datetime.h

/*
MIT License
 
Copyright (c) 2021 n700a
 
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
 
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
 
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
*/
 
#ifndef _MY_DATETIME_
#define _MY_DATETIME_
 
#include <string>
#include <sstream>
#include <iomanip>
#include <time.h>
#include <regex>
#include <vector>
#include <limits>
 
#if defined(_WIN32) || defined(_WIN64)
#include <windows.h>
#endif
 
#include "time_delta.h"
#include "unix_time.h"
#include "datetime_parser.h"
#include "datetime_constants.h"
#include "datetime_exceptions.h"
 
namespace EZ
{
    class Datetime
    {
        time_t m_unixTime = 0;
        bool m_isUTC = false;
        MyParser m_parser;
 
    public:
        Datetime(const std::string &timestamp, const std::string &format, const bool &isUTC = false)
        {
            m_isUTC = isUTC;
            setDateTime(timestamp, format);
        }
 
        Datetime(const std::string &timestamp, const char *format, const bool &isUTC = false)
        {
            m_isUTC = isUTC;
            setDateTime(timestamp, format);
        }
 
        Datetime(const char *timestamp, const std::string &format, const bool &isUTC = false)
        {
            m_isUTC = isUTC;
            setDateTime(timestamp, format);
        }
 
        Datetime(const char *timestamp, const char *format, const bool &isUTC = false)
        {
            m_isUTC = isUTC;
            setDateTime(timestamp, format);
        }
 
        Datetime(const std::string &timestamp, const bool &isUTC = false)
        {
            m_isUTC = isUTC;
            setDateTime(timestamp, DatetimeConstants::DEFAULT_INPUT_FORMAT);
        }
 
        Datetime(const char *timestamp, const bool &isUTC = false)
        {
            m_isUTC = isUTC;
            setDateTime(timestamp, DatetimeConstants::DEFAULT_INPUT_FORMAT);
        }
 
        Datetime(struct tm datetime, const bool &isUTC = false)
        {
            m_isUTC = isUTC;
            validateInput(datetime);
            m_unixTime = MyTM::my_mktime(datetime, m_isUTC);
        }
        Datetime(const time_t &unixTime = 0, const bool &isUTC = false)
        {
            m_isUTC = isUTC;
            validateInput(unixTime);
            m_unixTime = unixTime;
        }
 
        Datetime(const Datetime &original)
        {
            m_isUTC = original.m_isUTC;
            m_unixTime = original.m_unixTime;
        }
        Datetime(const int &year, const int &mon, const int &day,
                 const int &hour, const int &min, const int &sec,
                 const bool &isUTC = false)
        {
            m_isUTC = isUTC;
            struct tm datetime;
            try
            {
                datetime.tm_year = year - DatetimeConstants::TM_BASE_YEAR;
                datetime.tm_mon = mon - DatetimeConstants::MONTH_OFFSET;
                datetime.tm_mday = day;
                datetime.tm_hour = hour;
                datetime.tm_min = min;
                datetime.tm_sec = sec;
            }
            catch (...)
            {
                throw DatetimeException("ERROR: Failed to parse input to struct tm");
            }
            validateInput(datetime);
            m_unixTime = MyTM::my_mktime(datetime, m_isUTC);
        }
 
        ~Datetime()
        {
        }
 
        void setIsUTC(const bool &isUTC)
        {
            m_isUTC = isUTC;
        }
        bool isUTC() const
        {
            return m_isUTC;
        }
 
        struct tm structTm() const
        {
            validateInput(m_unixTime);
            return MyTM::my_mkStructTm(m_unixTime, m_isUTC);
        }
        std::string str() const
        {
            return m_parser.time2str(structTm());
        }
        std::string str(const std::string &format) const
        {
            return m_parser.time2str(structTm(), format);
        }
        std::string str(const char *format) const
        {
            return m_parser.time2str(structTm(), format);
        }
 
        std::string datetime() const
        {
            return str();
        }
        std::string date() const
        {
            return str("%Y/%m/%d");
        }
        std::string timesOfday() const
        {
            return str("%H:%M:%S");
        }
        int sec() const
        {
            auto tmpTm = structTm();
            return tmpTm.tm_sec;
        }
        int minute() const
        {
            auto tmpTm = structTm();
            return tmpTm.tm_min;
        }
        int hour() const
        {
            auto tmpTm = structTm();
            return tmpTm.tm_hour;
        }
        int day() const
        {
            auto tmpTm = structTm();
            return tmpTm.tm_mday;
        }
        int month() const
        {
            auto tmpTm = structTm();
            return tmpTm.tm_mon + DatetimeConstants::MONTH_OFFSET;
        }
        long year() const
        {
            auto tmpTm = structTm();
            return tmpTm.tm_year + DatetimeConstants::TM_BASE_YEAR;
        }
        long long unixTime() const
        {
            return m_unixTime;
        }
        int daysOfWeek() const
        {
            auto tmpTm = structTm();
            return tmpTm.tm_wday;
        }
        // TODO: ISO
        // int weeksOfYear() const
        // {
        //  auto tmpTm = structTm();
        //  return (tmpTm.tm_yday / 7) + 1;
        // }
 
        std::string timezone() const
        {
            auto tmpTm = structTm();
#if defined(_WIN32) || defined(_WIN64)
            TIME_ZONE_INFORMATION tzi;
            GetTimeZoneInformation(&tzi);
            std::stringstream ss;
            long bias = tzi.Bias;
            if (m_isUTC)
            {
                ss << "UTC";
            }
            else
            {
                ss << "(" << tzi.Bias << "min from UTC)";
            }
            return ss.str();
#else
            return std::string(tmpTm.tm_zone);
#endif
        }
        int isDst() const
        {
            auto tmpTm = structTm();
            return tmpTm.tm_isdst;
        }
 
        static Datetime now(const bool &isUTC = false)
        {
            time_t unixTime = time(NULL);
            return Datetime(unixTime, isUTC);
        }
 
        static Datetime minimum(const bool &isUTC = false)
        {
            return Datetime(time_t(DatetimeConstants::MINIMUM_SEC), isUTC);
        }
 
        //https://cpprefjp.github.io/reference/limits/numeric_limits/max.html
        static Datetime maximum(const bool &isUTC = false)
        {
            return Datetime(DatetimeConstants::MAXIMUM_SEC, isUTC);
        }
 
        std::vector<int> toVector() const
        {
            auto tmpTm = structTm();
            return {
                tmpTm.tm_year + DatetimeConstants::TM_BASE_YEAR,
                tmpTm.tm_mon + DatetimeConstants::MONTH_OFFSET,
                tmpTm.tm_mday,
                tmpTm.tm_hour,
                tmpTm.tm_min,
                tmpTm.tm_sec};
        }
 
    private:
        void validateInput(const time_t &time) const
        {
            if (time < DatetimeConstants::MINIMUM_SEC)
            {
                std::stringstream ss;
                ss << "Input time is out of range. minimum datetime is " << Datetime::minimum(m_isUTC).str() << std::endl;
                throw DatetimeException(ss.str());
            }
 
            if (time > DatetimeConstants::MAXIMUM_SEC)
            {
                std::stringstream ss;
                ss << "Input time is out of range. maximum datetime is " << Datetime::maximum(m_isUTC).str() << std::endl;
                throw DatetimeException(ss.str());
            }
        }
        void validateInput(const struct tm &datetime) const
        {
            time_t tmp = MyTM::my_mktime(datetime, m_isUTC);
            validateInput(tmp);
        }
        void setDateTime(const std::string &timestamp, const std::string &format)
        {
            struct tm tmpTm = m_parser.str2time(timestamp, format);
            try
            {
                m_unixTime = MyTM::my_mktime(tmpTm, m_isUTC);
                validateInput(m_unixTime);
            }
            catch (...)
            {
                std::stringstream ss;
                ss << "ERROR: "
                   << "\"" << timestamp << "\""
                   << " is in illegal time range." << std::endl;
                throw DatetimeException(ss.str());
            }
        }
 
    public:
        Datetime operator+(const long long &right) const
        {
            struct tm time;
            time_t unixTimeR = time_t(right);
            time_t retSec = m_unixTime + unixTimeR;
            return Datetime(retSec, m_isUTC);
        }
        Datetime operator+(const TimeDelta &right) const
        {
            return operator+(right.totalSeconds());
        }
 
        Datetime operator-(const long long &right) const
        {
            return operator+(-right);
        }
        Datetime operator-(const TimeDelta &right) const
        {
            return operator+(-right.totalSeconds());
        }
 
        Datetime &operator=(const Datetime &right_t)
        {
            m_isUTC = right_t.m_isUTC;
            m_unixTime = right_t.m_unixTime;
            return *this;
        }
        Datetime &operator+=(const long long &right)
        {
            time_t unixTimeR = time_t(right);
            m_unixTime += unixTimeR;
            return *this;
        }
        Datetime &operator+=(const TimeDelta &right)
        {
            return operator+=(right.totalSeconds());
        }
 
        Datetime &operator-=(const long long &right)
        {
            return operator+=(-right);
        }
        Datetime &operator-=(const TimeDelta &right)
        {
            return operator+=(-right.totalSeconds());
        }
    };
 
    std::ostream &operator<<(std::ostream &stream, const Datetime &time)
    {
        stream << time.str();
        return stream;
    };
 
    TimeDelta operator-(const Datetime &left, const Datetime &right)
    {
        time_t diffSec = left.unixTime() - right.unixTime();
        return TimeDelta(diffSec);
    }
 
    bool operator==(const Datetime &left, const Datetime &right)
    {
        auto diffSec = left - right;
        return diffSec == 0;
    }
 
    bool operator!=(const Datetime &left, const Datetime &right)
    {
        return !(left == right);
    }
 
    bool operator<(const Datetime &left, const Datetime &right)
    {
        auto diffSec = left - right;
        return diffSec < 0;
    }
 
    bool operator>(const Datetime &left, const Datetime &right)
    {
        auto diffSec = left - right;
        return diffSec > 0;
    }
 
    bool operator<=(const Datetime &left, const Datetime &right)
    {
        return (left < right) || (left == right);
    }
 
    bool operator>=(const Datetime &left, const Datetime &right)
    {
        return (left > right) || (left == right);
    }
 
}
#endif