Help adding alert to Indicator

I just want this indicator to alert.wav me when a new bar causes the graph to turn from Yellow to Green, or Yellow to Red or Green/Red turns Yellow. Green being bullish, Yellow is ranging, and Red is Bearish. Would be greatly appreciated. Thank you!
//±-----------------------------------------------------------------+
//| |
//| Copyright © 2004, MetaQuotes Software Corp. |
//|
//±-----------------------------------------------------------------+
#property copyright "Copyright © 2005, FX Sniper "

//---- indicator settings
#property indicator_separate_window
#property indicator_buffers 3
#property indicator_color1 Yellow
#property indicator_color2 Green
#property indicator_color3 Red

//---- buffers
double ExtMapBuffer1[];
double ExtMapBuffer2[];
double ExtMapBuffer3[];
int width;

extern int Rperiod = 5;
extern int Draw4HowLongg = 1500;
int Draw4HowLong;
int shift;
int i;
int loopbegin;
double sum[];
int length;
double lengthvar;
double tmp ;
double wt[];
int c;

//±-----------------------------------------------------------------+
//| Custom indicator initialization function |
//±-----------------------------------------------------------------+
int init()
{
//---- 2 additional buffers are used for counting.
IndicatorBuffers(5);

//---- drawing settings
SetIndexBuffer(2,ExtMapBuffer1);
SetIndexBuffer(1,ExtMapBuffer2);
SetIndexBuffer(0,ExtMapBuffer3);
SetIndexBuffer(3,sum);
SetIndexBuffer(4,wt);

SetIndexStyle(2,DRAW_LINE,STYLE_SOLID,2);
SetIndexStyle(1,DRAW_LINE,STYLE_SOLID,2);
SetIndexStyle(0,DRAW_LINE,STYLE_SOLID,2);

//---- initialization done
return(0);
}

int start()

{ Draw4HowLong = Bars-Rperiod - 5;
length = Rperiod;
loopbegin = Draw4HowLong - length - 1;

  for(shift = loopbegin; shift >= 0; shift--)
  { 
     sum[1] = 0;
     for(i = length; i >= 1  ; i--)
     {
     lengthvar = length + 1;
     lengthvar /= 3;
     tmp = 0;
     tmp = ( i - lengthvar)*Close[length-i+shift];
     sum[1]+=tmp;
     }
     wt[shift] = sum[1]*6/(length*(length+1));

//========== COLOR CODING ===========================================

   ExtMapBuffer3[shift] = wt[shift]; //red 
   ExtMapBuffer2[shift] = wt[shift]; //green
   ExtMapBuffer1[shift] = wt[shift]; //yellow
   
   //  for(c=loopbegin;c==shift;c++)
   // {
    if (wt[shift+1] > wt[shift])
    {
    ExtMapBuffer2[shift] = EMPTY_VALUE;

// ObjectCreate(“smiley_face”, OBJ_ARROW, 0, Time[shift], Low[shift]-Point*20);
// Print("time= ",Time[shift]);
// ObjectSet(“smiley_face”, OBJPROP_ARROWCODE, 242);
// ObjectSet(“smiley_face”, OBJPROP_COLOR , Red);
// ObjectSet(“smiley_face”, OBJPROP_WIDTH , 1);
// ObjectsRedraw();

    //ExtMapBuffer3[shift+1] = EMPTY_VALUE;
    //ExtMapBuffer3[shift+1] = EMPTY_VALUE;
    
    }
   else if (wt[shift+1] < wt[shift]) 
    {
    ExtMapBuffer1[shift] = EMPTY_VALUE; //-1 red/greem tight
   //ExtMapBuffer3[shift+1] = EMPTY_VALUE;
    
    }
     else 
     {
     
     ExtMapBuffer1[shift]=EMPTY_VALUE;//EMPTY_VALUE;
     ExtMapBuffer2[shift]=EMPTY_VALUE;//EMPTY_VALUE;
     }
    
  }

  return(0);

}
//±-----------------------------------------------------------------+

It seems not working.