;== test onset
; ss= rainfall TS
; Thres = Rainfall Total Threshold mm/day (20mm)
; Nrain = over # of days (3 days)
; Ndry = # of consecutive dry days following the onset aka true (10dys)
; rain= threshold for rainyday (1mm)
;=================
; remove one day because of NCL indxing

undef("onset4")
function onset4(ss:float,Thres:float,Nrain:integer,Ndry:integer,rain:float)
local i0,i1,i,j,nn,ss1,ss2,ss3,ss33,in_days,ii,donset
begin
donset=(/-999.,-999./)
;==== TESTING
;Thres=20.
;Nrain=3
;Ndry=5
;rain=1.
;ss=asciiread("tt1.csv",-1,"float")

nn=dimsizes(ss)
ss1=new(nn+Nrain-1+Ndry,float) ;# 3 days total
ss1=0.0
ss1(Nrain-1:nn+(Nrain-2))=ss
ss2=new(dimsizes(ss1),float)
ss3=new(dimsizes(ss1),float)
ss33=new((/Ndry/),float)
in_days=ind(ss1 .gt. rain) ; assuming at least one rainy day

;==CASE OF NO RAIN AT ALL
if (any(ismissing(in_days))) then
return(donset)  ; no rainy days
end if

j=0
do i=0,dimsizes(in_days)-1  ;assuming 
   j=in_days(i)
   ss2(j)=sum(ss1(j-(Nrain-1):j:-1)) ; 3 days sum
   ss33(0:Ndry-1)=ss1(j+1:j+Ndry)
   ss3(j)=num( ss33 .eq. 0.) ; # dry days
;  print("i="+i+" J="+j+" Tot3="+ss2(j)+" CCDry5="+ss3(j))

end do

i0=ind(ss2 .gt. Thres)
i1=ind((ss2 .gt. Thres) .AND. (ss3 .lt. Ndry))

;==CASE OF TRUE ONSET
if (any( .not. ismissing(i1))) then
donset(0)=i0(0)
donset(1)=i1(0)
return(donset)
end if
;===CASE OF FALSE ONSET ONLY
if (any( .not. ismissing(i0))) then
donset(0)=i0(0)
return(donset)
end if

;== CASE OF RAIN BUT NOT AN ONSET
return(donset)
end