pragma solidity ^0.4.21;

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) {
    // 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 a / b;
  }

  /**
  * @dev Subtracts two numbers, throws on overflow (i.e. if subtrahend is greater than minuend).
  */
  function sub(uint256 a, uint256 b) internal pure returns (uint256) {
    assert(b <= a);
    return a - b;
  }

  /**
  * @dev Adds two numbers, throws on overflow.
  */
  function add(uint256 a, uint256 b) internal pure returns (uint256 c) {
    c = a + b;
    assert(c >= a);
    return c;
  }
}

library DateTime {
        /*
         *  Date and Time utilities for ethereum contracts
         *
         */
        struct MyDateTime {
                uint16 year;
                uint8 month;
                uint8 day;
                uint8 hour;
                uint8 minute;
                uint8 second;
                uint8 weekday;
        }
        uint constant DAY_IN_SECONDS = 86400;
        uint constant YEAR_IN_SECONDS = 31536000;
        uint constant LEAP_YEAR_IN_SECONDS = 31622400;
        uint constant HOUR_IN_SECONDS = 3600;
        uint constant MINUTE_IN_SECONDS = 60;
        uint16 constant ORIGIN_YEAR = 1970;
        function isLeapYear(uint16 year) constant returns (bool) {
                if (year % 4 != 0) {
                        return false;
                }
                if (year % 100 != 0) {
                        return true;
                }
                if (year % 400 != 0) {
                        return false;
                }
                return true;
        }
        function leapYearsBefore(uint year) constant returns (uint) {
                year -= 1;
                return year / 4 - year / 100 + year / 400;
        }
        function getDaysInMonth(uint8 month, uint16 year) constant returns (uint8) {
                if (month == 1 || month == 3 || month == 5 || month == 7 || month == 8 || month == 10 || month == 12) {
                        return 31;
                }
                else if (month == 4 || month == 6 || month == 9 || month == 11) {
                        return 30;
                }
                else if (isLeapYear(year)) {
                        return 29;
                }
                else {
                        return 28;
                }
        }
        function parseTimestamp(uint timestamp) internal returns (MyDateTime dt) {
                uint secondsAccountedFor = 0;
                uint buf;
                uint8 i;
                // Year
                dt.year = getYear(timestamp);
                buf = leapYearsBefore(dt.year) - leapYearsBefore(ORIGIN_YEAR);
                secondsAccountedFor += LEAP_YEAR_IN_SECONDS * buf;
                secondsAccountedFor += YEAR_IN_SECONDS * (dt.year - ORIGIN_YEAR - buf);
                // Month
                uint secondsInMonth;
                for (i = 1; i <= 12; i++) {
                        secondsInMonth = DAY_IN_SECONDS * getDaysInMonth(i, dt.year);
                        if (secondsInMonth + secondsAccountedFor > timestamp) {
                                dt.month = i;
                                break;
                        }
                        secondsAccountedFor += secondsInMonth;
                }
                // Day
                for (i = 1; i <= getDaysInMonth(dt.month, dt.year); i++) {
                        if (DAY_IN_SECONDS + secondsAccountedFor > timestamp) {
                                dt.day = i;
                                break;
                        }
                        secondsAccountedFor += DAY_IN_SECONDS;
                }
                // Hour
                dt.hour = 0;//getHour(timestamp);
                // Minute
                dt.minute = 0;//getMinute(timestamp);
                // Second
                dt.second = 0;//getSecond(timestamp);
                // Day of week.
                dt.weekday = 0;//getWeekday(timestamp);
        }
        function getYear(uint timestamp) constant returns (uint16) {
                uint secondsAccountedFor = 0;
                uint16 year;
                uint numLeapYears;
                // Year
                year = uint16(ORIGIN_YEAR + timestamp / YEAR_IN_SECONDS);
                numLeapYears = leapYearsBefore(year) - leapYearsBefore(ORIGIN_YEAR);
                secondsAccountedFor += LEAP_YEAR_IN_SECONDS * numLeapYears;
                secondsAccountedFor += YEAR_IN_SECONDS * (year - ORIGIN_YEAR - numLeapYears);
                while (secondsAccountedFor > timestamp) {
                        if (isLeapYear(uint16(year - 1))) {
                                secondsAccountedFor -= LEAP_YEAR_IN_SECONDS;
                        }
                        else {
                                secondsAccountedFor -= YEAR_IN_SECONDS;
                        }
                        year -= 1;
                }
                return year;
        }
        function getMonth(uint timestamp) constant returns (uint8) {
                return parseTimestamp(timestamp).month;
        }
        function getDay(uint timestamp) constant returns (uint8) {
                return parseTimestamp(timestamp).day;
        }
        function getHour(uint timestamp) constant returns (uint8) {
                return uint8((timestamp / 60 / 60) % 24);
        }
        function getMinute(uint timestamp) constant returns (uint8) {
                return uint8((timestamp / 60) % 60);
        }
        function getSecond(uint timestamp) constant returns (uint8) {
                return uint8(timestamp % 60);
        }
        function toTimestamp(uint16 year, uint8 month, uint8 day) constant returns (uint timestamp) {
                return toTimestamp(year, month, day, 0, 0, 0);
        }
        function toTimestamp(uint16 year, uint8 month, uint8 day, uint8 hour, uint8 minute, uint8 second) constant returns (uint timestamp) {
                uint16 i;
                // Year
                for (i = ORIGIN_YEAR; i < year; i++) {
                        if (isLeapYear(i)) {
                                timestamp += LEAP_YEAR_IN_SECONDS;
                        }
                        else {
                                timestamp += YEAR_IN_SECONDS;
                        }
                }
                // Month
                uint8[12] memory monthDayCounts;
                monthDayCounts[0] = 31;
                if (isLeapYear(year)) {
                        monthDayCounts[1] = 29;
                }
                else {
                        monthDayCounts[1] = 28;
                }
                monthDayCounts[2] = 31;
                monthDayCounts[3] = 30;
                monthDayCounts[4] = 31;
                monthDayCounts[5] = 30;
                monthDayCounts[6] = 31;
                monthDayCounts[7] = 31;
                monthDayCounts[8] = 30;
                monthDayCounts[9] = 31;
                monthDayCounts[10] = 30;
                monthDayCounts[11] = 31;
                for (i = 1; i < month; i++) {
                        timestamp += DAY_IN_SECONDS * monthDayCounts[i - 1];
                }
                // Day
                timestamp += DAY_IN_SECONDS * (day - 1);
                // Hour
                timestamp += HOUR_IN_SECONDS * (hour);
                // Minute
                timestamp += MINUTE_IN_SECONDS * (minute);
                // Second
                timestamp += second;
                return timestamp;
        }
}

contract ERC20Basic {
  function totalSupply() public view returns (uint256);
  function balanceOf(address who) public view returns (uint256);
  function transfer(address to, uint256 value) public returns (bool);
  event Transfer(address indexed from, address indexed to, uint256 value);
}

contract ERC20 is ERC20Basic {
  function allowance(address owner, address spender) public view returns (uint256);
  function transferFrom(address from, address to, uint256 value) public returns (bool);
  function approve(address spender, uint256 value) public returns (bool);
  event Approval(address indexed owner, address indexed spender, uint256 value);
}

contract BasicToken is ERC20Basic {
  using SafeMath for uint256;

  mapping(address => uint256) balances;

    uint8 public decimals = 18;
    uint public allSupply = 54000000 ;    // 90000000 * 0.6
    uint public freezeSupply = 36000000  * 10 ** uint256(decimals);   // 90000000 * 0.4
    uint256 totalSupply_ = freezeSupply;  //  初始时 供应量为冻结量

  constructor() public {
      balances[msg.sender] = 0;
      //  冻结的货币量
      balances[0x0] = freezeSupply;
  }


  function totalSupply() public view returns (uint256) {
    return totalSupply_;
  }


  function transfer(address _to, uint256 _value) public returns (bool) {
    require(_to != address(0));
    require(_value <= balances[msg.sender]);

    balances[msg.sender] = balances[msg.sender].sub(_value);
    balances[_to] = balances[_to].add(_value);
    emit Transfer(msg.sender, _to, _value);
    return true;
  }


  function balanceOf(address _owner) public view returns (uint256) {
    return balances[_owner];
  }

}

contract NBToken is ERC20, BasicToken {

  using DateTime for uint256;

  string public name = "NineBlock";
  string public symbol = "NB";

  address owner;

  event ReleaseSupply(address indexed receiver, uint256 value, uint256 releaseTime);

  uint256 public createTime;

  struct ReleaseRecord {
      uint256 amount; // release amount
      uint256 releasedTime; // release time
  }

  mapping (uint => ReleaseRecord) public releasedRecords;
  uint public releasedRecordsCount = 0;

    constructor() public {
      owner = msg.sender;
      createTime = now;
    }

  modifier onlyOwner {
    require(msg.sender == owner);
    _;
  }



  function transferOwnership(address newOwner) onlyOwner {
    require(newOwner != address(0));
    owner = newOwner;
  }


  mapping (address => mapping (address => uint256)) internal allowed;

  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 allowance(address _owner, address _spender) public view returns (uint256) {
    return allowed[_owner][_spender];
  }


  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;
  }

  // 每天释放调用这个方法
  function releaseToday() public onlyOwner returns(uint256 _actualRelease) {
    return releaseSupply(now);
  }

  // 如果有哪天遗漏了，可以调用这个方法
  function releaseSupply(uint256 timestamp) public onlyOwner returns(uint256 _actualRelease) {
      require(timestamp >= createTime && timestamp <= now);
      require(!judgeReleaseRecordExist(timestamp));

      uint award = updateAward(timestamp);

      balances[owner] = balances[owner].add(award);
      totalSupply_ = totalSupply_.add(award);
      releasedRecords[releasedRecordsCount] = ReleaseRecord(award, timestamp);
      releasedRecordsCount++;
      emit ReleaseSupply(owner, award, timestamp);
      emit Transfer(0, owner, award);
      return award;
  }

  function judgeReleaseRecordExist(uint256 timestamp) internal returns(bool _exist) {
      bool exist = false;
      if (releasedRecordsCount > 0) {
          for (uint index = 0; index < releasedRecordsCount; index++) {
              if ((releasedRecords[index].releasedTime.parseTimestamp().year == timestamp.parseTimestamp().year)
                  && (releasedRecords[index].releasedTime.parseTimestamp().month == timestamp.parseTimestamp().month)
                  && (releasedRecords[index].releasedTime.parseTimestamp().day == timestamp.parseTimestamp().day)) {
                  exist = true;
              }
          }
      }
      return exist;
  }

  function updateAward(uint256 timestamp) internal returns(uint256 ) {

      uint passMonth  = now.sub(createTime) / 30 days + 1;

      if (passMonth == 1) {
          return 270000 * 10 ** uint256(decimals);
      } else if (passMonth == 2) {
          return 252000 * 10 ** uint256(decimals);
      } else if (passMonth == 3) {
          return 234000 * 10 ** uint256(decimals);
      } else if (passMonth == 4) {
          return 216000 * 10 ** uint256(decimals);
      } else if (passMonth == 5) {
          return 198000 * 10 ** uint256(decimals);
      } else if (passMonth == 6) {
          return 180000 * 10 ** uint256(decimals);
      } else if (passMonth == 7) {
          return 162000 * 10 ** uint256(decimals);
      } else if (passMonth == 8) {
          return 144000 * 10 ** uint256(decimals);
      } else if (passMonth == 9) {
          return 144000 * 10 ** uint256(decimals);
      }
      return 0;

  }

}