#!/bin/sh

USAGE="git-cvs-split [options] <repository> <subdirectory> [ref]"

die() {
        echo >&2 "$@"
        exit 1
}

usage() {
        die "Usage: $0 $USAGE"
}

STRIP_TAGS=

while case "$#" in 0) break ;; esac
do
        case $1 in
        -h|--help)
        usage ;;

        -s|--strip-tags)
        STRIP_TAGS=1 ; shift ;;

        -*)
        usage ;;

        *)
        break ;;
        esac
done

REPOSITORY=$1
if [ -z ${REPOSITORY} ]; then
        usage
fi

shift
SUBDIR=$1
if [ -z ${SUBDIR} ]; then
        usage
fi

shift
REF=$1
if [ -z ${REF} ]; then
        REF="HEAD"
fi

TARGET="${SUBDIR}.git"

#echo "REPOSITORY: ${REPOSITORY}"
#echo "SUBDIR:     ${SUBDIR}"
#echo "REF:        ${REF}"
#echo "TARGET:     ${TARGET}"
#echo "STRIP_TAGS: ${STRIP_TAGS}"

# we need to clone the repository to avoid touching it
git-clone --no-hardlinks ${REPOSITORY} ${TARGET} && cd ${TARGET}

# tags will be dangling after filtering, so we just remove them here
if [ ! -z $STRIP_TAGS ]; then
        for TAG in `git-tag`; do
                git-tag -f -d ${TAG};
        done
fi

git-filter-branch --subdirectory-filter ${SUBDIR} ${REF}
git-reset --hard
git-gc --aggressive && git-prune

exit 0