#! /bin/bash

compose_name() {
    if [[ $(which git 2> /dev/null) ]]
    then
        STATUS=$(git status 2>/dev/null)
        if [[ -z $STATUS ]]
        then
            return
        fi
        TARGET="./$(git rev-parse --show-cdup)$1"
        cd $TARGET
        echo "$(basename $(pwd))"
        cd - > /dev/null
        return
    else
        return
    fi
}

function usage {
    echo "`basename $0` [OPTIONS]"
    echo "Archives repository tree."
    echo " "
    echo "Options:"
    echo "  -f|--format FORMAT  ... Archive format ([targz], tarbz, zip)"
    echo "  -r|--revision REV   ... Revision (default=HEAD)"
    echo "  -p|--prefix PREFIX  ... prefix to add before directory paths in archive"
    echo "                          (default = repository name)"
    echo "  --no-prefix         ... suppress prefix before directory paths in archive"
    echo "  -n|--name NAME      ... Archive file basename"
    echo "                          (default = repository name)"
    echo "  -o|--output DIR     ... Archive output directory (default = current)"
    echo "  -h|--help           ... Show help"
    exit 1
}

NOPREFIX=0
while [ -n $1 ]; do
    case $1 in
    -f|--format)
        FORMAT=$2
        shift 2
        ;;
    -r|--revision)
        REVISION=$2
        shift 2
        ;;
    --no-prefix)
        NOPREFIX=1
        shift
        ;;
    -p|--prefix)
        PREFIX=$2
        shift 2
        ;;
    -n|--name)
        REPONAME=$2
        shift 2
        ;;
    -o|--output)
        OUTPUTDIR=$2
        shift 2
        ;;
    -h|--help)
        usage
        ;;
    *)
        break
        ;;
    esac
done

if [[ -z $FORMAT ]]
then
    FORMAT="targz"
fi

if [[ -z "$REVISION" ]]
then
    REVISION="HEAD"
fi

if [[ -z $REPONAME ]]
then
    REPONAME=$(compose_name)
    if [[ -z $REPONAME ]]
    then
        echo "FATAL: not a Git repository, or could not parse repository name (supply using '-p'/'--prefix' flag)"
        exit 1
    fi
fi

if [[ -z "$OUTPUTDIR" ]]
then
    OUTPUTDIR="."
fi

if [[ $FORMAT == "zip" ]]
then
    GITARCHIVEFORMAT="zip"
    EXT=".zip"
else
    GITARCHIVEFORMAT="tar"
    if [[ $FORMAT == "tarbz" ]]
    then
        EXT=".tar.bz2"
        COMPRESS="bzip2"
    elif [[ $FORMAT == "targz" ]]
    then
        EXT=".tar.gz"
        COMPRESS="gzip"
    else
        echo "FATAL: Unrecognized format '$FORMAT'"
        exit 1
    fi
fi

if [[ $NOPREFIX == 1 ]]
then
    PREFIXCOMMAND=""
elif [[ -z "$PREFIX" ]]
then
    PREFIXCOMMAND="--prefix=$REPONAME/"
else
    PREFIXCOMMAND="--prefix=$PREFIX/"
fi

ARCHIVEBASENAME="$REPONAME-$(git describe --always)"
OUTPUTPATH="$OUTPUTDIR/$ARCHIVEBASENAME$EXT"
if [[ $FORMAT == "zip" ]]
then
    git archive --format="$GITARCHIVEFORMAT" $PREFIXCOMMAND $REVISION > $OUTPUTPATH
else
    git archive --format="$GITARCHIVEFORMAT" $PREFIXCOMMAND $REVISION | $COMPRESS >$OUTPUTPATH
fi