#!/bin/bash

if [ $# -le 2 ]; then
  echo "$0 PSFILE PAGE1 [PAGE2...PAGEn]" >&2
  exit 1
fi

psfile="$1"
shift

fpage=$( egrep -n "^%%Page: 1 1" $psfile | sed -e 's/^\([0-9]\+\):.*/\1/' )
if [ "$fpage" == "" ]; then
  echo "cannot find first page" >&2
  exit 1
fi
 
fpage=$(( $fpage - 1 ))
totlines=$( cat $psfile | wc -l )
cat $psfile |head -n $fpage > head.$$

echo "$psfile has $totlines lines"

npages=1
for plist in $*
do
  ppage=$( egrep -n "^%%Page: [0-9]* $plist" $psfile |sed -e 's/^\([0-9]\+\):.*/\1/' )
  if [ "$ppage" == "" ]; then
    echo "page $plist does not exist" >&2
    continue
  fi
  echo "Page $plist start at line $ppage"
  gcut=$(( $totlines - $ppage + 1 ))
  echo "Page $plist, tail at $gcut"
  cat $psfile |tail -n $gcut > part.$$
  epage=$( egrep -n "^%%PageTrailer" part.$$ |sed -e 's/^\([0-9]\+\):.*/\1/' |cut -d"
" -f1 )
  if [ "$epage" == "" ]; then
    #se non trova PageTrailer, prova a cercare la pagina successiva...
    nplist=$(( $plist + 1 ))
    sucpage=$( egrep -n "^%%Page: [0-9]* $nplist" part.$$ |sed -e 's/^\([0-9]\+\):.*/\1/' )
    if [ "$sucpage" == "" ]; then
      echo "cannot find end of page $plist ..." >&2
      echo "it could be the last page... if it is not I can't do no more" >&2
      echo -n "Is it the last pages? [y/N] "
      read lastpag
      if [ "$lastpag" != "y" ]; then
          echo "cannot find page $plist trailer!" >&2
          rm part.$$
          continue
      else
          sucpage=$( egrep -n "^%%Trailer" part.$$ |sed -e -e 's/^\([0-9]\+\):.*/\1/' )
      fi
    else
      echo "Page $plist, succ is $nplist, found at $sucpage"
      epage=$(( $sucpage - 1 ))
    fi

  fi
  #epage=$(( $epage - 1 ))
  echo "Page $plist ends at line $(( $ppage + $epage ))"
  cat part.$$ |head -n $epage |sed -e "s/^%%Page: [0-9]* $plist/%%Page: $npages $npages/" >> head.$$
  npages=$(( $npages + 1 ))
done

npages=$(( $npages - 1 ))
rm part.$$
trailline=$( egrep -n "^%%Trailer" $psfile |sed -e 's/^\([0-9]\+\):.*/\1/' )
traill=$(( $totlines - $trailline + 1 ))
echo "Trailer starts at $trailline, tail at $traill"
cat $psfile |tail -n $traill |sed -e "s/^%%Pages: [0-9]*/%%Pages: $npages/" >> head.$$

mv head.$$ $(echo "$psfile" |sed -e 's/\.ps$//')-page.ps

exit 0