#!/usr/bin/env bash

set -euo pipefail

top="$(pwd)"
readonly top

usage()
{
    echo 'Usage: ./configure-version [--update | --clean]'
}

update-vpy()
{
    declare -r vpy=lib/bup/_version.py
    rm -f $vpy.tmp-$$
    local hash date desc
    hash=$(git log -1 --pretty=format:%H)
    date=$(git log -1 --pretty=format:%ci)
    desc=$(git describe --always --match="[0-9]*")
    cat > $vpy.tmp-$$ <<-EOF
	COMMIT='$hash'
	NAMES='(tag: bup-$desc)'
	DATE='$date'
	EOF
    if ! test -e $vpy || ! cmp -s $vpy $vpy.tmp-$$; then
        mv $vpy.tmp-$$ $vpy;
    fi
    rm -f $vpy.tmp-$$
}

if test "$#" -ne 1; then
    usage 1>&2; exit 1
fi

if ! test -f lib/bup/bupsplit.c; then
    echo 'error: cannot find bup source tree' 1>&2
    exit 1
fi

case "$1" in
    --update)
        update-vpy
        ;;
    --clean)
	rm -f lib/bup/_version.py lib/bup/_version.pyc lib/bup/_version.py.tmp-*
        ;;
    *)
        usage 1>&2; exit 1
        ;;
esac