//+------------------------------------------------------------------+
//| DinexSpace | Round Number Levels                                  |
//| Horizontal lines at round prices around the current price, with  |
//| stronger "major" lines every N steps. The step is chosen from    |
//| the price size or set by hand. Draws levels only, no signals.    |
//+------------------------------------------------------------------+
#property copyright   "(c) 2026 DinexSpace"
#property version     "1.00"
#property description "Round-number price levels around the current price, with major lines every N steps."
#property description "Automatic or manual step. Draws levels only, no signals."
#property strict
#property indicator_chart_window
#property indicator_buffers 0
#property indicator_plots   0

input group "Step"
input bool   InpAuto   = true;   // Automatic minor step
input double InpStep   = 10.0;   // Manual minor step (price)
input int    InpMajorK = 5;      // Major line every N minor steps
input int    InpCount  = 6;      // Lines above and below price

input group "Display"
input color           InpColMinor = C'70,70,70';      // Minor lines
input color           InpColMajor = clrSpringGreen;   // Major lines
input ENUM_LINE_STYLE InpMinorSty = STYLE_DOT;        // Minor line style
input bool            InpLabels   = true;             // Price labels
input bool            InpLblMajor = true;             // Labels on major lines only

const string PFX = "DNXRN_";
double g_lastBase = -1, g_lastStep = -1;

// About 1/100 of price rounded to 1, 2 or 5 x a power of ten (gold ~4000 -> 50, EURUSD ~1.10 -> 0.01).
double AutoStep(double px)
  {
   double raw = px / 100.0;
   double p10 = MathPow(10, MathFloor(MathLog10(raw)));
   double m = raw / p10;
   double nice = (m < 1.5) ? 1 : (m < 3.5) ? 2 : (m < 7.5) ? 5 : 10;
   return nice * p10;
  }

int OnInit()
  {
   if(InpMajorK < 1 || InpCount < 1 || InpCount > 50 || (!InpAuto && InpStep <= 0))
      return INIT_PARAMETERS_INCORRECT;
   g_lastBase = -1;
   g_lastStep = -1;
   return INIT_SUCCEEDED;
  }

void OnDeinit(const int reason)
  {
   ObjectsDeleteAll(0, PFX);
  }

int OnCalculate(const int rates_total, const int prev_calculated,
                const datetime &time[], const double &open[], const double &high[],
                const double &low[], const double &close[], const long &tick_volume[],
                const long &volume[], const int &spread[])
  {
   if(rates_total < 1)
      return 0;
   ArraySetAsSeries(time, true);
   ArraySetAsSeries(close, true);
   double px = close[0];
   if(px <= 0)
      return rates_total;
   double step = InpAuto ? AutoStep(px) : InpStep;
   if(step <= 0)
      return rates_total;
   double base = MathFloor(px / step) * step;
   datetime tLbl = time[0] + 3 * PeriodSeconds(_Period);

   // Rebuild only when the set of levels changes; otherwise just keep the labels next to the last bar.
   bool rebuild = (base != g_lastBase || step != g_lastStep || prev_calculated == 0);
   if(rebuild)
     {
      ObjectsDeleteAll(0, PFX);
      g_lastBase = base;
      g_lastStep = step;
     }
   int dg = (int)MathMax(0, MathMin(_Digits, MathCeil(-MathLog10(step))));
   for(int k = -InpCount + 1; k <= InpCount; k++)
     {
      double y = base + k * step;
      if(y <= 0)
         continue;
      long idx = (long)MathRound(y / step);
      bool major = (idx % InpMajorK) == 0;
      string nm = PFX + IntegerToString(k + InpCount);
      if(rebuild)
        {
         ObjectCreate(0, nm, OBJ_HLINE, 0, 0, y);
         ObjectSetInteger(0, nm, OBJPROP_COLOR, major ? InpColMajor : InpColMinor);
         ObjectSetInteger(0, nm, OBJPROP_STYLE, major ? STYLE_SOLID : InpMinorSty);
         ObjectSetInteger(0, nm, OBJPROP_WIDTH, major ? 2 : 1);
         ObjectSetInteger(0, nm, OBJPROP_BACK, true);
         ObjectSetInteger(0, nm, OBJPROP_SELECTABLE, false);
         ObjectSetInteger(0, nm, OBJPROP_HIDDEN, true);
        }
      if(InpLabels && (major || !InpLblMajor))
        {
         string lb = nm + "_lbl";
         if(ObjectFind(0, lb) < 0)
           {
            ObjectCreate(0, lb, OBJ_TEXT, 0, tLbl, y);
            ObjectSetInteger(0, lb, OBJPROP_ANCHOR, ANCHOR_LEFT_LOWER);
            ObjectSetInteger(0, lb, OBJPROP_FONTSIZE, 8);
            ObjectSetInteger(0, lb, OBJPROP_COLOR, major ? InpColMajor : InpColMinor);
            ObjectSetInteger(0, lb, OBJPROP_SELECTABLE, false);
            ObjectSetInteger(0, lb, OBJPROP_HIDDEN, true);
            ObjectSetString(0, lb, OBJPROP_TEXT, DoubleToString(y, dg));
           }
         ObjectMove(0, lb, 0, tLbl, y);
        }
     }
   return rates_total;
  }
//+------------------------------------------------------------------+