;
  }

  function max256(uint256 a, uint256 b) internal constant returns (uint256) {
    return a >= b ? a : b;
  }

  function min256(uint256 a, uint256 b) internal constant returns (uint256) {
    return a < b ? a : b;
  }
}


/**
 * @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() {
    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 {
    require(newOwner != address(0));
    owner = newOwner;
  }

}



/**
 * @title ERC20Basic
 * @dev Simpler version of ERC20 interface
 * @dev see https://github.com/ethereum/EIPs/issues/179
 */
contract ERC20Basic {
  uint256 public totalSupply;
  function balanceOf(address who) constant returns (uint256);
  function transfer(address to, uint256 value) returns (bool);
  event Transfer(address indexed from, address indexed to, uint256 value);
}


/**
 * @title SafeMath
 * @dev Math operations with safety checks that throw on error
 */
contract 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 max64(uint64 a, uint64 b) internal constant returns (uint64) {
    return a >= b ? a : b;
  }

  function min64(uint64 a, uint64 b) internal constant returns (uint64) {
    return a < b ? a : b;
  }

  function max256(uint256 a, uint256 b) internal constant returns (uint256) {
    return a >= b ? a : b;
  }

  function min256(uint256 a, uint256 b) internal constant returns (uint256) {
    return a < b ? a : b;
  }
}



/**
 * @title Basic token
 * @dev Basic version of StandardToken, with no allowances.
 */
contract BasicToken is SafeMath, ERC20Basic {

  mapping(address => uint256) balances;

  /**
  * @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, uint _value) returns (bool){
    balances[msg.sender] = sub(balances[msg.sender],_value);
    balances[_to] = add(balances[_to],_value);
    Transfer(msg.sender, _to, _value);
    return true;
  }

  /**
  * @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 (uint 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) returns (bool);
  function approve(address spender, uint256 value) returns (bool);
  event Approval(address indexed owner, address indexed spender, uint256 value);
}

/**
 * @title Standard ERC20 token
 *
 * @dev Implementation of the basic standard 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 ERC20, BasicToken {

  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 uint256 the amout of tokens to be transfered
   */
  function transferFrom(address _from, address _to, uint256 _value) returns (bool) {
    var _allowance = allowed[_from][msg.sender];

    // Check is not needed because sub(_allowance, _value) will already throw if this condition is not met
    // require (_value <= _allowance);

    balances[_to] = add(balances[_to],_value);
    balances[_from] = sub(balances[_from],_value);
    allowed[_from][msg.sender] = sub(_allowance,_value);
    Transfer(_from, _to, _value);
    return true;
  }

  /**
   * @dev Aprove the passed address to spend the specified amount of tokens on behalf 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) returns (bool) {

    // 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
    require((_value == 0) || (allowed[msg.sender][_spender] == 0));

    allowed[msg.sender][_spender] = _value;
    Approval(msg.sender, _spender, _value);
    return true;
  }

  /**
   * @dev Function to check the amount of tokens that 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 uint256 specifing the amount of tokens still available for the spender.
   */
  function allowance(address _owner, address _spender) constant returns (uint256 remaining) {
    return allowed[_owner][_spender];
  }

}



/**
 * @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 amount);
  event MintFinished();

  bool public mintingFinished = false;


  modifier canMint() {
    require(!mintingFinished);
    _;
  }

  /**
   * @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 = add(totalSupply,_amount);
    balances[_to] = add(balances[_to],_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;
  }
}




/**
 * @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 allow actions only when the contract IS paused
   */
  modifier whenNotPaused() {
    require(!paused);
    _;
  }

  /**
   * @dev modifier to allow actions only when the contract IS NOT paused
   */
  modifier whenPaused() {
    require(paused);
    _;
  }

  /**
   * @dev called by the owner to pause, triggers stopped state
   */
  function pause() onlyOwner whenNotPaused {
    paused = true;
    Pause();
  }

  /**
   * @dev called by the owner to unpause, returns to normal state
   */
  function unpause() onlyOwner whenPaused {
    paused = false;
    Unpause();
  }
}


/**
 * Pausable token
 *
 * Simple ERC20 Token example, with pausable token creation
 **/

contract PausableToken is StandardToken, Pausable {

  function transfer(address _to, uint256 _value) whenNotPaused returns (bool) {
    return super.transfer(_to, _value);
  }

  function transferFrom(address _from, address _to, uint256 _value) whenNotPaused returns (bool) {
    return super.transferFrom(_from, _to, _value);
  }
}

/**
 * @title LimitedTransferToken
 * @dev LimitedTransferToken defines the generic interface and the implementation to limit token
 * transferability for different events. It is intended to be used as a base class for other token
 * contracts.
 * LimitedTransferToken has been designed to allow for different limiting factors,
 * this can be achieved by recursively calling super.transferableTokens() until the base class is
 * hit. For example:
 *     function transferableTokens(address holder, uint64 time) constant public returns (uint256) {
 *       return min256(unlockedTokens, super.transferableTokens(holder, time));
 *     }
 * A working example is VestedToken.sol:
 * https://github.com/OpenZeppelin/zeppelin-solidity/blob/master/contracts/token/VestedToken.sol
 */

contract LimitedTransferToken is ERC20 {

  /**
   * @dev Checks whether it can transfer or otherwise throws.
   */
  modifier canTransfer(address _sender, uint256 _value) {
   require(_value <= transferableTokens(_sender, uint64(now)));
   _;
  }

  /**
   * @dev Checks modifier and allows transfer if tokens are not locked.
   * @param _to The address that will recieve the tokens.
   * @param _value The amount of tokens to be transferred.
   */
  function transfer(address _to, uint256 _value) canTransfer(msg.sender, _value) returns (bool) {
    return super.transfer(_to, _value);
  }

  /**
  * @dev Checks modifier and allows transfer if tokens are not locked.
  * @param _from The address that will send the tokens.
  * @param _to The address that will recieve the tokens.
  * @param _value The amount of tokens to be transferred.
  */
  function transferFrom(address _from, address _to, uint256 _value) canTransfer(_from, _value) returns (bool) {
    return super.transferFrom(_from, _to, _value);
  }

  /**
   * @dev Default transferable tokens function returns all tokens for a holder (no limit).
   * @dev Overwriting transferableTokens(address holder, uint64 time) is the way to provide the
   * specific logic for limiting token transferability for a holder over time.
   */
  function transferableTokens(address holder, uint64 time) constant public returns (uint256) {
    return balanceOf(holder);
  }
}

/**
 * @title Vested token
 * @dev Tokens that can be vested for a group of addresses.
 */
contract VestedToken is Math, StandardToken, LimitedTransferToken {

  uint256 MAX_GRANTS_PER_ADDRESS = 20;

  struct TokenGrant {
    address granter;     // 20 bytes
    uint256 value;       // 32 bytes
    uint64 cliff;
    uint64 vesting;
    uint64 start;        // 3 * 8 = 24 bytes
    bool revokable;
    bool burnsOnRevoke;  // 2 * 1 = 2 bits? or 2 bytes?
  } // total 78 bytes = 3 sstore per operation (32 per sstore)

  mapping (address => TokenGrant[]) public grants;

  event NewTokenGrant(address indexed from, address indexed to, uint256 value, uint256 grantId);

  /**
   * @dev Grant tokens to a specified address
   * @param _to address The address which the tokens will be granted to.
   * @param _value uint256 The amount of tokens to be granted.
   * @param _start uint64 Time of the beginning of the grant.
   * @param _cliff uint64 Time of the cliff period.
   * @param _vesting uint64 The vesting period.
   */
  function grantVestedTokens(
    address _to,
    uint256 _value,
    uint64 _start,
    uint64 _cliff,
    uint64 _vesting,
    bool _revokable,
    bool _burnsOnRevoke
  ) public {

    // Check for date inconsistencies that may cause unexpected behavior
    require(_cliff >= _start && _vesting >= _cliff);

    require(tokenGrantsCount(_to) < MAX_GRANTS_PER_ADDRESS);   // To prevent a user being spammed and have his balance locked (out of gas attack when calculating vesting).

    uint256 count = grants[_to].push(
                TokenGrant(
                  _revokable ? msg.sender : 0, // avoid storing an extra 20 bytes when it is non-revokable
                  _value,
                  _cliff,
                  _vesting,
                  _start,
                  _revokable,
                  _burnsOnRevoke
                )
              );

    transfer(_to, _value);

    NewTokenGrant(msg.sender, _to, _value, count - 1);
  }

  /**
   * @dev Revoke the grant of tokens of a specifed address.
   * @param _holder The address which will have its tokens revoked.
   * @param _grantId The id of the token grant.
   */
  function revokeTokenGrant(address _holder, uint256 _grantId) public {
    TokenGrant storage grant = grants[_holder][_grantId];

    require(grant.revokable);
    require(grant.granter == msg.sender); // Only granter can revoke it

    address receiver = grant.burnsOnRevoke ? 0xdead : msg.sender;

    uint256 nonVested = nonVestedTokens(grant, uint64(now));

    // remove grant from array
    delete grants[_holder][_grantId];
    grants[_holder][_grantId] = grants[_holder][sub(grants[_holder].length,1)];
    grants[_holder].length -= 1;

    balances[receiver] = add(balances[receiver],nonVested);
    balances[_holder] = sub(balances[_holder],nonVested);

    Transfer(_holder, receiver, nonVested);
  }


  /**
   * @dev Calculate the total amount of transferable tokens of a holder at a given time
   * @param holder address The address of the holder
   * @param time uint64 The specific time.
   * @return An uint256 representing a holder's total amount of transferable tokens.
   */
  function transferableTokens(address holder, uint64 time) constant public returns (uint256) {
    uint256 grantIndex = tokenGrantsCount(holder);

    if (grantIndex == 0) return super.transferableTokens(holder, time); // shortcut for holder without grants

    // Iterate through all the grants the holder has, and add all non-vested tokens
    uint256 nonVested = 0;
    for (uint256 i = 0; i < grantIndex; i++) {
      nonVested = add(nonVested, nonVestedTokens(grants[holder][i], time));
    }

    // Balance - totalNonVested is the amount of tokens a holder can transfer at any given time
    uint256 vestedTransferable = sub(balanceOf(holder), nonVested);

    // Return the minimum of how many vested can transfer and other value
    // in case there are other limiting transferability factors (default is balanceOf)
    return min256(vestedTransferable, super.transferableTokens(holder, time));
  }

  /**
   * @dev Check the amount of grants that an address has.
   * @param _holder The holder of the grants.
   * @return A uint256 representing the total amount of grants.
   */
  function tokenGrantsCount(address _holder) constant returns (uint256 index) {
    return grants[_holder].length;
  }

  /**
   * @dev Calculate amount of vested tokens at a specifc time.
   * @param tokens uint256 The amount of tokens grantted.
   * @param time uint64 The time to be checked
   * @param start uint64 A time representing the begining of the grant
   * @param cliff uint64 The cliff period.
   * @param vesting uint64 The vesting period.
   * @return An uint256 representing the amount of vested tokensof a specif grant.
   *  transferableTokens
   *   |                         _/--------   vestedTokens rect
   *   |                       _/
   *   |                     _/
   *   |                   _/
   *   |                 _/
   *   |                /
   *   |              .|
   *   |            .  |
   *   |          .    |
   *   |        .      |
   *   |      .        |
   *   |    .          |
   *   +===+===========+---------+----------> time
   *      Start       Clift    Vesting
   */
  function calculateVestedTokens(
    uint256 tokens,
    uint256 time,
    uint256 start,
    uint256 cliff,
    uint256 vesting) constant returns (uint256)
    {
      // Shortcuts for before cliff and after vesting cases.
      if (time < cliff) return 0;
      if (time >= vesting) return tokens;

      // Interpolate all vested tokens.
      // As before cliff the shortcut returns 0, we can use just calculate a value
      // in the vesting rect (as shown in above's figure)

      // vestedTokens = tokens * (time - start) / (vesting - start)
      uint256 vestedTokens = div(
                                    mul(
                                      tokens,
                                      sub(time, start)
                                      ),
                                    sub(vesting, start)
                                    );

      return vestedTokens;
  }

  /**
   * @dev Get all information about a specifc grant.
   * @param _holder The address which will have its tokens revoked.
   * @param _grantId The id of the token grant.
   * @return Returns all the values that represent a TokenGrant(address, value, start, cliff,
   * revokability, burnsOnRevoke, and vesting) plus the vested value at the current time.
   */
  function tokenGrant(address _holder, uint256 _grantId) constant returns (address granter, uint256 value, uint256 vested, uint64 start, uint64 cliff, uint64 vesting, bool revokable, bool burnsOnRevoke) {
    TokenGrant storage grant = grants[_holder][_grantId];

    granter = grant.granter;
    value = grant.value;
    start = grant.start;
    cliff = grant.cliff;
    vesting = grant.vesting;
    revokable = grant.revokable;
    burnsOnRevoke = grant.burnsOnRevoke;

    vested = vestedTokens(grant, uint64(now));
  }

  /**
   * @dev Get the amount of vested tokens at a specific time.
   * @param grant TokenGrant The grant to be checked.
   * @param time The time to be checked
   * @return An uint256 representing the amount of vested tokens of a specific grant at a specific time.
   */
  function vestedTokens(TokenGrant grant, uint64 time) private constant returns (uint256) {
    return calculateVestedTokens(
      grant.value,
      uint256(time),
      uint256(grant.start),
      uint256(grant.cliff),
      uint256(grant.vesting)
    );
  }

  /**
   * @dev Calculate the amount of non vested tokens at a specific time.
   * @param grant TokenGrant The grant to be checked.
   * @param time uint64 The time to be checked
   * @return An uint256 representing the amount of non vested tokens of a specifc grant on the
   * passed time frame.
   */
  function nonVestedTokens(TokenGrant grant, uint64 time) private constant returns (uint256) {
    return sub(grant.value,vestedTokens(grant, time));
  }

  /**
   * @dev Calculate the date when the holder can trasfer all its tokens
   * @param holder address The address of the holder
   * @return An uint256 representing the date of the last transferable tokens.
   */
  function lastTokenIsTransferableDate(address holder) constant public returns (uint64 date) {
    date = uint64(now);
    uint256 grantIndex = grants[holder].length;
    for (uint256 i = 0; i < grantIndex; i++) {
      date = max64(grants[holder][i].vesting, date);
    }
  }
}

/**
 * @title Burnable Token
 * @dev Token that can be irreversibly burned (destroyed).
 */

contract BurnableToken is SafeMath, StandardToken {


    event Burn(address indexed burner, uint indexed value);

    /**
     * @dev Burns a specific amount of tokens.
     * @param _value The amount of token to be burned.
     */
    function burn(uint _value)
        public
    {
        require(_value > 0);

        address burner = msg.sender;
        balances[burner] = sub(balances[burner], _value);
        totalSupply = sub(totalSupply, _value);
        Burn(burner, _value);
    }
}


/**
 * @title PLC
 * @dev PLC is ERC20 token contract, inheriting MintableToken, PausableToken,
 * VestedToken, BurnableToken contract from open zeppelin.
 */
contract PLC is MintableToken, PausableToken, VestedToken, BurnableToken {
  string public name = "PlusCoin";
  string public symbol = "PLC";
  uint256 public decimals = 18;
}