#!/bin/sh
#
if [ $# != "1" ]; then
    echo usage: editentry filename
    exit 1
fi

F=T
while test -z "$EDITOR"
do
    if [ $F = "T" ]; then
	echo 'You do not have the shell variable $EDITOR set.'
	F=F
    fi
    echo ''
    echo -n 'Enter the name of an editor: '
    read EDITOR rubbish

    if [ ! -x "$EDITOR" ]; then
	IFSS="$IFS"
	IFS=: F="$EDITOR"
	EDITOR=
	for D in $PATH; do
	    if [ -x "$D/$F" ]; then
		EDITOR="$D/$F"
		break
	    fi
	done
	if [ -z "$EDITOR" ]; then
	    echo "$F not found, please try again..."
	fi
	IFS="$IFSS"
    fi
done

cp $1 $1.tmp

E=T
while true
do
    if [ $E = "T" ]; then
	if $EDITOR $1; then
	    if cmp -s $1 $1.tmp; then
		mess="No changes to draft entry - shall I continue? "
	    else
		mess="Are you sure you want to make these changes? "
	    fi	
	else
	    echo 'Edit aborted...'
	    rm -f $1.tmp
	    exit 1
	fi
    fi

    echo -n "$mess"
    read YN rubbish
    case "$YN" in
	y|yes|Y|YES) 
	    rm -f $1.tmp
	    exit 0
	    ;;

	n|no|N|NO)
	    mv $1.tmp $1
	    exit 1
	    ;;

	e|edit|E|EDIT)
	    cp $1 $1.tmp
	    if [ ! -z "$rubbish" ]
	    then
		EDITOR="$rubbish"
	    fi
	    E=T
	    ;;

	u|undo|U|UNDO)
	    cp $1.tmp $1
	    E=T
	    ;;

	*)		
	    case "$YN" in
		\?|""|h|help|H|HELP)
		    mess='Options are:'
		    ;;

		*)
		    mess="\"$YN\" not understood -- use one of:"
		    ;;
	    esac
	    echo "$mess"
	    echo '     yes - to commit'
	    echo '      no - to abort'
	    echo '    edit - to continue editing'
	    echo '    undo - to undo last edit and edit some more'
	    mess='Try again: '
	    E=F
	    ;;
    esac
done