#! /bin/sh
#
###	zvi, zex, zed - gunzip file(s), edit, re-gzip
###	Usage: zvi/zex/zed file(s)-or-file(s)[.gz]
##
##	THESE PROGRAMS BOTH DO THE SAME THING: UNCOMPRESS ONE OR MORE
##	FILE(S), RUN vi, ex OR ed ON THEM, THEN RECOMPRESS THEM IN THE
##	BACKGROUND.
##
##	WHEN YOU GIVE IT MORE THAN ONE FILE TO EDIT, THE PROGRAM ONLY
##	UNCOMPRESSES THE FIRST FILE BEFORE STARTING THE EDITOR.  IT DOES THE
##	REST IN THE BACKGROUND WHILE YOU EDIT THE FIRST FILE.
##
##	ALL THE FILES YOU EDIT HAVE TO BE COMPRESSED BEFORE YOU START THE
##	PROGRAM.  BUT YOU DON'T HAVE TO TYPE THE .gz EXTENSION(S) IF YOU
##	DON'T WANT TO.  THAT MEANS YOU CAN USE WILDCARDS OR FILENAMES:
##		zvi *.gz
##	YOU CAN ALSO REDIRECT INPUT TO USE AN (UNCOMPRESSED!) EDITING SCRIPT:
##		zex aprog.c < exscr
##
##	WHEN YOU QUIT THE EDITOR, THE RECOMPRESSION STARTS IN THE
##	BACKGROUND.  IF THERE ARE ANY ERRORS, THE PROGRAM WILL SEND YOU
##	MAIL WITH A COPY OF THE ERRORS.

gzip=/usr/local/bin/gzip
fmt=/usr/ucb/fmt
mailer=/usr/ucb/mail
gunzip=/usr/local/bin/gunzip

# UNCOMMENT THE RIGHT LINE FOR YOUR UNIX:
# echo="echo -n" nnl= 	# BSD
# echo=echo      nnl="\c"	# SYSV
echo="echo -n" nnl= 	PATH=/usr/bin:$PATH; export PATH	# SunOS

# SHOULD HAVE A trap THAT ASKS ABOUT RECOMPRESSING
# AND CHECKS STATUS OF BACKGROUND gunzip JOBS.... SIGH.

case "$0" in
*zed) prog=ed  myname=zed ;;
*zex) prog=ex  myname=zex ;;
*zvi) prog=vi  myname=zvi ;;
*)	echo "$0: quitting: I don't know how to run myself!" 1>&2; exit 1 ;;
esac

t=/tmp/CMPRS$$	# TEMP FILE (REMOVED BY BACKGROUND JOB AT END)

# NOTE: need to understand two-word options like "-c command"
# and pass those to the editor.
for arg
do
	case "$arg" in
	-*)	echo "$myname: I don't understand options (yet)..." 1>&2; exit 1 ;;
	*)	# ASSUME IT'S A FILE...
		case "$arg" in
		*.gz) file="`expr $arg : '\(.*\).gz'`" ;;	# $arg WITHOUT THE .gz
		*) file="$arg" ;;	# ASSUME FILE HAS A .gz EXTENSION...
		esac

		if [ ! -r "${file}.gz" ]
		then
			echo "$myname: can't read '${file}.gz'." 1>&2
			$echo "Do you want to quit [yn](y)? $nnl"
			read ans
			case "$ans" in
			""|[yY]*)	exit 1 ;;
			*)	echo "$myname: I'll skip '$file.gz'..." 1>&2
				continue	# DON'T ADD $file TO LISTS
				;;
			esac
		fi
		
		# UNCOMPRESS FIRST FILE IN FOREGROUND (LATER, IF ALL ARGS OK):
		case "$files" in
		"")	fgfile="$file" ;;
		*)	bgfiles="$bgfiles $file" ;;
		esac
		# $files SHOULD HOLD *UNCOMPRESSED* NAMES.
		files="$files $file"
	esac
done

case "$fgfile" in
"")	echo "Usage: $myname file [files]
	You didn't give me any file names." 1>&2
	exit 1
	;;
*)	$gunzip $fgfile || {
		echo "$myname quitting: 'gunzip $fgfile' bombed." 1>&2
		exit 1
	}
	;;
esac

# IF gunzip BOMBS, WE'LL ALREADY BE IN THE EDITOR.
# sort-of FIX: SAVE ERRORS AND SHOW THEM WHEN EDITOR EXITS.
# IF NO $bgfiles, DON'T DO ANYTHING:
test -n "$bgfiles" && $gunzip $bgfiles >$t 2>&1 &

$prog $files
if [ -s $t ]
then
	echo "$myname: 'gunzip $bgfiles' bombed:" 1>&2
	cat $t 1>&2
	$echo "Should I try to gzip all files [ny](n)? $nnl"
	read ans
	case "$ans" in
	""|[nN]*) echo "$myname: warning: not gzipping $files" 1>&2; exit 1 ;;
	esac
else
	s="$myname gzipping ERROR in `pwd`"	# MAIL MESSAGE SUBJECT
	# USE trap TO ACT LIKE nohup WITHOUT THE nice: 
	sh -c "trap '' 1 15; $gzip $files >$t 2>&1;
	test -s $t && $mailer -s '$s' ${USER-$LOGNAME} <$t; rm -f $t" &

	echo $myname: re-gzipping $files in the background... | $fmt 1>&2
fi