#!/usr/bin/env bash

export USAGE='<remote>
'

# This is the recommended pattern from `man git-sh-setup`.
#
# shellcheck disable=SC1090
. "$(git --exec-path)/git-sh-setup"

set -euo pipefail

case "$#" in
    0)
        remote='origin'
        ;;
    1)
        remote="$1"
        ;;
    *) usage ;;
esac

git remote prune "${remote}"

# This grep "fails" if there are no matches, so temporarily disable error
# checking.
set +e
pruned_branches=$(git branch -vv | grep ': gone]')
set -e

if [ -z "${pruned_branches}" ]; then
    >&2 echo 'Nothing to do!'
    exit 0
fi

vipe <<< "${pruned_branches}" | \
    awk '{print $1}' | \
    xargs git branch -D