#!/usr/bin/env bash
set -euo pipefail

repo_dir=$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")/.." && pwd)
description=$(git -C "$repo_dir" describe --tags --long --dirty)
case "$description" in
  *-dirty) echo 'Refusing to package a dirty tree.' >&2; exit 1 ;;
esac
if [[ "$description" =~ ^(.+)-([0-9]+)-g([0-9a-f]+)$ ]]; then
  release_tag=${BASH_REMATCH[1]}
  count=${BASH_REMATCH[2]}
  hash=${BASH_REMATCH[3]}
else
  echo "Unexpected git describe result: $description" >&2
  exit 1
fi

case "$release_tag" in
  v[0-9]*)
    version=${release_tag#v}
    ;;
  [0-9]*_[0-9]*)
    date=${release_tag%%_*}
    time=${release_tag#*_}
    version="${date}.0.0-r${time}"
    ;;
  *)
    echo "Unsupported application release tag: $release_tag" >&2
    exit 1
    ;;
esac
if [ "$count" -ne 0 ]; then
  version="$version-$count-g$hash"
fi
printf '%s\n' "$version"