#!/bin/sh

BUILD_NUMBER_OLD=0
BUILD_NUMBER_CUR=0
BUILD_NUMBER_NXT=0
BUILD_FILE=build_number

if test "$1" = "--"; then
  num="$2"
  if test ! -z "${num##*[!0-9]*}"; then
    echo $2 > $BUILD_FILE
  else
    rm   $BUILD_FILE
  fi
#  echo $BUILD_NUMBER_CUR
#  exit
fi

if test -e $BUILD_FILE; then   # file exist
  BN=$(cat $BUILD_FILE)
  if test -n "$BN"; then       # file has content
    BUILD_NUMBER_CUR="$BN"
    BUILD_NUMBER_OLD=$((BUILD_NUMBER_CUR - 1))
  fi
fi

BUILD_NUMBER_NXT=$((BUILD_NUMBER_CUR + 1))
echo $BUILD_NUMBER_NXT > $BUILD_FILE

echo $BUILD_NUMBER_OLD $BUILD_NUMBER_CUR $BUILD_NUMBER_NXT