#!/bin/sh
# $NetBSD: pkgvi,v 1.13 2023/11/15 17:50:51 wiz Exp $
#
# Copyright (c) 2001 Tomasz Luchowski. All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
#    notice, this list of conditions and the following disclaimer in the
#    documentation and/or other materials provided with the distribution.
# 3. All advertising materials mentioning features or use of this software
#    must display the following acknowledgement:
#	This product includes software developed by Tomasz Luchowski for
#	the NetBSD Project
# 4. The name of the author may not be used to endorse or promote products
#    derived from this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
# SUCH DAMAGE.
#

set -e

progname=`basename $0`
editor="vi"
if [ "$PKGEDITOR" != "" ]; then
	editor="$PKGEDITOR"
elif [ "$EDITOR" != "" ]; then
	editor="$EDITOR"
fi

die() {
	_exitcode=$1; shift
	warn "$@"
	exit ${_exitcode}
}

warn() {
	echo >&2 "$@"
}

usage() {
	die 1 "Usage: $progname [+cmd] file [...]"
}

prepare_backup_files() {
	for file in "$@"; do
		[ -f "$file" ] || die 2 "$progname: $file: No such file"
		chmod u+w "$file"
		if [ -f "$file.orig" ]; then
			echo "$progname: Backup already exists."
		else
			cp "$file" "$file.orig"
		fi
	done
}

remove_unneeded_backup_files() {
	for file in "$@"; do
		if cmp "$file" "$file.orig" >/dev/null 2>&1; then
			echo "$progname: File unchanged."
			rm -f "$file.orig"
		else
			echo "$progname: File was modified. For a diff, type:"
			echo "pkgdiff \"$file\""
		fi
	done
}

main() {
	[ $# -eq 0 ] && usage

	cmd=""
	case "$1" in
		+*)	cmd="$1"; shift	;;
	esac

	prepare_backup_files "$@"

	$editor $cmd "$@"

	remove_unneeded_backup_files "$@"
}

main "$@"
exit $?