Adding alert to Naradaya-Watson indicator - TradingView

Question

for a very long time, I'm struggling with adding alerts about the trend change to the following indicator on TradingView. Here is the code:

study("Nadaraya-Watson Estimator [LUX]",overlay=true,max_lines_count=500,max_bars_back=500)
h = input(8.,'Bandwidth')
src = input(close,'Source')
//----
n = bar_index
var ln = array.new_line(0) 
if barstate.isfirst
    for i = 0 to 499
        array.push(ln,line.new(na,na,na,na))
//----
float y2 = na
float y1 = na
float y1_d = na
//----
line l = na
label lb = na
if barstate.islast
    for i = 0 to min(499,n-1)
        sum = 0.
        sumw = 0.
        for j = 0 to min(499,n-1)
            w = exp(-(pow(i-j,2)/(h*h*2)))
            sum += src[j]*w
            sumw += w
        y2 := sum/sumw
        d = y2 - y1

        l := array.get(ln,i)
        line.set_xy1(l,n-i+1,y1)
        line.set_xy2(l,n-i,y2)
        line.set_color(l,y2 > y1 ? #ff1100 : #39ff14)
        line.set_width(l,2)
        
        if d > 0 and y1_d < 0
            label.new(n-i+1,src[i],'▲',color=#00000000,style=label.style_label_up,textcolor=#39ff14,textalign=text.align_center) 
        if d < 0 and y1_d > 0
            label.new(n-i+1,src[i],'▼',color=#00000000,style=label.style_label_down,textcolor=#ff1100,textalign=text.align_center) 

        y1 := y2
        y1_d := d

In comments to the indicator, someone suggested adding the following lines to add alerts. However, when I add them I still get no working alerts.

Between lines 17&18 add:

m2 = 0.0
m1 = 0.0
m0 = 0.0

After line 44 add:

if m0 > m1 and m1 < m2
alerts("Estimator turns green")
if m0 < m1 and m1 > m2
alerts("Estimator turns red")

I know that it is a repainting indicator, but in the case of using a high bandwidth value (like 50) I find it very useful.

I would truly appreciate a community help with that issue, as I was trying to fix it on my own, but without any success.

Thanks in advance. Paul