#!/bin/sh

usage()

{

cat << EOF >&2

Usage:

  -h            show this HELP message

  -s  SRCDIR    set source directory

  -o  OUTPUT    set output header

  -p  PREFIX    set macro prefix

EOF

exit 1

}

# one

workdir=$(pwd)

srcdir=

output=

prefix=

while getopts "hs:o:p:" opt; do

	case $opt in

	h)

  		usage

  		;;

	s)

    		srcdir="$OPTARG"

    		;;

	o)

    		output="$OPTARG"

    		;;

	p)

    		prefix="$OPTARG"

    		;;

	\?)

    		printf "Invalid option: -%s" "$OPTARG" >&2

    		usage

    		;;

	esac

done

# two

if [ -z "$srcdir" ] || [ -z "$output" ] || [ -z "$prefix" ]; then

	usage

fi

cd "$srcdir" || exit 2

gitver=$(git rev-parse --verify HEAD 2>/dev/null) || gitver="unknown"

macro=$(echo "$prefix"_GIT_VERSION | tr '[:lower:]' '[:upper:]')

cd "$workdir" || exit 2

mkdir  -p $(dirname "$output") || exit 2

printf "#define $macro\t\"$gitver\"\n" > "$output"

# all done

exit 0