#!/bin/sh -efu

. shell-error
. shell-getopt

show_help()
{
	cat <<-EOF
	Usage: $PROG [options]

	Utility to convert submodules to brunches.

	Options:
	  -p, --prefix=STR   add STR to branch's names;
	  -f, --force        don't check untracked and modified files;
	  -v, --verbose      print a message for each action;
	  -V, --version      print program version and exit;
	  -h, --help         show this text and exit.

	Report bugs to http://bugzilla.altlinux.org/

	EOF
	exit
}

print_version()
{
	cat <<-EOF
	$PROG version $PROG_VERSION
	Written by Alexey Gladkov <legion@altlinux.org>

	Copyright (C) 2010  Alexey Gladkov <legion@altlinux.org>
	This is free software; see the source for copying conditions.  There is NO
	warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
	EOF
	exit
}


submodule_remotes=
workdir=
exit_handler()
{
	local rc=$?
	if [ "$rc" != 0 ]; then
		for s in $submodule_remotes; do
			git remote rm "$s"
		done
		git reset --hard HEAD
	fi
	[ ! -d "$workdir" ] ||
		rm -rf -- "$workdir"
}

TEMP=`getopt -n $PROG -o "f,h,p:,v,V" -l "force,help,prefix:,verbose,version" -- "$@"` ||
	show_usage
eval set -- "$TEMP"

force=
prefix=
while :; do
	case "$1" in
		-p|--prefix) shift
			prefix="$1"
			;;
		-f|--force) force=1
			;;
		-h|--help) show_help
			;;
		-V|--version) print_version
			;;
		-v|--verbose) verbose=-v
			;;
		--) shift; break
			;;
		*) fatal "unrecognized option: $1"
			;;
	esac
	shift
done

if [ -z "$force" ]; then
	out="$(git diff-index --cached --name-only HEAD)"
	[ -z "$out" ] ||
		fatal "Changed files found in the index."

	out="$(git diff --name-only &&
	       git ls-files --directory --others --exclude-per-directory=.gitignore)"
	[ -z "$out" ] ||
		fatal "Untracked or modified files found."
fi

trap exit_handler EXIT QUIT HUP INT TERM
workdir="$(mktemp -dt "$PROG.XXXXXXXXX")"

git submodule init
git submodule status |
while read commitish path dummy; do
	printf '%s\n' "$path"
done > "$workdir/submodules"

verbose "Checking submodules ..."
if [ ! -s "$workdir/submodules" ]; then
	message "no submodules found for this repository."
	exit 0
fi

verbose "Checking remote branches ..."
git remote > "$workdir/remotes"
while read name; do
	while read remote; do
		[ "$name" != "$remote" ] ||
			fatal "$remote: remote already exists."
	done < "$workdir/remotes"
done < "$workdir/submodules"

while read name; do
	branch="$prefix$name"

	message "Converting '$name' submodule to '$branch' branch ..."
	url="$(git config --get "submodule.$name.url")" ||
		fatal "$name: url not found"

	submodule_remotes="$submodule_remotes $branch"
	git remote add -f "$branch" "$url"

	find "$name" -mindepth 1 -maxdepth 1 -execdir rm $verbose -rf -- '{}' \+

	git merge -q -s ours --no-commit "$branch/master"
	git read-tree --prefix="$name" -u "$branch/master"

	git commit -m "Merge '$name' as our subdirectory"
done < "$workdir/submodules"

while read name; do
	verbose "Removing '$name' submodule section from git config ..."
	git config --remove-section "submodule.$name"
done < "$workdir/submodules"