#!/bin/sh
# licenced under GPL 2005 Yargo C Bonetti
CVSID='$Id: nago.sh,v 1.15 2010/01/29 00:07:49 yargo Exp $'

# external programs
pager=${PAGER:-more}
pager=more
browser=${BROWSER:-lynx -force_html}
telnet=${TELNET:-telnet}
#imgviewer=display
imgviewer=echo
#mync () { ${NETCAT:-/sys/pkg/sbin/nc} "$@" ; }
#mync () { socat -t9 tcp4:$1:$2 - ; }
mync () { read gf ; snarf "gopher://$1:$2/$gf" '-'; }
STDHOME=sdf.lonestar.org/

# just in case somebody changes the standard...
gopherport=70

gopherhome=${GOPHER_HOME:-$STDHOME}

# temporary files
tmpbase=${TEMP:-/tmp}
tmpprefix=`basename $0`tmp
dirtmp=$tmpbase/$tmpprefix.$$.dir
ftmp=$tmpbase/$tmpprefix.$$.tmp
stack=$tmpbase/$tmpprefix.$$.stack

if [ "$1" = "" ] ; then
 cat <<EOH
 usage: $0 [-h|<server>] [<directory> <port>]
 where <server> is a server in gopherspace, <directory> a subdir on it,
  and <port> the port to connect to (default $gopherport)
  e.g: $0 sdf.lonestar.org /users/yargo
 -h uses environment variable GOPHER_HOME as starting point
   (currently $GOPHER_HOME),
   or if that is empty, $STDHOME
   (only default port $gopherport is supported, and must be a directory)
 Note: will not work for retrieving a file directly! (undefined behaviour)
 ($CVSID)
EOH
exit 1
fi


rmexit () { rm -f $dirtmp $ftmp $stack ; exit $1 ; }

# make sure temporary files are writable
rm -f $dirtmp $ftmp $stack
if ! echo test > $dirtmp ; then
 echo "** cannot write into temporary file $dirtmp - giving up!"
 rmexit 9
fi
if ! echo test > $ftmp ; then
 echo "** cannot write into temporary file $ftmp - giving up!"
 rmexit 9
fi
if ! echo test > $stack ; then
 echo "** cannot write into stack file $stack - giving up!"
 rmexit 9
fi

if [ "$1" = "-h" ] ; then
# remove / and all after
 s_ser=${gopherhome%%/*}
# remove first / and all before, and prepend / again
 s_dir=/${gopherhome#*/}
 s_por=$gopherport
else
 s_ser=$1
 s_dir=/$2
 s_por=${3:-$gopherport}
fi
# selector type: directory
s_typ=1

echo "starting at $s_ser:$s_por$s_dir"

# get a directory $s_dir from server $s_ser , port $s_por,
# preprocess it, and store it
getdir () {
# get directory
 if echo "$s_dir" | mync "$s_ser" "$s_por" | sed -e 's/
//g;/^.$/d' >$ftmp
 then
  oldifs="$IFS"; IFS='	'
# line number counter
  ln=1
# add title = server directory, will also represent selectable line number
  echo "  0	 $s_ser:$s_por $s_dir" >$dirtmp
# now process every line in turn
  cat $ftmp | { while read ft rest ; do
# test filetype=1st character
   case $ft in
# i=fake, don't generate a number - note: there are TABs in the two strings!
   i*) echo ".	$ft	$rest" >>$dirtmp ;;
# otherwise it is an entry which may be selected: prepend number, increment
   *) echo "  $ln	$ft	$rest" >>$dirtmp ; ln=`expr $ln + 1` ;;
   esac
  done
  }
  IFS="$oldifs"
 else
# cannot get directory, error
  return 1
 fi
}

# definitions for actions:
ACT_back=0
ACT_select=1
ACT_quit=2
ACT_other=3

# show directory (in $dirtmp), and return selection type, dir, server, port
# and action in variables s_typ, s_dir, s_ser, s_por, s_act
selectdir () {
# take field 1&2 only, remove 1 char after first tab (filetype), store
# (note TABs in sed argument)
 cat $dirtmp | cut -f 1-2 |
  sed -e 's/	\(.\)\(.*\)/	\2 \/\1/;s/ \/[.i1]$//' >$ftmp
 ln=X
 act=$ACT_select
# repeat until legal linenumber given (note: 0 is legal!)
 while ! grep "^  $ln	" $dirtmp >/dev/null ; do
# show directory
  $pager $ftmp
  echo "enter line number (0 or b for back), (o)pen other, e(x)it, (q)uit!"
  read inp
  case $inp in
# set action flag
  q*|x*) ln=0 ; act=$ACT_quit ;;
  o*) ln=0 ; act=$ACT_other
      echo "other server? (empty=same)"
      read inp
      s_ser=${inp:-$s_ser}
      echo "port? (empty=$gopherport)"
      read inp
      s_por=${inp:-$gopherport}
      echo "directory? (may be empty)"
      read s_dir ;;
  b*) ln=0 ; act=$ACT_back ;;
  *) ln=${inp:-0}
     if [ $ln = 0 ] ; then act=$ACT_back
     else act=$ACT_select
     fi ;;
  esac
 done
 s_act=$act
 case $s_act in
 $ACT_back|$ACT_other) s_typ=1 ;;
 *) s_typ=`grep "^  $ln	" $dirtmp | cut -f 2 | sed -e 's/\(.\).*/\1/'`
    s_por=`grep "^  $ln	" $dirtmp | cut -f 5`
# if not enough fields, it's a top level address (server only)
    if [ "$s_por" = "" ] ; then
     s_dir=/
     s_ser=`grep "^  $ln	" $dirtmp | cut -f 3`
     s_por=`grep "^  $ln	" $dirtmp | cut -f 4`
# otherwise, directory is given as well
    else
     s_dir=`grep "^  $ln	" $dirtmp | cut -f 3`
     s_ser=`grep "^  $ln	" $dirtmp | cut -f 4`
    fi
    ;;
 esac
}

# save current point in stack
pushlevel () {
 echo "$s_ser	$s_por	$s_dir" >>$stack
}

# recall point from stack
poplevel () {
 s_ser=`tail -n 1 $stack | cut -f 1`
 s_por=`tail -n 1 $stack | cut -f 2`
 s_dir=`tail -n 1 $stack | cut -f 3`
 ln=`wc $stack | { read l dummy ; echo $l ; }`
 if [ $ln -gt 0 ] ; then
  ln=`expr $ln - 1`
  if head -n $ln $stack >$ftmp 2>/dev/null ; then cat $ftmp >$stack
  else :>$stack
  fi
 else
  echo "no more data in history, quitting"
  rmexit 0
 fi
}

# main program

# initialize stack with first arguments, save some "spare"
rm -f $stack
pushlevel

s_act=X
while [ $s_act != $ACT_quit ] ; do
 pushlevel
 if getdir ; then selectdir
  case $s_act in
  $ACT_back) poplevel ; poplevel ;;
  $ACT_other) echo "going to $s_ser : $s_por, fetching $s_dir" ;;
  $ACT_select) case $s_typ in
   1) echo "changing to $s_dir" ;;
   8) echo "telnetting..."
      $telnet $s_ser $s_por
      echo "** telnet finished, hit return to continue..."
      read inp
      poplevel
      ;;
# otherwise download
   *) echo "downloading $s_dir ..."
      if [ "$s_typ" = "7" ] ; then
       echo "please enter request string:"
       read request
       s_dir="$s_dir?$request" 
      fi
      if echo "$s_dir" | mync "$s_ser" "$s_por" >$ftmp
      then
       case $s_typ in
       0) $pager $ftmp ;;
       7) $pager $ftmp ;;
       g) $imgviewer $ftmp ;;
       h) $browser $ftmp ;;
       I) $imgviewer $ftmp ;;
       *) echo "cannot display file type $s_typ, only save" ;;
       esac
       echo "** enter local filename to save (empty: no saving)"
       read inp
       while [ "$inp" != "" ] ; do
        if [ -f "$inp" ] ; then echo "warning: $inp exists!"
        elif cat $ftmp >"$inp" ; then break
        else echo "error: could not write file $inp!"
        echo "enter local filename to save (empty: no saving)"
        fi
       read inp
       done
      else echo "cannot download $s_dir!"
      fi
      poplevel
   esac ;;
  $ACT_quit) echo "bye!" ;;
  *) echo "** unrecognized command, internal error! trying to go on..."
     poplevel ;;
  esac
 else
  echo "** error getting $s_dir from $s_ser:$s_por!"
  poplevel ; poplevel
 fi
done
rmexit 0

.