#!/bin/bash

# Returns the longest subpath of the given path
# which includes a .subgitrc file.

usage() {
	die $(cat <<-EOF
	Usage: subgit root [PATH]

	  Finds the root of the subgit container by walking up from PATH
	  until finding a directory with a .subgitrc file. Returns the
	  absolute path to that directory.
	EOF
	)
}

while [ "$1" ]; do
	case $1 in
	-h) usage;;
	--) shift; break;;
	-*) die "Invalid option $1";;
	*) break;;
	esac
done

[ $# -gt 1 ] && usage
path=$(realpath -m "${1:-.}")

root=$path
while [ 1 ]; do
	[ -f "$root/.subgitrc" ] && break
	[ "$root" = "/" ] && die "Not a subgit repository"
	root=$(dirname "$root")
done

echo "$root"