pragma solidity ^0.4.2;

contract DateTime {
        /*
         *  Date and Time utilities for ethereum contracts
         *
         */
        struct DateTime {
                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 (DateTime 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 = getHour(timestamp);

                // Minute
                dt.minute = getMinute(timestamp);

                // Second
                dt.second = getSecond(timestamp);

                // Day of week.
                dt.weekday = 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 getWeekday(uint timestamp) constant returns (uint8) {
                return uint8((timestamp / DAY_IN_SECONDS + 4) % 7);
        }

        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) constant returns (uint timestamp) {
                return toTimestamp(year, month, day, hour, 0, 0);
        }

        function toTimestamp(uint16 year, uint8 month, uint8 day, uint8 hour, uint8 minute) constant returns (uint timestamp) {
                return toTimestamp(year, month, day, hour, minute, 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;
    }
}

// Copyrobo contract for notarization
contract ProofOfExistence {
    
    string public result;

    function uintToString(uint v) constant returns (string str) {
        uint maxlength = 100;
        bytes memory reversed = new bytes(maxlength);
        uint i = 0;
        while (v != 0) {
            uint remainder = v % 10;
            v = v / 10;
            reversed[i++] = byte(48 + remainder);
        }
        bytes memory s = new bytes(i + 1);
        for (uint j = 0; j <= i; j++) {
            s[j] = reversed[i - j];
        }
        str = string(s);
        
    }
    
function strConcat(string _a, string _b, string _c, string _d, string _e) internal returns (string){
    bytes memory _ba = bytes(_a);
    bytes memory _bb = bytes(_b);
    bytes memory _bc = bytes(_c);
    bytes memory _bd = bytes(_d);
    bytes memory _be = bytes(_e);
    string memory abcde = new string(_ba.length + _bb.length + _bc.length + _bd.length + _be.length);
    bytes memory babcde = bytes(abcde);
    uint k = 0;
    for (uint i = 0; i < _ba.length; i++) babcde[k++] = _ba[i];
    for (i = 0; i < _bb.length; i++) babcde[k++] = _bb[i];
    for (i = 0; i < _bc.length; i++) babcde[k++] = _bc[i];
    for (i = 0; i < _bd.length; i++) babcde[k++] = _bd[i];
    for (i = 0; i < _be.length; i++) babcde[k++] = _be[i];
    return string(babcde);
}

function strConcat(string _a, string _b, string _c, string _d) internal returns (string) {
    return strConcat(_a, _b, _c, _d, "");
}

function strConcat(string _a, string _b, string _c) internal returns (string) {
    return strConcat(_a, _b, _c, "", "");
}

function strConcat(string _a, string _b) internal returns (string) {
    return strConcat(_a, _b, "", "", "");
}
   
  // string: sha256 of document
  // unit : timestamp 
  mapping (string => uint) private proofs;

  function notarize(string sha256) {
    // validate it has 64 characters
    
    if ( bytes(sha256).length == 64 ){
      // check if it is existing, don't save it
      if ( proofs[sha256] == 0 ){
        proofs[sha256] = block.timestamp;
      }
    }
  }
  
  // Input sha256 hash string to check
  function verify(string sha256) constant returns (string) {
    var timestamp =  proofs[sha256];
    if ( timestamp == 0 ){
        return "No data found";
    }else{
        DateTime dt = DateTime(msg.sender);
        
        uint year = dt.getYear(timestamp);
        uint month = dt.getMonth(timestamp);
        uint day = dt.getDay(timestamp);
        uint hour = dt.getHour(timestamp);
        uint minute = dt.getMinute(timestamp);
        uint second = dt.getSecond(timestamp);
        
        result = strConcat(uintToString(year) , "-" , uintToString(month),"-",uintToString(day));
        result = strConcat(result," ");
        result = strConcat( uintToString(hour) , ":" , uintToString(minute),":",uintToString(second));
        result = strConcat(result," UTC");
        


        //UTC Format: 2013-10-26 14:37:48 UTC

        return result;
    }
  }
  
}