#!/bin/bash

set -e

prepare() {
  if [[ -p /dev/stdin ]]; then
    echo "[ERROR] Use 'bash <(wget ...)' instead of 'wget ... | bash'" >&2
    echo "[ERROR] e.g. 'bash <(curl -sL https://git.io/release-go)'" >&2
    echo "[ERROR] e.g. 'bash <(wget -o /dev/null -qO - https://git.io/release-go)'" >&2
    return 1
  fi

  local tool
  for tool in git gobump goreleaser
  do
    if ! type "${tool}" &>/dev/null; then
      echo "[ERROR] ${tool} not found" >&2
      return 1
    fi
  done

  local err
  if ! err="$(git rev-parse --is-inside-work-tree 2>&1)"; then
    echo "[ERROR] ${err}" >&2
    return 1
  fi

  if [[ -n "$(git status -s)" ]]; then
    echo "[ERROR] there are untracked or unstaged files" >&2
    return 1
  fi

  local github_token
  github_token=${GITHUB_TOKEN}
  if [[ -z ${github_token} ]]; then
    read -p "GITHUB_TOKEN (paste here)> " github_token
    export GITHUB_TOKEN=${github_token}
  fi

  if ! gobump show -r ${VERSION_DIR} &>/dev/null; then
    local version_dir
    version_dir=${VERSION_DIR}
    if [[ -z ${version_dir} ]]; then
      read -p "Specify dir where the file that version info is written is located> " version_dir
      export VERSION_DIR=${version_dir}
    fi
  fi
}

ask() {
  local message input
  message="${1:-Are you sure?}"
  while true
  do
    read -r -p "${message} [y/n] " input
    case "${input}" in
      [yY][eE][sS]|[yY])
        return 0
        ;;
      [nN][oO]|[nN])
        echo "[INFO] canceled" >&2
        return 1
        ;;
      *)
        echo "[ERROR] Invalid input...again" >&2
        ;;
    esac
  done
}

main() {
  prepare || return 1

  local current_version
  current_version="$(gobump show -r ${VERSION_DIR})"
  echo "[INFO] current version: ${current_version}"

  local version next_version
  while true
  do
    read -p "Specify [major | minor | patch]: " version
    case "${version}" in
      major | minor | patch )
        gobump "${version}" -w ${VERSION_DIR}
        next_version="$(gobump show -r ${VERSION_DIR})"
        break
        ;;
      "")
        echo "[INFO] canceled" >&2
        return 1
        ;;
      *)
        echo "[ERROR] ${version}: invalid semver type" >&2
        continue
        ;;
    esac
    shift
  done

  if [[ -d .chglog ]] && type git-chglog &>/dev/null; then
    git-chglog -o CHANGELOG.md --next-tag "v${next_version}"
    git --no-pager diff
    ask "OK to commit/push these changes?" || return 1
  fi

  git commit -am "Bump version ${next_version} and update changelog"
  git push

  ask "OK to release?" || return 1
  git tag "v${next_version}"
  if [[ -f CHANGELOG.md ]]; then
    goreleaser --rm-dist --release-notes CHANGELOG.md
  else
    goreleaser --rm-dist
  fi
}

main "${@}"
exit