;+
; FUNCTION get_scan_struc_arr
;
; :Description:
; 	Obtain a structure storing SD data sorted by scan. Usually this function is 
; 	used by the other routines. 
;
; :EXAMPLES:
;   dat = get_scan_struc_arr( 'sd_hok_vlos_1' )
;
; :Author:
; 	Tomo Hori (E-mail: horit at stelab.nagoya-u.ac.jp)
;
; :HISTORY:
; 	2011/07/01: Initial release
; 	
; $LastChangedBy: jwl $
; $LastChangedDate: 2014-02-10 16:54:11 -0800 (Mon, 10 Feb 2014) $
; $LastChangedRevision: 14265 $
; $URL: svn+ssh://thmsvn@ambrosia.ssl.berkeley.edu/repos/spdsoft/trunk/projects/erg/ground/radar/superdarn/get_scan_struc_arr.pro $;
;-

FUNCTION get_scan_struc_arr, vn 
  
  ;Check the argument
  npar = n_params()
  if npar ne 1 then return, 0
  vn = vn[0] ;only 1st element is processed below
  if (tnames(vn))[0] eq '' then return,0
  get_data, vn, data=d
  vartime = d.x & var = d.y 
  if (size(var))[0] ne 2 then return, 0
  
  ;Strings consisting of vn
  prefix = strmid(vn, 0,7)
  suf = strmid(vn, 0,1,/reverse) 
  azmno_vn = prefix+'azim_no_'+suf
  scanno_vn = prefix+'scanno_'+suf
  get_data, azmno_vn, data=d
  azmno = d.y 
  get_data, scanno_vn, data=d
  scanno = d.y
  
  scan = scanno[uniq(scanno)]
  azmno_sorted = azmno[sort(azmno)]
  azm = azmno_sorted[uniq(azmno_sorted)]
  azmmax = n_elements(azm)
  nrang = n_elements(var[0,*])
  
  ;Create a 2-D scan array and its time array
  vararr = fltarr( n_elements(scan), nrang, azmmax )
  timearr = dblarr(n_elements(scan))
  beamtarr = dblarr(n_elements(scan), 2)
  nbeamarr = intarr(n_elements(scan))
  vararr[*] = !values.f_nan
  
  ;Store data into the 2-D scan array
  for i=0L, n_elements(scan)-1 do begin
    tscan = scan[i]
    idx = where(scanno eq tscan)
    if idx[0] ne -1 then begin
      timearr[i] = mean( vartime[idx] ) 
                  ;Time label is the average for tplot drawing
      beamt = minmax( vartime[idx] ) 
      beamtarr[i,*] = transpose( [ beamt[0], beamt[1] ] ) ; Start and end time of each scan 
      tazmno = azmno[idx]
      nbeamarr[i] = n_elements(tazmno) 
      tvar = transpose(var[idx,*])
      for j=0, n_elements(tazmno)-1 do begin
        az = tazmno[j]
        if az lt 0 and az ge azmmax then continue ;beam number is invalid!
        vararr[i,*,az] = reform( tvar[*, j], 1,nrang,1)
        ;debugging
        ;if (i mod 100) eq 0 then print, tscan,tazmno[(sort(tazmno))[j]]
      endfor
    endif
  endfor
  
  return, {x:timearr, y:vararr, beamt:beamtarr, nbeam:nbeamarr }
end