DearMQL5/Core/UEventQueue.mqh

//+------------------------------------------------------------------+
//|                                                  UEventQueue.mqh |
//|                                  Copyright 2026, DearMQL5 GUI Engine |
//|                                             https://www.mql5.com |
//+------------------------------------------------------------------+
#property copyright "Copyright 2026, DearMQL5 GUI Engine"
#property link      "https://www.mql5.com"
#property strict

///  Event types generated by DearMQL5 widgets.
enum ENUM_U_EVENT_TYPE
  {
   U_EVENT_NONE        = 0,
   U_EVENT_CLICK       = 1,
   U_EVENT_VALUE_CHANGE= 2,
   U_EVENT_SUBMIT      = 3,
   U_EVENT_DRAG        = 4
  };

///  Discrete GUI event packet.
struct SUIEvent
  {
   ENUM_U_EVENT_TYPE type;         ///< Category of event
   ulong             widget_id;    ///< FNV-1a hash of source widget
   double            float_value;  ///< Numeric payload (slider values, etc.)
   string            string_value; ///< Textual payload (edit boxes, etc.)
  };

///  Circular event buffer for decoupling widget interaction from consumer code.
class UEventQueue
  {
private:
   static SUIEvent s_queue[64];
   static int      s_head;
   static int      s_tail;
   static int      s_count;

public:
   ///  Resets the event queue.
   static void Clear(void)
     {
      s_head  = 0;
      s_tail  = 0;
      s_count = 0;
     }

   ///  Pushes an event to the queue.
   static bool Push(const ENUM_U_EVENT_TYPE type,
                    const ulong widget_id,
                    const double float_val = 0.0,
                    const string str_val = "")
     {
      if(s_count >= 64)
         return(false); // Buffer full

      s_queue[s_tail].type         = type;
      s_queue[s_tail].widget_id    = widget_id;
      s_queue[s_tail].float_value  = float_val;
      s_queue[s_tail].string_value = str_val;

      s_tail = (s_tail + 1) % 64;
      s_count++;
      return(true);
     }

   ///  Pops the next event from the queue. Returns false if queue is empty.
   static bool Pop(SUIEvent &event)
     {
      if(s_count <= 0)
         return(false);

      event = s_queue[s_head];
      s_head = (s_head + 1) % 64;
      s_count--;
      return(true);
     }

   ///  Returns whether there are pending events in the queue.
   static bool HasEvents(void)
     {
      return(s_count > 0);
     }
  };

SUIEvent UEventQueue::s_queue[64];
int      UEventQueue::s_head  = 0;
int      UEventQueue::s_tail  = 0;
int      UEventQueue::s_count = 0;