#!/usr/bin/env bash
set -e

hook() {
  local hook=.git/hooks/$1.sh
  # compat without extname
  if test ! -f "$hook"; then
    hook=.git/hooks/$1
  fi

  if test -f "$hook"; then
    echo "... $1"
    shift
    if test -x "$hook"; then
      $hook "$@"
    else
      . "$hook" "$@"
    fi
  fi
}

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

if test $# -gt 0; then
  remote=''

  # check for flags
  while test $# != 0
  do
    case "$1" in
    -c) need_changelog=true;;
    -r) remote=$2; shift ;;
    -m) msg=$2; shift ;;
    -s)
      test -n "$keyid" &&
          exit_with_msg "Please use '-s' OR '-u'"
      sign=true
      ;;
    -u)
      test -n "$sign" &&
          exit_with_msg "Please use '-s' OR '-u'"
      keyid=$2
      shift
      ;;
    --semver)
      test -z "$2" &&
          exit_with_msg "major/minor/patch required for --semver option"
      semver=$2
      shift
      ;;
    --prefix)
      test -z "$2" &&
          exit_with_msg "prefix string required for --prefix option"
      prefix="$2"
      shift
      ;;
    --no-empty-commit) no_empty_commit=true;;
    --) shift; hook_args="$hook_args $*"; break;;
    *) test -z "$version" && version=$1 ;;
    esac

    shift

  done

  if [ -n "$semver" ]; then
    if [ -z "$(git tag)" ]; then
      echo "there is no tag in the git repo" 1>&2
      exit 1
    fi

    latest_tag=$(git describe --tags "$(git rev-list --tags --max-count=1)")

    if [[ ! "$latest_tag" =~ \
        ^$prefix([^0-9]*)([1-9][0-9]+|[0-9])\.([1-9][0-9]+|[0-9])\.([1-9][0-9]+|[0-9])(.*) ]]; then
      echo "the latest tag doesn't match semver format requirement" 1>&2
      exit 1
    fi

    case "$semver" in
    major ) version="${BASH_REMATCH[2]}" ;;
    minor ) version="${BASH_REMATCH[3]}" ;;
    patch ) version="${BASH_REMATCH[4]}" ;;
    *     ) echo "invalid semver argument given: $semver" 1>&2
            exit 1
            ;;
    esac

    (( ++version ))

    case "$semver" in
    major ) version="$prefix${BASH_REMATCH[1]}$version.0.0${BASH_REMATCH[5]}" ;;
    minor ) version="$prefix${BASH_REMATCH[1]}${BASH_REMATCH[2]}.$version.0${BASH_REMATCH[5]}" ;;
    patch ) version="$prefix${BASH_REMATCH[1]}${BASH_REMATCH[2]}.${BASH_REMATCH[3]}.$version${BASH_REMATCH[5]}" ;;
    esac
  fi

  hook_args="$version"

  if [ -z "$msg" ]; then
    msg="Release ${version}"
  fi

  # shellcheck disable=SC2086
  hook pre-release $hook_args \
    || exit_with_msg "pre-release hook failed! Cancelling release."
  echo "... releasing $version"
  if [ "$need_changelog" = true ]; then
    git-changelog -t "$version"
  fi

  if [ "$no_empty_commit" = true ]; then
    git commit -a -m "$msg" || true
  else
    git commit -a -m "$msg" --allow-empty
  fi

  declare -a sign_args
  if [ "$sign" = true ]; then
    sign_args=("-s")
  fi

  if [ -n "$keyid" ]; then
    sign_args=("-u" "$keyid")
  fi

  # shellcheck disable=SC2086
  git tag "${sign_args[@]}" $version -a -m "$msg" \
    && git push $remote --tags \
    && git push $remote \
    && hook post-release $hook_args \
    && echo "... complete"
else
  echo "tag required" 1>&2 && exit 1
fi