//+------------------------------------------------------------------+
//|                                                  StateReader.mqh |
//|                             Copyright 2026, MetaQuotes Ltd. |
//|                                                     www.mql5.com |
//+------------------------------------------------------------------+
#ifndef REQUEST_LATENCY_LAB_STATE_READER_MQH
#define REQUEST_LATENCY_LAB_STATE_READER_MQH

#include "..\..\Include\RequestLatencyLab\Models.mqh"
#include "..\..\Include\RequestLatencyLab\TimeSource.mqh"

class CStateReader
  {
public:
   //--- чтение активного ордера по тикету
   static bool       ReadActiveOrder(const ulong ticket, long &state, double &volume_current,
                               double &volume_initial, string &symbol, long &type,
                               long &magic, ENUM_LAB_READ_STATUS &status);
   //--- чтение ордера из истории (требует HistorySelect с диапазоном)
   static bool       ReadHistoryOrder(const ulong ticket, long &state, double &volume_current,
                                double &volume_initial, string &symbol, long &type,
                                ENUM_LAB_READ_STATUS &status);
   //--- сбор уникальных сделок ордера в пределах выбранной истории
   static int        CollectDealsByOrder(const ulong order_ticket, const string symbol,
                                  ulong &tickets[], double &exec_units,
                                  const double volume_step, const double tolerance,
                                  int &api_errors, const int budget, bool &truncated);
   //--- позиция по тикету (именно тикет, не identifier)
   static bool       ReadPositionFacts(const ulong ticket, PositionFacts &pf);
   //--- полный снимок для одной записи (T6 первый успешный)
   static void       BuildSnapshot(const ulong sequence, const ENUM_LAB_OPERATION expected_op,
                             const ulong order_ticket, const double requested_units,
                             const double volume_step, const double tolerance,
                             CTimeSource *clock, const ulong position_ticket_hint,
                             const int history_scan_budget, ConfirmationSnapshot &snap,
                             const bool light = false,
                             const double callback_volume_units = 0.0,
                             const int callback_deal_count = 0);
   //--- R4-B2 (audit-4): публичный перевод лотов в units (единая точка
   //--- конвертации для событийной сверки; аналог VolumeToUnitsSafe).
   static bool       LotsToUnits(const double lots, const double step, const double tolerance,
                           double &units);

private:
   static bool       VolumeToUnitsSafe(const double volume, const double step,
                                 const double tolerance, double &units);
  };
//+------------------------------------------------------------------+
//| Внешние определения методов.                                     |
//+------------------------------------------------------------------+
bool              CStateReader::ReadActiveOrder(const ulong ticket, long &state, double &volume_current,
      double &volume_initial, string &symbol, long &type,
      long &magic, ENUM_LAB_READ_STATUS &status)
  {
   status = LAB_READ_UNKNOWN;
   if(ticket == 0)
      return(false);
   ResetLastError();
   if(!OrderSelect(ticket))
     {
      const int e = GetLastError();
      //--- B4 (audit-3): 4754 ERR_TRADE_ORDER_NOT_FOUND — ожидаемый
      //--- «ордер не найден» -> ABSENT_CONFIRMED; прочие ошибки (в т.ч.
      //--- 4756 SEND_FAILED) остаются FAILED (не доказанное отсутствие).
      status = (e == 4754 ? LAB_READ_ABSENT_CONFIRMED : LAB_READ_FAILED);
      return(false);
     }
   state = OrderGetInteger(ORDER_STATE);
   volume_current = OrderGetDouble(ORDER_VOLUME_CURRENT);
   volume_initial = OrderGetDouble(ORDER_VOLUME_INITIAL);
   symbol = OrderGetString(ORDER_SYMBOL);
   type = OrderGetInteger(ORDER_TYPE);
   magic = OrderGetInteger(ORDER_MAGIC);
   status = LAB_READ_FOUND;
   return(true);
  }
bool              CStateReader::ReadHistoryOrder(const ulong ticket, long &state, double &volume_current,
      double &volume_initial, string &symbol, long &type,
      ENUM_LAB_READ_STATUS &status)
  {
   status = LAB_READ_UNKNOWN;
   if(ticket == 0)
      return(false);
   ResetLastError();
   if(!HistoryOrderSelect(ticket))
     {
      const int e = GetLastError();
      //--- B4 (audit-3): только 4754 считаем подтверждённым отсутствием.
      status = (e == 4754 ? LAB_READ_ABSENT_CONFIRMED : LAB_READ_FAILED);
      return(false);
     }
   state = HistoryOrderGetInteger(ticket, ORDER_STATE);
   volume_current = HistoryOrderGetDouble(ticket, ORDER_VOLUME_CURRENT);
   volume_initial = HistoryOrderGetDouble(ticket, ORDER_VOLUME_INITIAL);
   symbol = HistoryOrderGetString(ticket, ORDER_SYMBOL);
   type = HistoryOrderGetInteger(ticket, ORDER_TYPE);
   status = LAB_READ_FOUND;
   return(true);
  }
int               CStateReader::CollectDealsByOrder(const ulong order_ticket, const string symbol,
      ulong &tickets[], double &exec_units,
      const double volume_step, const double tolerance,
      int &api_errors, const int budget, bool &truncated)
  {
   int found = 0;
   exec_units = 0.0;
   truncated = false;
   //--- аудит-2 B1: детерминированная выборка истории сделок до перебора;
   //--- не зависит от ранее выбранного контекста (HistoryOrderSelect и пр.)
   //--- B6 (audit-3): проверяем bool HistorySelect; при неуспехе возвращаем
   //--- -1 (ошибка API), положительное завершение не допускается.
   ResetLastError();
   if(!HistorySelect((datetime)0, TimeCurrent()))
     {
      api_errors++;
      return(-1);
     }
   const int total = HistoryDealsTotal();
   if(total < 0)
     {
      api_errors++;
      return(-1);
     }
   int       scanned = 0;
   for(int i = total - 1; i >= 0 && scanned < budget; i--, scanned++)
     {
      const ulong dt = HistoryDealGetTicket(i);
      if(dt == 0)
        {
         api_errors++;
         continue;
        }
      if((ulong)HistoryDealGetInteger(dt, DEAL_ORDER) != order_ticket)
         continue;
      if(StringLen(symbol) > 0 && HistoryDealGetString(dt, DEAL_SYMBOL) != symbol)
         continue;
      //--- уникальность тикета в собранном наборе
      bool dup = false;
      for(int k = 0; k < found; k++)
         if(tickets[k] == dt)
           {
            dup = true;
            break;
           }
      if(dup)
         continue;
      //--- R5-S4: буфер реестра исчерпан — явный неполный исход,
      //--- а не молчаливый обрыв (сигнал «не все данные» != «данных нет»)
      if(found >= ArraySize(tickets))
        {
         truncated = true;
         continue;
        }
      tickets[found] = dt;
      found++;
      const double vol = HistoryDealGetDouble(dt, DEAL_VOLUME);
      double       units = 0;
      if(VolumeToUnitsSafe(vol, volume_step, tolerance, units))
         exec_units += units;
     }
   //--- R5-S4: достижение бюджета сканирования — история, возможно, неполна
   if(scanned >= budget && budget > 0)
      truncated = true;
   return(found);
  }
bool              CStateReader::ReadPositionFacts(const ulong ticket, PositionFacts &pf)
  {
   pf.Zero();
   if(ticket == 0)
      return(false);
   ResetLastError();
   if(!PositionSelectByTicket(ticket))
      return(false);
   pf.ticket = ticket;
   pf.identifier = (ulong)PositionGetInteger(POSITION_IDENTIFIER);
   pf.type = PositionGetInteger(POSITION_TYPE);
   pf.volume = PositionGetDouble(POSITION_VOLUME);
   pf.magic = (ulong)PositionGetInteger(POSITION_MAGIC);
   pf.symbol = PositionGetString(POSITION_SYMBOL);
   pf.read_status = true;
   return(true);
  }
void              CStateReader::BuildSnapshot(const ulong sequence, const ENUM_LAB_OPERATION expected_op,
      const ulong order_ticket, const double requested_units,
      const double volume_step, const double tolerance,
      CTimeSource *clock, const ulong position_ticket_hint,
      const int history_scan_budget, ConfirmationSnapshot &snap,
      const bool light, const double callback_volume_units,
      const int callback_deal_count)
  {
   snap.Zero();
   snap.sequence = sequence;
   snap.expected_operation = expected_op;
   snap.order_ticket = order_ticket;
   snap.requested_volume_units = requested_units;
   snap.light_snapshot = light;                // R6-B1: вид сверки — явный признак (не deal_count)
   snap.check_start_us = clock.NowUs();        // начало построения снимка
   if(order_ticket == 0)
      return;
   long                 state = 0;
   double               vol_cur = 0, vol_ini = 0;
   string               sym = "";
   long                 type = 0, magic = 0;
   ENUM_LAB_READ_STATUS st = LAB_READ_UNKNOWN;
   if(ReadActiveOrder(order_ticket, state, vol_cur, vol_ini, sym, type, magic, st))
     {
      snap.active_select_status = LAB_READ_FOUND;
      snap.active_select_error = 0;
      snap.order_state_before = state;
      //--- R4-S3: поля *_volume_units всегда в units (лоты -> шаги объёма)
      double ini_u = 0.0, rem_u = 0.0;
      VolumeToUnitsSafe(vol_ini, volume_step, tolerance, ini_u);
      VolumeToUnitsSafe(vol_cur, volume_step, tolerance, rem_u);
      snap.initial_volume_units = ini_u;
      snap.remaining_volume_units = rem_u;
      //--- R4-S2: факты ордера для сверки ожидаемого контракта
      snap.order_symbol = OrderGetString(ORDER_SYMBOL);
      snap.order_type = OrderGetInteger(ORDER_TYPE);
      snap.order_magic = (ulong)OrderGetInteger(ORDER_MAGIC);
      snap.order_volume_lots = OrderGetDouble(ORDER_VOLUME_INITIAL);
      snap.order_price = OrderGetDouble(ORDER_PRICE_OPEN);
      snap.trading_state_known = true;
     }
   else
     {
      snap.active_select_status = st;
      snap.active_select_error = GetLastError();
      //--- проверка истории для терминальных состояний
      if(ReadHistoryOrder(order_ticket, state, vol_cur, vol_ini, sym, type, st))
        {
         snap.history_select_status = LAB_READ_FOUND;
         snap.history_order_error = 0;
         snap.order_state_before = state;
         //--- R4-S3: единицы объёма как units
         double ini_u = 0.0, rem_u = 0.0;
         VolumeToUnitsSafe(vol_ini, volume_step, tolerance, ini_u);
         VolumeToUnitsSafe(vol_cur, volume_step, tolerance, rem_u);
         snap.initial_volume_units = ini_u;
         snap.remaining_volume_units = rem_u;
         //--- R4-S2: факты ордера из истории
         snap.order_symbol = HistoryOrderGetString(order_ticket, ORDER_SYMBOL);
         snap.order_type = HistoryOrderGetInteger(order_ticket, ORDER_TYPE);
         snap.order_magic = (ulong)HistoryOrderGetInteger(order_ticket, ORDER_MAGIC);
         snap.order_volume_lots = HistoryOrderGetDouble(order_ticket, ORDER_VOLUME_INITIAL);
         snap.order_price = HistoryOrderGetDouble(order_ticket, ORDER_PRICE_OPEN);
         snap.trading_state_known = true;
        }
      else
        {
         snap.history_select_status = st;
         snap.history_order_error = GetLastError();
        }
     }
   //--- сделки ордера
   int api_errors = 0;
   if(light)
     {
      //--- B5 (audit-3): событийная сверка в callback выполняется адресно
      //--- и коротко: объём берётся из накопленных callback-сделок записи,
      //--- без полного прохода истории (запрещено в OnTradeTransaction).
      snap.deal_count = callback_deal_count;
      snap.executed_volume_units = callback_volume_units;
      snap.history_scan_failed = false;
      snap.api_errors = 0;
     }
   else
     {
      bool truncated = false;
      snap.deal_count = CollectDealsByOrder(order_ticket, sym, snap.deal_tickets,
                                            snap.executed_volume_units, volume_step,
                                            tolerance, api_errors, history_scan_budget,
                                            truncated);
      if(snap.deal_count < 0)
        {
         snap.deal_count = 0;
         snap.history_scan_failed = true;
         snap.api_errors = api_errors;
        }
      else
        {
         //--- R5-S4: прерванный скан (бюджет/ёмкость) = неполный исход
         snap.history_scan_failed = truncated;
         snap.api_errors = api_errors;
        }
     }
   //--- покрытие объёма: полное исполнение (для B3/B4 и CompletionPolicy)
   snap.coverage_complete = (requested_units > 0.0 && snap.deal_count > 0 &&
                             MathAbs(snap.executed_volume_units - requested_units) <= tolerance);
   //--- позиция (аудит-2 S7): адресная связь по переданному тикету
   //--- либо по DEAL_POSITION_ID сделок ордера; PositionGetTicket(0)
   //--- по символу не используется (ненадёжно на hedging-счёте)
   ulong pos_ticket = position_ticket_hint;
   ulong pos_identifier = 0;
   if(pos_ticket == 0)
     {
      for(int k = 0; k < snap.deal_count; k++)
        {
         const ulong dt = snap.deal_tickets[k];
         const ulong pid = (ulong)HistoryDealGetInteger(dt, DEAL_POSITION_ID);
         if(pid != 0)
            pos_identifier = pid;
        }
      if(pos_identifier != 0)
        {
         ResetLastError();
         for(int i = PositionsTotal() - 1; i >= 0; i--)
           {
            const ulong tt = PositionGetTicket(i);
            if(tt == 0)
               continue;
            if(PositionGetString(POSITION_SYMBOL) != sym)
               continue;
            if((ulong)PositionGetInteger(POSITION_IDENTIFIER) == pos_identifier)
              {
               pos_ticket = tt;
               break;
              }
           }
        }
     }
   PositionFacts pf;
   if(pos_ticket > 0 && ReadPositionFacts(pos_ticket, pf))
     {
      snap.position_found = true;
      snap.position_ticket = pos_ticket;
      snap.position_volume = pf.volume;
      snap.position_identifier = pf.identifier;
      snap.position_type = pf.type;
      snap.trading_state_known = true;
      snap.position_facts_last = pf;
     }
   snap.check_end_us = clock.NowUs(); // конец построения снимка; T6 ставит CompletionPolicy (п.7 аудита)
  }
bool              CStateReader::LotsToUnits(const double lots, const double step, const double tolerance,
      double &units)
  {
   if(step <= 0.0)
      return(false);
   const double ratio = lots / step;
   const double q = MathRound(ratio);
   if(MathAbs(ratio - q) > tolerance)
      return(false);
   units = q;
   return(true);
  }
bool              CStateReader::VolumeToUnitsSafe(const double volume, const double step,
      const double tolerance, double &units)
  {
   return(LotsToUnits(volume, step, tolerance, units));
  }

#endif // REQUEST_LATENCY_LAB_STATE_READER_MQH
//+------------------------------------------------------------------+