#!/bin/bash
#
# This scripts enables shebang lines like
#
#   #!/usr/bin/env lua-any
#   -- Lua-Versions: 5.1 5.2
#   -- Lua-Root: /usr/bin/lua
#   -- Lua-Args: -l foo
#
# That will pick the first installed interpreter among /usr/bin/lua5.1 and
# /usr/bin/lua5.2 and pass to if '-l foo' as well ass the name of the script
# containing the shebang and the extra arguments
# 
# License: MIT/X
# Copyright: 2015 Enrico Tassi <gareuselesinge@debian.org>

#set -x
set -e

FILE="$1"

if [ -z "$FILE" ]; then
	echo "Error: lua-any needs at least one argument"
	exit 1
fi

VERSIONS="`head "$FILE" | grep -i '^--[[:space:]]*Lua-Versions[[:space:]]*:' \
	| cut -d : -f 2- \
	| sed 's/^[[:space:]]*//' \
	| sed 's/[[:space:]]*$//' `"
ROOT="`head "$FILE" | grep -i '^--[[:space:]]*Lua-Root[[:space:]]*:' \
	| cut -d : -f 2- \
	| sed 's/^[[:space:]]*//' \
	| sed 's/[[:space:]]*$//' `"
ARGS="`head "$FILE" | grep -i '^--[[:space:]]*Lua-Args[[:space:]]*:' \
	| cut -d : -f 2- \
	| sed 's/^[[:space:]]*//' \
	| sed 's/[[:space:]]*$//' `"

if [ -z "$ROOT" ]; then ROOT=/usr/bin/lua; fi

for v in $VERSIONS; do
	if [ -x "$ROOT$v" ]; then
		exec $ROOT$v $ARGS "$@"
	fi
done

echo "Error: no suitable Lua interpreter found"
echo "Error: supported versions are: $VERSIONS"
exit 1