#
#   Receive a symlink to a package
#   Script run by ssh create a symlink to a package version
#   Works in bash and dash
#
#set -x
set -e

error() {
    echo ERROR: $*
    exit 1;
}

delete_dir() {
    if [ -d "$1" ] ; then
            chmod -R u+w "$1"
            rm -rf "$1"
    fi
}

# User options
while getopts D arg ; do
    case $arg in
        D) set -x ;;
        *) error Unknown option: $arg ;;
    esac
done
shift $(($OPTIND - 1))

# User arguments
pname=${1:?Need file name}
pver=${2:?Need package version}
tver=${3:?Need target package version}

dpkg="dpkg_archive"
[ -d $dpkg ] || error dpkg_archive not found

dpkg="dpkg_archive"
[ -d $dpkg ] || error dpkg_archive not found

#
#   Names of working directories
#
realdir="$dpkg/${pname}/${pver}"
newdir="$dpkg/${pname}/${pver}.NEW.TMPDIR"
olddir="$dpkg/${pname}/${pver}.OLD.TMPDIR"
pkgdir="$dpkg/${pname}"

#
#   Create package directory
#   Ensure its writable
mkdir -p "$pkgdir"
chmod u+w "$pkgdir"

#
#   Delete possible tmp directory
delete_dir "$newdir"
delete_dir "$olddir"

#
#   Create the temp symlink
#
ln -s "$tver" "$newdir"

#
#   Swap in the new directory - minimize disruption
#   Then delete the old
#
if [ -d "$realdir" ] ; then
    mv "$realdir" "$olddir"
fi
mv "$newdir" "$realdir"

#   Delete the original directory
delete_dir "$olddir"

# Fix up permissions on the package and package-version
chmod a-w "$pkgdir"