#!/bin/sh

CURRENT_DIR=$(pwd)
PKGNAME=$(basename $CURRENT_DIR)

FORMAT="tgz"
VERSION="1.0"
SPECDIR="$HOME/.specs"
OUTPUT=$SPECDIR/$PKGNAME
UPDATE_SOURCES=1

if [ -d $OUTPUT ]
then
  SPECFILE=$(find -L $SPECDIR/$PKGNAME -name '*.spec' | head -1)
  if [ "x$SPECFILE" != "x" ]
  then
    DEDUCED_VERSION=$(sed -n 's,^\s*Version:\s*\(.*\)\s*$,\1,p' < $SPECFILE)

    if [ "x$DEDUCED_VERSION" != "x" ]
    then
      VERSION=$DEDUCED_VERSION
    fi
  fi
fi

function die
{
  echo $@ >&2
  exit 1
}

function check_set
{
  VALUE=$1
  shift

  while [ $# -ne 0 ]
  do
    if [ "x$1" = "x$VALUE" ]
    then
      return 0
    fi
    shift
  done

  return 1
}

function compress_tar
{
  tee
}

function compress_tgz
{
  gzip
}

function compress_tbz2
{
  bzip2
}

function compress_txz
{
  xz
}

function extension
{
  case $1 in
    tar)
      echo tar
      ;;

    tgz)
      echo tar.gz
      ;;

    tbz2)
      echo tar.bz2
      ;;

    txz)
      echo tar.xz
      ;;

    *)
      die "Unkown format $1"
      ;;
  esac
}

while [ $# -gt 0 ]
do
  OPTION=$1
  shift

  case $OPTION in
    -f|--format)
      FORMAT=$1
      shift
      ;;

    -v|--version)
      VERSION=$1
      shift
      ;;

    -o|--output)
      OUTPUT=$1
      shift
      ;;

    --no-update)
      UPDATE_SOURCES=0
      ;;

    -h|--help)
      echo "Create archive from the current git repository

usage: $0 [ options ]

options:
  -f --format       Format of the archive (see supported formats below) (default: $FORMAT)
  -v --version      Set version of script (default: $VERSION)
  -o --output       Output directory or file (default: $OUTPUT)
     --no-update    Do not update sources file

  -h --help         Show this help message

Supported formats:
  tar
  tgz
  tbz2
  txz"
      exit 1
      ;;

    -*)
      echo "Unkown option $OPTION" >&2
      exit 1
      ;;
  esac
done

[ ! -d $OUTPUT -o ! -d $(dirname $OUTPUT) ] && die "$OUTPUT is not a file or directory"

check_set $FORMAT tar tgz tbz2 txz || die "$FORMAT is not supported"

if [ -d $OUTPUT ]
then
  SAVE_TO=$OUTPUT/$PKGNAME-$VERSION.$(extension $FORMAT)
else
  SAVE_TO=$OUTPUT
fi

git archive --format=tar --prefix=$PKGNAME-$VERSION/ HEAD | compress_$FORMAT > $SAVE_TO
echo "Archive saved to $SAVE_TO"

if [ $UPDATE_SOURCES -ne 0 -a -d $OUTPUT -a -f $OUTPUT/sources ]
then
  ARCH=$(basename $SAVE_TO)
  cd $OUTPUT
  md5sum $ARCH > sources
  cd - >/dev/null

  echo "MD5 checksum saved to 'sources' file"
fi