; 
; PURPOSE:  Calculate date and time that correspond to a fractional crn:Cl0
; CALLING SEQUENCE :
;  datetime_scrncl0_200905,crn,cl0,reso,year,month,day,hh,mm,ss,/plt
; IUPUT:   crn,cl0,reso
; OUTPUT:  year,month,day,hh,mm,ss,/plt
; MODIFICATION HISTORY :
;    First version: 20090531 by X. Zhao based on datetime_scrncl0.pro
;                   20060327 by X. Zhao
;    Second version: 20090610 by X. Zhao changing "reso=" to reso
;
pro datetime_scrncl0_200906,crn,cl0,reso,cl0i,year,month,day1,DTL1=dtl1,DTL2=dtl2

    if N_params() LT 1 then begin
       print,'datetime_scrncl0_200906,crn,cl0,reso,cl0i,year,month,day1,/dtl1,/dtl2'
       print,"crn=2081 & cl0=180.50"
       print,"resolution of 0.1, 0.05, 0.01, 0.05, 0.003, 0.009, 0.0003"
       return
    endif
    scrncl0=STRTRIM(crn,2)+':'+STRTRIM(FIX(cl0),2)
    spawn,'times ct'+scrncl0+' > outdata.d'
    date=' '
    get_lun,unit
    openr,unit,'outdata.d'
    readf,unit,date
    free_lun,unit
    spawn,'rm outdata.d'
    year  = fix(strmid(date,0,4))
    month = fix(strmid(date,5,2))
    day   = fix(strmid(date,8,2))
    hrs00=FIX(STRMID(date,11,2))
    hrs01=FIX(STRMID(date,15,2))/60.+FIX(STRMID(date,19,2))/3600.
    hrs0=hrs00+hrs01
    days0=day+hrs0/24.
    cl0_yyyymmddtime,year,month,day,hrs0,cl0i
    dcl=cl0i-cl0
    if ABS(dcl) gt 100 then cl0i=cl0i+360
    dcl=cl0i-cl0
if keyword_set(dtl1) then begin
print,'date,hrs0:',date,hrs0
print,'cl0,First cl0i:',cl0,cl0i
endif
    CASE 1 OF
       dcl gt reso: begin
                   if hrs00 eq 23 then begin
                      day=day+1
                      hrs0=hrs01
                      hrs=hrs0
                   endif else hrs=hrs0
        lbl1:      hrs=hrs+1.
                   cl0_yyyymmddtime,year,month,day,hrs,cl0i
                   dcl=cl0i-cl0
                   if ABS(dcl) gt 100 then cl0i=cl0i+360
                   dcl=cl0i-cl0
         if keyword_set(dtl1) then print,'cl0i,dcl:',cl0i,dcl
                   CASE 1 OF
                      dcl gt reso: goto, lbl1 
                      dcl lt -reso: begin
        lbl2:                   hrs=hrs-reso
                                cl0_yyyymmddtime,year,month,day,hrs,cl0i
                                dcl=cl0i-cl0
                                if dcl lt -reso then goto, lbl2 $
                                else day1=day+hrs/24.
                                   end
                      else: day1=day+hrs/24.
                   ENDCASE
                   end
       dcl lt -reso: begin
                    if hrs00 eq 0 then begin
                       day=day-1
                       hrs0=24+hrs01
                       hrs=hrs0
                    endif else hrs=hrs0
        lbl3:      hrs=hrs-1.
                   cl0_yyyymmddtime,year,month,day,hrs,cl0i
                   dcl=cl0i-cl0
        if keyword_set(dtl1) then  print,'cl0i,dcl:',cl0i,dcl
                   CASE 1 OF
                      dcl lt -reso: goto, lbl3
                      dcl gt reso: begin
                      ;         hrs=hrs+1.
        lbl4:                   hrs=hrs+reso
                                cl0_yyyymmddtime,year,month,day,hrs,cl0i
                                dcl=cl0i-cl0
                                if dcl gt reso then goto, lbl4 $
                                else day1=day+hrs/24.
                                end
                      else: day1=day+hrs/24.
                   ENDCASE
                    end
       else: day1=day+hrs0/24.
     ENDCASE
     hrs1=(day1-day)*24.
     hh=FIX(hrs1) & mm=FIX((hrs1-hh)*60) & ss=FIX((hrs1-hh)*3600-mm*60)
     if hh eq 24 then begin
        day=day+1
        hh=0
     endif
     if keyword_set(dtl2) then begin
        date_year_sec,year,month,day,hh,mm,ss,date1
        print,'Orig. cl0 and date from times:',cl0,' ',date
        print,'Last cl0i and date           :',cl0i,' ',date1
     endif

end