parameter i1 i2 nointer 

! Gets shifts between images
! Sorts files into stacks for CR rejections by pointing only
! Sorts files into stacks for combination by pointing and exptime
open input ./fields.lis
stat n=count[input]
string field {input}
call {field}setup

if acs==1
  n=2
end_if
if wfpc==1
  n=4
end_if
if mosaic==1
  n=8
end_if

if i1==0
  i1=1
  i2=n
else_if i2==0
  i2=i1
end_if

$mkdir oldcomb
$mv comb_*.out oldcomb/

! Do two passes. First pass will just use header shifts and will then
!   call PICCRS for CR rejection. Second pass will use the CR-rejected
!   frames and get shifts by cross-correlation

do ipass=1,2
  
 $'rm' cross.dat getshift.err
 do ifield=1,n

  if ifield>=i1&ifield<=i2
   if wfpc==1|mosaic==1|acs==1
    call {field}setup ifield
   else
    call {field}setup
   end_if

   call look ipass-1
   nn=ntot
   tmax=0
   do i=1,nn
     t={i:exptime}
     if (t>tmax) 
       iref=i
       tmax=t
     end_if
   end_do
   i=0
   do ifilt=1,nfilt
     do isort=1,2
       if isort==1
       ! For CR reject, sort by pointing only
         tmin=0 tmax=1e10 
         dmax=0.3
       else_if isort==2
         ! For combining , sort by pointing and exposure time
         if wfpc==1
           tmin=0.5 tmax=2.
         end_if
         dmax=0.5
       end_if
       npoint=0 
       string nf 'nframe%i1' ifilt
       do j=1,{nf}
         i=i+1
         if (i==iref)
           dx=0 dy=0 dxhead=0 dyhead=0
         else
           if ipass==1
             call getshift iref i 0
           else
             call getshift iref i 1
           end_if
         end_if
         if (i==1)
           dx0=dx dy0=dy
         end_if
         texp={i:exptime}
         call getfilt i
!         string filt {i:filtnam1}
         string var 'name%i1%i2.2' ifilt j
         if isort==1
           printf '%4f8.2 {filt} {i:exptime} {{var}}' dx-dx0 dy-dy0 |
              dxhead-dx0 dyhead-dy0 >>./cross.dat
           string rout 'crmask_{filt}'
         else
           string rout 'comb_{filt}'
         end_if
         jpoint=0 new=0
         if npoint>0
           do ipoint=1,npoint
             string xvar 'pdx%i' ipoint
             string yvar 'pdy%i' ipoint
             string tvar 'pexp%i' ipoint
             if (abs[dx-{xvar}]<dmax&abs[dy-{yvar}]<dmax&texp/{tvar}>tmin&texp/{tvar}<tmax)
               jpoint=ipoint
             end_if
           end_do
         end_if
         if jpoint==0
           new=1
           npoint=npoint+1
           string var 'pdx%i' npoint
           {var}=dx
           string var 'pdy%i' npoint
           {var}=dy
           string var 'pexp%i' npoint
           {var}=texp
           jpoint=npoint
         end_if
         string pdx 'pdx%i' jpoint
         string pdy 'pdy%i' jpoint
         string out '{rout}%i' jpoint
         string var 'name%i1%i2.2' ifilt j
         if isort==2
           if new==1
             printf '{{var}}_c0f %2f8.2' dx dy >./{out}.out
           else
             printf '{{var}}_c0f %2f8.2' dx dy >>./{out}.out
           end_if
         else
           if new==1
             printf '{{var}}_c0f %2f8.2' dx-{pdx} dy-{pdy} >./{out}.out
           else
             printf '{{var}}_c0f %2f8.2' dx-{pdx} dy-{pdy} >>./{out}.out
           end_if
           if j==1
             printf '{{var}}_c0f %2f8.2' dx dy >./{rout}.all
           else
             printf '{{var}}_c0f %2f8.2' dx dy >>./{rout}.all
           end_if
         end_if
       end_do
       if isort==1
         i=i-{nf}
         ! Find out if any of the pointings only have one image, in which case we will
         !   want to CR-reject them along with another pointing
         do jpoint=1,npoint
           string var 'n%i' jpoint
           string out '{rout}%i' jpoint
           open inpoint ./{out}.out
           stat {var}=count[inpoint]
           close inpoint
         end_do
       end_if 
     end_do
   end_do

  end_if

 end_do

if ipass==1
  oldshift=ishift
  ishift=1
  call piccrs
  ishift=oldshift
else
  $'rm' red/*[1-4].fits red/z*.img red/z*.hdr
end_if
end_do

$'rm' crmask.all
do ifilt=1,nfilt
  string nf 'nframe%i1' ifilt
  if {nf}==1
    $cat crmask_*.all > crmask.all
  end_if
end_do

$mkdir newcomb
$cp comb_*.out newcomb/
$diff oldcomb newcomb >./{field}.diffcomb

end