#!/bin/bash
# Copyright 2006 John Duncan
# Designed to enable PAN file attachment when invoked as the external editor.
# As such, it may be distributed under the same license conditions, or
# under the terms of the GNU General Public License v2.0 or higher (at your option).
# http://pan.rebelbase.com/ or http://www.gnu.org/licenses/gpl.html.

NAME="pan-attach"
VERSION="0.0.2006.10.07.0"

# set this to text, uuen, yenc, or leave it blank, as desired
DEFAULT_FULL=uuen
case $DEFAULT_FULL in
  uuen)DEFAULT_ENCODE=u;;
  yenc)DEFAULT_ENCODE=y;;
  text)DEFAULT_ENCODE=t;;
  *)DEFAULT_ENCODE=
    DEFAULT_FULL=unset;;
esac

BODYFILE=${1:--h}
################################################################################
# description and help display function

function display_help {
  echo -e $NAME \\t version $VERSION \\t Copyright 2006 John Duncan
  echo
  echo $NAME is designed to enable PAN file attachment when invoked as its
  echo external editor.  $NAME has one requirement, uuenview from the uudeview package,
  echo the home page of which is http://www.fpx.de/fp/Software/UUDeview/
  echo
  echo Set PAN\'s external editor to $NAME %t. \(%t is the name
  echo of the temporary edit file as pan passes it to the editor.\)
  echo $NAME takes only that single parameter, either the file containing
  echo the body text as passed from PAN, or -h or --help for this text.
  echo
  echo Within the passed file, $NAME will look for two special lines of the form below:
  echo
  echo %%ENCODE=\<type\>%%
  echo -e \\t where \<type\> is one of uuen, yenc or text.  \(The default is $DEFAULT_FULL.\)
  echo -e \\t \(uuenview also encodes to base64 and quoted-printable,
  echo -e \\t however, scripting their headers would require additiional
  echo -e \\t help from PAN.\)  The FIRST instance is taken, others are ignored.
  echo
  echo NOTE: pan \> 0.90 won\'t take yenc at the time of this writing!
  echo
  echo %%ATFILE=\</path/file\>%%
  echo -e \\t One file at a time, for now.  Again, FIRST instance.
  echo
  echo Environment:
  echo You can set the \$PAN_EDITOR variable if you don\t want to give up your
  echo real external editor functionality.  If $NAME finds that set and you didn\'t
  echo specify a file to attach, $NAME will forward the body thru to that editor,
  echo again as \$PAN_EDITOR %t.
}

################################################################################
# This section invokes help and exits if help was directly invoked
# or if the first parameter isn't an existing regular file with rw perms.

[ $BODYFILE == '-h' -o $BODYFILE == '--help' ] && display_help && exit

fail1="$NAME error: invalid syntax.\nThe first parameter must be a "
fail2="file.\nInvoke as $NAME -h to display the help screen."
[ ! -f $BODYFILE ] && echo -e $fail1 regular $fail2 && exit
[ ! -r $BODYFILE ] && echo -e $fail1 readable $fail2 && exit
[ ! -w $BODYFILE ] && echo -e $fail1 writable $fail2 && exit

################################################################################
# This section sets the encoding parameter, ${ENCODEAS}, to u|y|t,
# and deletes the corresponding magic string line from ${BODYFILE}.

# Grab %%ENCODE=text|uuen|yenc%% magic string, along with its lineno.
ENCODEAS=$(egrep -anxm1 %%ENCODE=\(text\|uuen\|yenc\)%% ${BODYFILE})
if [ ${ENCODEAS} ]; then
  # We recognized a magic encode string line
  # Delete that lineno.
  sed -i $(echo ${ENCODEAS}|cut -d: -f1)d ${BODYFILE}
  # Trim the lineno.
  ENCODEAS=$(echo ${ENCODEAS}|cut -d: -f2)
  # Trim the type to single-char
  ENCODEAS=${ENCODEAS:9:1}
else
  # defaulted
  case $DEFAULT_ENCODE in
    t|u|y) ENCODEAS=$DEFAULT_ENCODE;;
    *)echo $NAME error: no encoding line detected and no default set. Aborting!
      exit
  esac	
fi


################################################################################
# This section grabs the file to attach, ${ATFILE}, and deletes the
# corresponding magic string line from ${BODYFILE}.

# Grab %%ATFILE=/path/filename%% magic string and lineno.
ATFILE=$(egrep -anxm1 %%ATFILE=.*%% ${BODYFILE})

# If no file to attach, let's assume they just wanted to edit the file...
# and hope they have a sane $EDITOR set.
if [ ! ${ATFILE} ]; then
  if [ -x "${PAN_EDITOR}" ]; then
    exec ${PAN_EDITOR} ${BODYFILE}
  else
    echo "Couldn't find a file to attach!  If you want to pass"
    echo "through to an external editor of your choice, export"
    echo "the \$PAN_EDITOR variable, and $NAME will call it"
    echo "as \$PAN_EDITOR \$BODYFILE"
    exit 1
  fi
fi

# We recognized a magic attach-file string line, but don't know if it's valid yet.
# Still, delete that lineno. from ${BODYFILE}
sed -i $(echo ${ATFILE}|cut -d: -f1)d ${BODYFILE}
# Trim the lineno.
ATFILE=$(echo ${ATFILE}|cut -d: -f2)
# Trim to the path & file
ATFILE=${ATFILE:9}
ATFILE=${ATFILE%%%%}

#Is ${ATFILE} actually readable?  If not, error out.
if [ ! -r ${ATFILE} ]; then
  echo "The file you said to attach,"
  echo "${ATFILE}"
  echo "wasn't readable!"
  exit 2
fi

################################################################################
# OK, we know the attach file is readable, and we know what encoding to use, so...
echo >> ${BODYFILE}
echo >> ${BODYFILE}
uuenview -${ENCODEAS} ${ATFILE} >> ${BODYFILE}

################################################################################
# debugging aids
#konsole --noclose --nohist -e echo $
#exec kwrite $BODYFILE