//+------------------------------------------------------------------+
//|                                                   TimeSummer.mq5 |
//|                                  Copyright 2021, MetaQuotes Ltd. |
//|                                             https://www.mql5.com |
//+------------------------------------------------------------------+
#include "..\..\Include\PRTF.mqh"
#include "..\..\Include\DateTime.mqh"

#include <TimeZoneInfo.mqh>


//+------------------------------------------------------------------+
//| Server time zone and DST information                             |
//+------------------------------------------------------------------+
struct ServerTime
{
  int offsetGMT;      // time zone offset in seconds against UTC/GMT
  int offsetDST;      // DST correction in seconds (included in offsetGMT)
  bool supportDST;    // DST changes are detected in the quotes
  string description; // textual explanation of result
};

//+------------------------------------------------------------------+
//| Estimate server time zone and DST mode from H1 quotes history    |
//+------------------------------------------------------------------+
ServerTime ServerTimeZone(const string symbol = NULL)
{
  const int year = 365 * 24 * 60 * 60;
  datetime array[];
  if(PRTF(CopyTime(symbol, PERIOD_H1, TimeCurrent() - year, TimeCurrent(), array)) > 0)
  {
    // approx. 6000 bars should be acquired here
    const int n = ArraySize(array);
    PrintFormat("Got %d H1 bars, ~%d days", n, n / 24);
    int hours[24] = {};
    int current = 0;
    for(int i = 0; i < n; ++i)
    {
      const ENUM_DAY_OF_WEEK weekday = TimeDayOfWeek(array[i]);
      // skip all days except Sunday and Monday
      if(weekday > MONDAY) continue;
      // lets analyze the first H1 bar of the trading week
      // find out an hour for the first bar after weekend
      current = _TimeHour();
      // collect stats for opening hours
      hours[current]++;
      // now skip 2 days to check next week
      i += 48;
    }
    Print("Week opening hours stats:");
    ArrayPrint(hours);
    if(hours[current] <= 52 / 4)
    {
      // TODO: refine results using previous weeks
      Print("Extraordinary week detected");
    }
    // find most often time shift
    int max = ArrayMaximum(hours);
    // now check if a secondary time shift was also happened
    hours[max] = 0;
    int sub = ArrayMaximum(hours);
    // result variable init
    ServerTime st = {};
    int DST = 0;
    // winter/summer periods are not equal!
    // summer time can be 8 months per year
    // 52 is the full year in weeks
    if(hours[sub] > 52 / 4) // DST is supported
    {
      if(current == max || current == sub)
      {
        if(current == MathMin(max, sub))
          DST = fabs(max - sub); // DST is enabled now
      }
      st.supportDST = true;
    }
    current += 2 + DST; // +2 to get UTC offset
    // NB. when DST is enabled, time is shifted forward in the time zone,
    // but for outside it is looked like the time is shifted back
    // (everything in this time zone is happened earlier for others)
    // so to get standard time of the zone we need to add DST
    current %= 24;
    // time zones are in the range [UTC-12,UTC+12]
    if(current > 12) current = current - 24;
    current += DST; // if DST is enabled it's shown in offsetGMT according to MT5 rules
    st.description = StringFormat("Server time offset: UTC%+d, including DST%+d", current, DST);
    st.offsetGMT = -current * 3600;
    st.offsetDST = -DST * 3600;
    return st;
  }
  ServerTime empty = {-INT_MAX, -INT_MAX, false};
  return empty;
}


#define HOUR 3600
#define DAY (24 * HOUR)
#define WEEK 7

//+------------------------------------------------------------------+
//|                                                                  |
//+------------------------------------------------------------------+
datetime GetBarTime(const datetime time, const bool NextBar = false, string Symb = NULL, const ENUM_TIMEFRAMES TimeFrame = PERIOD_M1)
{
  if (Symb == NULL)
    Symb = _Symbol;
  return(iTime(Symb, TimeFrame, iBarShift(Symb, TimeFrame, time) - (NextBar ? 1 : 0)));
}

//+------------------------------------------------------------------+
//|                                                                  |
//+------------------------------------------------------------------+
datetime GetTimeDayOfWeek(const int Shift = 0, const ENUM_DAY_OF_WEEK Day = SUNDAY)
{
  const datetime Res = TimeCurrent() / DAY * DAY;
  return(Res - (((WEEK + (TimeDayOfWeek(Res) - Day)) % WEEK) + Shift * WEEK) * DAY);
}
// Аналог по серверному времени - https://www.mql5.com/ru/docs/dateandtime/timegmtoffset
// Работает для FOREX-символов, когда M1-история доступна за ближайшую неделю
int TimeServerGMTOffset( void )
{
  const datetime Sunday = GetTimeDayOfWeek();
  return(((int)MathRound((double)MathMin(Sunday - DAY - GetBarTime(Sunday), Sunday + DAY - GetBarTime(Sunday, true)) / HOUR) - 3) * HOUR);
}
// Аналог по серверному времени - https://www.mql5.com/ru/docs/dateandtime/timegmt
// Работает для FOREX-символов, когда M1-история доступна за ближайшую неделю
datetime TimeServerGMT(void)
{
  return(TimeCurrent() + TimeServerGMTOffset());
}

//+------------------------------------------------------------------+
//| Script program start function                                    |
//+------------------------------------------------------------------+
void OnStart()
{
  //PRTF(TimeLocal());
  PRTF(TimeCurrent());
  //PRTF(TimeTradeServer());
  PRTF(TimeGMT());
  PRTF(TimeGMTOffset());
  PRTF(TimeDaylightSavings());
  ServerTime st = ServerTimeZone();
  Print(st.description);
  Print("ServerGMTOffset: ", st.offsetGMT);
  Print("ServerTimeDaylightSavings: ", st.offsetDST);
  Print("\n\n");
  //---
  //PRTF(TimeLocal());
  PRTF(TimeCurrent());
  //PRTF(TimeTradeServer());
  PRTF(TimeGMT());
  PRTF(TimeServerGMT());
  Print("\n\n");
  CTimeZoneInfo my_time(ZONE_ID_BROKER);
  ENUM_ZONE_ID id = ZONE_ID_UTC;
  PRTF(my_time.GetCurrentTimeForPlace(ZONE_ID_BROKER));
  PRTF(my_time.GetCurrentTimeForPlace(ZONE_ID_UTC));
  PRTF(my_time.GetCurrentTimeForPlace(ZONE_ID_LOCAL));
  PRTF(my_time.ConvertTimeForPlace(TimeGMT(), ZONE_ID_UTC, ZONE_ID_BROKER));
  PRTF(my_time.TimeLocal());
  PRTF(my_time.TimeUTC());
  PRTF(my_time.IsDaylightSavingTime(TimeCurrent() - PeriodSeconds(PERIOD_MN1) * 7, ZONE_ID_BROKER));
  PRTF(my_time.IsDaylightSavingTime(TimeCurrent() - PeriodSeconds(PERIOD_MN1) * 7, ZONE_ID_UTC));
  
  
  //datetime localtime = CTimeZoneInfo::GetCurrentTimeForPlace(id);
  //datetime converted = CTimeZoneInfo::ConvertTimeForPlace(localtime, id, ZONE_ID_BROKER);
  //PrintFormat("%-49s | %s", CTimeZoneInfo::FormatTimeForPlace(localtime, id), CTimeZoneInfo::FormatTimeForPlace(converted, ZONE_ID_BROKER));
}
//+------------------------------------------------------------------+
/*
   example output MQ Demo
   (WARNING: TimeGMT != ServerGMT,
   because TimeGMT() - TimeCurrent() gives 3 hours difference,
   whereas ServerGMTOffset is 2 hours difference;
   probably DST is enabled all year round)

   TimeLocal()=2021.09.09 22:06:17 / ok
   TimeCurrent()=2021.09.09 22:06:10 / ok
   TimeTradeServer()=2021.09.09 22:06:17 / ok
   TimeGMT()=2021.09.09 19:06:17 / ok
   TimeGMTOffset()=-10800 / ok
   TimeDaylightSavings()=0 / ok
   CopyTime(symbol,PERIOD_H1,TimeCurrent()-year,TimeCurrent(),array)=6207 / ok
   Got 6207 H1 bars, ~258 days
   Week opening hours stats:
   52  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0
   Server time offset: UTC+2, including DST+0
   ServerGMTOffset: -7200
   ServerTimeDaylightSavings: 0

*/
//+------------------------------------------------------------------+