#!/bin/sh
set -e
fail () { echo >&2 "$0: $*"; exit 1; }

case "$1" in
edit|done) mode=$1
fi

case "$*.$1" in
1.-*)	fail "no options understood"		;;
1.*)	arg="$1"; shift				;;
*)	fail "need one arg"			;;
esac

case "$arg" in
*.git.tar)	base=${arg%.tar}			;;
*.git)		base=${arg}				;;
*)		fail "arg must end in .git[.tar]"	;;
esac

tryat_pre () {
	local b="$1"
	rm -rf "$b.tmp"
	if test -f "$b.tar" && test -f "$b.edit"; then
		echo "$b.edit exists, deleting possibly-obsolete $b.tar"
		rm "$b.tar"
	fi
}

tryat_edit () {
	local b="$1"
	if test -d "$b.edit"; then
		echo "$b.edit already exists"
		exit 0
	fi
	if test -f "$b.tar"; then
		mkdir "$b.tmp"
		(set -e; cd "$b.tmp"; tar xf "$b.tar")
		mv "$b.tmp/$b" "$b.edit"
		rm "$b.tar"
		rm -rf "$b.tmp"
		echo "$b.edit ready"
		exit 0
	fi
}

tryat_done () {
	local b="$1"
	if test -d "$b.edit"; then
		mkdir "$b.tmp"
		cp -al "$b.edit" "$b.tmp/$b"
		(set -e; cd "$b.tmp"; tar cf "$b.tmp/tar")
		mv "$b.tmp/tar" "$b.tar"
		rm -rf "$b.tmp"
		mv "$b.edit" "$b.tmp"
		rm -rf "$b.tmp"
		echo "$b.tar regenerated"
		exit 0
	fi
	if test -f "$b.tar"; then
		echo "$b.tar already exists and $b.edit doesn't"
		exit 0
	fi
}

tryat () {
	local b="$1"
	if ! test -f "$b.tar" && ! test -f "$b.edit"; then
		return
	fi
	tryat_pre "$b"
	tryat_$mode "$b"
	fail "unexpected situation in $b.*"
}

case "$arg" in
/*)		tryat "$base"
		;;
*)
		pwd=`pwd`
		tryat "$pwd/$base"
		tryat "$pwd/git-srcs/$base"
		tryat "$pwd/tests/git-srcs/$base"
		;;
esac