image-tag

#!/usr/bin/env bash

set -o errexit
set -o nounset
set -o pipefail

OUTPUT=--quiet
if [ "${1:-}" = '--show-diff' ]; then
    OUTPUT=
fi

# If a tagged version, just print that tag
HEAD_TAG=$(git tag --points-at HEAD | head -n1)
if [ -n "${HEAD_TAG}" ] ; then
    # remove `v` prefix from release name
    if echo "${HEAD_TAG}" | grep -Eq "^v[0-9]+(\.[0-9]+)*(-[a-z0-9]+)?$"; then
      HEAD_TAG=$(echo "$HEAD_TAG" | cut -c 2-)
    fi
	echo ${HEAD_TAG}
	exit 0
fi


WORKING_SUFFIX=$(if ! git diff --exit-code ${OUTPUT} HEAD >&2; \
                 then echo "-wip"; \
                 else echo ""; \
                 fi)
BRANCH_PREFIX=$(git rev-parse --abbrev-ref HEAD)

# replace spaces with dash
BRANCH_PREFIX=${BRANCH_PREFIX// /-}
# next, replace slashes with dash
BRANCH_PREFIX=${BRANCH_PREFIX//[\/\\]/-}
# now, clean out anything that's not alphanumeric or an dash
BRANCH_PREFIX=${BRANCH_PREFIX//[^a-zA-Z0-9-]/}
# finally, lowercase with TR
BRANCH_PREFIX=`echo -n $BRANCH_PREFIX | tr A-Z a-z`

echo "$BRANCH_PREFIX-$(git rev-parse --short HEAD)$WORKING_SUFFIX"